backfire at start up?

[tigmaned]

this was the first time my 86 has done this?? got home from work and want to move the vette and at start up it backfired, i turn the kep to off position and then re started and was fine?? is this a sign my timing is off?

 

[RWDsmoke]

From my experience, Ignition problems usually cause it to pop throught the exhaust, and the coil would be my first guess. Timing would have to be way off to cause that and then it would do it all the time. If it pops through the intake it's usually a lean condition, and I would start with a fuel pressure check. Fuel pump seems to be the most likely suspect.

 

[froggy47]

My 96 did that a few weeks ago, nothing since. I'd ignore it unless it happens on a regular basis.


My ck eng light came on & went off by itself a couple of days later.

 

[tigmaned]

thanks for the advice, that is one thing i have been delaying, is check the fuel pressure? not sure why it should only take a second?

 

[froggy47]

No problem to ck it, my small understanding of backfires is that it's usually electrical & timing related.

I'm just saying not to start throwing parts at it unless it happens some more.

Of course if you are due for plugs & wires (like me) I'd go for it.

 

[tigmaned]

yeah you know tonight i started it 3 times shut it off and didn't do it? hey she almost old enough to drink, but she starts!! working on changeing out the power steering fuild, it gray looking right now! i don't feel like opening up the system so i am pumping out the old grey looking fuild and puting more in, run it and turn wheels left to right 20 times, shut off and do it again. hey its only $2 something a quart. its almost all clean now, a little more driving and i'll check it again and do it more to get some lucas power steering fuild in it.

 

[Vettefan87]

Did it backfire through up through the intake? Or out through the exhaust?

 

[tigmaned]

not sure, i had the hood down and was seating on the sill? it almost sounded like it was in front of me? but not real sure? exhaust leak maybe?

 

[froggy47]

yeah you know tonight i started it 3 times shut it off and didn't do it?

It has to be a full cold start/warm up/shut down/ Like overnight.