Help on 95 s320 misfire
 

Hey! I have a 95 benz s320 that is driving me crazy. Let me give the whole history of the car. The lower harness was fried the car didn't want to start, so i rewired the lower harness and still the car didn't want to start, so i took out the spark plug drop some oil on each cylinder to boost up the compression then the car started right up. And now i am having problem with the car loosing power when i am driving at high speed on the high way doing like 80 and the car loose power. When i floored the gas pedal the car is not moving. I check the ETA and the wires were fried also, so i sent it to bba to get rebuild i install the ETA thinking that my problem was solved and still the same problem the car keep on misfire, so i took it to a tech shop who only specialize in german cars. He put the car on the computer and he got cylinder 2 and 5 misfire so he told me my problem was the harness and i asked him if he was sure and said yes. We change the harness still the same problem, changed fuel pump and relay, 3 new coils, spark plug and wires, mass airflow sensor, cranshaft sensor, fuel filter, air filter, 02 before the catalytic converter, fuel rail including all the injectors and the car is still loosing power when i drive at high speed and still misfire on cylinder 2 and 5. He said the timing was off a tooth he adjusted it and still the same problem. compression is good, and no leak on the intake. He said the ecu is not good the fact then when the car act up cylinder 2 and 5 as well as injector 2 and 5 don't work. We got another ecu still same problem. When the car loose power when i drive at high speed after 20 miles and come to a complete stop, it stalls. if i restart it the engine shakes like crazy because two cylinder don't work. If i disconnect the battery terminal for a few and plug it back the car will give me another 20 miles at 80 mph and do the same thing again. Floor the gas pedal and the car is not moving. I was wondering if anyone have an input of what might be the problem because the car is misfire. if i reset the misfire and drive the car for a few the code came back. And i am also having a problem with the car on first gear it jump beside all the rest of the gear are fine. The trans code says upshift delay switchover solenoid. i was wondering if it's a big job

This is code 26 correct? This is nothing to worry about. The Mercedes have this "feature" so they don't let the car up-shift till the transmission fluid is a little bit warm. I have driven my (ex) 95 E320 with this code for 45000 miles, never any issues.
For the rest of your issues...I don't know. looks like you have done everything possible to resolve it. Perhaps someone else will share some knowledge.

Tech can't find a solution for the misfire.
 

I think so, now it's jumping on first gear now, beside that all rest of the gear are fine. for the misfire i took the car to a mb tech and even them having hard time to solve the problem and i spent around $1400 and problem still no solve, so the tech is charging me for guessing i should of guess myself and i wouldn't spent that much. No one seems to have an idea what is causing the problem. I think i'll just junk the car or part it out.

When he changed the wires, did he change the stubby sticks that go right under the ign. coils?? Some techs just assume those never go bad when they do. Make sure on that... My car had that problem. Also, check the wires that go from the Ignition module to the ignition coils.
Another cause I have heard about that is the over voltage protection relay....

all the ignition system changed and still getting misfire
 

He changed everything the engine harness, spark plug and spark plug wires including all the boots. What's is weird is when the car lost power after driving at high speed and i come to a complete stop it stalls, i have to disconnect the battery terminal for a few to fix whatever is causing the problem until another 20 miles. If i reset the misfire after i drive like two blocks it comes right back. Cylinder 2 and cylinder 5 don't work the car act up that's why he said it was the ecu and the car is still doing the same thing after we replace the ecu.

try a new OVP relay then... If you're that far into it, might as well try that as well....

My car don't come with the OVP relay. I think it has a computer that have some fuse on it that replaced the ovp relay i change the computer as well because i had purchased the all set of computer from ebay and still getting the same problem

sakpase, take your 1995 S320 to a MB dealer. The Service Department will be able to diagnose the problem properly. Once you learn the root cause of the problem seek a refund from the MB tech who randomly replaced parts without resolving the problem.

They are using the same computer the dealer is using. And they only repair german cars and can't find the problem. I wonder if taking it to the dealer will worth it, because they use the same star computer and can't find a solution, by the way i don't think they will give me my money back easily. I think i would have to take them to court to get my money.

MB don't know anything either. My dad has 94 E420 that has a rough idle and he took it to MB and they hooked up STAR to it and didn't find any problems. They suggested they would change the wiring harness and start from there. ---> I'm sure they would have liked to do that job.

That's exactly what i am worried about. Is to take it to the dealer and spend $150 and they can't see what caused the problem i think i'll just part this car out or trade it, so what did your dad do with his car?

Did anyone do a compression test?

All those parts - were they OEM?

Have you tried downshifting to a lower gear and running at the same RPM you experience when you're going 80 to see if it's road speed or engine speed related?

The tech did a compression test and told me the compression test was good. I didn't tried downshifting to a lower gear. When he reset the misfire code and i drive the car for a few the misfire come right back. I was wondering if the misfire could be because of a defective crankshaft sensor since i changed it before the problem started happing and does the lower harness have something to do with it because i had rewire it myself. It's only since 2 and 5 that is misfiring.

Mystery problem
 

The dealer does know their stuff. And so does the STAR system.
The problem is the wiring harness.
It is the only component on the car that will create intermittent mystery problems.
Until you replace it, you cannot properly diagnose anything.

That's why I refrain from any 93-95 Mercedes....

If you reading everything from the start dhaghighi you will see that the tech replaced everything. Started with the engine wiring harness and all the ignition system and the car is still doing the same thing.

Does it throw off any codes?

Once they've been replaced, they're just as good as the rest. They're not too ridiculously expensive either, especially if you locate a wrecked car with a harness that had already been replaced.

It throws p0300 with an obd 2 but when the tech check it on the star it says cylinder 2 and 5 not working. he put a new coil and injectors and still misfire

harness
 

Actually I read that you rebuilt the lower harness.
Is there any old harness or wiring in your engine bay?

If this guy changed all these items to fix the problem, and it is still not fixed, I would really stick-it-to-him. You probably won't have to go to court if you show up with your evidence and present your case to him. If he's smart, he will realize that he will lose to you in court.

These mechanics have to be held accountable....not just change a bunch of parts and cross your fingers.

Now he has no choice now, he should of say if he couldn't fix it instead of chaging all those parts. I hope so because i keep all my receit. It's either he fixed it or take all their parts out and give me my money back if not i'll make sure i ruin their reputation by calling them to street court.

So the last status is that "injectors on 2 and 5 don't work"? Have they been retested? Another thing to make sure is taht the injector seals (o-rings) are good.
By the way, what part of the world is the car in?

The oring in the injectors are good there is no leak no where to be foud. The car is in New York the

Good luck with that.:rolleyes: You'll have to take it to a different shop that's willing to sign an affadavit and testify; not likely.

P0300 is a misfire code on multiple cylinders; misfires are most commonly caused by a lean condition (no gas) or can be caused by a clogged exhaust (among many, many other things). I'd use a noid light on the injectors ($20) to make sure they're firing or remove the upstream O2 sensors and drive it to see if driveability improves - if so, the cat is probably collapsed.

Hey dhjenkins you said remove the upstream 02 sensor to see if the
driveability increase, you talking about the sensor before the catalytic converter right. The tech still have the car i had a talked with him about taking all the parts out and give me my money back since he can't fix the problem and he insisted that he'll fix the problem to give him sometimes, so we'll see.

Yeah, the one between the converter and the engine. If the cat is collapsed, the exhaust will come out of the O2 sensor bung.

Oh alright! I will try that when the tech give me the car if he doesn't fix the problem i'll try that

You can also use an IR thermometer to find extreme temperature differential before and after the cat to determine if it's bad. Some bad cats get so hot they will even start glowing after a highway run.

Of course, an excess amount of unburned gas going through the cat will make it run extra hot, too; which will, of course, lead to premature cat failure.

I've tried the IR trick, but it's just not reliable enough for me; then again, that goes with the territory when you service multiple makes.

Just another suggestion and by no means the only option.

When the car act up like thant and don't want to take gas when i floor it on the high way and i come to a complete stop it stalls, so i restarted it and the engine shake like crazy because two cylinder is not working so i open the hood to see if the catalytic converter is glowing, but it's not. For the cylinders to work now i have to disconnect the battery terminal for a few and connect it back and the car will give me another 20 miles and then act up again, so i wonder if it was the catalytic converter it wouldn't do that all the time regardless disonnect the battery or not right? I will definetly tried the IR thermometer test, because you never know. For the IR thermometer test i have to take the o2 before the catalytic out and stick it there right, get the temp, and after stick it in the muffleur and compare the temp correct? If it's higher before the catalytic converter that mean the cat is no good right? And any suggestion where i can get a good IR thermometer. Thanks

DIsconnecting the battery will clear the memory so that the mechanic can't get good codes. It sounds like some sensor (eg O2) takes 20 minutes to "correct" itself into a bad condition. Taking scanner readings right after battery reconnect and then after the misfirings restart should show which sensor has the different reading.

When the car act up and i checked it with an obd2 i get code p0300 random multiple cylinder misfiring and when i check the freeze data i remember getting long term fuel trim -100 don't know what that is

The car was at the mb tech for almost two weeks and he called me today and told me that he found the problem to come to the shop. I had a problem removing the crankshaft position sensor that was a small piece that broke in the transmission and i dig it in and it felt by the flywheel damage the side of the flywheel where it's suppose to touch by the cps. The tech told me that was the cause of my misfire so he's replacing the flywheel and changing the cps sensor, so i was wondering if that could really be the cause of my misfiring from cylinder 2 and 5.

PROBLEM SOLVED
 

Thanks everyone my problem is now solve. The problem was the flywheel that was bent from me removing the old cps sensor out that was broke in the transmission. I hit it and i mess up one of the flywheel thing that control coil 2 and 5. Now all the ignition system is my car are new now. That thing cost me alot of money i hope the car last me a long time. What i have to deal with is the transmission that is acting on first gear now.

sakpase, it's difficult for me to believe you bent the flywheel trying to remove the CPS. The starter motor likely produces more stress on the flywheel each time the engine starts than you could generate attempting to remove the CPS. I would like to see pictures of the damaged flywheel.

It's not the flywheel teeth that is bend. The flywheel have 3 sides on it that control by each coil. The fact that the cps sensor broke. I had to removed the oil filter housing and the air intake and i hit it the broken cps down with a long screw driver with a hammer unfortunatly one of the 3 sides on the flywheel that is reading by the magnet on the cps sensor bend a little it, because one side was up right under the cps sensor. I'll post a pic with a the broken cps sensor so you could see it.

Glad to hear you got it fixed. It should be good for another 10 years now with all that was done to it.

If i will be good for another 10 years i wouldn't mind spending almost $2,000 on it. And now i have to deal with the transmission that is acting up on first gear now, beside first gear all the other gear are fine.