Just to let everyone know, I worked on helicopter engines in the Army but have NO IDEA what I'm doing when it comes to my truck engine but am slowly learning. So, if I sound stupid......... First my truck began to shut off at idle and would restart easily but would stall again at acceleration. Also, when going up any incline what-so-ever the acceleration went WAY down. Real bad when driving 40 mph on a 65 mph highway.
Took it to the parts store and was told that it was a bad TPS. We even plugged in the TPS to the socket in the parking lot and the engine went from sputtering to purring. Replaced the TPS and now the truck will not start at all. Read the codes and got 22 & 122. 122 concerns the TPS so I ignored it but the 22 indicated the MAP sensor. Replaced it. Still won't start. Took voltmeter readings and TPS was fine but only half the correct voltage was at the MAP. Maybe I checked it wrong?? Replaced spark plugs today. Got to the last plug on the driver's side firewall and fuel was dripping from the tip. Is this right? I'm wondering if maybe I have a leaking fuel injector and flooded engine. What do you think? Please help. This is my only mode of trans and it's been down for two weeks. Too broke for professional repair shop. Besides I like doing it myself.

 

Also, I forgot to add that the truck is EFI and that I went through a tank of gas in a day and a half before I got to the parts store.

 

sounds to me like atleast one sticking injector. Also, you didn't say whether or not you replaced the map sensor. Also did you check the tps for the proper adjustment. All these ?'s just so we can be sure what to suggest next.... good luck.

 

I did replace the MAP and we adjusted the TPS so that it showed 1 volt per the Haynes Manual. It's not the adjustable kind but it said to rotate it until the output voltage was 1 volt.
If my engine is severly flooded how do I go about clearing it? I have already tried cranking it while pushing the gas pedal to the floor and that didn't work. I saw on a web site that you can pull a couple plugs and lightly stuff some rags in the holes and when you crank it the fuel will shoot out into the rags. Has anyone ever had to do this? I guess my main goal at this time is to just get it to start.

 

I dont think its the injectors at all... Injectors rarely go, I would guess your fuel pump is too weak to run the vehicle ... check the psi delivered to the fuel rails. I had that problem with my I6... Try the second tank if you have one, replace the fuel filter and try it. If not buy a new fuel pump and it should run... If one cylinder is flooded doesnt mean the other 5 will not get the engine going. So a sticking injector is out. Id go with a fuel pressure problem.

 

HEY I'M NEW TO THIS SITE BUT YOU DID NOT SAY IF IT WAS FIRING OR NOT.IF IT AIN'T YOU MIGHT START AT THE COIL OR CHECK AND MAKE SURE IT HAS NOT JUMPED TIME.IF IT HAS IT WOULD PROBABLE BE BACKFIRING.I HAVE ALSO SEEN THE MODULE IN THE DISTRIBUTOR GO BAD.YOU CAN TAKE IT OFF AND CARRY IT TO A PARTS STORE TO HAVE IT CHECKED.

 

It is cranking but not starting. Is that what you mean by firing? If you work on it for long periods of time though it stops cranking and just clicks. Then if you go back to it later it cranks again.
I guess I'll have to go get a fuel pressure tester kit tomorrow. Does anyone know exactly where the Schrader valve is? I know it's on the fuel rail, has a cap on it, and is similar to a tire valve (so Haynes says) but I don't think I even know where the fuel rail is. The manual is not real clear on that.

 

Take out a plug wire and get someone to watch it while you crank the truck. Put the wire near the header or another metal piece with a good ground. You should see a blue arc to the metal from the plug wire. If you don't have spark, fix that first. The schrader valve is on the drivers side just behind the distributor.

 

The Shrader valve on my 90 is a couple of inches behind the distributor on the driver side. Firing means that you get occasional combustion when you crank it, or that the plugs "spark" depending on the context. In this case it could mean either. I'd go back to what you were doing just before it stopped running at all, and be sure you have it right.

 

NO TO THE REPLY. I WAS WANTING TO KNOW IF IT WAS GETTING A SPARK AT THE SPARK PLUGS.ON EFI ENGINES THE FUEL RAIL IS ON THE TOP OF THE INTAKE DIRECTLY ON TOP OF THE INJECTORS.MY BRONCO'S ARE CHROME TUBES AND THE SCHRADER VALVE IS ON THE RIGHT SIDE STANDING IN FRONT OF THE GRILLE LOOKING AT THE ENGINE.

 

Ya know, Jim, that's exactly what I thought. You don't just put in a TPS and then it not be able to start at all. It started just fine before so I figured the TPS was put in wrong (boyfriend installed it, yes I'm female) but we were all over the TPS with the multimeter and every test listed in the Haynes checked out exactly correct. That's why I was thinking it might be badly flooded and maybe the sputtering/stalling/slowing under a load and the fact that it won't start weren't necessarily linked. On the other hand, I'm wondering if maybe one caused the other.
Tomorrow I'm gonna switch fuel tanks and try to start it. If it's a no go, then pull a plug wire to check for the blue arc. If I've got that then it's off to Autozone for the fuel pressure tester. Any other suggestions are definately welcome. Thanks to all who have given help so far!

 

These trucks in my experience are bad about fouling that no 8 plug. What I learned working at the ford dealer is that most often it is just the poorly designed pcv valve going into the no 8 intake runner. Is it possible it was oil and not fuel?
Also the symptoms you describe , if it was fuel on the plug, sound an awful lot like a completely melted burned out cat. did it smell weird at all before it died? The haynes manual says how to test forr it. Just throwing ideas out there but I would really suspect the cat if you were dumping fuel. It trashes them in a hurry. a melted down cat from fuel problems often will not let the engine start and will also give a false code for the map sensor due to the engine vaccume being messsed up real bad.

 

Okay, I definately have fire. I checked the plug wires as described above and shocked myself. Thanks for for that. Anyway, I bought a Fuel Pressure tester today but it was too dark to use it by the time I got off work. I'll try it tomorrow. No strange smell and I'm pretty sure it was fuel. It definately smelled like fuel and seemed to be more like the consistance of fuel versus oil. I'm assuming cat means catalytic converter?