Can I pay for Diagnosis for my Misfires? - PeachParts Mercedes-Benz Forum

ps2cho · #1 11-02-2007, 02:55 PM

Hi guys,

It has been such a long time and I am honestly getting so sick of my 1988 Mercedes 300TE Misfiring constantly.

Me and my dad have gone through so many things trying to figure this out (he doesn't have a lot of time free to do everything...)

and I just feel this will never be figured out. Fixing it is NO problem! We can do it all..we just can't figure out what the heck the problem is that is causing the misfire!

We have done so far:
* OVP
* Voltage Regulator
* Injector's+Seals (previous owner)
* New Fuses
* Non-Resistor OEM Bosch H9DCO's
* New Bosch Ignition Wires
* Distributor+Cap (previous owners)
* Valve Stem Seals
* Breather Hoses
* I checked for leaky pipes/cracked pipes
* Compression is perfect (1/ 180, 2/ 180, 3/ 185. 4/ 185, 5/ 195, 6/ 190)

Can I just take the car somewhere and have it diagnosed? Do mechanics do this for relatively cheap for like a couple hundred dollars?

I'm on the edge of just buying a new car...but I really don't want to do that. It's embarrassing having other people in the car with me and I avoid it at all costs because the damn thing shakes so much. I've lived with it for 18 months now and I'm drawing the line soon...

Thanks, ps2cho

300B · #2 11-02-2007, 07:32 PM

Have you ever changed the fuel filter?

DavidMichaels · #3 11-02-2007, 11:02 PM

Check your mixture. If the air/fuel ratio isn't right, it will misfire. Mine is an 88 300TE also. had the same problem.

ps2cho · #4 11-03-2007, 01:43 AM

Quote:

Originally Posted by 300B

Have you ever changed the fuel filter?

I have a full oil change every 3000 miles and have changed the fuel filter each time.

Quote:

Originally Posted by DavidMichaels

Check your mixture. If the air/fuel ratio isn't right, it will misfire. Mine is an 88 300TE also. had the same problem.

Yep we did the mixture and tried all different types of ratios.

Diesel911 · #5 11-03-2007, 01:55 AM

I am assuming that this is not a diesel car. You should call some Auto Diagnistic shops and explain you problem and ask what it would cost to find out what is wrong. You do not have to get it repaired by them. They should give you a printout of what they checked and the results.
You also said that the previous owner did somethings. Don't count on that he did a good job or even that it was done (is there paper work on what was done).

ps2cho · #6 11-03-2007, 01:59 AM

Quote:

Originally Posted by Diesel911

I am assuming that this is not a diesel car. You should call some Auto Diagnistic shops and explain you problem and ask what it would cost to find out what is wrong. You do not have to get it repaired by them. They should give you a printout of what they checked and the results.
You also said that the previous owner did somethings. Don't count on that he did a good job or even that it was done (is there paper work on what was done).

He had the receipts for the things he changed. This is the reason why they sold the car to me for $3000 because they put a good $2000-$3000 into parts and the problem still persisted.

Diesel911 · #7 11-04-2007, 12:16 PM

If he put that much $ into the car if you can find the problem you should have a good car.
Did he ever take it to an auto diagnostic place?
Engine misses are caused by basic things; wrong fuel mixture (covers air/fuel), wrong timing, no or poor ingition spark and poor compression. What can cause those 4 things to be incorrect can be complicated.
In the old days you were able to check all of these as there was no computer on the car to deal with (and no electronic emission controls either); but now trouble shooting can be a nightmare.
The eingine diagnostic analyzers (that they have in a shop not a hand held one) they have today can even tell you if the compression is bad (they measure the resistance of the spark jumping across the gap high compression = high resistance).
Of course it is your choice. I would at least call a diagnostic center and see what they charge.
Best wishes.

whunter · #8 11-04-2007, 12:29 PM

ShopForum > General Discussion
Good MB Shops
http://www.peachparts.com/shopforum/good-mb-shops/

ps2cho · #9 11-06-2007, 08:23 PM

Ok got quoted $80 to have it looked at tomorrow morning! So will post back tomorrow afternoon with what happened!

Fingers crossed everybody! I really hope they can figure it out.

deanyel · #10 11-06-2007, 10:35 PM

Quote:

Originally Posted by ps2cho

I have a full oil change every 3000 miles and have changed the fuel filter each time.

There's your problem - you're changing the fuel filter too often. Just kidding - but you are changing it too often - it's a 60,000 mile item.

ps2cho · #11 11-07-2007, 01:21 AM

Sorry your right. I was getting confused with the oil filter I think... I just remember we changed it when we got the car (one of the first things we did). I have another one for a later date.

ps2cho · #12 11-07-2007, 06:21 PM

Ok got it looked at by the local Benz shop...He first adjusted the mixture to the exact place where it should be...He drove it around but ended up not being exact as to where the problem lies.

He put on the notes:
-Test engine found fuel mix to rich
-Adjust fuel mix found kick down
-Cable strut clean and lube cable
-Found rust at Fuel Distributor
-Possible rust inside gas tank

He said in his professional opinion, I should just leave the car alone as it drives fine...it's just the idle that is irratic. But honestly I'm not driving a car that shakes this hard when I pull up to every light.

So you guys think that I should find a nice looking used fuel distributor and replace that first? As for the gas tank, my dad said he can take it into his work and get all the rust off for relatively cheap.

One thing he did while the car was running though...He unscrewed the screws to the Fuel Injectors a little and fluid came out (I am assuming thats the gasoline? Sorry noob)...why did he loosen them? He also was spraying brake cleaner all around the injector lines (I am assuming to check for leaks correct?)

He also said using Costco gas makes the engine rust so use Chevron...I know this isn't the problem...but just wanted to see what you guys also think about that.

I wonder if I will ever be able to get this fixed...

lee polowczuk · #13 11-07-2007, 06:26 PM

are you sure your motor and transmission mounts are fine?

ps2cho · #14 11-07-2007, 06:27 PM

Quote:

Originally Posted by lee polowczuk

are you sure your motor and transmission mounts are fine?

Yes. The engine is misfiring and it's erratic...it's different every day so it's not the mounts. You can hear it misfiring at idle with the hood up.

He also said using Costco gas makes the engine rust so use Chevron...I know this isn't the problem...what do you guys think about that?

jfreezn · #15 11-07-2007, 11:08 PM

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Does the engine EVER run smooth at idle, like cold or hot? Or damp days or dry days? Have you tried driving it without the fuel tank cap on? What about misting the plug wires with water in the dark, any external sparks you can cordinate with the misfire? Is the spark plug you mentioned the correct plug for that engine? I know that trying to upgrade plugs, especially Bosch, is NOT a good idea in a Mercedes.

I am betting it is the ignitor, which I believe has a tired capacitor in it.

Good luck, and be sure and let us know what fixes it!

Jim in Phoenix