1992 Chevy Lumina Van Help...

[yamahor]

So, I have a friend who described a problem she'd having with her van, but I haven't heard it myself. She said sounds like a backfire under the hood occasionally. So, what whould cause a Lumina Van V-6 to backfire though the intake? Timing? Carbon buildup? Common lumina van problem? Anything else?

 

[mike04busa]

I would check fuel pressure or the plugs and wires you may be running lean or have a misfire.What year is it anyway?You got my 500th post.

 

[Mr Bogus]

A fast way to narrow issues is a trained ear... disable ignition system and spin the motor over.. does it have a "low hole" unless you know the sound, get a seasoned tech to do this for you. If it sounds like a cylinder is low, plugs need to come out and run a compression test.. From there you can determine whether the valve covers need to come off.(to further diagnose issue)

Knowing "when" it pops is of help too... on the hit, cruising, starting

most common issues:
crossfire (either in cap or between wires)
flat exhaust lobe on cam.. (chevy was notorious for this)
broken/bent/damaged valve train part (either intake or exhaust)
intake valve hung open by debris
Bad alternator diode bridge (pretty rare)
blown gasket between cylinders (pretty rare)

 

[GSXRFANN]

Hey Yamahor, you still seeing that girl? Not trying to be nosey or anything. I just haven't heard any updates. Hope everything is going good for you man!!

 

[riccoh]

if the trained ear doesn't work try taking it into the highest elevation you can find, up the hills that is, and under small incriments of acelerations and darker the better, look for blue sparks coming from the trottle body, there use to be a small problem with the 91-92 tbi system that cause this to damage the injector. this causing it to backfire(injector ball stuck open and the ecu will pull timing-triggered delay and resume spark) and in many cases this was the cause of small engine fires....I still have vivid memories of it... my uncle lost all his hair because of it.... it was funny...

hope this help
if not do what my uncle did.... pushed the ^*&% off the same cliff... just make sure u take your wallet and phone out first... yes 14 years later and I'm still cracking up about this incedent... heck I'm going to call him know ....

 

[Bosshound]

I Have the Perfect Solution. "Get a New Car"

 

[TruWrecks]

If it does it reliably I would check the timing belt. A compression test would be a good first step.

 

[mike04busa]

I't's funny how I asked the year if it was right in the topic.How have you madeout?Does it run ok otherwise?That motor will have a timing chain and not a belt,It would have to have some good miles on it to have been through A chain.(A 92 will have the ing. coils down under the front of the eng.The ing. module is under there also they get bombarded with alot of heat.I am thinking it is a 2.8 litre?

 

[proud dad]

throttle body injection or SFI
some of the eary 90's Lumina vans came with TBI,if it is TBI check the simple things first..check cap,rotor,coil wire, they would burn up under alot of miles[weak spark under load]...and low fuel pressure can cause this also.Alot of things can cause backfire check the easy things first.

 

[yamahor]

Thanks guys. Looks like I'm gonna check plugs and wires for her (or tell her to have her mechanic do it) and go from there.