Kind of strange thing happened. 95 Yukon backfire and lost power.

[Wyo yukon]

We took our new to us, 95 GMC Yukon SLE 4x4 on some forest service roads today. Ran perfect until we turn off a main dirt road to a FS road. It back fired, lost power, no throttle response. then slowly regained everything. Not 1-2 min later it did it again this time she died completely. Only to start right backup we continued up the trail for a bit more than turned around. It ran great all the way home.

it had over 3/4 of a tank for gas. running about 40 # oil press, about 180 degrees, voltage was good. The trail she backfired on was at an incline but nothing that was steeper than we hadn't hit earlier in the day. It is the factory TBI 350 with 249K on her.

I am puzzled on what could be wrong/what caused the backfire. Lost of fuel to the TBI?

Thanks
Tim

 

[OR VietVet]

Suspect fuel pressure problems? Did you check plugs, wires, fuel filter, cap, rotor and any intake leaks? You said is new to you.

 

[Fless]

Moved this thread from the 2000-2006 section.

 

[Eman85]

249k? What do I get if I guess correctly? Star with all of the basics and go from there. Does the CEL work? Did it come on and any codes stored?

 

[Wyo yukon]

@Eman85 you get the satisfaction of helping someone out. LOL. No CEL no codes.

 

[Fless]

@Eman85 you get the satisfaction of helping someone out. LOL. No CEL no codes.

Does the CEL illuminate for a few seconds when you turn the key on? You know, the cluster light bulb test.

 

[Wyo yukon]

yep.

 

[exp500]

How is idle speed? A little hi maybe? Checked for vac leaks?
Where is ignition timing set?#

 

[strutaeng]

"I am puzzled on what could be wrong/what caused the backfire." Well, without any additional testing or diagnostics, so are we. LOL

The TBI are known to have common pick-up coil failures.

My brother once showed at my house pulling his 90 RCSB C1500 saying he needed help pulling his bed because the fuel pump was bad. So we pull the bed, and I ask him how he'd determined it was the fuel pump. He shrugged and basically just blamed it because the truck wouldn't start. SMH

After about 15 minutes spent with a test light and spark tester and a bit of Google (I'm not familiar with the TBI but I'm pretty decent diagnosing electricals), I found the pick-up coil was bad. He looked it up and the part itself was almost as much as a complete distributor that came with a new pick-up coil. So he went to buy one, swapped it and the truck fired up. Not saying that's your problem. Test for spark, then go from there.

Pop your distributor cap and check for crusties, especially of you live in the rustbelt or humid regions.

 

[Eman85]

@Eman85 you get the satisfaction of helping someone out. LOL. No CEL no codes.

I get a lot of satisfaction helping people that help themselves.

 

[Fless]

I get a lot of satisfaction helping people that help themselves.

Quoting my dad: "Can I help you out? Which way did you come in?" Then he'd grin.