1990 LT5 368 with stage 1 cams performance issues

[Kevin]

does the car still have the secondaries in?

[QB93Z]

Hi Brandon, welcome to the Registry Forum.

I have a 1990 Lingenfelter 368 with modified cams and a set up similar to yours except mine has stock dual-mass flywheel and stock 3.45:1 differential.

I notice, to a smaller degree, some of the low rpm performance issues that you have described. The engine seems to have less power below 3000 rpm than my stock ZR-1's.

That being said, for your description, I would investigate possible faulty primary injector just because it is a 1990.

Despite the low rpm performance issue, the car is a a solid performer on the drag strip. Best 1/4-mile so far is 12.26 at 120 mph.

Good luck and enjoy.

Jim

[blr33439]

I contacted the previous owner for some additional information. The car was running well after Corey tuned it(several years ago). The secondary injectors were replaced approximately 5 years ago but the car has been sitting. Unknown status of primary injectors. The cams are stage one from South Georgia Corvette.

My initial instinct is leaning toward bad primary injector(s). Any recommendations from here. Best source for injectors and appropriate size for this engine.

[ZZZZZR1]

FIC. www.fuelinjectorconnection.com


Call John Banner. Ask for stainless steel injectors



David

[A26B]

Originally Posted by blr33439

I contacted the previous owner for some additional information. The car was running well after Corey tuned it(several years ago). The secondary injectors were replaced approximately 5 years ago but the car has been sitting. Unknown status of primary injectors. The cams are stage one from South Georgia Corvette.

My initial instinct is leaning toward bad primary injector(s). Any recommendations from here. Best source for injectors and appropriate size for this engine.

I would agree with your instinct and would seriously consider a complete set of 16 new SS matched injectors from Jon at FIC. I have yet to hear of successful, long term results from repalcement of just some of the injectors.

Let me know if I can help you with any gaskets or seals. Jon/FIC now keeps Jerrys Gaskets & Seals in stock so you can get the whole, turn-key package from him.

[blr33439]

I looked at the injector options on their webpage
http://www.corvetteinjectors.com/sho....php?groupid=3
I see that they are all flow matched.
How much difference is there between the three options they have for 1990-1992. I noticed there is some price variability. Any opinions on ideal flow rate for the engine combination I have. Also, what gaskets am I likely to need for the upcoming work.

[A26B]

I would get these:
http://www.corvetteinjectors.com/sho...p?productid=32

Stock injector flow rates will be more than adequate for your engine.

For the injector replacement, Jon, will have everything you need regarding gaskets & seals, set of plenum gaskets, primary injector lower seals, fuel feed & return block seals and the fuel pipes to regulator & rails seals. The injectors come with all the seals for the tops and the bottom of the secondaries.

[blr33439]

I pulled the intake today. The secondary throttle bodies are still in place. I tested the injector resistances(15 at 12ohm(normal) and 1 at 9.8ohm(bad) but it was a secondary injectory). I pulled them completely but found no obvious issues. Anyone ever sent injectors in before rebuilding or buying new. I don't want to spend several hundred dollars to still be chasing the problem.

[Kevin]

normal is 12.5-15 ohm, you have a second one going bad

[-=Jeff=-]

Originally Posted by Kevin

normal is 12.5-15 ohm, you have a second one going bad

And more will follow suit.. the 90 injectors don't like ethanol. if you want to save some $$ you can buy FIC rebuilts, they have a 3 year warranty..

I have these on my 90
http://fuelinjectorconnection.com/sh...&productId=165