[slayton93]

My car is really starting to stump me, it is a brand new engine with 334 miles on the clock and hasnt run right the entire life of it. the car always hesitates no matter what, i give it gas and it doesnt even have its full amount of power and barely responds. i have replaced the fuel filter, pump, ignition coil, tfi module, checked for vacuum leaks, had it tuned, timing set to 12*. The car runs really hot. then the other day it was still hesitating and such but then i shut it off, had lunch and went to go home and it started running really bad, it would not keep a steady idle on the tach, the tach was flying EVERYWHERE. ive never seen it fly around so much. the idle was not really changing though. it is also pulling low vacuum for some reason, about 10 pounds and also backfires when it gets hot and i let off the gas. it is supposed to be 440hp at the crank and it is real far from that. it has the tfs stage 1 cam so im not totally sure what timing is supposed to be at. please help someone i really wanna drive this without having to worry about it breaking down and this annoying hesitation, thank you everyone.

 

[93ksstang]

First things first you need to see if it has any codes being thrown and see what they are. Also I would check and make sure your dizzy isn't 180 degrees out. It sounds like the timing is out of wack but if you had it tuned on a dyno they should have known something was wrong then and fixes it not tuned it. Was this a crate engine or did you have it assembled?

 

[slayton93]

i will remove the dizzy and put it to tdc and try that, also it was assembled as a long block in rhode island, rest was done by me

 

[chc_1989]

Are you running cats on your car?

 

[jmast]

Don't dicount the tfi because it's new. I bought a new one that turned out to be defective. I had the same problems, crazy idle, crazy hesitation, and crazy tach. turned out to be the tfi that I just bought (Accel). The tfi, coil, tach, and computer share a common curcuit. This is the wire coming off the neg terminal on the coil. It also has a 22K ohm resistor in it that sometimes fails. But the first thing you want to do is run a self test and pull codes. That will give you an idea of where to look and probably save you time and money so you don't end up chasing a ghost (like I did). Also, start your troubleshooting easy, check for proper grounds, loose connections, etc.

 

[Smurf stang]

All good suggestions by 93k and jmast. Also my car had a little problem like that and my tach was acting funny for a few days till one day it just quit. It turned out to be my MSD box died on me so if you are running one check it out also.

 

[Dajerseyrat]

The running hot and backfiring sound like it is out of time on the dizz. Had the same issue with my SBC motor. Was one or 2 teeth off on the dizzy.

 

[slayton93]

i have come to figure out i think i need an adjustable fpr and bump the pressure up a few lbs. checked the plugs and all looked lean, it also backfires thro the intake indication a lean condition

 

[jmast]

What was your fuel pressure? Also, did u pull codes? You don't need a scanner for this, just a paperclip. We're talking about a 93 right?

 

[Smurf stang]

The stock fuel pressure regulator is more than adequate to do the job and the backfiring out of the intake doesn't sound fuel related.

Did you pull the codes yet?!?!?!?

 

[93ksstang]

Back firing through your intake is a timing issue. Not a fuel issue. Just because its newcomponents doesn't mean they are good. Some thing is off or not working properly. Also when you adjusted the timing did you pull the spout out to adjust it. If you put the distributor in then tried to adjust the timing without pulling the spout the as soon as you left it alone the computer would compensate and move back to what the timing was of you dropping it in.

 

[slayton93]

removed spark plug 2 and 6 because the rotor is facing directly in the middle of them both, put a screw driver in six and there was nothing at all, put the screw driver in 2 and the piston was up past the spark plug hole, could this mean the distributor is off a few teeth?