new '94 E420 owner needs help on poor running...

[alfa_holic]

Hi all:

Bought what I thought was the perfect car...one owner, little old lady who never drove over 70 mph, 64,000 miles, 100% dealer serviced with all records and receipts.

Paid next to nothing for the car, as the check engine light was on, and the car hesitated and stumbled badly. Was referred to an Indy who said the wiring to the throttle actuator was bad, and replaced it with a Beckmann engineering refurb. Then came the need for the cruise control module, followed by a fuel injection cleaning. Check engine light went off, cruise worked again, but the stumbling became intermittent.

Ran premium fuel and drove it like I stole it for 100 miles. Sometimes it idled perfect, other times barely ran under load. Back to the shop for another FI cleaning (no charge this time) and ran fine the 30 miles home. Sat for four days, went to start yesterday and cannot even drive the car now.

The Indy has had the car 4 weeks and we have had it 4 days...so on the frustrated end of a $3K bill and no relief. I hate to be a checkbook mechanic and even more don't like replacing parts and "try this" approach. The Indy now says I need to replace the fuel injectors, but I am not yet convinced.

Have a new fuel filter, set of plugs and wires, all Bosch OE and am going to put that in. Was also thinking of using SeaFoam in the oil, gas tank and breather hose from the brake booster to see if that helps.

Any helpful comments or thoughts are much appreciated. Just want to get this baby rolling again! Thanks! Jim

[Jayare]

Hi Jim,

Thanks for your post and welcome to benzworld. Has anyone bothered to check the distributor caps and rotors? Put one bottle of Techron in the tank and don't fool around with the other additives. I don't think fuel is your problem. Has anyone pulled the codes?

When you have a few minutes, please complete your profile. For all I know, you could be a few blocks from me or another forum member that could lend you a hand.

Good Luck and again, welcome

Jayare

[deanyel]

Sounds like the mechanic is guessing now. Injectors at 64k would be unprecedented. Even at 200k you don't replace them, you get them refurbished for under $20 each. You need to build the code reader and learn to read the codes yourself - lots of info in the archives.

[betapi]

If the wiring to the throttle actuator were bad, I suspect your wiring harness is too. search here on wiring harness. you find out all too soon.

[fredvillanueva@gmail.com]

when i first got my benz she ran well, but started stumbling. I replaced the plugs and wires- better but no cure. Put in all 3 brand new coils. She runs like a champ now. Total cost around 220 from autohausaz for all.

[AKHARMON]

...and get a new mechanic

[fredvillanueva@gmail.com]

Originally Posted by AKHARMON

...and get a new mechanic

Amen to that Bro. Sounds like you walked into a vampire who plans to bleed you slowly.

[ronmiller609]

Originally Posted by betapi

If the wiring to the throttle actuator were bad, I suspect your wiring harness is too. search here on wiring harness. you find out all too soon.

Have the upper and lower wire harnesses been replaced by you or PO? If not, that should be your first order of business. +1 on the search referenced above.

[macdrone]

Coils?? same motor as me and the coils are under the ABS pump and no one ever replaces them.

[edcarls]

Originally Posted by fredvillanueva@gmail.com

Put in all 3 brand new coils.

Did the same and fixed the rough idling on my 94 E320. E420 V8 may have different set up. But, I think plugs are ignited by high voltage coming from the coil(s) that would cause misfire if defective.