I have a 1989 Corvette at work that will start and is very hard to keep running. The car stalls unless you play with the gas. Here is the question I have. We sent this car to get checked out and this is what we were told.

The car has a chip in the ecm and because of that when they try to read what codes are set with the tech 2 it comes back with no data.

Could this be true? I find it hard to believe that an aftermarket chip would prevent reading codes? The car is an 1989 with a six speed and I have tried to locate a new or used stock chip. The shop says they can't find the problem until they can read the codes.

If I bought a new hypertech chip and installed it would I be able to read the codes.

Can someone chime in with their ideas???

 

Im by no means an expert on ecms, but I do have an aftermarket chip in my 89. Its a piggyback chip from Moates that snaps into the original chip so the programing could be changed after a new high performance motor was installed..The 89 Corvette is sometimes very hard to get connected to my laptop computer or my hand held scanner..Sometimes I have to try 4 or 5 times before it will connect..Maybe this is the problem they were having and they gave up before they could get it to connect..I don't know anything about the Tech 2 program but Datamaster on my laptop and my Auto XRay 6000 scanner will both read the information on my chip once it connects...You may want to post this in the tuning section , some of those guys know much more about this ......WW

 

They can short Pin A to Pin B on the diagnostic connector and turn
the ignition on. The ECM will turn on the cooling fan and energize
some relays.

The Service Engine Soon indicator lamp will blink any codes.
It will blink 12 three times, any codes three times then 12
again three times which indicates the end. The codes will
continue to cycle again unless you turn the ignition off.

The DTC's for a Mem Cal or Cal Pak error are 51 and 52.

There was a technical service bulletin which I believe included
at least 86-91 Y body vehicles concerning no serial data when using
a Tech 1.

The solution was to use a GM Pin E Adapter.
It was an adapter that plugged on to the end of the Tech 1 cable.

I don't have a Tech 2 but do have a Tech 1. My guess is the Tech
2 also needs this adapter to work on the 89 Corvette.

Here's a link showing the adapter. Scroll way down until you
see GM Pin E adapter. It says it's needed for 86-89 Y body cars.
I think the info is wrong. I have a 90 and need this adapter
when I use the Tech 1.

http://www.boschdiagnostics.com/part...3100parts.aspx

The 89 used Multec fuel injectors (gray body colored injectors). They failed because the injector coil windings were exposed to the fuel.

Eventually the coil winding insulation deteriorated and the coil winding would short out. If this car still has the original injectors use an
ohm meter and measure the resistance of the injector coils.
They should measure around 16 ohms.

Check the resistance hot and cold. Some times you can isolate
the problem by disconnecting the injector connector. Remove one
and see if the engine runs better. If no change move on to the
next injector.

 

Thank You for the help. I will pass this along

 

Last month I was getting similar issues with my MEMCAL and EMC aroding to the codes I was pulling. After replacing them both... it turned out to be the Mas Air Flow sensor. If you/they unplug the MAF sensor located after the air filter and before your throttle body and the car runs normally then than that is your problem. It took me awhile to figure out that was the issue being that I received no codes saying the MAF sensor had went.