Hello, all i am new here so please forgive me for any retarded questions i may ask. However, i bought this 1991 GMC , it had a 1998 5.7 put in with the computer from the same truck motor came from. It is a 5 speed manual transmission. when i bought the truck, i drove it home, put 20.00 gas in it, drove to work and home for about a week or two. my wife talked me into filling it up with gas, so i did. drove it prob 2-3 days. it started banging out while driving. the more i drove it the worse it got.
Here is the problem to jump ahead of all that took place, i checked the fuel pressure, showed 60 psi at initial crank, dropped to 50-55 psi. i pulled upper intake off, changed out the fuel regulator, put new gaskets in upper intake when i put it back together. there was rust looking stuff on the regulator screen, cleaned all the gunk and rust out installed new regulator. checked fuel filter, was clean as a whistle. cranked truck, ran good for about a mile. thought was fixed headed back home it started back acting as it did before. with my memory from past project i worked on. I unplugged the Air mass flow sensor with my hand over the sensor it seamed to stop banging out. ran to parts store and got a new one. put it on drove to work, left that night, hard to start. once started done great about 2 miles down the road started banging out as if it was running out of gas, then catch back up. made it home, changed the fuel >>>pump<<< out. okay now it want run. At one minute, i could pour gas in the throttle body and it would crank but die directly after it ran out. i thought for a minute that the spider assy, was bad costing $300 i was weary about changing it out. so i had a friend to come over take a look at it, pulled #1 plug out, was gas fouled badly. so i replaced the plugs , cap and rotor as the rotor and cap had some wear in it. now the truck is not firing but i can hear the fuel pump coming on, i can hear the spider assembly coming on while leaning over the motor.

Cap of all i changed out.

1) fuel regulator
2) Air mass flow sensor
3) Fuel pump
4) New cap
5) New rotor
6) new AC Delco Rapid fire plugs.

Went a few to pick up a crank sensor, and cam sensor. Any ideas what i am over looking or helpful ideas what to look for to do? Its driving me nuts

 

Changes the crank sensor this morning, I have fire now with the battery dead waiting on to charge.
I see 21 views but no comment ?? No clue guys? I'm open to any suggestions

 

Ok, so I changed my crank sensor and cam sensor, however after I did this, I checked my fire, perfect but still want run. I can pour gas into throttle body it will idle until it runs out of gas, so my next step is pulling off upper intake for the third time to remove the injector from the hole n see if they are spraying out gas, with the ignition coil unhooked of course,

 

Well it's a little easier to just pull out a spark plug and see if it's wet. If the plug is wet, then it's getting gas. If it's not wet, suspect power to the injectors being an issue. Check all your fuses, recheck fuel pressure. Use a spark tester to test for spark.

Considering your truck is has a vortec engine, make sure your distributor is setup properly. Make sure that when the engine is in the #1 firing position, the rotor on the distributor is pointing to the #8 stamped into the distributor housing.

 

Thanks for the response nullhead, the plugs are dry, I have not touched the timing so it should be fine. Ill have to rerent fuel pressure gauge to recheck it. I checked the plug that goes to the injector system. On each section one side or the other is hot, I'm assuming the other is the ground to complete the circuit. Was looking for a noid light to verify and be certain that the injectors should is get the fire as it should. After doing some research found some saying how to make one then found one saying you can use a test light to perform the test. So this morning I did, I could only check one as its hell doing this by yourself. It gave me my blinks as it should of.

Fire
Fuel
Air
Compression

Is the four factors that makes an engine run, I have verified all but fuel, if there is any other way to check this spider mechanism anyone know of please let me know. I do know that the computer sends the pulses to each injector. If that's working its leading me to my spider assembly. The only way I know to check it is to undo all injectors in the upper intake to see I it's actually spraying fuel or not??? Any more ideas?

 

Or could the spider thingy be air locked? By any chance? What I have read it's just a type of relay????

 

Well today I am unable to tinker with my truck due to working 12's at my job. Dropped by autozone this morning to check out this noid light, they had a set to rent, so I grabbed it so I can verify my computer is working properly. Hope I can try it in the morning ��

 

Wish you were nearby I'd love to check out the wiring of your ECM. That's the only thing stopping me from firing up my truck

 

Well, I rented the noid lights that costed 27.50. Yesterday morning checked my plug for consistent pulse to my injector assembly. A note I would like too add, the ignition coil has to be plugged up to get the computer to send your pulses. I'm still confused about that. But it is what it is. So knowing that I have fire going to my injectors, I call around for prices on the injector assembly,
Auto zone 299.99 one year warranty
Oreilys 320.00. One year warranty
Napa. 399.00 inc tax , 3 year warranty

Think I'm going with napa Friday morning for the warranty .


Ill post my results then. Wished I knew how too add videos or pics here if available

 

What about my ECM wiring do you need perhaps I can try to help ??