Classic FAST SEQ. Car wont start!

BUFORD93

BUFORD93

Member
Joined
Jul 10, 2005
I am in the process of trying to get my new combo started. I have a 235 cid motor roller cam, alum heads, 96 pound injectors ect. I have a classic fast box and a fast stand alone wiring harness. Long and short of this story is the car will not start. This is what I have checked so far.

1. car has spark
2. program loaded correct
3. Fuel PSI is 45 poiunds.
4. 12 volts
5. tps reading 11 on the fast dash
6. I have voltage at the injectors.
7. I seem to have no fuel.
8. cam sensor tab in place

I think the injectors are not pulsing or not pulsing enough. The car will try to start with a little sputter or small pop. I have moved the cranking fuel up and down with no change. Any help with this problem would be great!
 
You have probably flooded it out and soaked the plugs from putting too much cranking fuel or don't have enough. Try 5 ms -6 ms cranking fuel for about 60 degree ambient temp. Or your throttle blade is set to low and not getting enough air iin the motor to keep it running, or your afterstart is not enough. Try setting the cells with the key on with the car not running to about 35 and the idle cells to the same value where you think it will run at 1st start.
 
Are you able to see any rpm readings during cranking on the fast during a datalog? Are you sure you are getting a constant spark? Is the cam sensor installed correctly at 25 ATDC?
 
Update.....

Checked every thing to day with no luck. I reset the cam sensor, new plugs, checked all the grounds and even put in a new battery. I did test the voltage to the injectors, I show power to the injectors with the key on. When cranking the motor the injector plug looses power. Also when cranking the motor their is now signs of the injectors clicking or anything. Any ideas would be great.

Thanks in advance.
 
One side of the injecotor is +12v the other side goes to ground when the ecm tells it to fire. YOu should not be losing 12 volts on the 12 volt side. Use your meter neg prob at the battery - and plus probe to the constant power side of the inector, voltage may drop 1-2 volts or so during cranking but should not go lower. Make sure your not measuring the switching side of the injector that goes to gnd when the injector fires.


If you logged information as I mentioned, you will prove the fast is getting a crank trigger input, you will see the rpm move on the main sensor dash. You may get a cam sensor sync also, but I have seen cars that you don;t get this until higher rpm. DO you get rpm signal when cranking on the fast on the rpm for logging?
 
I am showing RPM on the dash board when cranking about 200 rpm or so. Also I just just ran a 12v sorce to the C3I module term c and got the injectors to pulse.
 
Thats a good sign, it now should run, remember starting fuel stops around 400 rpm, so if it starts and dies above 400 rpm in your data log, you will need to increase the afterstart fueling. However just to get it running increase the cells in the ve table near idle, it should run. I can;t see it needing any number over 40 to run, 40 would be real fat. If it does keep stalling and wont start look at the plugs ruight away, make sure they are not wet. Then you will know your already too rich on the cranking fuel. If there dry start increasing the cranking fuel but do not exceed 15 ms, try about 9-11 ms see if it improves. I did quote 5-6 ms before but now looking it thats the target for a warm engine not cold. my error.
 
My Classic FAST Seq is VERY sensitive to the cam sensor setting. I can set it perfectly one 25deg. It will stutter abover 10psi. I move it one way it's worse.. the other way it's fine.

Then if it's too far off it won't even start like what your having. I'd suggest taking a marker and marking where the cam sensor is now. Then go ahead and move it a little one way and then after several moves and tests starting go back to center and go the other way. Once you have it set you should be fine.
I bet it's just not on the sweet spot.
~Scott
 
We ran another series of test today. I can get the injectors to fire by running a a 12v source to the C3I module term c and got the injectors to pulse. And I can connect the B and C treminals on the crank sensor plug and get the injectors to pulse. Is it possible for a crank sensor to be bad and still show RPM on the FAST dash?

Thanks All
 
Update... I put a new crank sensor on the car tonight. Tried to start the car no luck. I then started to turn the cam sensor counter clock wise then I got the car to run for about 3 seconds then it would die. Any suggestions on what my next move should be?

Thanks
 
Mark the cam sensor so you have a idea where that 25deg mark is then move it one way a little at a time till it runs if not back to center and back the other way.

Like I said a few posts ago my Classic Fast is very sensitive to this setting and won't run unless it's in the sweet spot.
~Scott
 
Update.. I got the car to run today although not very well. I got the car to Idle on its own for quite awhile, enough to check the tranny fluid test all the gears ect. The car has a real bad miss at idle almost like it has a plug wire off or crossed but it dont. At idle I am show ing 1.5 -2.0 injector duty cycle, MAP is around 45-50, and the Wide band O2 is stuck a 3.53. The Wide band reads 100 with the key turned on.

Thanks
 
Chuck Leeper said:
"The Wide band reads 100 with the key turned on."
Huh??
Click to expand...

I think that 100:1 a/f ratio would be ok for hydrogen, but not gasoline, I think you better pin out that harness before you continue.
 
Sorry, I ment the MAP reads 100 with the key turned on. I got the miss out of the car today with a fresh set of plugs. Now the O2 is stuck on 3.53, I think the O2 is bad.
 
It is impossible for the A/F to read that low on a Classic FAST. I would assume you are talking about the UEGO voltage :confused:
 
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