1988 5.7 back firing

[84CUCV]

this is a suburban a friend of the family is looking at. owner said he started it a while ago and it backfired. some small things went on fire. few small hoses. insulation off the wires.

we looked at it. fixed what we needed too. replaced the wires. cranked it with the air cleaner off. second time we cranked it. it fired. saw a fireball form the tbi. nothing caught this time.

what could this be? think the one injector is not working now.

thanks

 

[Stomis]

Check firing order and timing first.

My buddy did a tune up on his TBI chevy and he goofed the firing order up. That thing would throw some wicked flames.

 

[84CUCV]

ok ill start there thanks

 

[84CUCV]

anyone else?

 

[Fabrimacator21]

Does it do it with the air filter on?

 

[84CUCV]

nope didnt try that

 

[84CUCV]

fire order is good. other ideas ?

 

[doop300]

Check and make sure the wires going to the injectors arent open or melted so if or when gas gets on them it wont go up in flames, had it happen while goin down the freeway before, not fun. Other than that its probably your timing.

 

[Stomis]

Yep you definitly missed a melted wire somewhere...

The vacuum should be easy, like 3 hoses but I think the case in hand is that there is something that has been melted, burnt, affected by the fire that you simply overlooked.

Checked your manifold pressure with a gauge. That will tell you if you missed a vacuum line somewhere.

Check the SES connector and see if theres any codes. You may have something erratic thats not showing or possibly a burnt light. Theres a chance the sudden heat possibly could have shorted a MAP or something of that nature.

Start with that and go from there. My money would be on the above poster and say since the injector wires are in the line of fire something happened there.

If its around town i'd be more than willing to come give you a hand one day.

 

[84CUCV]

thanks for the help. sorry truck is up north nj at a friends place

 

[K5dreamer]

dizzy 180* out. either physically or electronically.

I had the wire connectors on the ignition control module backwards on my 1989 RS Camaro with a TBI 305, and it blew fireballs out of the trottle body. exactly as described.

also, a backfire shouldnt cause an engine fire unless there is ALOT of fuel already laying around. If there was enough fuel around to start a fire, im voting for 180* out even more. but it could just be bad timing. try setting it by vacuum in case the timing chain is stretched.

 

[84CUCV]

thanks will be working on it when the rain stops

 

[Stomis]

dizzy 180* out. either physically or electronically.

I had the wire connectors on the ignition control module backwards on my 1989 RS Camaro with a TBI 305, and it blew fireballs out of the trottle body. exactly as described.

also, a backfire shouldnt cause an engine fire unless there is ALOT of fuel already laying around. If there was enough fuel around to start a fire, im voting for 180* out even more. but it could just be bad timing. try setting it by vacuum in case the timing chain is stretched.

Yep this falls under the timing category

My Monte Carlo did this when i swapped it from CCC to mechanical. IDK sometimes you just get unlucky when you roll the dice hoping your on compression stroke.

 

[K5dreamer]

true.... but its kinda like saying youve been in an accident. does that mean you took your foot off the brake, and rolled two inches into a poll? or did you get rear ended by a mack truck. timing can be off by a few degrees..... dizzy 180* out causes fireballs