Cranks, no start, black exhaust

Hi, I am trying to get a 94 geo tracker to start, and it sounds like it’s really trying. The engine keeps sounding like it’s catching, maybe even starting for a split second, but it won’t start and when it sounds like it’s catching there’s a think black smoke coming out of the exhaust. I know that this means I have a very rich fuel mixture and I’m burning way too much gas, but I was wondering what can cause the rich fuel mixture? My ECU is fine, my injectors all pass, fuel pump and regulator are fine.

I know it is also missing an air filter, which is on it’s way but I figured I could at least see if it would start without it. I am hooking up the MAF sensor though, but I left the IAT sensor off. The timing was off for the distributor when I first tried to start it, so it flooded a bit before it got to where it was catching. could that be all it is? too flooded?

Got spark?

Try holding the accelerator down while trying to start it. If it’s flooded the extra air flowing through will purge the excess fuel out. When (and if) it starts ease off the accelerator quickly.

This used to work with flooded carbureted cars but I’ve seen it work with fuel injected cars too, especially with throttle body injection. It’s worth a try.

You should test the injectors. Probably one or more stuck open.

If you were working on this car trying to fix something say, or do some maintenance, then afterward it wouldn’t start so you cranked and cranked, that may have flooded the cylinders with gas. If you think that might be what happened, and this has happened to me too, the best thing to do usually is to remove the spark plugs, all of them, crank it a couple times, then let it sit overnight so the gas can evaporate. When I had this happen on m VW Rabbit, I couldn’t get it to start no matter what I did, but when I did the spark plug thing and a 12 hour wait, upon reinstalling the spark plugs it started as normal on the first attempt.

Hmmm, as a novice, I’m wondering about not having the air temp sensor (if that’s what you meant) connected. I believe it is a main input for the MAF and fuel mix.

If you’re certain that the injectors are pulsing and not being held open and that the fuel pressure regulator diaphragm is not a problem you need to examine the ignition timing very closely.

Hard starting (and black smoke once running) can often mean the timing is retarded too much.

A clogged catalytic converter can also cause many of those symptoms.

@Bing … I wouldn’t expect a disconnected IAT sensor to prevent the engine from starting. At least if I was the person writing that part of the engine computer program, if the IAT showed up as disconnected, I’d just make an assumption for the temperature, like 60 degrees or something innocuous. so the engine would start and run pretty good at most temperatures.

A disconnected IAT should turn on the CEL though, since it probably affects emissions. But it might take several start/run cycles for the code to switch from pending to active.

Does it have enough fuel?

Does it have enough oil?

Have you checked compression . . . if it’s too low, the engine will either not start, or it will take extended cranking before building up enough compression to start

If the compression is indeed too low, it could very well be due to tight valves. Shims on this engine, I believe

I’ll just throw this in. A few years or maybe more ago, one of our more reliable regulars had a problem getting a car started. Everything checked out but the fuel had gone stale. Fresh fuel and the problem was solved.

compression is good, 125 psi on all cylinders. I’m going to try it again today, it’s had time to evaporate so hopefully it’ll be alright. Thank you for your help!

I don’t think the fuel is the problem, it has almost completely new gas in it.