No start when cold

[Calebfoster400e]

Hello everyone. New to the group here.

I have a 92 400e that’s been quite the headache. Bought the car wrecked and non running. Replaced both fuel pumps (seized) and the car ran great. One day after about 30 mins of driving it wouldn’t start after coming out of the store. Replaced caps and rotors, and the crank sensor. Still no start. Had it towed home. Turned out to be a blown 10 amp fuse in the base module. Replaced it and the car started and ran fine.

Next day decided to dig into why the fuse blew. Quickly realized the harness was pretty bad. Replaced it and now it will only start with the 4 pin temp sensor unplugged. No codes are present.

Can someone tell me what’s going on here? Has an intermittent miss at times. But that usually stops after cutting the car off and back on

 

[gsxr]

No codes are present.

Are you use a hand-held blink code reader to check each system separately via the 38-pin diagnostic port? Zero codes on pin 4 (fuel) or pin 17 (ignition)?

... now it will only start with the 4 pin temp sensor unplugged. Can someone tell me what’s going on here?

Could be a defective 4-pin temp sensor... if it's reading a much different temp than actual, the engine may have starting problems. Measure the resistance when cold and at operating temp and use the chart at this link to see if resistance values are close to spec.

Has an intermittent miss at times. But that usually stops after cutting the car off and back on

There shouldn't be an intermittent miss, and it shouldn't stop by turning the engine off & on. What brand caps/rotors were installed? What spark plugs are installed, how are the wires, have you checked the resistance of the plug boots, is there any liquid on the back of the insulators, is there any oil residue at the lower edge of the caps, etc etc etc...


BTW, welcome to the forum!

 

[Calebfoster400e]

Are you use a hand-held blink code reader to check each system separately via the 38-pin diagnostic port? Zero codes on pin 4 (fuel) or pin 17 (ignition)?




Could be a defective 4-pin temp sensor... if it's reading a much different temp than actual, the engine may have starting problems. Measure the resistance when cold and at operating temp and use the chart at this link to see if resistance values are close to spec.




There shouldn't be an intermittent miss, and it shouldn't stop by turning the engine off & on. What brand caps/rotors were installed? What spark plugs are installed, how are the wires, have you checked the resistance of the plug boots, is there any liquid on the back of the insulators, is there any oil residue at the lower edge of the caps, etc etc etc...


BTW, welcome to the forum!

I wasn’t aware that you needed to check for codes independently. I was under the assumption that the asr light would illuminate if there were any fault codes.

I’m thinking it may just be the temp sensor. Everything that could go wrong and cause this issue has been replaced unless it is vacuum related.

Wires look fine. Although I haven’t checked the resistance. Caps and rotors are Bosch. And plugs are Bosch. No moisture in the caps. Nothing on insulators. A slight bit of oil around the edge of the caps but it’s a very very small amount. The intermittent miss I feel is a separate issue than the no start issue. I should be able to figure that one out myself.

 

[gerryvz]

I wasn’t aware that you needed to check for codes independently. I was under the assumption that the asr light would illuminate if there were any fault codes.

I’m thinking it may just be the temp sensor. Everything that could go wrong and cause this issue has been replaced unless it is vacuum related.

Wires look fine. Although I haven’t checked the resistance. Caps and rotors are Bosch. And plugs are Bosch. No moisture in the caps. Nothing on insulators. A slight bit of oil around the edge of the caps but it’s a very very small amount. The intermittent miss I feel is a separate issue than the no start issue. I should be able to figure that one out myself.

It's critical that your upper and lower wiring harnesses be replaced and NOT be original. Especially the upper harness -- if it is original, it's going to be toast, and the source of gremlins that you will never be able to stop or fix until it is replaced.

HOW-TO: Determining the age of your engine wiring harness | "HOW-TO" Tutorial Articles

See attached photos. The manufacturing date of the harness will be on the tag. If the date is 1996 or newer, the harness is not original. The new replacement harnesses made from at least 1998-up (possibly earlier) have improved insulation and do not fail after a few years like the originals did...

www.500eboard.co

The temp sensor alone isn't going to cause missing issues. That is going to be ignition-related.

There are extensive resources here about all possible ignition issues (most commonly it's the caps/rotors PLUS the insulators behind them), as well as how to pull codes.

Info on diagnosing and identifying common ignition-related problems:

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Ignition problem traced to faulty insulators behind distributor caps | M119 Engine

Postby J. M. van Swaay on Mon May 18, 2009 5:41 pm I posted this problem a few weeks ago in the diagnostic area, thought I'd follow up here before spending lots of money on parts: 1994 E500 119.974 engine 78,000 miles new engine wire harness Symptoms: Intermittent rough running and...

www.500eboard.co

The ASR light only relates to the ABS and ASR systems. There are multiple systems that can and should be checked, and they can illuminate various lights and store codes for a number of systems on the car.

More information about how to check codes is at the link below.

HOW-TO: Checking DTC's (Diagnostic Trouble Codes) on the 500E/E500 | "HOW-TO" Tutorial Articles

UPDATE: To buy a pre-built code reader, click here for an affordable one from eBay. If you do not have a "breakout box", make sure you select the type of reader with the small 1mm pins, i.e. for 400E, not the type with the large 4mm pins. A breakout box is highly recommended... this has numbered...

www.500eboard.co

FYI - HOW-TO: Checking DTC's (Diagnostic Trouble Codes) on the 500E/E500 | De-Coding

UPDATE: To buy a pre-built code reader, click here (NLA by 2023) or click here (still available in 2023) for an affordable one from eBay. If you do not have a "breakout box", make sure you select the type of reader with the small 1mm pins, i.e. for 400E, not the type with the large 4mm pins. A...

www.500eboard.co

MB Diagnostic Trouble Code Reference Guide | De-Coding

Very comprehensive reference guide on codes. Only caveat is that this guide covers models up to and including Model Year 1993. GSXR's listing available on his web site (click here) is specific to our .036 cars (all years, through 1995), but this general reference guide is exhaustive whether...

www.500eboard.co

 

[Calebfoster400e]

It's critical that your upper and lower wiring harnesses be replaced and NOT be original. Especially the upper harness -- if it is original, it's going to be toast, and the source of gremlins that you will never be able to stop or fix until it is replaced.

HOW-TO: Determining the age of your engine wiring harness | "HOW-TO" Tutorial Articles

See attached photos. The manufacturing date of the harness will be on the tag. If the date is 1996 or newer, the harness is not original. The new replacement harnesses made from at least 1998-up (possibly earlier) have improved insulation and do not fail after a few years like the originals did...

www.500eboard.co

The temp sensor alone isn't going to cause missing issues. That is going to be ignition-related.

There are extensive resources here about all possible ignition issues (most commonly it's the caps/rotors PLUS the insulators behind them), as well as how to pull codes.

Info on diagnosing and identifying common ignition-related problems:

M119 engine coughs, stutters, backfires, won't rev | M119 Engine

We have acquired my in law 1995 E420 with only 54k on the clock. Several months ago, I changed oil, brake fluid, installed new pads & rotors, replaced 12 year old Michelins, fuel filter and caps/rotors ...car ran great, 23mpg highway. After sitting for about 3 weeks, it made it about 2 miles and...

www.500eboard.co

FYI - Essential M119 Ignition "Tune Up" mods [Distributor cap vent / slot] | M119 Engine

Hi all, I have been meaning to address this on my little used 500E for years.... it is a problem I myself recognised about 5 years ago when I first looked at an m119 distributer cap..... Compare to any other distributor cap of the era such as an m104 and you will see there are NO ventilation...

www.500eboard.co

Ignition problem traced to faulty insulators behind distributor caps | M119 Engine

Postby J. M. van Swaay on Mon May 18, 2009 5:41 pm I posted this problem a few weeks ago in the diagnostic area, thought I'd follow up here before spending lots of money on parts: 1994 E500 119.974 engine 78,000 miles new engine wire harness Symptoms: Intermittent rough running and...

www.500eboard.co

The ASR light only relates to the ABS and ASR systems. There are multiple systems that can and should be checked, and they can illuminate various lights and store codes for a number of systems on the car.

More information about how to check codes is at the link below.

HOW-TO: Checking DTC's (Diagnostic Trouble Codes) on the 500E/E500 | "HOW-TO" Tutorial Articles

UPDATE: To buy a pre-built code reader, click here for an affordable one from eBay. If you do not have a "breakout box", make sure you select the type of reader with the small 1mm pins, i.e. for 400E, not the type with the large 4mm pins. A breakout box is highly recommended... this has numbered...

www.500eboard.co

FYI - HOW-TO: Checking DTC's (Diagnostic Trouble Codes) on the 500E/E500 | De-Coding

UPDATE: To buy a pre-built code reader, click here (NLA by 2023) or click here (still available in 2023) for an affordable one from eBay. If you do not have a "breakout box", make sure you select the type of reader with the small 1mm pins, i.e. for 400E, not the type with the large 4mm pins. A...

www.500eboard.co

MB Diagnostic Trouble Code Reference Guide | De-Coding

Very comprehensive reference guide on codes. Only caveat is that this guide covers models up to and including Model Year 1993. GSXR's listing available on his web site (click here) is specific to our .036 cars (all years, through 1995), but this general reference guide is exhaustive whether...

www.500eboard.co

Yes the harness was replaced with one manufactured in 2011. Not original and the wire insulation is in great shape. I don’t think the missing issue is correlated with the temp sensor. However the long crank or no start I feel is related. The car runs flawless with the temp sensor unplugged.

 

[gsxr]

I wasn’t aware that you needed to check for codes independently. I was under the assumption that the asr light would illuminate if there were any fault codes.

The ASR warning light will only illuminate if there is an ASR-related fault and, most likely, the ASR system is non-functional when this illuminates. However there can be plenty of other fault codes on the other computer modules (there are 6 total powertrain modules on USA cars with a CEL). Gerry posted links above to help you with checking codes.

I’m thinking it may just be the temp sensor. Everything that could go wrong and cause this issue has been replaced unless it is vacuum related.

Test before replacing, and if you need a replacement, buy OE/Genuine or get a good used one. The aftermarket ones are likely junk.

Wires look fine. Although I haven’t checked the resistance. Caps and rotors are Bosch. And plugs are Bosch. No moisture in the caps. Nothing on insulators.

Keep in mind these engines specify non-resistor plugs, which are getting harder to locate these days, but are still available. However, resistor plugs will not cause a misfire, so don't lose sleep over this. Recommended gap is 1.0mm which is slightly larger than the FSM spec of 0.8mm.

A slight bit of oil around the edge of the caps but it’s a very very small amount.

It doesn't take much oil near the spark of the rotor to potentially cause problems. However, once you get the car running well it would be a good idea to locate the leak source and correct it. Most likely the cam solenoids need to be replaced or re-sealed to cure this (search the forum for details).

The intermittent miss I feel is a separate issue than the no start issue. I should be able to figure that one out myself.

Agreed: fix the no-start issue first, then chase the intermittent miss. Also need details if the miss is cold, warm, hot, all of the above, only at idle, under partial or full load, etc.

 

[Calebfoster400e]

The ASR warning light will only illuminate if there is an ASR-related fault and, most likely, the ASR system is non-functional when this illuminates. However there can be plenty of other fault codes on the other computer modules (there are 6 total powertrain modules on USA cars with a CEL). Gerry posted links above to help you with checking codes.



Test before replacing, and if you need a replacement, buy OE/Genuine or get a good used one. The aftermarket ones are likely junk.




Keep in mind these engines specify non-resistor plugs, which are getting harder to locate these days, but are still available. However, resistor plugs will not cause a misfire, so don't lose sleep over this. Recommended gap is 1.0mm which is slightly larger than the FSM spec of 0.8mm.



It doesn't take much oil near the spark of the rotor to potentially cause problems. However, once you get the car running well it would be a good idea to locate the leak source and correct it. Most likely the cam solenoids need to be replaced or re-sealed to cure this (search the forum for details).



Agreed: fix the no-start issue first, then chase the intermittent miss. Also need details if the miss is cold, warm, hot, all of the above, only at idle, under partial or full load, etc.

I this car has no check engine light. That’s why I assumed it was ASR

The new sensor came In today, it is oem but I figured the car is 32 years old so it wouldn’t hurt to replace it regardless. One less thing to go wrong down the road.

Is it possible that one of the fuel pumps have died. They don’t quite sound the way they used to. And could this be a left hand module issue? When we got the car it had the clicking relay issue which eventually shorted the relay so I put the pumps on a toggle switch. I know it’s a not how it should be fixed but if it isn’t causing problems then it should be fine.

 

[gsxr]

Some 1992-1993 400E that were 49-state have no CEL and no DM (Diagnostic Module). These have a black emissions decal over the passenger headlight.

A new sensor never hurts! Hopefully it's actually OEM (which is different than OE/Genuine) and not an off-brand.

If the fuel pumps are original from the early 90's, they're overdue for replacement (Bosch only, nothing else). For safety reasons the high pressure hose should be replaced as well if it's not recent OE (no aftermarket allowed). Details on all the fuel pumps/hoses are at this link.

The LH module is the fuel injection module, this triggers the relay. When the capacitors inside the LH module fail it causes the relay to click, the fix is replacing the capacitors. The relay almost never fails.

Check rail pressure at the test port located almost immediately above the 4-pin temp sensor, under a hexagon shaped cap.

 

[Calebfoster400e]

Some 1992-1993 400E that were 49-state have no CEL and no DM (Diagnostic Module). These have a black emissions decal over the passenger headlight.

A new sensor never hurts! Hopefully it's actually OEM (which is different than OE/Genuine) and not an off-brand.

If the fuel pumps are original from the early 90's, they're overdue for replacement (Bosch only, nothing else). For safety reasons the high pressure hose should be replaced as well if it's not recent OE (no aftermarket allowed). Details on all the fuel pumps/hoses are at this link.

The LH module is the fuel injection module, this triggers the relay. When the capacitors inside the LH module fail it causes the relay to click, the fix is replacing the capacitors. The relay almost never fails.

Check rail pressure at the test port located almost immediately above the 4-pin temp sensor, under a hexagon shaped cap.

Temp sensor seemed to have fixed it. Thank you