I am sure this has been covered, but I am at a total loss. It will start and run on starting fluid, has good spark, has 40 PSI at the rail, has 12v at red wire at injectors with the key on, attached noid light and I get a pulse but it is very weak, and checked resistance at the injectors and they are 14 ohms. I hope someone can help before I get full coverage and start a fire. I was going to replace the tps thinking that it might be reading clear flood mode, but realized that I wouldn't get pulse at injector, right? Also thought same about ignition module. If it's not working, no pulse right? The weird thing is I'm getting pulse but it is very weak. Please help I have spent days on this and am no closer than I was at the begining.

 

Anyone got any ideas, I'm willing to try anything at this point.

 

sounds like bad grounding. im not positive on your 92, my 88 had a single ground to the battery negative which i had not rehooked and i chased my butt for 3 weeks. also you probably have a eec relay like mine. and mine was shot had weak pulse at noid.

 

Try unplugging the MAP(electricly). Weak noid pulse is evident of a MAP that's giving the ECM incorrect BARO info. Check the center wire on the MAP. Should be around 158 HZ KOEO. Every 3 HZ or so going down equates to about 1000' in elevation. If this didn't make it start, unplugging the vaccum line on the MAP. Connect your mighty vac and draw about 10''. See if it starts then. If it does check your cranking vacuum. Needs to be at least 5''.

 

Ok, I think I may have it. I unplugged the tps thinking that maybe it was reading wot and in flooded mode. It started and ran for 2 sec. then died. Went to the parts store and had to order tps. Will have it tomorrow. This is the closest I've had it to starting yet. I will let you guys know what happens tomorrow.

 

I replaced the tps and nothing. I have the day off today and will try the map suggestions and the eec relay. Held a screwdriver to my ear and the injectors and they all seem to fire equally. changed all the plugs and they smell like gas after cranking. I just dont know. Compression is 120psi cold, as I cant get it to run to warm up.

 

Pull the vacuum hose off the Fuel Pressure Regulator (FPR) and see if any fuel comes out when you crank the cold engine with the coil unhooked.

 

Ok, it runs. I checked the MAP sensor and it was bad so I replaced it. Truck started right up. Its a Christmas frickin' miracle. Thanks for all the help, I don't need full covarage insurance now. :-) You guys are awesome.

 

I have a 1992 ford f super duty that ran fine 2 days ago and the other day went to get in it and it'll crank all day but won't start. I have fuel and I have spark there is just something going on that will not let the fuel pump kick on with the key but if i bypass it it kicks on i have been all throught this truck right down to the inertia switch and nothing has worked any ideas would greatly be appreciated.

 

I am not sure what you are saying.
You say you have spark and fuel and then you say the pump will not click on.

If you are saying when you turn on the key the pump will not start for one second and quit. But if you ground pin #6 of the self-test connector and turn on the key the pump will run.
If this is what you are saying you have either bad wiring from the self-test connector to the computer or a bad computer.

 

unplug map sensor and start your truck then replace the map sensor

 

I unplugged fuel pressure regulator and no fuel came out

 

Start your own thread. This thread is almost 8 years old. Tell us what is happening and what vehicle you are working on.