I've been off-roading for over 20 years and had several modified Jeeps with various motors. I recently purchased a Jeep CJ7 that already had a 1993 Chevy C1500 TBI 5.7 motor in it. Guy who had it wheeled all over the Southeast and out West. He let it sit in his basement for a couple years due to his work travel schedule. He decided to sell and went to fire it up. It would idle fine but he couldn't even drive it up the driveway (on a hill) as it would stall when you gave it gas. Now you could rev the motor all you want sitting still but once in gear (it's a manual - SM465) and gave it gas it had no power.
I pulled the trigger and bought it at a discounted price. I got it home and replaced the fuel filter (it was pretty dirty!). It ran better but still had power issues and would throw a Code 42. I replaced the EST circuit and ignition module. No change. Played with the motor for several weeks with new injectors, map sensor, IAC, fuel regulator, TBI rebuild, knock sensor. Checked all wires for open loop, bad ground. Added more engine grounds (body to frame, body to battery, frame to battery, etc). Forgot to mention, the timing was checked (set to 0 with bypass wire disconnected) I replaced the computer (16146299). Transferred the AWLB chip to the new computer. (There is not catalytic converter and muffler was taken off and run to see if there was an obstruction in it as well.) A couple weeks ago I went for a test drive in the neighborhood and all of a sudden I had POWER! The throttle had a lull in it but it would GO! Ocassionally it sputtered when I got on the throttle but would get it. The next few days it went right back to normal. NO POWER.
I broke down and took to a mechanic. He was stumped. He said the best he could get it to run was disconnecting the bypass wire and advancing the timing (basically eliminating the computer control).
Since I planned on do a major overhaul on the Jeep I began tear-down. I pulled the cage, built a new dash with all new auto-meter gauges, put in new fuel cell (along with all new fuel lines), new carter p5001 fuel pump, new crate motor from Summit (replaced with same motor, stock 5.7 TBI) and installed a Painless wire harness (wanted to eliminate any wire issues). I even got a new eprom and installed it just in case the old one had gone bad. I have a fuel pressure gauge on the back of the TBI (supply side of course) and it stays at 12 PSI. I tried an adjustable FPR, but turned all the way down it was at 14-15. The motor is running rich.
Like I said before it will start right up and idle (even though it doesn't sound like a healthy idle) but when you try to drive it, no power. It will also backfire through the exhaust when you give it quick throttle. Painless calls for using the 1227747 ECM, with ASDU eprom and 16060836 calpak. I have the ECM and eprom and I'm waiting on the calpak to come in the mail. I'm gonna try the new computer/chips and keep my fingers crossed but doubtful.
Any reccommendations?
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