We just got the FAST system installed on my 94Z and the car will not start. I was told that the program that was sent with it would be good enough to get it at least started, but I have had no luck with it.
The car started and ran fine before the install. It will turn over and sometimes run for a few seconds (very rough). It also pops through the exhaust and acts very much like it is out of time.
I am pretty sure we wired everything correctly (although anything could have happened). The car is getting fire and the injectors are working. It actually fooded while we were trying to get it started.
We used a wiring harness from Precision and also got the tune from them. I have talked with them and a couple of people from FAST with no success.
Is there something that needs to be wired into the opti? Anyone else had any similar problems? Any help will be greatly be appreciated. The car has been down nearly a year and I can't wait to get it on the road again.
Thanks

 

I've been down this road before... first, make sure the fuel pump is on while the car is running. If you still have the stock ECM controlling the fuel pump relay, you'll need to make sure that the stock ECM is getting the opti's low res signal! If you are using the stand-alone harness, be sure to splice into the low res wire. If not, the fuel pump will prime, but won't turn on when your engine is running.

I'm kinda foggy on this, but there is a parameter that tells the FAST system the number of degrees before TDC that it will receive the low res signal... it should be set correctly at PT, but if all else fails, check with others that run the FAST system and see what this value is. Note: my value w/ the stand-alone harness was way different than someone else had with the adapter harness... if you have TDC marked on your balancer with a timing pointer (not likely for an LT1 owner, but I did for this very reason), an easy way to check is get a timing light on it... set the timing tables to 10* everywhere, and chance the parameter in FAST until it is correct. Mine was set correctly from PT.

All this being said, you problem is most likely your cranking fuel table... It took to me awhile to get my car fired, and it all came down to getting this table right. Start low (maybe 1ms if you have *big* injectors), and raise the value up 2ms everytime it doesn't fire.

 

Thanks for the info Eddie. I am using the stock ecm to control the fuel pump. I guess I can keep an eye on the fuel pressure gauge to check the fuel pump. All of this is completely new to me and I appreciate your help.
Thanks,
James

 

Like I said, make sure that the stock ecm is getting that low res signal, or your motor will only run for a few seconds! I don't remember which of the four wires going to the opti is the low res signal, but you should be able to figure it out by the pinout that FAST gives you. Good luck!

 

I believe you will find it is 6 degrees.

 

We did not have anything to wire into the opti directly. There were only a few wires for the ignition that wired into the stock ecm wiring harness. The harness is from Precision and the guy that I need to talk to won't be back untill Wed.

 

I got my setup from Precision as well (I was the first one to get a FAST [then, it was made by Fel Pro] for a 4th gen from them, and they weren't much help)... some will argue otherwise, but I had a less than wonderful experiance with them - that's another story, though.

Anyway, I hooked up my stand alone harness to the engine, and de-pinned all the factory sensor/injector wiring to the stock ECM, with the exception of the transmission stuff (VSS, reverse lock-out, etc.) and the low-res wire that went to the opti. Take the low res wire that went from the stock PCM to the opti, and splice it into the low res wire in the FAST stand alone harness... your finished and ready to fire it up at that point!

If I could go back and do it again, there is no way in hell I would use the Precision stand alone harness... what a PITA! If it's not too late, I'd call up a few of the FAST/DFI vendors and get a "jumper" harness... much less work! It's basically a small piggy-back adapter harness that lets the FAST ecu use the factory harness - it also keeps all the sensor inputs into the factory ECU.

 

I have a Fast Tracks Performance harness. I had to splice about 40 wires into the factory harness. It took about 5 hours.

 

Just curious... does the FAST have to be set up at the factory for the Opti high/low res input, or can you select input type on one of the setup screens?

Does the FAST have an output compatible with the stepper-motor idle control used on the LT1? I know I had to leave idle conrol on the stock PCM, because the MoTeC (version I have) can only drive a PWM IAC controller.

Be careful trying to parallel pure resistance loads into two computers... it won't work. Examples are the temp sensors like IAT and coolant. If the sensor is supplied with a +5V bias from the ECM (e.g. TPS, MAP), I believe you can parallel it, but pure resistance loads I think the readings will be incorrect.

 

The FAST has to be programmed from FAST to use it with the opti signals... the firmware can be 'flashed' for different inputs by FAST, but you can't do it yourself. I was going to send my ECU back to be reprogrammed from the opti hi/low res signal to a Northstar pick-up signal, and they said "no problem, send it in".

The FAST ecu was completely compatable with the LT1 IAC stepper motor. All in all, it was amazing how easy it was tune the car... After we got the cranking fuel vs. coolant temp table dialed in, it literally took 30 minutes of driving to get 95% of the tuning done on the car (me driving, and a Accel DFI veteran working the laptop). The DFI guy was amazed with how easy it was to dial in the car - he said it would take someone with DFI a month, working 40hrs a day, to get done what we did in less than an hour (he could have been stretching it a little, but the point was the FAST/WB02 makes it a breeze).

 

I hate to hear that you have had a bad experience with Precision. I have talked to them a couple of times about this and they have not been able to help any at all. They told me that the guy who does all of that work is out of town and will not be back untill Wed. I was going to have them tune the car once it was up and running, but now I don't know. Maybe I can find someone else to do it that is fairly close. Any suggestions???

 

I have the same harness, and I'm going to be wiring it in tomorrow. Do you splice the wires into the harness, and still leave them connected to the stock PCM, or are they completely disconnected from the stock PCM, and into the Fast Track harness?

 

Some wires are spliced into the PCM wire (ie three way connection) some are cut and solder.

I found the instructions from Fast Track real easy to follow.

However I'm having trouble with "dead" cylinders.

http://web.camaross.com/forums/showt...threadid=97223

 

Which wires are spliced 3 ways? The instructions with my harness says * indicates a 3-way splice, but I don't see a * anywhere in the directions?

 

Where it says "splice" that is a three way splice.

Where is says "connect" it means cut and connect as a two way connection. - ie the injectors are all "connects".

Hope that helps.