Evan Vette

Hello, working on a 96 vette with the typical intermittent no start. Especially on very hot days. I suspect issues with the ccm. I've bypass the key with resistor a long time ago. I know how to bypass the security relay for the starter. The problem I have is the fuel enable circuit. It's supposedly circuit 229 from the red plug on the computer position #25. But that position has no wires connected to the pin. What am I missing here? Is there a chance this is different since it's the last year for the c4 and first year for obd11. Anyone else go down the rabbit hole? Thanks for any help.

WVZR-1

You obviously don't have the FSM because of your mention of incorrect connector and circuitry. Do you have the FSM(Factory/Field) Service Manual? I believe you look into doing something with the 'denso starter. Will contacts and a plunger correct it? Maybe!

Evan Vette

I do not have a service manual. Are you suggesting a problem with the starter? Starter works fine. When i have the no start issue i can bypass the security relay. The car will start but wont run because its not getting fuel. Hence I'm missing the 2nd part of the vats system to bypass. The fuel enable ckt.

s carter

Not to harp on what WVZR-1 asked but does your manual look similar to this (but for your year) a FACTORY manual, Hays/Chilton and Some of the E-Manuals can have gaps.

Evan Vette

I do not have any service manuals. Been looking online at diagrams and following the directions for a complete vats bypass I purchased. Again looking for help with the fuel enable circuit 229.

WVZR-1

For a '96 that's not the circuit!

Does your car 'ALWAYS CRANK' even when HOT?

Many years ago a fellow posted thoughts regarding 'Fuel Enable(FEDS)' on later Corvettes. I don't recall anyone ever posting back regarding the square wave device like you've purchased. This post was regarding a '95 which I don't believe used the connector and circuit you mentioned.

I doubt a device like you've purchased will work with a PCM/CCM

https://www.corvetteforum.com/forums...post1590032999

Evan Vette

It's very intermittent. Mostly hot as in ambient temperature not a hot running car. Even then as I said earlier I can make the car start in this bo start situation by jumping out the security relay, essentially bypassing that part of the vats system. The car will turn over but not run more than a few seconds due to the vats system not allowing fuel.

WVZR-1

Whose 'by-pass' did you buy? Mention that and if someone has used it successfully with a later C4 with a PCM & CCM they'll likely post back.

I would imagine for sure that IHBD will respond.

ChumpVette

You could always go back to “Timers Shop” for tech support for the bypass you bought that didn’t solve the problem.

IHBD

After 1991 there is no circuit 229. (blue wire).

You can't use the timers.shop signal generator on any a 1992-1996 LT1/4. (I don't know what the 92-95 ZR-1 uses for Fuel Enable.) It won't work because the ECM is looking for a 'code' on the data line circuit 800. 1992 and later no longer utilize a separate circuit 229 that carries a square wave signal. It's "data" on circuit 800.

You may or may not know this. Beginning in 1990, if the SECURITY light is solid-ON with the key in RUN, you have an active VATS inhibit. If the SECURITY light is OFF with the key in RUN, your no-crank / no start is not "VATS".

If you don't have a solid on SECURITY light with the key in RUN, you may want to learn about using the onboard diagnostics to query the CCM for its codes. There's another current thread (today) that addresses the onboard diagnostics.