Just got a custom burned chip for my '91 Z28.
The car now is having issues.
When coming to a stop, SES light comes on, the cars goes to a real low idle, stumbles a few times and dies.
Code is 24.
Car is a 5.0tpi and was originally an auto.
It has a few mild mods including a cat-back exhaust.
I have converted to a 5speed and just put a LT1 cam in it.
I have been running a Hypertech thermomaster that was for the auto tranny set-up.
Since I just did the cam, I figured a new chip was past due.
Now the car has this issue, but only with the new chip.
No issue with the Hypertech chip, or just the original chip.
(although I have always thought this car has had a stumble in it since I have owned it)
I put the new chip into my other '91 Z28 which is an original 5 speed car.
It has the exact issues with the new chip.
I contacted the programmer who is going to reflash the chip, but he sounded stumped as to why the issues are happening.
I am wondering if anyone else has seen this with a new chip and what we may need to look at.
The programmer has a good reputation for his custom chips and some other fellow tpi users have been happy with his product.
Any thoughts or insight is appreciated.

 

Code 24 is typically a VSS error which may make sense in that the ECM does not know the vehicle is stopping. It could also be faulty or loose wiring to the ECM. Check the connectors push each wire individually into the connector to make sure they are tight. Make sure that the Memcal is fully latched. push down on each end until you hear a audible click. Sounds like it is dropping down into limp home mode for some reason.

 

Never had any issue like this with either car.
Only with the new chip in and on both cars.
Not had an issue without the chip what so ever.
Only time this occurs on either car is with this chip in.

 

I didn't catch that you tried it on two cars. You sure he programmed it for a manual transmission? Anyway, sounds like maybe a program problem and it sounds like he is re-doing it. Good luck.

 

Well, I have to assume he did...
Has a sticker on it that says "5speed"....
The Hypertech chip and factory chip is for an auto and its never had a problem like this.
Was having a different problem last year (ended up being a weak fuel pump) and had a friend ride with me while observing a scanner.
He says: "well thats weird"..
I said what..
He says " this crazy thing is telling me the torque converter is locked"...
I say oh, this car used to be an auto, the computer thinks it still is...
Anyway, thanks for the input.
Has to be something with the new chip, but what?