Was running good then after heavy throttle won't idle and is missing/backfiring
SubscribeI have 400+ miles on new rebuild. The other day I gave car approx. 3/4 throttle from rooling start about 1/4 mile from house...very fun. Had to let off gas and apply heavy brake to not miss turn into driveway. As I pulled into carport engine died and when I restarted it it was missing and did not want to idle. As I applied throttle respnse improved and engine seemed to run okay. As I let off of throttle back to running bad. Looked for vacuum leaks nothing obvious. weather has been bad here and haven't had opportunity to investigate further. ANY suggestions. Thanks!
Senior Member
In my experience, it's been either the fuel pump or distributor control module failing.
I would check the fuel pressure at the rails. Not sure how to check the control module but they should be fairly cheap at your local parts store.
Hope this helps!
I would check the fuel pressure at the rails. Not sure how to check the control module but they should be fairly cheap at your local parts store.
Hope this helps!
You might want to check for a stuck open egr valve or possible broken IAC vavle. I'd check the fuel pressure too.
Member
im kinda havin the same prob with mine...runs ok warm but doesnt idle spectacular..checked my fuel pressure and got 41 when it was off and ab 38 when running....already replaced my IAC valve and have recently put a used distributor in and same prob still....any help? its an 87 TA TPI 305
you need to check your egr valve and make sure it is closed. You may have it disconnected and not in use, but if you have some back pressure in your exhaust i can push open your egr and cause problems. there could also be some build up that has become lodged in there that is keeping it open a little which will cause a bad idle.
Thanks for the replies guys. Had my old ESC (the one in the car is fairly new) and swapped it out this afternoon. No joy. I will look into the EGR this weekend, it starts tomorrow for me. Replaced the 30lb Viper injectors I had installed during the rebuild with 24lb Bosch3s from FIC. When I replaced the plenum it was hitting the top of the egr valve ( this is the first time I had not removed or loosened at least one of the runnertubes). I ground down the bottom of the plenum and barely got it to fit. Think I will pull the plenum for the umpteenth time and check everything again.
Thanks for the input,
Robert
Thanks for the input,
Robert
Found my problem... loose fan belt causing low voltage. Engine has March billet brackets and pulleys, but they didn't offer one for smog pump. Made my own and it is flexing. Back to drawing board.
Found problem...lose fan belt causing low voltage at idle. Engine has March billet brackets and pulleys, but kit didn't come with smog pump bracket. Built my own and it appears to be flexing. Back to drawing board!
Good luck.
Tags backfiring, heavy, idle, lt1
