Rough running.....

[325issguy]

Hey guys,

I have a m52 swapped 87. Tonight on my way home from work I had a problem. I left work fine then after a minute or two the throttle was almost like ON/OFF in the fact that there was no power unless you revved it. I then pull over, the lights are dimming as I pull over, the idle is surging from very low to a bit over idle.

I cut the car off for a few and try it again and the car will die if i dont give it gas but will rev up if i make it. I was thinking of trying to replace the fuel filter tommorow. Also, my idle has been a little jumpy lately and my battery died on the 20 minute ride home from having the flashers on. Is there any way a dead battery could cause my car to run like this?

Thanks for the help,
If there is anyone if VB that wants to lend a hand let me know I need to get this thing back runnning.

[sharksforthecup]

Could be a bad Battery, but more than likely its the alternator. Might want to check your connections and make sure your alternator is charging the battery.

[325issguy]

Little update... Dont think its the fuel filter because the car will pull up to red line after i get it from bogging.


Now it does not run by itself for more than a few seconds. If i unplug the plug to the intake it runs a little bit smoother and I can get it to run smooth up top, but not idling.

Also, in the injector harness on the engine, there is a little gray box that has KABELMETAL written on it and 1738183 is the part number. This box is cracked, I was wondering if it was some sort of inline fuse or something.

Also, I was wondering what the green S light is for on the m3 dash, that comes on occationally and I havent noticed it often since owning the car.

[325issguy]

Also, I have tried a different battery with no luck.


I think I am running realllly rich and flooding the engine. It smells like it and all of my spark plugs are getting covered in gas.

[RedTRex]

Definately sounds like your alternator is dead - or for some reason is not providing power (i.e. wiring problem) ..... your first big clue is the battery being dead from using the flashers ..... and yes the car will run like crap with a bad alternator. Autozone will test it for free.

[Kerrath]

Do you have power steering? I know its a longshot but a recent problem on my mom's volvo sounds similar. Alternator not generating enough power, generally running like crap, the battery wouldn't charge and power steering would at times bog down with lots of check engine light coming on.

The rubber in the crank pulley was shot through and only when it was at higher RPMs did it make enough friction to actually pull the other stuff. Since her cams were driven off the pulley and not off the crank like M50s I know that accounted for engine problems, but I dont know how much it'd affect running on these.

Once again, just a long shot. Probably not worth checking unless a whole lot of stuff is suddenly not working right.

[325issguy]

Had the alternator tested yesterday and the alt. was dead. Replacement getting in this afternoon.

Thanks everyone

[325issguy]

Well.... Thought it was the alt. But after replacing it with no luck, I am still looking for the problem. I know i am getting gas and stuff... Just have to figure out why Im getting too much.

Does anyone know what the green "S" light on the m3 cluster means? Mine keeps blinking and it did not before.

[mattdk318i]

did you get a new bat.? or get it tested?

[325issguy]

Have tried 3 seperate batteries. I think Im taking it to a shop today or tommorow. Cant afford to not have a car for any longer.

[325issguy]

One new symptom. When I drive the brakes do not work much or at all. I think that is just because of the rough really low idle. Really am stumped... Maybe will try a new battery today.

[M-technik-3]

You said that when you undo the Maf it smooths out the car? Do you have a friend or some one near by with an S52 or M52? Borrow their maf install it see if that helps. Cold be dirty or cracked and in limp home mode.

The run like butt when damaged. Also have you tested the charging system like everyone has mentioned. Lack of vacuum, how is your ICV attchment?

Battery will not affect brakes.

[jrdeamicis]

If it runs better with the MAF unplugged its either

A) A vacuum leak
B) A dead MAF

If it drives fine but has a lumpy idle with no MAF. I would start there. Brake parts cleaner will help find leaks.

[325issguy]

It is not firing at all in cylinder 3 it appears. The headers are hot on every cylinder except 3. I swapped coils from one cylinder to another but nothing changed. Im about to pull the plug and see if im getting spark on that cylinder.

[RedTRex]

I will throw in a second opinion that you have a vacum leak now.............