Just wanting to know if any of you have the 89 or later 360 trucks and if you have put a better intake manifold on it with the adapater plate to keep the factory tbi and if it's worth the money. Truck runs pretty good but it has a backfire in it at low revs which I believe is a fuel pressure or IAC problem. I also read that the heads on these "pre-mag" engines don't work well with carbs.

 

Had a similar problem with my tbi 318, it was the egr valve . Maybe check that ... The cheapest and most effective upgrade is to make you own intake spacer . If you have a machine available

 

Thx for the reply dirt. I will probably make my own as i have researched and found 2 made out of steel for like 100 bucks and i could whip one up for less than 20. Oh and i dont have an egr any more lol. Friend of mine and myself think it is in the fpr its needs a new one and a filter anyway still has the stock fpr and iac from the factory lol.

 

If you don't have an egr, that could be the problem. The TBI still thinks you do.

 

In the furthering of my education I would like to hear how you think an IAC or fuel pressure problem could cause a backfire.

 

Well if the fuel pressure regulator is bad or going that way then it will intermitently cut fuel pressure to the injectors which will cause a delayed fire or dry fire. As far as yge idle air control i need to replace it because of the poor idle quality sorry i didnt specify that one.

 

In my experience a delayed fire or dry fire will show up as a miss not a backfire. Lack of fuel won't cause a backfire. Back fires are usually caused by timing issues or excessive heat buildup that cause fuel ignition at inappropriate times or in inappropriate places or both.

 

100% correct...a missing EGR, bad IAC, injectors, fuel pressure regulator can not cause back firing.

 

How are your spark plug wires? I had a garbage set of wires on my truck for a while that started cross-firing after a few months. That was no fun. If I got on the throttle hard at low RPMs at would backfire out the tailpipe like none other.

 

Quick check for plug wires. Get a spray bottle of water and mist the wires after dark.