85 eta rough misfire black soot from exhaust

[2.5-12]

haha, yep. mine will actually briefly hydrolock with all the fuel, then start cranking again -- then I get thick white smoke out the back for a few seconds while the cat burns off all of that fresh fuel.

hmm, I am going to probably just order a full set of intake gaskets and o rings and just do it anyways. but I'll start with that small one :p

[crazyman]

Yes it did, alot. Tried to give a tiny bit of throttle to help and the system freaked an almost flooded it. So after that I said f***it and just let it crank till it caught.

[2.5-12]

You have almost the same issues as what I just fixed and it wound up being bad gasket/loose bolts on the cold start injector adapter to the intake(the piece that the cold start injector bolts to). Hope that helps.

good to know -- another vote for vacuum leak.

did your car take a bit of cranking on cold start?

[crazyman]

You have almost the same issues as what I just fixed and it wound up being bad gasket/loose bolts on the cold start injector adapter to the intake(the piece that the cold start injector bolts to). Hope that helps.

[2.5-12]

So, I think that's it for this weekend. I am going to swap the TPS and the 3-4 sensors on the thermostat housing to see if that makes any difference.

(Forgot my smoke machine downtown, derp)

Fuel pressure and fpr behavior are apparently normal, so that's good.

[2.5-12]

so tested fuel pressure at 27psi, but when I removed the vacuum line to the FPR I got a perfect 37psi..

in the video, the fuel pressure spikes when I hit the throttle -- is that normal?

patched the fuel leak and it runs a lot better, attached another video, found a crack in the intake manifold, but its not letting air in.

...havent smoke tested it just yet...

https://www.youtube.com/watch?v=gf9Or2M2Ngs

[dnguyen1963]

I have a similar setup. The output of the fog machine goes into a large enclosed tub. I then use an aquarium pump to pump the smoke into the engine. The small pump is perfect to keep the pressure at about 4 psi. Don't forget to plug the exhaust and intake.

[2.5-12]

I have swapped coils, but I should try another just in case

my winter car is a perfect running eta as well, so I will probably take parts and swap on that to see just because they are known working.

I have a ghetto intake smoker made from a DJ fog machine and some very high temp rated hose, I will smoke test it for giggles. (kinda hope you guys are right on an intake leak coming form nowhere, would be cheap and easy to remmedy)

one thing I just thought of... TPS?

[dnguyen1963]

Not to appease me, but I would be happy if you can get your E30 going again. You might also want to check the ignition coil. A weak coil might not give out a strong spark resulting in rich running condition.

[2.5-12]

I'll smoke test the intake to appease you guys.

anything else in the mean time potentially problematic?

[jlevie]

while this is true, I doubt it would cause the highly rich fuel mixture.

Intake leaks can lean out the mixture to the point that the engine is misfiring, which will result in there being partially burned and unburned fuel in the exhaust. Which will look like the engine has too rich a mixture.

[2.5-12]

ok, lets move on to what I should check besides vacuum leak

it isn't a vacuum leak, I know them well in M20s and this has a different set of behavior.

I will check injectors for impedance and operation with a stethescope

beyond that -- remember it is running filthy pig rich.. sticking cold start injector, improperly flowing fuel injector

I will remove the plugs to see if they are fouled, and to check the gap. probably remove the disto cap again to check and make sure nothing is screwed up there.


anything else to check?

[dnguyen1963]

I listened to your video. I still think you have vacuum leaks. It is worthwhile to look at the injectors to make sure that they are not leaky. Have you removed the spark plugs to see if they are fouled? For troubleshooting E30, it is best to eliminate vacuum leaks before doing anything else.

[2.5-12]

while this is true, I doubt it would cause the highly rich fuel mixture.

[dnguyen1963]

Whenever you work on a 20+ yrs engine, you will undoubtedly jar something loose. Have a smoke test done to find the vacuum leaks. Vacuum leaks can come from many other places beside the intake boot.