So I finally thought I was gonna get my car tuned and dynoed. Well I guess I was dreaming!

I got the lsj injectors installed a few weeks back and only got a few hours of street tuning done on them but got them under control enough to drive it. So I went back saturday to finish up. Plugged the HP tuners into it and the iat was -40...so we went searching and found the iat sensor harness was pinched between the transmission and bell housing and was ground the sensor out. So it was either take the tranny apart for the 3rd time in a week or cut it and re-wire it. Re-wiring was the more logical idea . So we got the sensor re-wired and everything was reading ok at this point. So it was time to do some street tuning. So we plugged the adapter for the laptop into the 12v cigarette lighter and off we went to get some data. So not too far from shop the dash lights and all the guages shut off for a second and turned back on. The laptop connected back to the wideband and ecu so we kept going. This happened another 4 or 5 times and then the computer froze. So back to the shop we went. Got back and we lost everything and no time left to do more tuning. So that was the end of day one.

Day 2...woke up early in the am to go back and try some more street tuning. So we plugged everything in and went for a drive. Except this time we didn't plug the laptop in but rather let it run on its own battery for a while. So this was going well. Got some data and was able to change a few settings to get the fuel under control a bit more. The battery on the laptop was getting low so we plugged it in to charge it. Everything seemed to be running ok at first. Then the car lost all the guages like the last time, everything went dead but the car was still running, and after one second everything came back on. So we kept going for a while. This occured a few more times in the next half an hour. Then we were attempting to get some more data by giving it more throttle coming onto the highway and it did it again, this time froze the laptop and lost everything for the last 30-45min. So at this point we were pretty pissed off and didn't think the tune was gonna work. So we ended up unplugging the laptop and running as much as we could with what was left.

So the moment of truth. We had the injectors tuned a little better, car seems to be running decent when not in boost so it was time to do some WOT runs to see what the fuel was really like. So we slowed down to 80 km/hr, put it in 4th and put it to the rug. Well this was about the last time my car saw boost.

At 3200-3400rpm the car was producing somewhere around 5psi and was seeing 6 degrees of knock! So needless to say there is something majorly wrong. The car is going into the shop tomorrow to see if they can find something with the electrical. It was appearing that the ecu was only seeing 12.1-13v much lower than the 14.2 the alternator was producing. Anyways, this my story of a weekend gone bad. My battery is bad, as it only holds a charge for an hour after the car is turned off and goes dead after the car isn't running with the doors open with the dome lights on after 15-20min. So first order of things is to get a new batter and start figuring whats going on. There was a few codes that HP tuners was picking up, can't remember what they were now off the top of my hear but one was a short/broken speed sensor in the left wheel and another was something involving voltage and the ecu. So hopefully they are able to find something wrong with the car cause I don't want to spend the summer trying to figure out what is going on. I will post again to let anyone know that is interested and hopefully have some progress in the next few days.

It is not uncommon to see that kind of KR on a 2.4. Have you lowered the timing tables?



FU Tuning

As you said you've had the trans in and out several times recently, check ALL your grounds under the hood.





14.330 @ 96.37mph

get a new battery and stop using your cig lighter outlet to power ur laptop. wire the power inverter directly to the battery. and like blownblackz said, check ALL your grounds. your computer is actually grounded at the block.


01' Z24 5 speed
422whp/400wtq
T4 Turbocharged
Built LD9
HP Tuners

So I got the battery replaced and the mechanic plugged in his reader and went for a drive and he did a 4th gear pull and he said the computer didn't pick up any knock at that point in time. He is gonna check over the grounds and make sure the harness that got caught in the transmission is secure and make sure nothing else is caught in there that may be getting grounded out. I am hoping that all it was is a dead battery and the alternator couldn't support the electrical demands of the car and laptop. Its looking like I won't be able to get it back to get it tuned/dynoed for a few weeks but I would imagine we will do some street runs to make sure everything is back to normal before we throw it on the dyno to finish tuning it.

sounds like the main ground for the engine harness is loose, or not grounded. Front of block, right by the bell housing. Try turning on your heat, if the grounds are off, it either wont work, or will kill the gauges.





SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
W41 BOI - '78 Buick Opel Isuzu W41 Swap

I put a new battery in and the car seems to be starting ok...We cut off that rubber boot around the positive wire connector to the battery thinking it may give a better connection...I'll have to wait and see how the car makes out in the next few days. I had the fan/heat on today when I was driving and had no issues. Car seems to have more juice, starting a lot stronger than it was. I hope I can get it tuned next week. Its been over a month that I have been putting around in the car not being able to drive it like I want to. I'm still a little worried about the knock issue I was having the last time we street tuned it. I'm praying that its not gonna do it again. I only have a 2.7" pulley with meth so I can't see that causing it. I bought a 2.6" to put on it so hopefully I will be able to run the smaller pulley. I don't know much about tuning so this is all new to me. I'll do some research soon to see if I can find out regarding spark/knock and see what may be causing it.