Dual 5Ls

Well, the 500 has now got me in a pickle here. A little while ago, the check engine light came on and I would get a miss at idle, hot or cold, sometimes speratic, sometimes bad enough that it felt like a rad cam was in the car. Then, under heavy load acceleration it would miss quite bad and bog down. Sometimes it won't happen, then it will. But I've noticed that it does do it when its cold, and if I've driven the car for say an hour or so. Another interesting thing, is if I take a corner sharp at all at low speeds (foot off gas), it will die immediately. So I replaced the spark plugs with Bosch +4s and did an oil change at the same time (needed one), and that did no good. So, I asked some guys, and they all said, replace the MAF. So, being STRAPPED for cash, I got one from a '95 S500 with 66k miles and put it in. No difference. I checked the service records, and this problem had been "fixed" once before at the dealer. They said it was a broken plug wire which they replaced, and also a faulty engine wiring harness (the big guy). That is of course now out of warranty. The engine wiring harness I'm really unsure of it being replaced though. Says in the notes that the wiring harness needs replacement, but in the bill it shows it was replaced, so I can only assume that the note was before the fact and left in. So what the heck is going on here?

dtkw

If anything is replaced, on the bill, you would see the part numbers on.

barry S320V

Got a call from my son today, he was realy pissed off, as his vw 16 valve gti concked out on the freeway on the way to work.
He recently replaced the battery as he was having "electrical demons". He is so pissed he is going to dump the gti which he loves, and get a pickup.

So I go over and open the hood. When he cranks the engine it turns over real slooow. I then jump started it with my battery, it started immediately, and ran fine. Soon as I took jumper cables from my car off it quit within a minute.

So put the multi testor on the battery, showed 11 volts. not good from a brand new battery, jumped his gti again, tested with the multi testor. His alternator was producing zero volts. This is after having it tested at the battery shop of course, and being told "your alternator is fine".

Tomorrow he will install a rebuilt alternator.

Saving from doing the work yourself instead of buying a new truck, about $25,000.

s500c

Hey dual, have the dealer or repair shop check your ignition control module (ICM). I really hope it's not the problem , but those are the same syptoms I was having with my '95. A new unit runs about $2000.00 and a used/rebuilt one goes for about $600-$$700. The funny thing is dealer told me the unit could'nt be rebuilt. Anyways, that cured my problem.

Dual 5Ls

Hey thanks, I'll check on that ICM.
I was also thinking the other day, what about it being something simple like clogged catalytic converters, or a faulty O2 sensor? The ignition thing seems like, but it dying when I turn is just weird... Also, has anyone done the timing chain replacement themselves? I'm told it needs to be done at 150 or 160k, but no one but the dealer will do it.

dtkw

Timing chain? No, I paid someone to do it. My generic MB mechanic figured a way to change it without removing a lot of stuff. That's probably his secret.

Dual 5Ls

Ok,
So after thinking about it some more, its really just confusing me more. On my 928, it has a dual distributor, and when it ran on 4cyl mode, it was REAL slow, but felt like the 500 does. So, its not a distributor or coil going out or I'd have a severe loss of power. I'm thinking maybe a fuel pump, or fuel filter. But something is really running intermittently, and I highly doubt its the 02 sensor, and clogged cats wouldn't make the car bounce at idle, nor would it kill the car in a turn. Anyone had a fuel pump go out or any other things like this happen? And another thing I noticed, I had been driving my car for about an hour and then got on the freeway, but at one point the car was losing power fast, and I was floored in 3rd gear, not passing 62mph. So, I'm stumped and don't want to just throw money at it until I get it right. Any help is as always, much appreciated.

barry S320V

What kind of gas are you using? I had a problem once when I tried that blended gas with alcohol in it. Another cheap thing to try is to put some methyl hydrate in the tank in case you picked up some water in the tank, which would get sucked up when you turn a corner.

Barry

Dual 5Ls

Hey Barry,
I use only Chevron supreme. Its been doing this over multiple tanks. I'm leaning towards a fuel filter or fuel distributor now.

barry S320V

Always lots of things to elminate when trying to diagnose a problem.
I read a thread a few months ago that was warning about the small pipes that connect the various sensors etc. The problem described was that these pipes are hard plastic instead of rubber, and can be easily cracked allowing vaccume leaks and so on causing false readings and associated problems.
Barry