99 e300d idle problem when hot - Page 2 - PeachParts Mercedes-Benz Forum

jay_bob · #16 06-19-2013, 05:09 AM

Whoa that is a big clue right there

The W210 has a problem with the rear light assemblies. They can short out or fail in several different ways.

The engine management ties into the brake lights due to the drive by wire cruise control. If you have a short or bad ground in one of the rear lights that can definitely upset the voltages appearing at the engine control module.

I would do 2 things.

1 - check your system voltage make sure you are at 13+ V when operating. If you don't have a meter, hold down the REST button on your climate control for 5 seconds until the display says 01 on the left, then press the left AUTO repeatedly until the left side says 24, the system voltage will be on the right. Press Rest again to exit.

2 - Inspect your rear brake lights to make sure they come on correctly with and without the tail lights on. If you have odd behavior in the lights (like a tail light that glows when you are off the brake but turns off when you step on the brakes) inspect the tail light housings for shorts or loose connections.

mbonly · #17 06-19-2013, 03:51 PM

Quote:

Originally Posted by jay_bob

Whoa that is a big clue right there

The W210 has a problem with the rear light assemblies. They can short out or fail in several different ways.

The engine management ties into the brake lights due to the drive by wire cruise control. If you have a short or bad ground in one of the rear lights that can definitely upset the voltages appearing at the engine control module.

I would do 2 things.

1 - check your system voltage make sure you are at 13+ V when operating. If you don't have a meter, hold down the REST button on your climate control for 5 seconds until the display says 01 on the left, then press the left AUTO repeatedly until the left side says 24, the system voltage will be on the right. Press Rest again to exit.

2 - Inspect your rear brake lights to make sure they come on correctly with and without the tail lights on. If you have odd behavior in the lights (like a tail light that glows when you are off the brake but turns off when you step on the brakes) inspect the tail light housings for shorts or loose connections.

Great info, this morning I dropped it off at the dealer and they are saying that it looks like a compression problem and they need another 2 hours at 132/hour so i decided to bring it home and do the comp test my self. Now what compression tester do i use and are there any special tools to take out the injectors.?

mbonly · #18 06-19-2013, 05:41 PM

ok now I got to the heart of the problem, when I got home from the dealer I loosened the injector lines one by one and low and behold the #4 cylinder stayed the same when I cracked it open, all others caused the engine to bog down so its either a loss of compression on that cylinder or the injector is bad. Now what do you think? Given the fact that it runs fine when its cold I would lean towards the injector been bad because if it was a loss of compression it would run rough when its cold, any imput?

TMAllison · #19 06-19-2013, 05:47 PM

Swap injectors and see if #4 fires and the new hole doesn't.

Need a 22mm - 4.5" long, very thin walled socket and two heat sheilds.

mbonly · #20 06-19-2013, 08:58 PM

if I replace the injector would I need to have it calibrated?

KarTek · #21 06-19-2013, 10:39 PM

A new or decent used injector should pop within specs. I'll look around tomorrow. I think I have 8 spare injectors and I should be able to find a pretty good one with mileage similar to what yours have. I'll just send it to you in trade for your defective one.

mbonly · #22 06-20-2013, 01:10 AM

That'll be great Thanks......

KarTek · #23 06-20-2013, 08:24 PM

OK. all of my spare injectors are 115 bar but I found one that's popping at 120. I can send you that one to run on for a while, if you send me your defective one, I'll open it up and see if I can fix it with spare parts and then send it back to you.

Also, are you anywhere near Brooklyn? I have friends in town from the city and I could send everything back up with them to hand off to you. I'll send you a couple heat shields and a socket too.

mbonly · #24 06-21-2013, 01:47 AM

Quote:

Originally Posted by KarTek

OK. all of my spare injectors are 115 bar but I found one that's popping at 120. I can send you that one to run on for a while, if you send me your defective one, I'll open it up and see if I can fix it with spare parts and then send it back to you.

Also, are you anywhere near Brooklyn? I have friends in town from the city and I could send everything back up with them to hand off to you. I'll send you a couple heat shields and a socket too.

This is the beauty of this board that we go out of our way to help our fellow diesel owners, I really appreciate You taking the time to look this up for me but I had no choice but to order one locally as I really need the car and I didn't want to continue using it like this. I will install the new one tomorrow and report back with results. Once again Thanks KarTek.....

mbonly · #25 06-21-2013, 05:22 PM

PROBLEM STILL THERE.
Today I installed the new injector and idle shake continues, now it seems like the problem was not the injector but its somewhere in the pump, here is what I did: I installed the new injector and noticed it runs exactly the same so I pulled it and put the old one in and connected the fuel line to the new one and observed the spray pattern, it looked like very little fuel was being sprayed so I disconnected the #1 cyl line and installed the injector on it and the difference is very noticeable, on a scale of 1 to 10 if the number 1 cyl is a 10 then the #4 cyl which is the suspect one is a 2 maybe a 3. The injector lines at the pump are totally dry, where should I go next? could this be the delivery valve for that cyl? Don't know where to go from here.

KarTek · #26 06-21-2013, 08:42 PM

The delivery valve is so simple I can't imagine what would go wrong with it. The only other thing is the element itself and the rack/element tab position. If it's slipped, that cylinder will have less fuel than the rest resulting in a shake.

I think it happened to someone else here and I suspected that an unscrupulous mechanic had moved it intentionally to try to convince the guy to fork over $3000 for a new pump. All the mechanic has to do is move the tab back into position and like magic, the car runs perfectly again.

The rack and tabs are under the side cover.

mbonly · #27 06-22-2013, 05:13 AM

Quote:

Originally Posted by KarTek

The delivery valve is so simple I can't imagine what would go wrong with it. The only other thing is the element itself and the rack/element tab position. If it's slipped, that cylinder will have less fuel than the rest resulting in a shake.

I think it happened to someone else here and I suspected that an unscrupulous mechanic had moved it intentionally to try to convince the guy to fork over $3000 for a new pump. All the mechanic has to do is move the tab back into position and like magic, the car runs perfectly again.

The rack and tabs are under the side cover.

Not exactly sure what you mean by "rack /element tab", do you mean the fuel rack? sorry but this engine is new to me....

KarTek · #28 06-22-2013, 07:37 AM

Sorry for the awkward wording. The pump on this car is identical to your '87's from the controller forward. The fuel rack has "tabs" on it that can be loosened and slid fore and aft to control the quantity of fuel for each cylinder.

I would take the side cover off (fairly easy) and do a quick measurement between the tabs to see if they're fairly close to one another (evenly spaced) +- a couple mm. If #4 is abnormally close to #5, then it may have slipped.

mbonly · #29 06-22-2013, 11:41 AM

Ok I will try that today

mbonly · #30 06-23-2013, 01:21 AM

Sorry for the long post folks but this problem is driving me insane. Here is what I did today:
when the car was cold I connected the old injector on the suspect #4 line and the spray pattern was the same as on #1 cyl. yesterday I had done the same but with the engine hot and the idle problem present and the spray was barely noticeable so today I proceeded to inspect/adjust the rack "tabs". The spacing between the tabs was not as KarTek had described, the space between #1 and #2 was 16.56 mm and between #2 and #3 it was 15.78 but those where the only two I could measure because my tool was too long, I took a socket that fit almost perfect between #1 and #2 and compared to the others and found that #5 and #6 had almost the same spacing but #5 and #4 where much closer together and also #4 and #3 as well so I proceeded to slide the #4 tab forward about 3mm to increase the volume. Since number 4 is the suspect cyl I though that I had this problem in the bag. Put everything back together and the problem is still there and it didn't change one bit it didnt even improve or get worse. I just dont get it, if the IFI only controls fuel volume and shut off on the pump then why is this cylinder getting less fuel but only when hot. I don't understand why the pump sends less fuel to that particular cyl when the engine gets hot. I have ruled out compression because I can definitely see a substancial difference in the amount of fuel out of the injector depending on temperature and if it was compression then it would run rough when cold as well.