I have issues.......

[Dan B.]

I have ALL sorts of issues but the ones I need SCS help with are pushrod 5.0L related!!


Recently finished the HO conversion on my 1988 T-bird Sport Coupe. I put in a '88 Mustang GT motor, Explorer upper/lower intake, 70mm BBK TB/EGR, under drive pulleys, 1-5/8" shorties, 2.5" BBK offroad H, Flowmaster mufflers. Also used stock HO injectors (orange top) and a BBK FPR w/ gauge. The car also still runs SD w/ a DA9 computer and T5, I did not do the MAF conversion.

Here's the problems.


First....high idle. It hold steady at 1200rpm. Today I tore the intake off to search for vaccum leaks and found none....all the lines are either hooked up or plugged if not used. Also cleaned the TB, IAC and blocked off the EGR (it was in the way of the FP gauge). I adjusted the throttle screw and it did not help.


Second...it's got a sputter. When setting still at idle (1200rpm) it sounds like it has a miss. The FP is steady at 39#, drops to mid 30's when floored. When adding fuel and setting still (under no load) the sputter is mid-RPM (2500-ish) but floor it then it rips to 6K. The other sputter is driving....when accelerating smooth it goes along good. Floor it and the car goes flat, not fall on its face flat, but just does not go any faster. Back off the pedal a little bit and it picks up smooth.

I also tried to check the TPS voltage today. It was reading 1.7-1.9. I know it should be .98-.99. The idle is high and I don't know if this is leading to the high reading or what's going on. When I tried to adjust it, it only dropped to 1.6v.

When stopped on the road I can rev it up to 4K and side step the clutch...it will hone the tires and rev to 6K nicely till I lift or the car catches up to the tires. Occassionally when I do this and lift, it will pop back through the TB.

I think that is about all and I'm not leaving anything out.

Any ideas??? Looking for help here......want to get this thing going.

[Mark Aubele]

First thing I would do is open the holes up on the TPS and get it adjusted properly. Is the TB staying open slightly (causing the higher reading)?

[yeahloh95]

I think it is tPs related also

[Dan B.]

First thing I would do is open the holes up on the TPS and get it adjusted properly. Is the TB staying open slightly (causing the higher reading)?

At first the adjustment bolt did have it open and the idle was around 2K. I turned it out until it did not even touch and the idle was still at 1200. It was also sticking and would cause the idle to hold at 1500. After a good cleaning and extra return spring (just for peace of mind) it closes the entire way but as I mentioned earlier still stays around 1200. I knew about the trick of opening up the TPS holes but didn't know if maybe something else may be the problem that I was overlooking. I'll give that a try tomorrow night.

[Mark Aubele]

I wouldn't even touch anything else until that TPS voltage is correct, the computer thinks the car is at part throttle...

If you want another ECU to try I have a speed density ECU circa '87 laying out in the garage, and I am probably going to be at PRP tomorrow if you want to try it after you get the TPS figured out.

[Dan B.]

Mark....thanks. May get into the TPS later this evening or Sunday AM. I'll post up the results.....maybe even a burnout vid just for giggles.

[Dan B.]

OK.....just came in from playing with my TPS. Had to open both sides up to get enough twist on it. With the key on the reading is .97. When running the reading is 1.17. The idle is still high at 1200. Also still sounds like it has a miss.......it will set there running smooth then jump around a little and smooth back out.

Ideas??

[PaxtonShelby]

Does anyone have a good TPS you could borrow and swap just to see if that solves your problem?

[jaa55]

I wonder why its changing values when its running??? its not like the throttle is depressed it should stay the same.

You dont have a weak ground or something do you??? You did have the entire engine out right?

[Dan B.]

You dont have a weak ground or something do you??? You did have the entire engine out right?

Yes.....the entire engine and trans were out. I'm not a wiring guy so I'll take any leads that are offered......or help!

Swapped the TPS last night....still reads high (1.4+).

Fuel pump also starting to make some noise...so swapping pumps is going to be in order.

[blksunshine88]

Dan whats the timing set at and did you set it with the spout connector out?