Odd fix to my chronic problem

[mzarifkar]

I have mentioned the running like crap issue in the Las Vegas instrument cluster post. But here is the jist of it. Car runs like crap.
Low power, erratic idle, with some occasions of complete powerloss, backfiring through the manifold when trying to rev up. again, runs like crap.

I have managed to patch this problem by disconnecting the MAF sensor. This presumably places the car in some sort of backup mode. It performs acceptably doing so.

Any ideas?

Sparks are new. Coils are not new, but coil resistance was at the high end of acceptable margin (per bentley). no indication of fusible link break. A new MAF did not solve the problem. I don't suspect fuel pump failure since it works fine without the MAF.

[E34-520iSE]

Sounds like the car has serious sensor issues dude!

Regards,

Shaun M

[632 Regal]

sounds like a charging/ground issue somewhere. Have you ran the OBC voltage program to see whats happening electronically? You have too many issues going on at once to even start to figure it out, go for the basics now.

[mzarifkar]

sounds like a charging/ground issue somewhere. Have you ran the OBC voltage program to see whats happening electronically? You have too many issues going on at once to even start to figure it out, go for the basics now.

OBC check 9 holds steady around 14.00-14.25V

[bsell]

OBC check 9 holds steady around 14.00-14.25V

Is the ground for the engine computer harness common to any other system? I ask as these grounds are usually in the engine compartment where they are exposed to years of water and corrosion-inducing stuff. This contamination can 'lift' the ground on a mechanically tight joint.

So I suggest what should be a quick and easy check of the engine bay grounding points. Yes, take them loose and scuff the connections to ensure solid electrical contact.

If this doesn't help, then run the sensors feeding the computer. What about the cam/crank position sensors? I had a buddy here fix his stumbling with a new cam sensor...

Brian

[Grantus]

I had similar issues with my 520i , after checking fuel pump, injectors, coils etc. etc. It turned out to be a split pipe up under the inlet manifold.

[mzarifkar]

I had similar issues with my 520i , after checking fuel pump, injectors, coils etc. etc. It turned out to be a split pipe up under the inlet manifold.

Was it a vacuum line of sorts or the inlet manifold

[Grantus]

It was a rubber pipe that connects to the manifold. ( M50 engine). I had to take the manifold off to get to it. I cant find a diagram anywhere to point it out for you.

[JD525IA]

I had similar issues with my 520i , after checking fuel pump, injectors, coils etc. etc. It turned out to be a split pipe up under the inlet manifold.


On my old 528I, the old rubber intake boot had a hole in it and what you got was poor power, bad idling, etc., like he describes above.

Check those boots and hoses!!

JD