Drivability problem

[Raffaelli]

Hi, I just picked up a 1992 400e as a birthday/Christmas present for my wife. It's silver w black interior, 150k miles. I paid $1000 for it, and is not my first cheap Benz. My other car is a black 1993 190e with a 2.6 automatic, with only 235k miles.

Anyway, so a friend of a friend sold me this car. He bought it approx. a year ago, and has trying to iron out the drivability problems. He told me it "ran perfect," but would stall after an hour of driving. Said he replaced cam sensors, engine harness, plugs and wires...it ran for a bit and I when u test drove it, it hesitated some, but ran strong. After that, it wouldn't start again till I discovered the crank sensor was bad. Junkyard 2.6 crank sensor and it started right up.

Of course it's been sitting up a long time with no gas in it, 6 new gallons of gas and a can of seafoam and I drove it home. I think it had water in it, because from a stop, it could barely pull itself, cruising 30+ it ran perfect.

By the time I got home, it cleared itself out, exept for not having any power above 4 thousand rpm. It just hits a wall. Any pointers to look into? I'm thinking a maf meter, but maybe something else?

Sorry for the book, but it's my first m119, and I'm unfamiliar. Thanks! Oliver R.

 

[gsxr]

Buy or build a blink code reader (click here, read the top 3 "sticky" threads) and clear codes from all 6 powertrain modules, then drive it and see which codes return. It doesn't matter what codes are present now, it matters which ones come back quickly.

Top of the list is removing distributor caps for inspection. You can check the MAF by disconnecting it, if the car runs fine with the MAF unplugged but won't run with it connected, then it's likely the MAF is bad. If it still runs poorly, it's probably not the MAF.

 

[jhodg5ck]

+1 on caps/rotors..I'd bet some $$$ they have moisture in there.
Check the harness on your ETA, if it hasn't been replaced it's Shot.

Also, I'd go in and replace or @ least rotate all the fuses in the fuse box.

 

[Raffaelli]

Ok, just to update. My wife and I were driving to the grocery and ran it damn near empty in the parking lot. It actually ran out of fuel, but had enough in it to make it to the pump.

Filled the tank and the sucker would barely run. Fuel pumps were howling more than usual. Tried to make it home but would stall after a couple mins. Let it cool, dive more, stall, replete....

Ordered two new Bosch pumps and a hangst filter for $190 shipped.

Proud to report the thing runs perfect, the 4k rev wall is gone and the pumps are whisper quiet.

 

[gsxr]

... Fuel pumps were howling more than usual.... would stall after a couple mins. Let it cool, dive more, stall, replete....

Ordered two new Bosch pumps and a hangst filter for $190 shipped.

Proud to report the thing runs perfect, the 4k rev wall is gone and the pumps are whisper quiet.

Thanks for the update! I'm wondering if the pumps are starting to reach the end of their service life at ~20 years, and we might start to hear more stories like this...

 

[gerryvz]

I have had to replace the fuel pumps (pairs) in my 560SEC and E320 wagons over the past 5 years. I think it's the poor quality fuels that we have in this country....the ethanol eventually gets to the pumps.

Another thing that's bad for the pumps is to run them with low fuel, particularly in situations where they could get starved. The fuel going through these rotary pumps both cools and lubricates them.

Luckily the Bosch pumps are still relatively cheap, and available at sources like Amazon.com and AutohauZ for really good prices these days (see this thread). I have not (yet) had to do the pumps on my E500 but I'm sure that day is a'comin'...

If your pumps have 125-150K or more miles on them, you're living on borrowed time and it's a good idea to have a pair in reserve. ALWAYS replace the fuel filter at the same time you do your pumps (and if you are running an M117 with CIS-E, also not a bad time to replace the fuel accumulator too).

Interestingly, while my (former) M104.99X powered E320 wagon used two of these fuel pumps, my M104.99X-powered G-wagen uses only ONE of these same pumps.

Cheers,
Gerry

P.S. It's really best to fill your tank back up when it hits the 1/4 tank mark. I'm guilty of this, but best not to wait until the yellow triangle goes on, indicating you're running on the last few reserve gallons.

 

[Klink]

I apparently read right past the "no power above 4K" mentioned in your first post Inadequate fuel delivery to the fuel injection system is overwhelmingly the most common cause of a high load "rev wall".

It is the primary symptom of inadequate fuel delivery from failing pumps, plugged filtering, or both. It is also the primary symptom present if a single pump on a twin pump equipped vehicle fails completely. And interestingly enough, since it is also mentioned in the initial post, this occurs relatively commonly after a vehicle has been allowed to sit idle for a number of months. In these cases, dissection of the failed pump usually reveals corrosion damage from a small quantity of water that settled in the lowest spot.

Glad all is currently well, and thanks for the update.

 

[Raffaelli]

Ok so it has been a couple months and the wife has enjoyed the car. About 3 weeks ago she says it shuddered at stops sometimes. Of course I drive it and it runs perfect. So 3 weeks ago I drive it to work and on the way back the thing acts up BAD. Feels like it's running on 4 cyl, or super lean because of it backfiring thru the exhaust.

I scratch my head and let it sit. Fast forward to today and I got a bug to figure this car out. Tested fuel pressure. About 60-65 or so w vacuum disconnected. I was honestly expecting one of my fuel pumps burned out....nope. Then I pulled the caps and found this...

 

[Raffaelli]

Now I have to find some new ones and replace he drivers window motor. Whoopee!

 

[jhodg5ck]

I'm not surprised...I've seen a bit worse, but not by much

Letting them get THIS bad is really hard on your wires, coils ans your EZL...

Jono

 

[gsxr]

And THAT, folks, is what BAD distributor caps look like!!

 

[Raffaelli]

Just got done replacing the caps/rotors w new parts. Spent $240 for the setup in Bosch. Also found a vaccum leak at the firewall going to the climate control check valves.

Still need to fix the drivers door window. But it drives good now. Car had some cheapie looking Bosch plugs in it. They were new, but I don't think they are correct. I'll look into that tomorrow.

 

[gsxr]

Correct plugs are Bosch F8DC4 non-resistor. They should be cheapie-looking. Don't use fancy plantinum/iridium/yttrium/unobtanium electrode plugs, the M119 doesn't like them. Aftermarket F8DC4 are made in Russia, or you can get German-made ones from the dealer if you're picky.

 

[gerryvz]

Aftermarket F8DC4 are made in Russia, or you can get German-made ones from the dealer if you're picky.

Slight clarification: BOSCH-branded F8DC4 are made in Russia. German-made examples of the F8DC4 (also made by Bosch but with the MB star) are available from the dealer at 2-3x the cost.

 

[gerryvz]

Slight clarification: BOSCH-branded F8DC4 are made in Russia. German-made examples of the F8DC4 (also made by Bosch but with the MB star) are available from the dealer at 2-3x the cost.

By the way, if anyone needs factory MB Bosch F8DC4s (made in Germany) please let me know. I am now in business selling them for great prices. I will put an ad up (illustrated and good description) of course in the Parts FS sub-forum.

 

[nocfn]

pm sent

 

[Raffaelli]

4 thousand rpm wall is back. Maybe those Bosch pumps aren't as great as you think.

So how do I diag a faulty pump? Remove both and bench flow test them?

Oh and casually bought a 5.0l out of a 93 sl500 today....

 

[gsxr]

4k wall... have you checked exhaust backpressure?

 

[Raffaelli]

So the past few days I've been trying to figure out what was the deal with my car, and finally found it!

I thought (after doing a ton of reading) that the neutral safety switch could be causing the engine to think its in park/neutral. Recently with the starter problems led me to think so. But didn't replace anything. Checked fuel pressure 50-60 plus when it bogged, even in park.

Unplugged the maf and drove around, a smidge better, but no...

Read about a forum member with the same problem, CATS!

Took it to my exhaust buddy's shop, (hoping he had an exhaust guage), up on a lift, one wasn't even warm even after I just got there. Oh and rattled like a bucket full of rocks. Happy to report a problem found and fixed. (Thanks for the tip GSXR). Id post pics, but do t feel like dealing with photobucket anymore...


I've never had this car run this strong. I just blasted on a few ramps and it's pretty quick! I'm thinking of hitting the track tonight for some times. I bet 14.0-14.50 ish. Sucker is stout.

 

[gsxr]

Glad you found it! The tall gears hurt ET's at the dragstrip a little (but help with traction). Assuming you are near sea level, a strong 400E should run in the mid/high 14's at low/mid 90's for trap speed. Don't forget to drop tire pressure to around 20psi and do a burnout to warm up the tires. And shallow stage!

 

[Raffaelli]

GSXR, couple of questions...

I bought a 5.0 m119 a little while ago. What would be a guess on some speeds if that engine was dropped in? I know the rear diff is pathetic for acceleration. This New Years I'll be in California and have a line on a 3.27 210mm setup. (But don't know what to do for a locker/lsd)

I have a nitrous kit already.

Any opinions and suggestions to a guy who doesn't mind getting some ponies out of this German tank?

 

[gsxr]

With a 5L engine in the .034 chassis, it should be mid/low 14's at high 90's with stock gearing. The 2.24 gears hurt the ET but don't reduce trap speed. With 2.82 gears, limited slip, and a 5L engine you should get into the high 13's at low 100's. Maybe better with good weather.

I'd skip the 3.27 idea, the high revs would get old fast, and it would just cause traction problems at launch. With the extra torque from the 5L, even 2.82 will make a huge difference, and you can find 2.82's without much trouble (either ASR or non-ASR). If your 400E is non-ASR, you could get a 3.06 which wouldn't be too bad. Without ASR, definitely plan on a Quaife or WaveTrac. If your car has ASR, forget the 3.06 diffs, they are almost impossible to find in an ASR housing (I've been looking for a few years).

 

[jhodg5ck]

3.27's would Suck.

IMHO the 4.2 does a lot better with the 2.82 vs the 5.0. You can tell the shorter stroke in the 4.2 is happier revving/on the cam.

+1 with Dave....

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[Raffaelli]

Ok so last night driving home I get into it in first gear. Hit higher rpms and notice a loud whining coming from the car!

Definitely a bearing about to fail whine. Started getting loud at about 3000 rpm and got progressively louder with rpm. Had a supercharger type of howl to it. I drive home, and on the way, it just quits making noise all of the sudden. Make it home.

Do today, it has a very rough idle. Will hold it steady, but feels like 3 or so cyl aren't hitting properly. Off idle runs great. Lots of power, doesn't skip a beat.

Pulled caps, plugs, did a compression test, (#140-150 across). Cannot pin down the faulty hole (or 3).

Opinions?

Have a feeling it burned a valve with the cats being plugged up.... Grrrr

 

[gsxr]

The howl could have been a belt-driven accessory. I wouldn't worry about the engine failing. First check out the simple stuff like belt tensioner pulley, air/smog pump pulley, alternator, AC, etc. Best case is to get the engine making the noise again, and loosen the belt to see if the noise goes away .

The rough idle is PROBABLY unrelated. If you burned a valve, that hole would show poor compression... and power would be down... and it wouldn't run smooth at higher RPM. Idle issues tend to be ignition related. Did you replace the insulators/bowls behind the rotor bracket? If not, remove them and inspect the back side... if there is any liquid, wipe them dry with solvent and re-install everything. If you already installed new insulators with the new caps+rotors, nevermind.

Side note - what spark plugs are you using (brand / model), and is the gap standard 0.8mm, or the Klink+Jono recommended 1.0mm?

 

[Raffaelli]

Bosch plugs, can't remember the model number, all gapped properly.

The day after it started running rough (Jan 1st) the car gave me a ton of problems. My friend came over, we did a thorough compression test. All were ~120 or so psi. He and I could narrow it down to two holes. (Pass #2 and driver #3 back). On top of that, driving to his house it snapped the throttle cable end (the plastic block on the motor). A zip tie gets me rolling.

On the way back, boom! Car all of the sudden grinds like crazy from the drivers front. Towed it to my house.



outer wheel bearing grenaded instantly. Had to cut the race off the spindle.

I sat and thought about it. This morning armed with a can of starting fluid, I sprayed down looking for leaks. 100% sure the TB or maf rubber/gaskets are leaking air. Intake needs to come off.

 

[jhodg5ck]

Find a shop w/ a smoke machine and test it that way. The spray is good for gross leaks, not so much small/medium.

Jono

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[Raffaelli]

I'll try to make one. I used to have a smoke machine, bastard was handy, but over 800 bucks.

just did a vaccum reading at idle. 16.5in. Fluctuates about .5 + or - of that with the rough idles rpm.

Anyone know how much the 8 rubber upper to lower plenum rubbers are? My parts guy told me $9 each aftermarket. I'm wondering if mb is cheaper

 

[jhodg5ck]

my really strong advice when it comes to anything rubber and esp anything intake and rubber...order up the Genuine MB bits. You really don't want to go back in a year and do that job again.

Also plan on having @ least 4-6 cans of GOOD carb clean around to tidy up inside that intake. Alt, you can buy some BG carb clean that non aerosol and let that soak when you have the manifold off...some old toothbrushes will be your friend here.

jono

 

[gsxr]

Are you sure the 8 intake rubbers are leaking? If so, yeah the intake has to come off. But if the leaks are at the ETA/MAF, you don't need to pull the manifold.

The 8 donuts (117-140-02-65) are $9 MSRP each from the dealer, $7.25 or so wholesale. I see aftermarket from MTC for less than $2/ea, don't buy those. I'd be willing to take a gamble on Conti (CRP) back when they were ~$3, but Conti are up to ~$8 now and at that price you are better off with the OE donuts for $7. Like Jono said... you don't want to be re-doing this job when the Chinese rubber degrades in a year or two.

 

[Raffaelli]

Built this little gem. Confirmed my suspicion some donuts were leaking. Not shop quality thick fog, but it'll do...



but I thought it would have a huge leak. They appear to be a couple small ones. Oh well, intake has to come off to get resealed anyway... Maybe the maf is goofy also...

 

[jhodg5ck]

Hey, it works! And a hell of a lot cheaper then my 1K$ unit...!!

Not surprised you have leaks...seeing it more and more...just Age is becoming a factor now...

If ya wanna get fancy, re-route the breather that feeds into the intake through a proper centrifuge/catch can...keep it pretty in there!

Jono

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[Klink]

Hey, Maui! Show them your smoke generator! :cigar: Why isn't that on out smiley list?