My engine is starving for fuel at low RPM, the car hesitates and then jumps at about 25MPH. Can someone tell me WTF is causing this...already replaced the fuel pump and filter and cleaned out the entire fuel system. I really don't want to have to get new fuel injectors at $50 a pop but if that is the problem, I guess I have no choice. Any help or suggestions would be appreciated. Thanx.

 

Daddy-F,

I can only presume that you're talking about your Formy, and it has the TPI engine. Correct me if I'm wrong.

How are the idle speed and quality? If you are going lean at throttle tip-in, that isn't uncommon on TPI cars, but can be minimized by adjusting the throttle minimum air position to the high end of the range. If the throttle plates are fully closed and all idle air is passed by the IAC, the air directly behind the throttles is basically "dead", I.E., not moving at all. On throttle tip-in, the air must suddenly accelerate from "zero" and find it's way around the throttle plates. Since you Air Force guys don't have steam cats, you know how long that can take - you don't hit rotation velocity as soon as the wheel brakes are released...

If you haven't already done so, clean the throttle body. Remove, clean, and lightly lubricate the IAC. Reassemble the TB and set the minimum air position at about 500-550RPM in drive instead of 400-450. This should force some more air around the throttle plates and help alleviate the "dead air" syndrome on tip-in.

If you decide you have an injector issue, don't drop $400 on a set. Check out your options for cleaning and flow-matching instead. I've experienced excellent results with this service from Cruzin' Performance. Typical cost was $10.00 per injector the last time I had is done. The deal used to be that if you had a set cleaned and flow-matched, they would clean the ninth injector (cold start) at no charge. That may have changed, but it is well worth it in any case. You'll also get a good set of 'O' rings and retainer clips back with your set of injectors - worth over $25.00 alone.

If you clean up the TB and get the minimum air set correctly and still have problems, report back and we'll diagnose from there. I have a procedure for testing injector flows that is crude but can be effective.

Incidentally, any other details about what's been done might be helpful (ignition, timing, new parts, etc.).

 

Thanks for all the input. The only thing that I have done to the car sisnce I got in September of this year is put new oem parts on it. So the engine and drive train is still as stock as you can get. I will have to try all that you suggested after I get back from Christmas leave. Thanks again; will definately shoot you a message back.