This weekend Turbo_z came back to do some tuning on my car and look at the logs. Well we took the car out and tested it and the air flow was still down, but we noticed something else that was weird. I had a voltage drop again. It dropped from 13.8 volts down to 12.8 volts. The car also started dropping the TPS % down to 80%. Several other odd things were occuring with the PCM. I constantly get Data read errors when the car is being looked at on data master. Every few seconds it gets an error. I've swapped pcms with a known good one and i still have the same problems. Its not the cable because it never has the problem on Turbo's car. When i had my scanmaster on the car it never showed the errors, i guess because they happen so quickly. I'm starting to think this is an electical problem, or at the very least i need to get this fixed before i look at anymore mechanical areas of the car. Any ideas on what can be causing the voltage drop? I already have the racetronix fuel pump and harness kit and that gained me a volt. Please if you have any ideas please post. This is making me sick.

 

http://www-personal.ksu.edu/~bperkins/datalogs.zip

I have 4 logs saved from the other day in that link. They are only viewable with TTS Datamaster. EVERYBODY can download datamaster for free and read unlimited files with it. With that out of the way... Ill point out some readings that have me stratching my head.

Pay particular attention to logs 3 and 4. In all the logs youll notice there are checksum errors and random DTCs that never seem to cause any obvious drivability problems. Originally I thought maybe he had some exposed wires or pinched wires from his TA dash install that was throwing off the data and because his motor was not acting up.(thinking back though these errors showed up in logs before his dash install) However if you look at the Rec# 2028 in log3 youll notice the PCM attempted to add 80+ degrees of timing BUT it was then retarded 8 degrees and you see an incredibly high knock count! That is telling me the motor was ACTUALLY SEEING 80 DEGREES for an instant. If youd scroll on thru the log youll find another rec. where the timing is really high but dont see the same knock retard or knock count as in the first case which originally lead me to believe the data was corrupted... now I believe the timing was so far off there was nothing to ignite in the cylinder and therefore no knock. Now moving on to a even more puzzling date.... take a look at rec. #4121 and #4064. In this case you find RPM errors. In each of the 2 cases the system voltage dropped to 2.4 volts and several other sensors just went crazy... I have no idea on whats happening there b/c it appears to be running rich and lean at the same time.

Last is log4. Near the end we captured a brief WOT burst and you can see the system voltage is still very low despite replacing the fuel pump. The TPS sensor again was losing voltage and the motor was running lean.

I have told him to just sell the car and buy an LS1 but he insists we fix the problem so here we are.

 

I'd clean off all the grounds(especially the pcm ground on the side of the block) really good.

 

If you are just talking about the big ground strap that mounts near the ICM and coil its clean and i've added a second one a while back because my dad always preaches you have to have a good ground.

 

I believe hes talking about the one down on the motor mount on the pass side and it looked ok to me.

 

Its not actually on the motor mount its behind the motor mount. The wire is very small and attaches to a stud on the side of the block. It's in the same group of wires that the knock sensor is in and the little wire on the starter.

 

Hmm interesting. I'll look at it this weekend. I think i might of broken that eyelet off and had to put a new one on when the motor swap was going on. Something to look into. Thanks Man. Any other ideas will be looked into too.

 

Any veterans care to take a stab at this one?

 

Not unless the logs are posted in .csv format, but you appear to have decided that's out of the question.

 

Can you post them like that Brad? I'd love to have Fred's help.

 

http://www.ttspowersystems.com/softw...ee/ee-full.zip

 

Made Special for Fred

 

Got 'em.... just need to find some time to look at them. Thanx

 

Thanks for looking at them Fred. I really appreciate it, the car is making me sick enough i just want to sell it.

 

bump