Recently I changed all my wires and coils with some cheap replacement parts. Car was running fine until it decides that it is going to power down slowly at 75mph. The throttle was unresponsive, but I could cut the car off while rolling and cut it back on again so electrical seems to be ok. I am getting misfire codes only, sometime 1-2-3 some time 3-4-6 and so there is no rhyme or reason for the misfires and so I am wondering if it is fueling.

I changed out my fuel pump, back to my original pump because the new cheap one was quite loud and when the car dies, I don't think I can hear the fuel pump click on when i try to start the car after it's been running.

So, car dies after about 40 miles. If I let it sit for a couple of hours, it will go about 40 more and then cut off.

Car will actively misfire in 3 rd gear at 3500 rpms or higher resulting in check engine light and sometime flashing check engine light. If I keep the car under 3500 rpms, there is no misfire, no check engine lights, no codes, but the car still will die after about 40 miles of driving.

What could it be?

 

Mobilefitt,

Not trying to be an a$$ but I would refer to your first sentence....

"Recently I changed all my wires and coils with some cheap replacement parts"

A "cheap" coil or wires can very easily cause misfire issues.

 

I would suspect the RCM or the fuel pump relay in the RCM.

 

Some people don't have to try..... to learn how to read the entire concern before typing away....


I just want the car to keep running after 40 miles. Why would the car die with no codes, including no misfire codes, after 40 miles? I can re-install the the original coil packs and wires once I determine it is not a fueling issue. If cheap coil packs and Prenco wires are known to make a 3.2 die after about 40 miles, with no codes, then thank you sir for your reply. It has truly helped me to understand why DD dies on the way home from work with no check engine light and no misfires.

BTW, the car misfires at RPMs above 3500. This may be a symptom of, less than perfect fueling as well. I was thinking, fuel pump, fuel filter, or the relay or some part of it.

I was under the impression that the relay malfunction would be accompanied by a fault code. Someone with some sense, please chime in.


Thanks

 

So you made a change to the engine, it now does not want to run right - and you don't think it's the change you made?

My car was throwing misfire codes like crazy at 105,000 miles. Changed 12 plugs and 12 wires - fixed. $189 for the set from Needswings. Buy good stuff and you should be fine.

 

I'm confident that the relay is my concern at this point. Thanks for the attempts to help but the misfires are a symptom, not the problem here. Maybe the coils and wires are crap but it doesn't explain the car dying with no codes.


DID I SAY THERE WERE NO CODES UNLESS THE CAR BREAKS 3500 RPMS? I can drive to work and back and keep the car under 3500 rpms to avoid the check engine light and misfires. No it's not fun, but until i get to the bottom of it, I need to get around.

Is it possible that a failing fuel relay would keep the car from performing at higher RPMs? ie. has anyone else had this exact experience? Speculation at this point is just frustrating as hell.

Did I mention that the car performed perfectly for 6 days with the new coils and wires before it started misfiring at Higher RPMs.

 

From what I have read on this forum our cars have a pressure regulator in the fuel filter. At idle the fuel rail will have about 55 psi, but as the rpm increases the pressure will drop down because of our fuel pumps output. So you may have a fuel filter problem with the regulator, but I would suspect the fuel pump you are using doesn't have the needed capacity at higher RPM. You may want to replace both with OEM parts. If that doesn't work you are back to the coils and plugs you have recently installed.
The relay is also a possible problem. I have had fuel pumps work fine so long as the engine was running cool, but as it heated up it would cause a problem with the pump and the car would die. Might be something similar with the relay is happening.

 

No ,you did not; Explaining all the symptoms, will help more than sarcasm. At this point, it's apparent that something is getting hot an breaking down. First guess, the coils,like it or not. Second guess ,fuel system, being filter clogging or the fuel pump going out,. I'm not there to help you with diagnostics , but it seems you are on the right track. With no codes ,it's hard to say , It's X,Y, or Z.

 

Forget the wires and coils that's not your problem your problem is fuel-related it is obvious at higher RPMs the engine is leaning out , in other words starving for fuel and causing the misfires because it is running out of fuel, determine what's causing it and you will fix your problem, I would concentrate on looking at fuel pump fuel filter or fuel lines.

( car slowly Powers down at 75 miles per hour) classic symptom of running out of fuel.

 

I agree I think it's the fuel filter regulator.

 

My Borg Warner CPS would run fine at low rpms and freak at around 4000. It didn't matter if I was full throttle or not. If you can accelerate full throttle until 3500 to 4000 before the problem begins I'd take a look at the CPS. Perhaps it got pulled or tugged during the wire instal causing a bad connection.

If not the CPS I'd take a look at the alternator too. Not enough juice and weird things start happening. Eliminate what you can without spending $$ and soon you'll find the why.

Les

 

Good advice

 

I cannot figure out if the fuel pump in use is the OEM one that was changed for some unknown reason and possibly put back on the car or the noisy cheap pump that replaced the OEM one.
So I have no opinion, just questions.

 

To eliminate (or verify) the fuel pump relay, force the contact on the relay closed and go for a ride.
Preferably 20 miles out turn around and come back so yer close to home if it's something else lol!

 

Thanks for the input.

I have conducted the relay repair. It was easy! Solder 3 points with fresh smooth paste.
I replaced my new (cheap and loud fuel pump) with the oem pump (piernberg) or something like that.

I have put back the old fuel filter as well.


I am going to use my stock wires and the new coils for my first test drive.

I KNOW THAT CHEAP PARTS ARE NOT IDEAL. I have discovered that our cars do not like cheap parts, but finding cheap parts should be one of the benefits of driving an 11 year old car. WE own the redheaded step child of cars when it comes to Chrysler Parts and Technicians that have a clue. MB techs turn their nose up to this car but if they knew what we know......

BTW, all my cheap parts have warranty and are returnable. I get them in 2 days and the few that work out are quite gratifying. My coils are RED! If i could find OEM red coils, I would have bought them.... Wires are from Prenco. They look identical to the wires I took out of the car. I will report back later today, once I torque my plugs to spec and get the wires back on.

 

I'm glad you got all that straightened out and I hope everything works out for you and you get to enjoy your car again,
PS, I still think it was the fuel filter regulator on the new filter there has been numerous cases where new fuel filter regulators malfunction.

 

That's the Mystery No Start repair.


The relay (if bad) needs to be removed and replaced. I have seen the relays fail intermittently.

 

so, since the fuel relay repair, and replacing the fuel filter, I checked the plugs to find that one was cracked. I replaced 6 plugs on one side and I'm calling it a night. I went for a drive and the car is running much better. 4th gear in high rmps, the car misses, and feels like it's shutting down half the engine.
I've not tried to drive the car any distance to see if it's going to cut off after 40 miles until I can get this misfire completely gone.

The fuel filter poured black fluid out of the in line. I wonder if I got some really bad gas or something.

 

Progress! 6 more plugs to go. That's a lot of work. CHECK the two posts above by tighed1.
Black gasoline doesn't sound good. Maybe the rubber is going bad on the fuel line. A fuel filter won't fix that but the OEM MBenz # is 002 477 30 01

 

So test drive on six new plugs, six old.

Misfire at about 85 mph in 4th gear. Also 500 code and 503 wheel speed sensor.

Who can tell me about this code?

I did just replace the steering knuckle, but I used the old speed sensor when I did it.

Is it possible that I damaged it somehow in the removal? Will this cause misfires at high rpms?

Thanks again for taking a look at this with me.