1990 F-250 5.8 EFI manual trans.
Will not start
Left for work this morning, barely made it out the drive way and the truck stalled as I was putting it in second gear. (I was rolling from 1st to second)
Tried starting it, wouldn't start. Got mad, cranked it and pressed the gas peddle up and down like a carb, got it to start and rev up, but it sounded choked down and would not stay running. Pushed it back into the driveway and got a ride to work. After work I took out my OBD1 code reader, went ahead and ran the codes doing a KOEO (key on engine off), keep in mind the engine was cold at this point, threw codes 21 and 24 coolant sensor and Intake temp sensor out of range, separator code 10 and continuous memory code 11.
I went ahead and replaced my fuel filter to see if I was getting any blockages, needed to be done anyways. For the last 100 miles before the engine shut off on me it acted like it had no power, only sometimes. other times it would have power, but its always felt like it could give me more than what it was given me. I was going to address this issue next week, but it looks like I have no other choice but to figure it out now.
I tried starting it an hour ago, it'll pop a little bit out the tail pipe but won't fire.
Tomorrow I will check for spark at the plug boots to spark plugs. Wires and Distributor/TFI(or IDM)(WAI Global) have about 600miles on them, motor is brand new too, 600 miles. All sensors new besides Throttle Position Sensor, Idle air Control and O2 sensor.
I will be testing the pressure at the fuel rail if I can get myself to the tool rental. Don't remember what values I need to be looking for, about 30 IIRC.
Please get back to me with some inputs, thanks!

 

 

Just completed the fuel pressure test with the KOEO, fuel pressure at the rail is 40psi, but takes 4 key cycles to get there, maxes around 42psi (7 cycles), bleeds off about 1 psi per minute. Pulled the FPR vac line, no fuel in the vacuum line or coming out the vac port on the FPR. I think I will move onto ignition. One thing that concerned me, here is a picture of the fuel quality coming out of the rail.

I almost thought it was diesel, with its diesel like color. Does not smell like diesel to me, and it lights well in the firepit!

 

what does it smell like, gas, diesel, or varnish?
it almost looks like you have a tank of bad fuel.

 

Yes it almost does look like a bad tank of gas… it smells like fuel to me, gasoline. It burns well too. I did fill up last night, I’m gonna call the gas station and see if they know, if not I can get a sample from them and show you guys what I put in the tank.

 

well, diesel burns good too once lit. i wonder if it is a mix of diesel and gas?

 

It could be yea. Are there any rudimentary tests I can run to determine if it is diesel? It lit fine with a lighter, is what i meant, I just used my firepit (that was not lit) to be safe.

 

Did your fuel pressure change when you cranked it?

 

damn I don’t know why I didn’t think of doing that… I’ll go pick up that test kit again. I’ll be kicking myself all the way to the store for that. I might make a trip to that gas station a little later, I’m gonna grab a sample from the pump.

 

All right I tested pressure at the rail. I am using one of those O'reilly's rental tools and I know that with these testers you cant have them too tight or they take too long to read, and if they are too loose they will leak. I think i got the sweet spot, here goes the results of the test. Cycled the key 4 times to get to 40 psi, held, then when I cranked, the pressure needle slowly dropped to 21 psi in about 6 seconds of cranking, and stayed there. This test was done using the rear tank fuel pump. Here are the results of the front tank fuel pump. cycled the key 3 times, KOEO pressure was 38psi, when cranking, pressure stayed at 37-38psi.
Sounds like my FPR is okay, and my rear fuel pump is failing, but my front pump is good, and the truck still wont start, but it will pop here and there out the tailpipe.

 

Have you checked timing? Popping through the exhaust is one symptom of timing. I would not try anything on the tank with whatever that is in it. It needs to be siphoned out.

 

I checked for spark and it’s weird, sometimes I can get spark, but most of the time there’s no spark at all. I even went as far as pulling the spark plug wire off the spark plug, stuck a screwdriver in there and held my fingers to it, tried grounding it that way to metal as well, no spark. Super strange. Starting to sound like a failing TFI, I’ll check timing and spark on all cylinders. I’ll see what I can do about shyphoning 15gallons.

 

For some reason aftermarket ignition modules have a terrible reliability record. Do you have the old distributor to try?

 

OK disconnect your spout and see if spark returns. You can always take the truck to a shop to have them siphon the gas AFTER you get it running.

 

okay I think it’s the TFI, I’m not getting spark at all, and when I do it’s extremely weak. I checked my timing and it seemed to have slipped, it was pointed towards cyl8 on the cap at 10BTDC. Reset the timing to 10BTDC at cyl 1 on the cap, I have a feeling it’s that TFI, coupled with the timing being off. This truck is such a pain! I’m gonna test the TFI and then replace it with a spare I have hanging around to see if it fires