All -
It's been a while since I posted to this group, my ISP dumped Usenet and I have avoided using Google Groups like the plague. But here I am.
I have a 5.0 '89 LX. I've basically replaced the entire drive train. I installed a Ford Racing 5.0 crate motor (M-6007-XEFM) with a M-6250- E303 cam, .498" lift intake and exhaust, duration at .050" is 220 degrees intake and exhaust. It has Ford Racing aluminum GT-40 cylinder heads M-6049-X303 with 1.94" intake valves and 1.54" exhaust valves.
For fuel/air delivery I added 24# injectors, a C&L 70mm throttle body, EGR spacer, C&L 76mm mass air kit calibrated for 24# injectors, K&N open element filter and Typhoon intake.
It has 1 & 5/8" shorty headers, BBK h-pipe and high flow cats, and
2.5" pipes.It also has a new AOD transmission and 3.73 posi gears in the rear.
It runs OK when under throttle, but it doesn't idle worth a crap, and at highway speeds on cruise control it seems like it is surging/ bucking. Sometimes it doesn't want to start, either - I have to crank it and crank it before it will finally fire up.
We've checked and rechecked for vacuum leaks and we're very confident there are none. My mechanic has tested every sensor he can think of, replaced several, everything indicates all is well. It just won't idle or run at a constant speed well. He did say that the plugs were pretty white when he checked them, indicating we're running a little lean. C&L said this is expected since it's running an open air filter
- their intake gear is really designed to run with the stock airbox. Another odd thing which has happened a couple of times is that when I accelerate hard I hear a light backfire - almost more of a loud "poof" than a bang, if that makes any sense, then it blasts off.
My mechanic also bumped the high pressure fuel regulator up from the recommended 38 to more like 43 on the recommendation of a peer of his who does a lot of work on Mustangs.
The last thing we're going to try is to get a programmable chip and have the ECU programmed by a shop here in Austin which has a programmer and a dyno.
Does anyone have any suggestions as to anything else I should look at? I am very hopeful that a reprogram will get this thing to run more civilly. If a new ECU chip still doesn't do it I am considering maybe going to 30# injectors, as Ford Racing said that's what they'd recommend to get the full 340HP from this crate motor.
Honestly, I am much more interested in this thing driving civilly than quarter mile times. It's my daily driver and I'm pushing 40. Good manners are more important to me these days. :-)
Thanks for reading this, Thomas