Americanstig

Well I went and picked up my RX7 yesterday. It has a Corvette LS1 in it with a Corvette computer. Got it home and changed out the rear struts so the tires wouldnt get rubbed and started trying to fire it up. Ended up blowing a relay. So we replaced a relay and tried again. Well we got fuel pressure back ~60Psi and it ran for a minute but it wasnt really revving correctly, sort of slow and sluggish at first and then it would start backfiring and shooting fireballs. So obviously it was too rich. We dialed back the fuel pressure regulator to 58 because thats what I am told is stock pressure and it continued. So we decided to pull a plug. Ended up finding out 7 out of 8 were pretty much fouled out and the 8th was damn close. So we changed them out. Seemed to do better. Got the car to run for a about 10-15 minutes at an idle, revs were still a little rough but figured it was just the computer trying to figure its **** out. However the car abruptly died. Wouldnt start again. The problems came back. Shooting gigantic fireballs and obviously running too rich. So we dialed the fuel pressure back a little more just to see if maybe the pressure was too high. Problems continued and we couldnt seem to get the fuel mixture right. Checked the battery to make sure it was sending out 12v and it was. But I have run out of thoughts.

My only ideas now are some sort of vacuum leak because it seems that when you press the clutch or brakes it effects the idle more than it should. A computer tuning problem that is overloading the car with fuel when it gets to temperature. A bad temp sensor. Or a bad coil pack. We are going to reconnect the gauge cluster this morning and try to get them working right and check each coil pack and spark plug wire. I am trying to eliminate every possibility before blaming the computer because I have bought another computer before and it ended up being something else. So if you guys have any ideas i would be more than happy to listen and take advice.

mark21742

Cam or crank position sensor? I'm just throwing out a guess

Americanstig

Yeah, I had considered that a possibility since that is what caused my camaro to have similar issues. I am going to wire up the gauges and see what the Tach reads and then I will be checking those sensors.

mark21742

If you can pull known good sensors out of your other car or s frirnd's car and swap them you Feb eliminate things quicker

Americanstig

We have a guy coming down that has a code reader and he is going to see if it is saying a sensor is bad. I really think it is that more and more. It would make the most logical sense. The in line Fuel Regulator is brand new and only about 3 weeks old, and i doubt it is bad, so something electrical is telling the computer it needs to dump more fuel. Camshaft/Crankshaft sensor would do that. Camshaft sensor could **** up the firing order too i think. but not sure, honestly never messed with a camshaft sensor before.

Americanstig

Okay so we figured it out. It was actually a combination of things. 1) the Coolant Temp Sensor for the computer was bad and need to be replaced. It was trying to tell the computer that the coolant was all over the place so i guess the computer started loading up the car with fuel to make sure it didnt lean out. BUT the main issue was the Crankshaft sensor. While when we pulled it, it looked brand new, it appears it was faulty. Swapped out and it ran fine. Did blow a radiator hose though. LOL. But appears for now she is running fine. I have coilovers on the way and today I am ordering new Coilovers, Plug Wires, and a bump steer kit. So we will see how she runs after all that.

mark21742

I've bought several new but bad sensors, starters and altenators....just sucks to put a bad part in then have to pull it bad out to Exchange it again

Exidous

iTrader: (11)

Oddly enough the GM ECU is greatly affected buy a working or broken coolant temp sensor. My car ran like total crap when I had a bad connection on the sensor. AIT you can get away with but coolant temp has to be working correctly.
Check out Justin Samberg on the norotor forums for a good bumpsteer kit. It's the strongest one I've found yet.

Americanstig

The AIT isnt even hooked up on my car since I redid the intake piping. I just have the AIT plugin for the sensor ziptied and the sensor isnt even in the car. I have read that it will run better with it plugged in but it isnt something that will hurt the car or even make a HUGE difference. But I have replaced ever other sensor so I am sure I will replace that one too. I am ordering a new front bumper and a new hood atm. I have been shopping the norotor forum for a while. I was looking for that guy that makes door handles for them but no dice yet.

Exidous

iTrader: (11)

You'd actually be suprised about the different the AIT can make. I didn't have one for about a month after my swap. I went to the GM dealership, picked one up, plugged it in right there, left the parking lot and said to my self, "holy ****". I believe the ECU goes into a pseudo limp mode and retards timings without it plugged in. There is a bias table (don't mess with this table unless you want to do a lot of tuning) in the ecu that controls the balance of the coolant vs AIT with a bias towards the coolant. It most certainly does affect how the car runs just not nearly as much as the coolant sensor.