88 Shelby Problems

[1993CobraGT40]

I have an 88 Shelby Daytona with issues. The car was the in-laws daily driver until the timing belt went out 4 years ago. The car has sat until I recently replaced the timing belt but it does not run right. It idles fine but when you rev it up it starts to pop and runs rich. Once it won't rev past 3500 without losing all power. The car is timed correctly as we checked this several times and everything lines up. It has fresh fuel, plugs, wires, cap, rotor and HAP. The computer is also new. I could not find any vaccuum leaks. Any suggestions would be appreciated. Thanks

Robert

[NAJ]

First be sure all basics are correct,ignition timing,firing order,spark at all 4 cylinders, etc.
Then check to see if any fault codes are set.
If all of the basics are correct and there are no faults your problem is mechanical.

[mwrenn]

You put fresh gasoline in right?

[1993CobraGT40]

Yep, I've got fresh gas in the tank. I haven't checked the codes yet but spark is good to all four cylinders, firing order correct, timing perfect. Could the wastegate potentially be a problem if it is stuck or not working properly? Unfamiliar with turbo's but was curious about the wastegate. Thanks

[85boostbox]

when you timed it did you unplug the coolant temp sensor time it and the plug it back in

[mwrenn]

I doubt if it's the wastegate at this point, all that does is control the amount of boost.

Do you know if your getting good fuel pressure at the rail? I would be a little suspicious of the fuel pump after the car sat that long, wouldn't hurt to change the fuel filter too if you haven't already done so. I don't have my book here at home to give you a fuel pressure value, NAJ could help with that. There is a schrader valve on the rail to hook a pressure gauge to.

If it idles ok then starts missing under load, I would suspect plug wires, but those are new. I just keep coming back to the fuel, after you've checked all the ignition system, the fact that it idles ok then won't rev, has me scratching my head. LOL
Where did you get the new computer for it?

[1993CobraGT40]

I can't say if we pulled the sensor off or not. I will go back out and re-time and pull it off. What exactly does it do?

[impuresoul2k3]

sets the computer/ecu in a limp mode which causes the timing not to jump around like it does with the CTS plugged in

[1993CobraGT40]

I forgot to list it but I do have a new pump/filter installed already. The ECU came from NAPA. The plugs seem black/sooty which leads me to think fuel as well. The car rpm's "surge" when you get up around 3,000-3,500

[mwrenn]

The other thing that occurs to me is a faulty or intermittent ground on the injector harness. Long shot but easy to check. I don't know anything about the NAPA ECU. I've always stuck with NOS Mopar or one of the vendors on this site for my calibrations.
Why did you replace the ECU? I wonder if you could plug in the old one and see how it runs.

[GLHNSLHT2]

napa reman scary. Seen one on a VNT car and the boost was so slow to spool it was sad.

[1993CobraGT40]

I will check the grounds again to make sure. I have had the car for a year and put the belt in when I first got it. I deployed to Afghanistan and just now able to work on the car again. At the time it didn't run right after changing the belt and an "expert" told me the ECU's go out all the time sooooo, long story short I didn't do enough research and dropped the money for a new ECU. I gave them the old one becasue the core charge was substanial. I probably should have stayed away from a reman but.......

[NAJ]

I posted the service manual page for the Ignition timing procedure.
Static rail pressure is 53-57 psi and should hold,if it drops suddenly there is a problem.With the engine running rail pressure will drop 1 psi for every 2" hg applied to the FPR and increase 1 psi per 1 lb of boost.

[1993CobraGT40]

Well timed it again with the coolant temp sensor pulled and same problem. The boost gauge nudges just over 0 and it falls off from there. Looking at the turbo the rod from the vaccuum canister to turbo/waste gate does not move at all. Manually grabbing it you cannot move it, like it is stuck in place. Any thoughts? Thanks

Robert

[GLHNSLHT2]

the car should run and idle fine even if the wastegate was stuck shut.