91 ZR-1 Cutting Out Under Load

[GregCrowe]

Originally Posted by Jeffvette

It is adjustable, it swings up and down after loosening the two screws that hold it on. The acceptable range is .46 to .62 volts at closed throttle.

Mine doesn't. It has 2 fixed screw locations with no pivot, no slots, no adjustment.

[phrogs]

you need to take off the cover

[GregCrowe]

Originally Posted by phrogs

you need to take off the cover

Take off the cover on what? There's nothing to take apart on the TPS. It's a sealed unit just like every other TPS GM has been using since about 1990.

[phrogs]

I was refering to the silver cover that covers the tps partialily and is conected to the throttle body it coveres the torx screws

Originally Posted by GregCrowe

Take off the cover on what? There's nothing to take apart on the TPS. It's a sealed unit just like every other TPS GM has been using since about 1990.

Originally Posted by GregCrowe

Mine doesn't. It has 2 fixed screw locations with no pivot, no slots, no adjustment.

This is what it should look like. There are slots where the screw goes through. Plenty of room for adjustment

[GregCrowe]

Originally Posted by Jeffvette

This is what it should look like. There are slots where the screw goes through. Plenty of room for adjustment

Oh man, am I stupid. I was looking at the passenger side of the throttle body for the TPS, just like a TPI or LT-1 car. I guess that's the IAC motor is there. You're right, the TPS is just as you said but on the drivers side.

[GregCrowe]

Finally got some time to work on the car today and yanked the upper plenum and replaced the plugs and wires. This was at the advice of 2 Mercury Marine ZR-1 guys who know the cars. Car fired up perfectly afterwords but as soon as it warmed up a little........... same damn problem!!!! misfire under load. At this point I'm guessing primary injectors or computer. I'm really getting tired of this.

The car has been down for almost 4 months now and I really don't have the time to keep chasing it. Somebody convince me to find to the problem and not sell this car. At this point I'm really hating the car. I've owned it for 7 years, have put on about 1500 miles and have had to take the plenum off 4 times for various problems.

[tomtom72]

Greg,

I just want to say that your experience is not isolated. I went thru the same thing when my 1* injectors went out to lunch. The car had the same "miss" but not just under load. You could hear & feel it at idle. I learned one thing thru all the trials I've had with mine since I became a Z owner.....learn how to work on the car myself. That, and the first owner knew when to say when...he sold it before it drove him nuts.

I also hate to say this but I'm leaning to the alky getting to the injector coils and the "junk" in the F/F not helping the spray pattern on the nozzles. The only trouble is RC's are 1100 for the set...or there abouts. The GM stuff I think is more and then there are the Accels recently discovered that are like half the price of either of the previously named parts. The skinny on the accels is you need to call Mr. Haibeck & get different O-rings for the primaries to work. I did mine last year about this time and used the 205 RC, $1064.00 delivered for all 16. Registry members get a discount down to 68 ea.

Ofcourse when I pulled the plenum I changed a bunch of stuff besides the injectors. CCV box was leaking so gasket & hoses, 2* solenoid was N/G, coils & wires, vacuum hose assembly, tank, both temp sensors, 2* actuators, cleaned up the harness grounds, di-electric on all the weather tight connector gaskets, etc, etc...I was paranoid!

I was starting to regret, or question the wisdom of my purchase...truth! The only thing is when it was done & the baby fires up....man it was all again. The cash put a dent in the budget for sure but I did by a used car after all. Oh, and the punch list ain't done yet....I'm still playing catch up, and it isn't even anything fun like a P & P job or headers or anything to get me closer to the C5's & C6's I hang with on cruises! I'm one of the only antiques in our little cruise group...but I keep up!

I guess what I'm saying is hang in there & when you solve the problem you will feel good about what you've learned! Then when you go for a ride you'll even feel better....I know I do!

Tom

[GregCrowe]

I'm curious why you haven't sent the original injectors off for disassemble, cleaning and rebuild ? It's been many years since I've done that but when I did, it made a world of difference in TPI cars from the same time period. When they do that, they check the spray pattern and make sure the injectors are working properly.

Sounds like the easiest and least expensive thing to try now might be to order a new computer from GM. It would sure help if the car would throw a check engine light.

[Z Factor]

Originally Posted by GregCrowe

At this point I'm guessing primary injectors or computer. I'm really getting tired of this.

The car has been down for almost 4 months now and I really don't have the time to keep chasing it. Somebody convince me to find to the problem and not sell this car. At this point I'm really hating the car. I've owned it for 7 years, have put on about 1500 miles and have had to take the plenum off 4 times for various problems.

I hear your frustration and know you do not want to bite the bullet and go the injector route, but sorry to say that is most likely your problem.

As to not selling I can give you several reasons but here are two very good ones . First is that when your baby is running right you have a great time that cannot be matched by other cars, especially in a moderate price range (assumption on $$ ). The second reason is that if you were to try and sell it with the existing problem, you are not going to get as much for it as you would if it were in tip top shape. The bottom line is that you bought it for a reason and just need to get it running right to recapture the great feeling of owning a KOTH