Many problems with my M50...

[Jim Lepage]

I have some problems with my M50 Vanos engine. I got it scanned and we had codes for MAF, O2 sensor and TPS. Since that I changed the MAF and O2 sensor and the problems are still there.

Problem 1- it vibrates at idle and sometimes the idle isn't constant when it's warmed

Problem 2- it smells bad

Problem 3- poor mileage

Problem 4- it rattles a lot at idle and at low speed

Problem 5- it vibrates (grinding feeling at the steering wheel with a small grinding sound) when I'm rolling and turning right


Please help me to find what cause those things, I want my engine to be quiet and smooth like before. If my explanation are difficult to understand let me know (damn french Canadians... :) ).

[MattM]

1 - vacum leak, ICV clogged, MAF not working correctly
2 - Cat bad?
3- unless you bought a special chip you econoguage wont be accurate
4 - need more details.... if you have a mechanical fan that will make a bit of noise...
5 - you have air in your power steering system or or a leak.. Did you use ATF for the system? Brakes locked? Bad wheel bearing?

[e30Rob]

3 - what diff are you using?

[7pilot]

5. This might be a LFront wheel bearing.

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[Jim Lepage]

1 - vacum leak, ICV clogged, MAF not working correctly

I'll check that. I also completly forgot to wrote that at my last motor oil change I put too much oil in the engine. It was cold outside and the 20w50 took a bit of time to drop in the pan. I drove it like that and the idle problem started. I removed the exceed of oil and the problem stayed. Could the ICV got oil in it and got clogged ?

2 - Cat bad?

I don't know but it didn't smell like that before.

3- unless you bought a special chip you econoguage wont be accurate

I know, it never works

4 - need more details.... if you have a mechanical fan that will make a bit of noise...

I use the aux. fan. It's rattleling like that since the idle vibrations problem happen. I bet the rattles will stop if I fix the idle.

5 - you have air in your power steering system or or a leak.. Did you use ATF for the system? Brakes locked? Bad wheel bearing?

I don't know what oil is in my ps system. My brakes are fine. Yesterday I checked and the wheel bearing seems fine but I have a little side play in the steering rack. Could the vibrations comes from that ? Maybe it's the tie rod ? I'll also do a ps fluid change.

[Jim Lepage]

3 - what diff are you using?

3.73 open diff.

[Spaz]

3.73 open diff.

Which transmission?

[Jim Lepage]

Which transmission?

Getrag 260. I know my gearing is short but the mileage I do is worse than before. My spark plugs and fuel filter are new.

[zav3n]

did u check and make sure the parts u swapped were good?

[Jim Lepage]

did u check and make sure the parts u swapped were good?

The MAF is good but I don't know about the O2 sensor. I borrowed it to my friend.

[jrdeamicis]

Remember that the vanos could be slightly off to which causes a slight burble in the idle.

[Kerrath]

If you didn't get this straightened out, I'll throw in that my bad O2 sensor caused a throbbing idle which made really bad vibration. It also didn't show up on stomp tests, only when I took it to a dealer to have them hook it up to an OBD machine.

[e30polak]

I have some problems with my M50 Vanos engine. I got it scanned and we had codes for MAF, O2 sensor and TPS. Since that I changed the MAF and O2 sensor and the problems are still there.

Did you change the TPS and forget to write that in? That obviously is causing some of it.

The inconsistent idle could be a number of things: MAF, ICV, vacuum leak, injectors, spark plugs/coil packs.

Try running the car without the MAF plugged in to rule that out. Do that with the O2 sensor as well and see if there are any changes.

Make sure none of the injectors are clogged.

Are you running a cat? If so it may be clogged.

Are you running proper sized injectors for your tune (stock, if you're stock)? Which fuel pressure regulator are you running?