early 87 325e worst misfire I have ever seen (beating dead horse)

[joecrotch]

yes I have searched the boards. Been reading and trying stuff for a week already.

Hey guys, Haven't been around in about 8 years! Got out of the E30 scene for a while. Had a kid, built a few American muscle cars, as well as a couple other projects. Still got the 400 HP Saab though.

But anyway bought a 1987 (early) 325e a week ago. Really want to get back in the E30's and this little 4 door is gonna be my turbo project. Goal is to get it running and driving good before tearing down for turbo build. Problem is I bought it with a bad misfire. from what I can tell its only firing on 2 or 3 cylinders. and it does it throughout the entire rpm range. Don't know if this is related but the rpm and gas gauge jump around until it gets to about 4k rpm. I think that's just SI batteries though. if that fuse that comes of the battery in the trunk was blown it wouldn't start at all, right?

Figured it was something simple like a CPS or coolant sensor or the usual. Well I have checked CPS and speed sensor per Bentley and they check out good. Coolant sensor is at the lower end of acceptable ohms.

Replaced or checked
Spark plug wires
Spark plugs
cleaned and refurbished AFM
checked coolant sensor
checked cps ohms
swapped out DME with known good one
sprayed down the entire engine with ether to check for vacuum leaks

Basically I'm looking for any crazy Ideas that other people have found that caused a horrible misfire. Off the wall stuff that I haven't thought of yet. I refuse to give up on this car. I will bring it back from the dead even if it kills me!

Thanks so much for reading my post!

[GCAutosports]

It can be dirty or bad gas/petrol

[GCAutosports]

Distributor/rotor

[GCAutosports]

Bad injectors

[Kershaw]

Harmonic balancer was giving me a horrible misfire a year ago. Made the car barely drivable. This was an on i though. Not sure how you'd check that with an eta though, your trigger wheel is on the flywheel.

[modernist]

Compression check?

[joecrotch]

Compression was perfect don't remember exactly but 150ish across the board.

Bad gas!!!! I have not thought if that. And now that you mention. The whole car when running smells like nasty gas. I thought it was just because PO cut the muffler off.

Is there any additives you guys have used or am I better off just dropping the tank (good time to do fuel pump too hmm)?

[joecrotch]

And just FYI the car in my signature is long gone. Need to change it out.

[jeffnhiscars]

The only way to fix bad gas is to change your diet

[itsonlygeorge]

Drain the tank. There is a plug on the passenger side.


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[101]

Some OEM fuel tank have a small plug to drain the fuel out. The other option would be to remove the fuel supply hose at the rail, jump the fuel pump relay and use the fuel pump to pump out the old gas.

Either way, change the fuel filter afterwards.

Check the fuel pressure both with and without the fuel pressure regulator vacuum connected and make sure it is within spec. Low fuel pressure could be a culprit.

If your ignition system is sound and the compression numbers are good, I'd check to make sure all the injectors are getting the signal to fire. A noid light can be used for this purpose.

It would also be worth it to check the valve adjustment and make sure that is within spec.

My final step would be to remove the injectors and have them cleaned and flow checked.

[joecrotch]

Thanks for all the great info, Super stuff! Already got some ideas I had not thought of.

Had a bit of a break through today, I guess you could call it. I was rechecking stuff and pulled off my cap and rotor. After inspecting the cap I noticed a weird groove worn into 3 of the posts. Then I pulled the rotor which had almost no metal left on the contact point. I have a m20 on a stand, which is the one I'm building from the ground up for powa!!! I pulled the cap and rotor off that and slapped it on the car. cranked it up and it sounded about 50 percent better. So being that is also a used cap, I'm gonna order a new one. I still think the gas is bad so I'm gonna use the fuel pump to drain and replace. But i'm thinking this problem may be more than just 1 thing. It may be a cumulative issue from years of not maintaining the car.

getting this motor running is going to be as expensive as my turbo build if this keeps up lol.

[5Toes]

I bet its the injectors. probably flowing terribly crossed the board.. its around 50bux to rebuild them all and I HIGHLY RECOMMEND IT ON ALL E30s

I use mepeh.com

[GCAutosports]

For bad gas just get rid of it... you probably have a rusty tank.... then you know you have bad injectors if they are ticking loudly... also have a look at your pump while youre at it and make sure they work if not... save youre money get an aem 300 fuel pump and do a single intank pump

[joecrotch]

I bet its the injectors. probably flowing terribly crossed the board.. its around 50bux to rebuild them all and I HIGHLY RECOMMEND IT ON ALL E30s

I use mepeh.com

I'm thinking of just slapping some 19# Ford injectors. I can usually find them pretty cheap!

For bad gas just get rid of it... you probably have a rusty tank.... then you know you have bad injectors if they are ticking loudly... also have a look at your pump while youre at it and make sure they work if not... save youre money get an aem 300 fuel pump and do a single intank pump

You don't think the 300 will be too much flow on the stock motor? I think its a good idea though. That way the fuel system is ready for the FI. AEM or Aeromotive, I want reliability if i'm gonna spend that much on a pump. Is there any issues with removing the stock filter and replacing with a clear style under hood one. That way I can keep an eye on it and its easier to change.