92 f150 5.0L seems to flood at start up. Need help!!

I just got this truck. It last ran about 6 months ago for one day anyway. Before that it sat for about a year because it had a fuel pressure problem the previous owner could not figure out.

When I got the truck a couple of days ago it had dead battery and a bad solenoid that was open across the power to starter but would click away when the key was turned.

I replaced the battery and solenoid and when I turned the key it started on first try like half of second after turning the key. I was so excited that it cranked I figured the problem must be minor. It ran for like 10 minutes like a champ. It ran rough like it needed a tune up but it ran.

While it was running I switched tanks and the roughness smoothed out considerably. That leaves me to think the gas is bad or or I have a very minor problem with one tank. Maybe a dirty pickup or a bad gasket on top of the tank or bad gas cap.

When I stopped it and tried starting it shortly thereafter, the truck would barely start and when it did black smoke billowed out of it and the raw, unburned fuel odors were noxious. The only wat to start it was holding pedal all the way to floor just like a flooded engine on a carberuted model. Even this did not work unless it sat a couple of minutes. Then it would start again and run rich while billlowing out black smoke.

I performed a KOEO test because it would not restart at that point. I got an 11 which means pass, and a 16, and 18. The 16 is no IDM signal received and 18 is no sprout signal/bad word angle or something like that.

The IDM code seems to imply it is the ignition module.

The only times I had a module fail it was dead and wouldn't run the vehicle. I've never had one that ran the engine great then not run at all.

Another suggestion was the Coolant temp sensor. Does that make sense? I know it controls the fuel among other things.

I know if it gets no fire it will appear it is flooding. But when it starts it smokes black a pretty long time and never really clears up. It is like the problem never goes awy.

Another post said the ECM saw me pushing acccelerator to floor as a command to turn off fuel pumps till it started which may explain why it never would start up again if the pump was off while turning the key. Is this true about pressing gas down?

If the injectors were that bad it should not have run and idled so well the first 10 minutes. So what about the fuel pump relay sticking open sometimes? Is that very likely?

I'm considering replacing the fuel pump relay( ($6.00) and the coolant temp sensor as I'm sure it is about as cheap. I am also buying a fuel pressure test set from Harbor Freight to check the pressure on the rail. I amy also have coil and Ignition module checked at Autozone.

I am looking for help as the searches I pulled up had many of same symptoms but no final results to whether they fixed theirs or not.

I do not want to change three hundred dollars or more of needless parts only to find the problem was simple the whole time.


More info that may or may not be needed.

1992 5.0L engine with 220,000 miles.
Automatic transmission rebuilt
nonexistent muffler and ruptured tail pipe( from raw fuel in pipe and muffler)
Both exhust manifolds are cracked and need to be replaced


Thanks
Scott

OK for daily update now. I bought a fuel pressure tester and I have 39 PSI on one pump and 42 PSI on the other. It bled down on one test very rapidly, but on the thirty or so others it held the whole time.

It also started right up today and ran pretty good. After I shut it down it would not restart no matter what.

I then put an inline spark tester on two of the cylinders while it wouldn't start and both times the light lit about equal to the speed the engine was turning over. So I am getting spark either weak or off time because of the ECT sensor that may be faulty.

Scott

You may have varnish build up in the gas. When this crappy gas sits for some time, it begins to form a varnish in whatever componants it is in (fuel pump,injectors,ect). Sounds like the injectors may not be closing all the way when you turn the engine off, which would allow the fuel to keep spraying until the pressure is depleted. A friend of mine ran into the same problem with his Chevrolet truck. He put a tuned Port Injection engine his project truck and let it sit for a long time. When he got around to try to start it, it would hit a lick, but when he sprayed fuel into the intake, it would breifly run. Turns ou the injectors were clogged with varnish. He went to a local parts store and bought a can of "seafoam" fuel aditive. He poured this stuff into the injector lines and let it soak. Next day, the engine started up, ran rough for a short time, then smothed right out. I would put a whole bootle in with about a 1/4 tank of gas or so and let it run. The seafoam should get rid of the varnish. Hope this works.

Well I'll keep that in mind. I had a pressure guage on the rail and it held pressure after the engine was off 29 of 30 times. Also the first time every day I start it it runs quite well. Today I ran it for nearly 20 minutes and it idled fine. Then I started it a second time and nothing. It just flooded out. I pulled the plugs and they were soaked with gas.

I am going to run some Lucas upper cylinder lube and cleaner through the tank when I get it running correctly.

Thank you for your help,
Scott

Just to let anyone in the future that does a search on this problem, I seemed to have fixed it. I replaced the ECT (electronic coolant Temperature) sensor that is located above the thermostat and it starts now every time. It still runs a little rough but the plugs are covered in fuel and still need to be replaced.

I also have a burned SPOUT from where the previous owner allowed it to sit on the manifold. That may be some problem also, but the check engine light went out so I may leave well enough alone for now till I notice ant timing issues.

Anyway this seems to be a common problem from other posts I read so I hope this will help someone later. The ECT adjusts the air/fuel mixture on start up like a choke would have done. When the temp rises the voltage changes and it runs less rich.

Thanks
Scott