$61 1228746 ???

[pmkls1]

Well, this is definietly an area that I have plenty of experience in as my current car is an '89 firebird and I have owned several 3rd gen f-body cars. Some questions that may help you at least are where the engine came from and is the tranny original to the car. The f-body cars never came with an L05 so I know it came out of something else. If the trans came out of something else, then there may be a compatibility issue between the VSS and the buffer. My point here is than this might be an issue that is totally unrelated to you. I am not familiar with the 1228063 ecm, however. IIRC the 1228746 was a direct replacement for it though, correct ? My only other thought was the pinouts for the 746 and 063 ecm's and wether they were the exact same. Data logs on the 746 will only give you limited info unfortunately. You will be able to see some of the critical info relating to idle speed, but there is very little info that you can see with any of the .adl files that I could find.

[Tunedperformance]

the reason for ecm change was for better code and for the L05 swap, He had a machine shop do the engine work and can give very little detail on the engine other than its a real mild build /cam . For all the information I have read the 063 was a one year odd ball ecm and I have read people swapping to the 746 no repining. I cant seem to find the pinout for the 063 to verify the vss input pin. He bought the car with a t5 so who knows what year that is from. even if it had the wrong vss 4k from a 90-92 tpi to a buffer his speedometer would be way too fast. Im not thinking it the old ecm with l03 worked with no error but hes wanting a better tune and was going to start too datalog in the near future to see if he needs any more refining on the anlu.bin I sent him. Still waiting on a guy to reply on tgo for me to get him another ecm and go from there. I appreciate all the input and help.

[Tunedperformance]

The guy hasnt got back to me on getting a replacement ecm yet. I just got some more information from rbob on tgo. This was on another post that a kid is having a code 24 on his tpi 165 ecm not moving. maybe a vacuum leak or iac issue.


It can happen due to the way the malfunction test for the VSS works. It is tricky to figure out if the vehicle could be moving or not. The test basically uses LV8 or MAP along with RPM to decide whether the vehicle is in motion.


If the ECM thinks that the vehicle is moving, whether it is or not, and no VSS signal it sets the code for it.

[EagleMark]

Sounds like it will set if MAP is to low, like with a cam. Even though no VSS reading, MAP says under load. If it is there should be a way to change the test to lower MAP. We had simalar issues with code 32 EGR test, when test was preformed it was not within set paremeters.

[Tunedperformance]

he had messaged me this morning and found a vacuum leak with the gasket under the tb. He has also just replaced the iac and was going on vacation and said he will let me know whats going on when he comes back and sets the iac min speed. always leaning more ;)

[Tunedperformance]

I appreciate the help on this. Forgot too update. I sent him another ecm it fixed the idle and Burned a new eprom for the guy and deleted the malf 24 works great . ;)