Mandi Jayne Burks

So my husband's best friend did a thing...he knows how much my husband and I are obsessed with his dad's jacked up older chevy. He just so happened to come upon this amazing find. He talked to the lady about the truck and found out that about 15 yrs ago, her son who had owned the truck and was restoring it, died and she couldn't bring herself to get rid of it, so its been sitting in her yard since his death. The truck is a rebuild, with a crate motor 5.7 350, only has 10,000 miles on it. So his best friend bought it & cleaned it up, did an oil change, replaced the fuel pump not assembly, and they added a 3-in lift. Its a dream truck for my husband and I. His friend drove the truck for almost a week about 120 miles or so, it ran amazing for a truck that sat up so long. we drove it home, about 110 miles round trip it drove like a lifted chevy bumpy as hell but fun. We've been driving it for the past 2 weeks, no issues at all. My husband took the truck back on the 110 mile trip to his buddies and back, when he got home he said that the truck started acting up about 20 miles from the house, acting as though it was misfiring. So I tested it out truck started, idled, but could tell it was misfiring. So we did a tune up fuel filter, wires and plugs. Suddenly a truck that has been running for weeks, gone on long trips will crank but not start. Next we tried replacing the ICM, Distributor cap....same issue. So, I think maybe its just outta gas. so we get gas...same issue. Another buddy comes over with a similar truck and says the oil pressure sensor..we replace it. Same issue now the windows also wont roll up. They try testing to see if we get spark and now we have no spark, fire or windows. They test for voltage and nothing, we replace the coil & fuel pump (not with the assembly)....same issue. so I end up going back to get the assembly. clean the gas tank. (and call it a night). I'm praying that the issue is resolved. But we had a 1988 GMC 1500 that had the same issues with a crate motor and we never got the truck to run right again....so im hoping for the best but trying to prepare myself for whats next if this doesn't work. The truck sat for 15 yrs yet fired right up and literally drove until we did a tune up. If this doesn't fix the issue I'm trying to get imput on what else it can be. My husband is broken hearted because he loves this truck. But I'm at a loss for how it went from driving to not in a matter of minutes. No check engine light comes and it doesn't signal any issues what so ever. So now I'm here hoping to get some ideas or thoughts on the issue.

Gumby22

1) Were there any indications of mouse or rodent nesting in the engine bay or cab? If so, thoroughly inspect the wiring harnesses near the nests; and even if there was no indication at all, remove the glove box (2 screws on either side with lid open) and check anyway. The ECM is there and I’ve seen multiple trucks of this era with nests in this location.

2) You don’t mention checking fuses. See if the ECM/IGN and INJ A fuses are good - don’t let your eyes deceive you either - fuses can look good and still be bad. Use a meter or test light to verify.

3) Check for codes anyway - the light doesn’t have to be on for codes to be stored. Jumper pin A to pin B then turn the ignition on and count the check engine light blinks. A pause between blinks indicates different digits (example - blink, pause, blink blink blink, pause, is code 13). DON’T BE FOOLED - the first code you get will be code 12, system pass, and it will repeat 3 times before the next code blinks out. This is normal protocol for the ECM.

Mandi Jayne Burks

There was no rat infestation. Minus the rusted out parts the truck is in decent shape for sitting 15 years the person that swapped the motors left the wires kinda messy but my husband and friend have checked every wire from the engine to the fuel pump,all the grounds are good, all the fuses are working properly, the fuel pump does turn on and weve replaced the wires, plugs, oil pressure sensor, coil, distrub. cap, icm, fuel pump and assembly, by all accounts the truck should fire. But thats not the case, after all this, its drained the battery the automatic windows stopped working and we've tried todo the jumper however we have no check engine light to go on.. so we have everything but fire .

Gumby22

Ok. There’s only so many things that can affect spark, so that narrows it down.

First, fully charge the battery. Don’t attempt further diagnosis using a jump pack or with the charger connected.

Disconnect the 4 wire connector from the ICM at the distributor and Check for spark. If it has spark, the pickup coil in the distributor is bad - I’d recommend just replacing the distributor - a new unit will have the ICM and cap with it so you can save the ICM you bought as a spare.

Mandi Jayne Burks

Well, obviously this is sound advice lol my husband & his buddy..did that exact same thing and were gonna get a distrub. But theres no way in hell were doing it without our machanic present because we had an 88 gmc and wen thru this same thing, and I swear the distrub. was its downfall. we never could get it back in time and it was a nightmare. thank you for your advice the soonest it can be here is monday. I guess we will know if it drives or dies haha

kr4kk13

Im on a 1989 suburban that sat for 8.5 years

this is what I have come to bear witness too......

that made it go from running for 150 miles to not even starting.... Im waiting for oil pressure sensor as we speak cause old one i tore off out of frustration


1. All electrical big wires especially ground ones and ground ribbons. Replace them..... the battery went dead from sitting which causes the wires to accept moisture into the sleeves of plASTIDIP YOU CALL THE protection and allow corrosion to take place causeing them not to do their job what everr that may be.... so battery to frame, to starter, to frame to fireewall off block and from block to frame.....

also run a dedicated ground wire to the fuel pump only after you

drop the tank

remove the fuel assembly and put 3-5 gallons of vinegar cleaning strength white, BLM LOL, and let it sit for two days Toss it around let it eat up all the corrosion in the tank .... pressure wash out and let summer dry its bones...


get vaseline or connetion electricl greease and remove all connections of relays and wire connectors under the hood and inspect for corrosion

inspect the rear of the fuse box, i found two wires one a constant and one intermittent that were melted together behind the fuse box under the dashboard.



after all this don remove fuel line from back of tbi or carb and turn key making sure you got adequate pressuree and flush lines after replacing filter AGAIN cause the minute debri can **** it up again for you

oh year and if its tbi

take the injectors off and reversed spray them out lok up homemade injerctor cleaning kit works perfectly with a tire valve nipple neck rubber sleeve and a can of carb lcleaner and a ir pressure hose....
'

inspect wires if this doesnt work cause you havwe a tear in a the wiring harness somewh4eere....

still no start

try start im limp mode



hotwire fuel relay from battery

disconnect ecm terminal brown and black wire on firewall drivers side
disconnect tps and iac and map
put paperclip jumper in aldl a and b


then start

wont be driveable but at least you know she aint dead.....


good luck



My bitches name is Bourbann....... whats yours???

89 suburban 7.4 L TBI WITH 40k miles

and i have burned up a wiring harness and four fuel pumps and one of every sensor in the last 8 months and driven herless than 200 miles......Not a lemon, jjust a bitch of a chevy

Harryfagina

I had gremlins in my 88. Ripped the intake out a threw it down the driveway. Put an edlebrock rpm manifold on and an old quadrajet and pulled most of the relays and fuses. Runs fine now.