Starting problem - Cranks but won't fire without ether

[Jim Rosenthal]

A few months ago, I found that my 1992 500E wouldn't start. It would crank briskly, but wouldn't fire. Fuel tank was not empty. If given a shot of ether, it would start and run- including for a 20 minute local drive. After shutting it off, it would restart, but if left overnight, it wouldn't start, and would require another ether shot.

We found that when left beyond a certain amount of time without restarting, the pressure in the fuel rail at the front of the engine was zero. Evidently, the M119 engine seems to start on residual pressure retained in the fuel system, possibly by the check valves in the fuel pumps. The fuel pumps do not seem to being operating until the engine has started from that residual pressure. We think that when the engine catches and runs, it also signals to the pumps to start operating.

We've decided to replace the fuel pump check valves and the fuel filter as a first step. If anyone has had a similar problem with their car, I'd like to know of it. I did look to see if this problem has been discussed on this board in the past, but I am not very good at searching this forum's formidable data base.

Thanks to all for help and information, in advance. Glad to see this forum is still running and thriving. These are extraordinary cars.

 

[gerryvz]

The pressure is designed to leak down in the fuel system (fuel rail) over time, and there is a spec from MB as to the leakage rate. Generally it's more focused toward leakdown within a matter of hours, rather than days/weeks/months.

Here are somne fuel pressure guidelines, per Mercedes:

Indeed there is a check valve at each fuel pump (these rarely go bad, but can) as well as a larger, round fuel pressure regulator located on the fuel rail. This larger FPR is the one that more often goes bad, and generally the symptom is hard starting, especially when cold. It's well documented here on the forum. If you haven't tested this larger fuel pressure regulator, please use the link(s) below to test, and if needed, replace the larger FPR.

Please check these threads for reference:

HOW-TO: Replacing M119 / M104 fuel pressure regulator | "HOW-TO" Tutorial Articles

GSXR edit: Click here for "How to" writeup on checking pressures. One issue that pops up from time to time with the M119 (LH injection) and M104 (HFM injection) is the weakening and/or failure of the fuel pressure regulator. This is located in-line on the fuel rail and is a round, silver unit...

www.500eboard.co

HOW-TO: Checking M119 & M104 fuel pressure | "HOW-TO" Tutorial Articles

GSXR edit: Click here for "How to" on replacing FPR. For diagnosing issues with the M119 such as difficult cold and hot starts, it's important to be able to check the fuel pressure. This gives an idea as to the pressure at the injectors during various running conditions of the engine. It can...

www.500eboard.co

The fuel pumps are designed to prime when you turn the key to position #2 (don't start the car). You (or a helper near the rear of the car) should be able to hear the pumps run for approximately 1-2 seconds when turning the key to position 2. This is the priming action that happens ahead of starting. I would recommend turning the key to position 2 and hearing if things prime audibly. If so, then your pumps should be working and delivering fuel OK.

The fuel pumps are controlled by the LH injection computer (in the CAN box), electrically through the (green cubic) fuel pump relay located beneath the passenger-side rear seat bottom.

You may also want to check your ignition system. There is a major issue with M119 engines with the distributor caps, where moisture gets into the caps and causes tracks that cause poor starting and running. We have a fix for this problem, which is not difficult to do. I would say that at least 50% of the folks here on the forum have experienced this issue. There are probably several dozen threads here about these ignition issues with the un-vented caps/rotors and the moisture issues. One example thread on this topic can be found here.

I wouldn't rule out ignition as it is a more common problem.

I have attached a document from the factory service manual that provides a full overview of the fuel system and all of its control inputs, parameters, and specs.

 

[gsxr]

+1 with Gerry's post above.

Based on your description, it sounds like the pumps are not priming the system and pressurizing the fuel rail. If there's no rail pressure when you turn the key on, that means the pumps are not running for 2 seconds like they should, when the key is first turned to position 2. The root cause is almost guaranteed to be a failing LH module. (Edit: The fuel pump relay located below the rear seat is a possibility, but this is an extremely rare faliure. 99% of the time, the relay is not engaged because it is not being energized by the LH module, not because the relay has failed. As noted below, it's easy & cheap to try this first!)

Do you have a spare LH module to test with? It can be from any M119 LH-SFI engine, any year, any chassis, any displacement. If the replacement module cures the problem, then source a correct 1992 5.0L module for your car.

DO NOT bother replacing the check valves at the fuel pump. If the pumps are old or original, replace with new Bosch pumps, which include new check valves. If the pumps have already been replaced in about the past 10 years, the pumps and check valves should be fine. Same with the filter, if it's been replaced within the past 60kmi, don't mess with it. If you touch anything back there, make sure to inspect all the fuel hoses as described in this thread.

 

[sheward]

I defer to the previous posters experience however I experienced a very similar starting problem which turned out to be the fuel pump relay referenced. Although I've not read of many failing it's cheap and easy to try. Nice to carry a spare as well.

 

[Jim Rosenthal]

Thanks to all, and I will continue to work on this and report back. Information VERY much appreciated.

 

[Alphasud40]

If your diagnosis leads to a failing LH control unit. New capacitors might cure your woes. I have those if you need them. Also because your ECU has the WOT enrichment feature and control units are getting harder to find consider buying a 93-95 LH module and just swap the EPROM. They are in a socket and can be moved without any soldering work.

 

[gerryvz]

This guy and his starting spray and diagnostics somehow reminds me of the @gsxr.....

 

[Jim Rosenthal]

If your diagnosis leads to a failing LH control unit. New capacitors might cure your woes. I have those if you need them. Also because your ECU has the WOT enrichment feature and control units are getting harder to find consider buying a 93-95 LH module and just swap the EPROM. They are in a socket and can be moved without any soldering work.

Thank you! I think we're going to replace the FPR first, and associated bits, and see if that cures the problem. Stay tuned.

 

[Jim Rosenthal]

As noted above, it's likely to be the fuel pressure regulator. We're going to look at it again Thursday and see if we can pin it down to that.

 

[gsxr]

Have you confirmed if the pumps are running? If not, the regulator won't help.

However, if the regulator is old or original, it's good preventive maintenance to replace on principle. OE or Bosch only.

 

[Jim Rosenthal]

The pumps are definitely running. We did replace the regulator and the little vacuum hose that goes with it. Bosch parts from FCP. However, that didn't improve things.

What DID improve things was replacing the car's battery. Sal (my mechanic and electrician guru) had noticed that the old battery would crank the engine for 15-20 secs, but then start to slow down. He wondered if the voltage was flagging and whether it was high enough to operate all the circuits that need to function to get the engine to start. So I brought a new battery up to the garage where the car is, and swapped it in. We also changed the fuel filter, since it was ancient and had not been changed in my ownership of the car.

I am not completely convinced we are out of the woods, yet. But the engine cranks briskly and catches. It took quite a while to prime the fuel system with the new filter in it (I probably ought to have filled the filter with fuel before putting it in, but it is positioned horizontally and would have been difficult to do without spilling it all over the place) But once primed, it starts and runs nicely. The old battery was January 2016, and clearly tired.

My original plan was to take the car down to Virginia for a few days, for family holidays. But I decided not to; I don't want to end up with a nonrunning car on a holiday weekend etc. So I'll drive another car down there, and then move the 500E home and drive it for a few days. Taking a car that's been stored for months right out on a long trip on Christmas weekend seems like asking for trouble.

I wish a happy holiday for everyone, especially everyone on this forum, who have been so helpful to me and others with their cars. The 500EBoard is the best forum focused on one model (or group of models) that I've ever seen. It's invaluable. Thank you all again.

 

[gsxr]

Hi Jim,

It's extremely unlikely that low battery voltage was causing a no-start condition. And, the battery should never need to crank the engine for 15+ seconds. The engine should fire within 2-3 seconds of cranking, usually less. If it still is not firing immediately, something is wrong beyond the FPR and battery. Note that an old, failing starter will crank the engine much slower than normal even with a new battery - but still should result in cranking for more than 2-3 seconds. On the bright side, a new battery never hurts and at 8 years old, it was a good idea to replace proactively.

There's no need to try and fill the new fuel filter, as you noted this is nearly impossible anyway. Cycling the key on/off several times will run the pumps 2 seconds each time and fill up the filter, and push fuel to the rail. Or, you can jumper the fuel pump relay and manually force the pumps to run continuously for a short time (say, 10 seconds) to prime the system.

The new fuel pressure regulator should cure the start problem, assuming the pumps are running while cranking. Let us know how it goes when you return from your trip!

 

[gerryvz]

My E500's starter failed back at Christmas of 2007. The characteristics of a failing starter are indeed slower than normal cranking and starting - it is very difficult to tell the difference between a slow starter and a weak battery. My starter eventually failed by just refusing to crank at all (happened to be when I parked the car while out Christmas shopping). The new starter was MUCH more energetic from the get-go.

I agree that a new battery shouldn't affect starting -- the battery will either have enough juice to crank the engine, or it won't. That said, a 2016 battery is definitely past its prime and ready for replacement. I just replaced a November 2016 battery on our 4Runner a few months ago. My G-wagen AGM battery is living on borrowed time, also November 2016 from when I lived in Houston.

Interestingly, my 560SEC AGM battery was last replaced in 2014, also when I lived in Houston. It is weak, but is OK as I have it on a battery maintaner. I have a new AGM Group 49 battery on my garage shelf waiting to go into the car.

Interestingly, as a side note, I have found that my M119 in the E500, which starts as normal / it should, takes a bit longer to fire than both my M104 (HFM injection) and M117 (KE-Jet injection). Both of those engines, even when cold, take about 0.5 second to start and run. The M119 is 1-1.5 seconds. Again, with strong battery and good starter.

 

[sheward]

My experience with starters and batteries supports this as well. I replaced the battery in my 60,000-mile car October 2015. It stays on a maintainer. This car always starts in about 1.5 seconds however the starter spins noticeably faster than my 180,000-mile car. I replaced the battery in this high mile car in January of 2020. This car starts in the same 1.5 seconds but the starter spins noticeably slower than the other.

As an aside, I show nothing in my records that indicates distributor cap/rotor/insulator replacement in the 15 plus years I've owned the 60,000-mile car. I do seem to recall having the ignition start/stumble condition years ago after a wash of the engine bay. If I replaced these items without recording, it was many years ago. More than say 15 years. Even though this car is not driven regularly, it never runs less than perfectly.

Many owners have experienced trouble with new caps and rotors over the past 7 to 10 years. Some is due to not changing insulators but not all. I believe the early caps were of a higher quality and I hoard 2 sets of nearly new items I was lucky to find on parts cars years ago. I treat them as somewhat prized possessions. I know I need help, but I'm beyond help now.

I hope you have things sorted out and you have an enjoyable holiday, Jim.

 

[Alphasud40]

Actually I have had situations where a battery will crank an engine fast enough to start but voltage at the modules falls under the threshold to wake up. As our cars get older resistance of terminals and connections go up which can create enough voltage drop to cause issues during a crank event. I would be inclined to install the old battery and checking voltage between battery + and the ECU and EZL. My .02

 

[Bogeyman]

I have a W113 280SL that was always hard to start. 4 or 5 cranks before it would kick off. I replaced the starter with a rebuilt Bosch and the problem solved. I would guess it turns over almost twice as fast as the original.

 

[Jim Rosenthal]

Thanks to all! I would describe things as "partly out of the woods but not completely". The car will start if it's been left for a day or two, but it takes 15-20 secs cranking to catch. The starter seems fine- cranks it over briskly. The fuel pump relay is fine, the pumps run briefly when starting the car up, as they are supposed to. Sal suggested we replace the pumps- we think they are not pressurizing the fuel rail. I am also going to crank the engine and make sure there's spark- I realize that's quite old fashioned but I'd like to make sure. We are also going to install the set of new plugs I got from a good gentleman here a while back, which somehow never got put in.

My prior experience with this car was that it started nearly instantly in the past. Something is still wrong with it. OK, this is a bit of a puzzle.

 

[Eno]

I would do two things:
1. Make sure the contact pins inside the plastic piece socket that holds the green fuel relay are tight in order for the fuel relay to sit firmly/tight on the plastic socket.
2. Try a spare good LH module and press it tight down.

 

[Jim Rosenthal]

Sure. I'm going to have to find a good LH module. By any chance, do you know the PN for it? If it isn't outrageous, I'll order one.

 

[gerryvz]

You need to pull your caps, rotors, and MOST IMPORTANTLY, the insulators behind the caps/rotors. Inspect them for carbon trails on the insides of the caps. Also inspect the inside of the caps, and the insulators, for moisture / oil film. Inspect the camshaft seals for any oil seepage/leakage. This will eliminated the exceedingly common ignition system as a source of problem.

An LH unit is going to be outrageous from MB. Just get a used 5.0 liter unit (either WOT or non-WOT) from a member here. Unfortunately I am out of them, having sold off my considerable stock of them over the past couple of years.

 

[Jim Rosenthal]

We did the caps and rotors etc a few years back, but we will pull them and inspect them as noted. I'll put up a post for a used LH unit. I hope someone has one. As you say, from MB it will cost an arm and a leg.

 

[gerryvz]

By any chance, do you know the PN for it? If it isn't outrageous, I'll order one.

https://www.500eboard.co/forums/wiki/?title=500E-and-E500-CAN-Computer-Part-Number-Reference

 

[gsxr]

Sure. I'm going to have to find a good LH module. By any chance, do you know the PN for it? If it isn't outrageous, I'll order one.

Jim, modules can get changed by previous owners, and part numbers changed during production as well depending on the month/year. Remove the CAN box cover and see what the part number is on your existing module. If it's a 1992 USA model year, it's likely either 012-545-62-32 or 014-545-17-32.

Keep in mind that used modules can be a bit of a gamble unless the seller confirms that it has been properly tested, and not just "removed from a running vehicle"... however, new ones are NLA. And, new ones had been $2k-$3k or so when still available.

 

[Jim Rosenthal]

Good advice, and I will take it. Thank you.

Today we changed out the fuel pumps for Bosch OEM replacements. Not difficult, but lots of cranking and a little ether to get her to fire up. (however, we HAD emptied the fuel system lines in the process of changing the pumps. She finally fired, ran well, and did a half hour test loop with no difficulty. Also restarted several times with no problem.

The real test is whether she will start tomorrow. I hope so. Thanks to all for the suggestions. Definitely going to look at the LH module and see what the PN is. I also have a box of old service records and I'm going to take those home and read everything and see if this was a problem before, etc.
Happy New Year, everyone.

 

[Alphasud40]

Thanks for the update. Happy new year!

 

[Joncf]

This isn't related, but on page 22 of this PDF document, it explains how fuel is cut off from certain cylinders if ignition faults are detected. This prevents overheating of the catalytic converters due to raw fuel entering them.

Why does this seem to NOT be the case? Many forum members, including myself, have had secondary ignition failures which have caused EXACTLY this problem. For example, if you permanently lose all power at one distributor... why does the LH module continue to inject fuel into the half of the engine that is NOT getting spark? I read another thread where this happened to someone, and their cats were literally GLOWING red... probably about to start a fire.

My best guess would be that the EZL is unable to recognize that type of failure situation, so no fault is detected. I'm assuming it only works properly if there are misfires occurring in individual cylinders, and not an entire bank.

 

[Alphasud40]

This was technology in its infancy. Later systems incorporated that when OBD 2 was mandated in 1996 vehicles. I was suprised to read LH and EZL had that capability at all a while back. All EFI systems I work on post 1996 will turn individual injectors off after a certain number of misfires occur. The injector will remain disabled until the next start cycle. Even with that protection strategy I still see catalytic converter damage if the owner continues to drive the car especially when going through warmup cycles when more fuel is injected to compensate for increased internal friction and fuel condensation on cold intake ports and comb chambers.
Also consider loosing spark on 4 cylinders for 100 ignition cycles is a lot of unburnt fuel vs. 1 cylinder misfiring.

 

[Jim Rosenthal]

Progress report: things are a bit better, although probably not totally back to normal. She seems to fire up cold after about 10 secs cranking. This is too long, but I've decided to drive her for a while and run some injector cleaner through the engine on this tankful of premium. It's possible that one of the injectors is leaking down. (at least we think that's possible). I'm not going to head out on any long trips but will get a few hundred miles on her and see if things stay the same or improve.

 

[gerryvz]

Very highly unlikely that the injectors are the problem. Injectors for these cars are exceedingly reliable.

With long cranking, that does sound like a fuel pressure issue.

What was the situation with the caps and rotors? I’ve seen ones go bad that are just a few months old, if moisture gets in there or there is an oil leak/mist at the cam seals.

Also, was the main fuel pressure regulator changed?

 

[gsxr]

Injector cleaner will not help.

This was mentioned several times earlier in this thread, but you MUST connect a fuel pressure gauge to the test port at the front of the fuel rail, to verify there is full pressure when the starter first engages, prior to the 10 seconds of cranking. You can buy a fuel pressure gauge from the local McParts/FLAPS, or order from Amazon. This is absolutely #1 on the list of items to check next.

I own this OTC gauge:
https://www.amazon.com/OTC-5630-Fuel-Pressure-Test/dp/B000R5IASC/

Here's a similar unit that is cheaper:
https://www.amazon.com/3640-Professional-Injection-Pressure-Tester/dp/B000EVU8NY/

 

[Jim Rosenthal]

An update: I ordered a used LH module for the 500E, and also ordering a gauge to check the fuel pressure, which as Dave mentions I think may be low even though we've replaced the pumps. Report to follow on those items. The car is difficult to start, runs somewhat rough, and stumbles when cold. Once warmed up it runs very well.

But we've decided to tackle some other problems, since the car is in the auto-infirmary. We removed the radio head and trunk unit and I sent them off to Becker to be rebuilt. I read some updates on this forum about replacing the CD changer with an Alpine, which I may do when the dust settles after getting the engine straightened out. I've owned several Alpine auto audio components and always had excellent luck with them. The dash instrument cluster is coming out to replace the plastic gears in the odometer and trip meter. She'll get an oil and filter change, and possibly other fluids as well.

A good friend of mine in the area (Pasadena) builds guitar amps and has serviced all my vintage Fenders for decades. If it comes down to a cap job on the LH module, he can do it; his soldering skills are far better than mine.

Again, thanks to all for the help and progress report to follow.

 

[nocfn]

Jim - be sure that you go thru the adaptation process on that new LH. I did not, and I still had similar issues. Clear codes, let things adapt then take her for the test drive.

 

[Jim Rosenthal]

Uh oh. I have no idea how to do this. Fortunately my friend who is the brains of the outfit may know. I thought cars as old as 1992 didn't have codes etc. Thanks for letting me know.

 

[Jim Rosenthal]

Aaaannnddd... Becker called and apparently the trunk unit of the radio got wet at some point- probably a leak as the car was never in a flood- but they can still rebuild it, or supply me with another one. It goes on....

 

[Jim Rosenthal]

How does one perform the adaptation? These cars at this age don't have OBD-2, as far as I know. Is there a procedure written out somewhere?

 

[gerryvz]

It’s posted here on the forum in at least 5 different threads. Simple procedure.

 

[Jim Rosenthal]

Here's a progress report of sorts on my 500E.

The car had or has a few other problems besides the hard starting. We decided to do an oil change, replace the hood pad, send the Becker radio off for overhaul with Becker, and take out the instrument cluster and replaced the odometer gears. Yesterday, we got the oil change done, put the radio back in (Becker had to replaces the trunk unit was it was water-damaged, but I can't see for the life of me where water got in, there is no evidence of anything ever being wet in there. Anyway it works fine, now)

We also installed a replacement LH module. Before we did that, we used the OBD 1 code reader to see if any codes were set (none) We then disconnected the MAF and verified that the car WOULD set a code for that, which we then cleared. We also attempted to measure the pressure in the fuel rail, and made a nice mess with the cheap pressure gauge kit made in China.

The car seems to run better with the 'new' LH module, but it still has the cold start problem; it runs roughly until the auxiliary air pump stops and it is warmed up. We think possibly there is a problem with the engine's electronics not being able to sense that the engine is cold- I assume there is a coolant temperature sensor someplace in all that spaghetti in there.... it appears there are several candidates up by the thermostat housing.

Comments or suggestions much appreciated. I'm learning a lot, and at the rate we're going, I may get to drive it in the spring. We've had several snows in Annapolis, and I'm not in any hurry to get her out of the garage.

 

[gsxr]

There are 3 coolant temp sensors at the front of the intake manifold. Only one of them, the 4-pin sensor B11/2, is for the engine computers (fuel + ignition). Click here for a PDF from the FSM with a resistance/temp chart, so you can verify if the sensor is reading somewhat accurately. Alternately, an SDS with HHT-Win will read the actual temperature values the computers read from this 4-pin sensor.

 

[gerryvz]

Also, don't forget the intake air temperature sensor in the driver's side air intake tube.

Ain't no way my car is leaving my warm and dry garage. Though my G-wagen is seeing yeoman's duty this week in all the snow.

 

[Jim Rosenthal]

Thank you! Mine isn't leaving the garage until it 1) warms up and 2) enough rain to wash all the road salt away. In the meantime, we'll chase the coolant temp issue and see if that's the cold start and rough running when cold problem.... I appreciate the help VERY much.

 

[Jim Rosenthal]

Back at it today, with a replacement coolant temp sensor. Fingers crossed.

 

[Jim Rosenthal]

And no help. Hmmm.

 

[Jim Rosenthal]

Well, the good news is that we removed the instrument cluster and Sal replaced the odometer gears which were stripped, and buttoned it all back up. The kit of new plastic gears is more like a departure point of how to fix it all. The odo and trip operate (on my car, anyway) from a little electric motor controlled by a variable resistor controlled in turn by the car's velocity. You have to carefully ream out the new little plastic gear to fit, etc. But it's all back together and seems to work.

I say seems to because the weather up here is wet enough that I'm not letting the car out of the garage, and it still runs so poorly that it's more important to figure out the starting and cold running issue than anything else. I'm going to put a fuel pump relay in today, not because I necessarily think it's the problem but because it's easy to do, not expensive, and it gets it off the list of possible problems. The hunt for the cause goes on. My hope is to have the car running well by the time the weather warms up and dries out.

We basically began this little adventure with a list of things that we knew the 500E needed: the radio, the odo/trip, etc, and then the car surprised us with the cold starting/running issue. That is why these posts hop around a bit. (my apologies) But as my friend says, what one man can build, another man can repair, so it's just about getting to the bottom of it all.

 

[gsxr]

Well, the good news is that we removed the instrument cluster and Sal replaced the odometer gears which were stripped, and buttoned it all back up. The kit of new plastic gears is more like a departure point of how to fix it all. The odo and trip operate (on my car, anyway) from a little electric motor controlled by a variable resistor controlled in turn by the car's velocity. You have to carefully ream out the new little plastic gear to fit, etc. But it's all back together and seems to work.

The replacement gear should not need modification, nor reaming, to fit. Details are here. It should be a press fit.

We basically began this little adventure with a list of things that we knew the 500E needed: the radio, the odo/trip, etc, and then the car surprised us with the cold starting/running issue. That is why these posts hop around a bit. (my apologies) But as my friend says, what one man can build, another man can repair, so it's just about getting to the bottom of it all.

Backing up to the original no-start problem: Had the car been running flawlessly prior to being parked for severeal months? And then out of nowhere, it simply would not start without ether sprayed down the throttle body/MAF?

 

[Jim Rosenthal]

Dave, the little gear was almost a press fit. Actually, it might have been, but I think Sal didn't want to press that hard.

The car ran fine when put away. Never had this problem. It's kept in a dry garage on a float charger, and covered. I don't see any signs of mouse damage or anything like that, and there seem to be enough cats and snakes around to keep mice out of the garage.

BTW, thanks for watching this thread. I really appreciate the help I've gotten here on this perplexing malady. Obviously I'm floundering a bit, but I'd be worse off without you all.

 

[Jim Rosenthal]

OK, some progress, as follows:

I thought I had replaced the LH module. Sal figured out that we replaced a module, but not the right one. Today we put a pressure gauge on the fuel rail, after a small mod to the gauge so it wouldn't spew fuel all of the engine. We then removed the (brand new) fuel pump relay and used a PowerProbe to turn the fuel pumps on. The gauge had read zero pressure in the rail when cranking the engine. When we tickled the pumps using the PowerProbe, the pressure shot up to sixty and you could hear the fuel filling the rail. The engine started right up.

With the back seat out, we noticed the relay was chattering and the rail pressure gauge was vibrating as well. There is a post Sal found from the owner of a 400E with a similar problem- a chattering fuel pump relay- which was cured by fitting a new LH module.

I got back on eBay and ordered a used LH module, verifying that its number is from the list quoted up above in this thread. I should have it this week and we'll see if that cures our fuel delivery issues.

At one point we thought the problem might be a leaky injector, but the system seems to hold pressure pretty well, once it actually has it. If the 'new' LH module makes the car run reliably, I'll put some miles on and and try to figure out where I can send the original one to get it repaired. If it's only a blown capacitor, I have a friend who owns a guitar amplifier company. Perhaps he can not only fix the LH module, but get my engine to sound like Jimi Hendrix. What a deal THAT would be. Pop the hood and you see a few hundred watt amp heads.

 

[Alphasud40]

That definitely sounds like the LH module is to blame. Let me know if you want a set of capacitors to take to your friend.

 

[Jim Rosenthal]

I definitely will. Actually I'm fairly decent at soldering for small repairs, I just put together a cable for a Hammond organ, I might could do this. Is there a way to test the old LH module and see which ones are bad, or are they usually replaced as a group? Thank you.

 

[Alphasud40]

I definitely will. Actually I'm fairly decent at soldering for small repairs, I just put together a cable for a Hammond organ, I might could do this. Is there a way to test the old LH module and see which ones are bad, or are they usually replaced as a group? Thank you.

You can sometimes see the bad capacitor because they leak their electrolytes. Other times they dry out and basically just go open circuit. Due to age if one has gone bad they are replaced as a group. Only 6 are needed. I think others can chime in on the success rate of replacing the capacitors after experiencing a failure. It’s worth a try.

 

[Jim Rosenthal]

It sounds like I should take a look inside the case of the original LH module, and if there's nothing catastrophic happened in there, I should buy the capacitors from you and install them. The LH module that I have coming is not one for a 500E; I couldn't find any on the list that had the WOT feature. Hopefully, it will get the car running reliably, but I would like to repair the original if it's possible.