M10 misfire running rich

[BronzitM10]

hello i have a 84 318i and ive had it in the shop and they didnt do anything for the car. it has a new MAF put on it, new chain, timing checked valves checked. the head was checked and its still running like crap.

Does anyone have an idea on why it would be running rich? the guy told me the computer last said it was the fuel pump or fuel pressure regulator. but it really dont seem like that. any help would work

[Interstate90]

I have a similar problem with my car.

My vacuum advance was not working properly. When I replaced my distributor, it cleaned up the misfire a bit.

Which spark plugs are you using? Should be Bosch WR9DS
The valve timing is tricky. Per the book, it should be adjusted to 0.010 cold. But, I have also read that adjusting it to 0.080 warm is a much better adjustment.

Other than this, I would check your spark plug wires and check your plugs to make sure they are firing.

If you still cannot find the issue, just advance your timing a bit. At least you can use up that extra fuel properly!

[Jaxx_]

The valve timing is tricky. Per the book, it should be adjusted to 0.010 cold. But, I have also read that adjusting it to 0.080 warm is a much better adjustment.

can you confirm these numbers?

[petrolhead]

.........
The valve timing is tricky. Per the book, it should be adjusted to 0.010 cold. But, I have also read that adjusting it to 0.080 warm is a much better adjustment.

Other than this, I would check your spark plug wires and check your plugs to make sure they are firing.

If you still cannot find the issue, just advance your timing a bit. At least you can use up that extra fuel properly!

I've no idea about the "book" you're referring to but the Factory Repair Manual says 0,15-0,20 mm cold.
Let's say you start the procedure "hot" and even manage to get the valve cover off before it cools. The first valve clearenses you might get right, but it'll cool by the time you reach the last two. And yes it does matter.

-Jarno

[Interstate90]

From the Bentley, Engine-22.

It was from memory and I guess I had them mixed up.

The adjustment of 0.008 (wups missed a zero) warm was from a post by GoodnTight from bfc. He also suggested different plugs with a specific gap. I do not have that post handy, but I am sure with a thorough search you could find it.

[Jaxx_]

https://lh3.googleusercontent.com/--UvuRxr4J1s/Tsq_-P-wq7I/AAAAAAAAEcw/RQm65Nwf3iA/s720/Valve_Clearance.jpg

From the Bentley, Engine-22.

It was from memory and I guess I had them mixed up.

The adjustment of 0.008 (wups missed a zero) warm was from a post by GoodnTight from bfc. He also suggested different plugs with a specific gap. I do not have that post handy, but I am sure with a thorough search you could find it.

well you have it flip flopped... .008 cold and .010 warm...right?

I gapped my plugs to .036 and the car is running so much better than at factory spec. but then again, I probably have a more powerful coil(but it is wasted spark)

[Interstate90]

well you have it flip flopped... .008 cold and .010 warm...right?

I gapped my plugs to .036 and the car is running so much better than at factory spec. but then again, I probably have a more powerful coil(but it is wasted spark)

Yeah, they were flip flopped. :)

Which plugs do you have?

[Hey_You]

A rich running condition can be caused from a faulty o2 sensor, or CTS. Run the Bosch coppers, these old engines hate modern plugs. Also make sure your FPR is is working correctly (not ruptured)

[Jaxx_]

I run bosch coppers or NGK coppers in everything I own.

[BronzitM10]

The shop had put the same ones in that a parts store gave me...i think they were like champion or whatever..i was planning to change them out anyways because that could be the problem..@Jaxx which NGK do you use? the parts store can get me like 2 different ngk coppers but not the bosch. and i do not want to try bmw here. ill more likely order the bosch one to be on the safe side..i had changed the FPR but it didnt change anything at all.

Thanks for the input greatly appreciated.

[KenC]

It could be the FPR. Try the O2 sensor also.

[BronzitM10]

So i changed the plugs and the FPR and it cleaned up the runnin rich alot. sounds a bit better..but there is still a misfire..how can i check the static timing my uncle was trying to tell me how but he couldnt remember where the hole is.

Me and my dad also were running it then unhooked the vacuum line to the distributor and it continued to run and seem to get no vacuum. anyone know what could cause that?

like i said its mainly a misfire right now..

[Hey_You]

I would replace your distributor cap and rotor (if not done already) and check your plug wires. To check your wires, get a squirt bottle and spray some water on them while the car is running. If the misfire becomes worse when doing so, replace the wires.
Note: DO NOT TOUCH THE WIRES WHEN DOING THIS!!!!!!!!!!!

[Jaxx_]

I would replace your distributor cap and rotor (if not done already) and check your plug wires. To check your wires, get a squirt bottle and spray some water on them while the car is running. If the misfire becomes worse when doing so, replace the wires.
Note: DO NOT TOUCH THE WIRES WHEN DOING THIS!!!!!!!!!!!

i prefer to look at the wires when its really dark and see if you can notice arching to the body.

[BronzitM10]

the cap rotor and wires are all new. ill check the wires though.