Tom400CFI

In the 'Vette Kart ('89), I removed and sold the IP. In doing so, I severed the path between the VSS and the ECM; the ECM doesn't know how fast the car is going, it throws a code and idles like poo (until I re-start it).

Any reason why I can't jump PIN D11 to PIN D12 on the UP connector? Would that get it done?

Kevova

No. the IP acts as a buffer convertering the AC VSS signal to a digital signal for ECM. GM used vss buffer modules in different cars and trucks in the eighties. IDK which one would be easiest to use.

RWDsmoke

Which ECM are you using? That doesn't look like an 89 wiring diagram to me.

Tom400CFI

IDK which ECM...which ever came stock in an '89.

The wiring diagram may well be erroneous. It's from Mitchell, which when you get into older stuff, it gets very generic, unfortunately. In fact, if you look at the PIN D12 in the diagram above, an orange wire going to the ECM...If I scroll to the diagram that contains the ECM, that orange wire doesn't exist. Just the brown one.

That sucks about the buffer being in the IP. Any recommendations as to how to create a work around would be great. Car would run drive a lot better if I could get this working again.

RWDsmoke

The IP has a circuit to drive the signal to the ECM. I am using a Vettaid IP which uses Autometer analog gauges. The Autometer speedometer has built in output to the ECM. This is the 89 VSS schematic

Tom400CFI

Thanks for posting this, RWDsmoke. Guess I need to get an Autometer speedo w/a buffer in it. Thanks for posting.

WVZR-1

You should only need to convert the VSS signal to 2000 pulse that I believe the '89 ECM wants to see.. I'm quite sure that any of the DRA/ERA in the after-market will do it. Many GMs did this using DRAC modules in the mid/late 80's. The least expensive out there now is the Dakota SGI-5 E. Most use this device for speedo/odo correction. It will do RUN only also.

In these instruction sets there should be a set that you can utilize for your needs.I didn't spend any time with the 'instruction set' but I'd think there are certainly a 'fit'.

http://www.dakotadigital.com/pdf/SGI-5e.pdf

If there's someone local that does 'PROM' stuff you could likely disable in the PROM. I haven't seen Scott Hansen around recently but I believe he dd VSS disables.

http://www.scotthansen.net