Starts & Dies
This is my second Fitech, first one installed and ran like a dream. I cannot say that for this one... For some reason I am having trouble getting this unit fired up and running with consistency. It will start and run on the prime and then dies. I can see fuel squirting into the TB and then is just peters away and dies. I can keep it running by feathering the throttle (1800-2500 RPM, constant bumping) and will finally die when voltage to the pump drops <9.0 (blew fuses initially). Red wire is running off the battery side of starter, when ran off the key it pulsed; good voltage at the white wire. I have good grounds, I have tried adding and removing fuel at the crank and warm-up setting and have turned off FuelCUT. I cannot get any low idle (<1000) behavior. Therefore, there is something in the settings that I cannot get right. I have also jacked around manually with the idle blades and I am struggling getting it back within shouting distance. What am I missing?
Which Fitech model do you have and does the Fitech have a external Fuse and Relay box, which if it does, would make it a gen 2 version. Something is off with the fuel pump or circuitry if you are blowing fuses and voltage is dropping to below 9v to the pump. Is the pump intank or external and what brand?
- 30001
- external fuse (in harness)
- Fitech in-tank pump
Could noise at the tach wire cause a voltage drop? I can get it to run at high-idle (~2000) while feather the throttle, yet once I let off it dies. Something is trigger a voltage drop. The pump is wire to the battery side of the starter, when hooked to key it pulse but stays running.
No noise wont cause a voltage drop. You have the old gen Fitech. Noise on the tach wire can cause the unit to stall as it is getting wrong tech readings , which is critical. Check the handheld to see if you are getting any codes. Is your distributor a aftermarket one or a GM one? Stick to a genuine GM distributor as it wont give you problems like the aftermarket ones do. I have done this on many cars who were having all sorts of issues with a aftermarket distributor. Since you have a older Fitech unit, I would highly recommend installing a relay to power the fuel pump and use fitech to trigger the relay. That is what I do and it also always gives a full 12v or more to the pump. Alot of pumps dont like PWM. It also protects the ECU as the fitech unit can drive a pump up to 15 amps max, and the pump you are using is drawing 13 amps which is too close to the 15 amps. I use a Walbro, made in the USA pump that only draws 8 amps. The Fitech pump is a POS china junk. Also check your IAC. There is a new procedure to set that up where your adjust the front and back butterflies with the adjustment screw. Initially what I do is remove the fitech from the car and preset the from and back butterflies by unscrewing the adjustment screw to where it just lets of the tab that opens and closes the butterflies and than turn in 1 1/2 to 1 3/4 turns front and back. Much easier to do when off the car. This usually starts the car with no issues and than you do the final IAC adjustment to between 3-10 by equally adjusting front and back screws.
Wow, thanks for the feedback it’s outstanding.
- using aftermarket dist and 6al, thus I have a lot that can go wrong; I think my tach signal is sketchy. Good call out I need to go back to simple and then add parts. I can source a gm distributor. My previous install was a dream, so I was over confident in my install.
- no codes
- do you have a diagram for a relay? I assume this if off the orange wire. I used a tanks pump previously.
- Any way I can avoid PWM?
- Thanks for the adjustment details
- what is the chance this a issue with the ECU?
Yes get rid of that aftermarket distributor and stick to a stock GM distributor. That should solve the starting and dying issue as long as you setup IAC properly ( critical). Once you install a relay to power the fuel pump, PWM wont be a issue. Here is a diagram. Pin 30 is power from the battery and make sure to install a fuse with 10gauge min wire. Pin 87 goes to the plus side of the fuel pump. The orange wire from the fitech goes to pin 86 and pin 85 goes to ground. Fitech will trigger the relay on and the battery/alternator will power the fuel pump. Dont think it is a ECU issue YET. I made that mistake last year with the exact problem like yours and it was the aftermarket distributor that was causing the problem. As they say, keep it simple, stupid.
Thanks for the addition feedback. I have some work to do, so stay tuned.