94 k1500 intermittently dies under load

[Spankbank850]

Hey guys newb to the forum here and this 94 has got me fooled! For starters it's a 94 5.7 tbi motor. 4x4 4l60. 310k miles completely stock other than exhaust. It started about a month ago when the truck would die on me when I was in OD lugging up hills. I would be able to get out and tap on the fuel filter and pump, fire it up and go on about my day. Easy fix. Replaced the fuel pump and filter. Got the whole unit and not the rebuild kit. Well it didn't stop my issue. So I moved to spark. Replaced coil, plugs, wires, cap, rotor"accel brand", & ignition control module. Still having the same issue. Just dies whenever it feels like it. I'll let it sit for a minute and it'll fire back up and drive. Sometimes for 30 feet and sometimes all the way home. Thinking I should check all the grounds maybe something is getting an intermittent bad connection? Unplugged the egr vacuum line and pig tail at idle with not change in idle. Truck has gutted cats. Idk guys I'm stumped. I appreciate any tips or info yall might have.

Edit.. I'm no longer having the problem only under heavy load. It'll just randomly die now but never at idle.

 

[movietvet]

Welcome to the forum from Oregon

How does it die? Is it like it is starving for fuel, chugging? Or it shuts off like a light switch? Any CEL? When the egr is unhooked, what does it do when driving?

 

[Spankbank850]

Man it honestly acts like it's starving for fuel. As it's trying to shut off if I pat the gas it acts like it's running out of gas. It's not like I cut the ignition off. But it'll also back fire through the exhaust sometimes right before it dies. Haven't tried driving with the egr unhooked yet, and you'll have to forgive me man, I'm not sure what CEL stands for off the top of my head.

 

[Spankbank850]

Also I haven't pulled the throttle body and cleaned/rebuilt it yet. Should probably eliminate that issue as well

 

[scott2093]

I'm not sure what CEL stands for off the top of my head

Check engine light
a.k.a.
SES
Service Engine Soon

Have you tried jumpering the aldl connector to see if any codes are stored?

Best would be to crab a real scanner and see what the data says but, maybe you have codes stored that could tell you......

goofy Engine coolant temperature sensor will cause all kinds of problems too....but there are so many things..... should start trying to peek to see if computer is telling you something....

 

[Spankbank850]

Ahh DUh. LOL yeah it'll come on and shut off randomly. I didn't know that about the temp sensor. Tried to use a cheepo obd1 scanner and couldn't get it to read anything. I'm 90 percent sure that temp sensor needs changing. The gaauge has been kind of funky since I've owned it.

 

[Spankbank850]

Check engine light
a.k.a.
SES
Service Engine Soon

Have you tried jumpering the aldl connector to see if any codes are stored?

Best would be to crab a real scanner and see what the data says but, maybe you have codes stored that could tell you......

goofy Engine coolant temperature sensor will cause all kinds of problems too....but there are so many things..... should start trying to peek to see if computer is telling you something....

I'll hit the search bar and see If I can find out how to jump that aldl and find the stored codes. Thanks for the info

 

[Spankbank850]

Welcome to the forum from Oregon

How does it die? Is it like it is starving for fuel, chugging? Or it shuts off like a light switch? Any CEL? When the egr is unhooked, what does it do when driving?

Sorry bud just realized I didn't actually reply to you so wasn't sure if you got the notification.

 

[movietvet]

I got it. You can unplug the temp "sensor" and see what happens and you can pull the IAC valve and check the pintle and clean and use carb clean when you do. The port where the pintle moves is also known for carbon build up and can be cleaned.

You have a coolant temp sensor for the fuel injection system. Acts like a choke. You have a coolant temp sender that feeds info to gauge. The sensor will be right at the thermostat housing. The chugging feeling is a classic sign of a fuel delivery problem and even though you have a new fuel pump and filter, there still may be fuel delivery system components causing problems.

 

[Spankbank850]

FYI. There are two temp sensors on these engines. One in the driver side head for the temp gauge and one on the intake manifold next to the thermostat housing for the engine pc. They do not share functions.

FYI. There are two temp sensors on these engines. One in the driver side head for the temp gauge and one on the intake manifold next to the thermostat housing for the engine pc. They do not share functions.

Sounds like I need to replace both then if the gauge is acting up. Thanks for the info boss