New FI symptoms

[DJ]

OK. I finally have her starting and staying running. But just barely.

At least some progress.

It runs badly and barely revs with the accelerator. I've not started troubleshooting this new situation yet but thought I'd throw this out for suggestions.

I THINK I may have a bad TPS but need to do more checking.

Also, what's a good setting to start with for the idle air screw? It's currently out a good ways.

[davidb]

Unlikely it's the throttle position switch . Check it w/an ohm-
meter : loosen the two screws, rotate it, watch the meter .
Zero is what you want w/engine off . Adjust your idle 1ST .
Supposedly TPS's only show untoward behavior @ revs .
You may have a bad AFM which may involve a bad 'puter .
Good luck !

[Will]

DJ- you have a weber BB, right?
You changed the clocking of the TPS and you verified that it closes JUST as the throttle plate touches down, and the throttle is free to open fully, right? And you used the original throttle position SWITCH and not the almost identical looking throttle position SENSOR that goes on the Weber BB with no reclocking, RIGHT??

Just checking.
-Will

[DJ]

Yup, yup, yup.

Got the right TPS and it's fine, the AFM is fine and known good, the ECU is known good, got no air leaks, brand new fuel pump is working fine. Now re-testing idle air bypass and fuel pressure.

[DJ]

Thanks to my good friend Steve Garran who was kind enough to come spend several hours in 100 degree heat with me in the garage with his oscilloscope, we've now verified that my components (ECU, idle bypass, ignition module, double relay, etc.) are all good.

We also proved beyond the shadow of a doubt that the engine is only running on 2 cylinders and that 2 of my injectors are apparently not firing or at least not firing correctly. A review of my receipts shows that I had the injectors refurbished in February of 2003 so they've been sitting idle in the engine on my test stand since then. It's easy to imagine that they are probably stuck.

Accordingly, I've ordered a full set of new injectors and should have them on Friday. If that doesn't solve the problem I'll be looking for a carb and manifold. :o

[chrisc]

Glad to hear you have a new avenue to attack :)