5.7 hasn't any spark, any sugggestions?

[seeare]

I have a 1992 silverado 5.7 vortec 4x4. I replaced the fuel pump and the fuel hoses, fuel filter, the brakes lines, spark plugs, distributor cap and rotor, coil, general tuneup. I was ready got in crank it over it turns but no spark. I need some suggestions the engine just spins and spins but it doesn't have any fire.

Help please.

[sandorjoben]

It's a Vortec 350 and not a TBI 350? How long have you had the truck? I have a TBI 305 and had a similar problem a few days after I bought the truck, I discovered then a previous owner had wired in a switch that killed power to the fuel injector pod on the throttle body. Have you checked with an inline spark tester to be certain that there's no power going to the plugs?

[seeare]

It is definately a TBI, I guess I don't know what the Vortec means. I suppose it could be a 305, can't tell the difference. But I have pulled the plug and cranked it over, and I have fuel but no fire.

[sandorjoben]

The Vortec engines showed up in "94 I believe and have combustion chambers designed to create a "Vortexing" effect on the fuel air mix for increased power, less pollution, blah blah blah, I believe they also use Sequential Fuel Injection(SFI). 305 and 350 both appear the same on the outside, the only external visual difference I've ever noticed on the two TBI engines is that the air cleaner on the 5L usually has a single wingnut and the 5.7L most often has two.

It sounds like you've replaced just about everything in your ignition system, double check your connections and go from there.

Don't know if you posted this thread in the 88-98 part of the forum, but you might get more help over there, you could also try the electrical or engine/drivetrain section on the forum.

Dave

[RandyP]

His 5.7 TBI should be the same as in an 87 R/V10 Square, and the 88-91 Suburban etc squares. The vortec actually came out in 85 I think? But was only a 4.3 6 cylinder, the real Vortec's came out in 96 in the trucks.

rfmaster is our resident TBI guru, you might pm him and get his attention for in here. I think he's accidentally learned more about TBI motors than I'll ever fathom knowing.

[spudz]

This may sound crazy, but every tbi on the planets ignition model went bad this week at work....... I've never put so many in since I started working on cars. I even bought a s10 the weekend with a 4.3 tbi that was suposed to be a bad motor. ENDED up being the module. I dunno whats going on. Just saying. Its something to look at.

[csb#356]

That's what I was thinking, Ignition module is pretty much the only thing you didn't replace, so may as well. Also make sure you have power going to the distributor itself. check your fuses.

[Don SC]

It does sound like an ignition coil failure. Surprised you didn't replace that too when you put the new coil in. It's right behind the coil. When you checked for fuel flow, did you look into the throttle body to see if gas was flowing down the inside of the throttle body when it was being cranked over?

[seeare]

guess I have a 305 and taking some notes and going back at it. Thanks for you input.

[mooseknuckles]

What about ignition module?.....had a similar prob on my IROC once.

[83burban]

ground strap in for the coil in the cap not replaced?

[primrrd]

did you remember to put that little titty between the coil and cap that makes contact w/ the center of the rotor?
(i forgot to put the rotor in my dodge one time.... i fiddled and fiddled, then finally reached in my pocket and ....DOH.....)

[rayfinseats]

Replace the ignition module. When they go bad, no spark. I have had 2 chevy trucks do that. HEI ignition?

[seeare]

Thank you to everyone looks like the spark is back..changed the pick-up coil inside the distributor.
15.00 dollar part caused all that trouble.