FI troubleshooting

[dnudelman]

I'm back chasing down why our 1980 FI spider won't run. Just a little
background to those you missed the post in November.
We bought the car with a seized 2000 motor. Transplanted a running 1800 motor
and bolted on the FI. New FI temp sender, rebuilt injectors, hoses.
The PO had bypassed the double relay so the fuel pump was switched on by the
key. I've restored the wiring to original, found the double relay bad and
replaced it. I've tested the timing of the cold start switch, seems to work.
Fuel pressure is ok.

So now, the car starts right up. Warms up, idles at 1800 and dies. Unplugged
the cold start injector, car won't start. When warm, car starts, idles at 1800
for a minute or two and then dies. Seems like something is shutting off the
fuel feed.

Suggestions on my next steps?
Thanks

[So Cal Mark]

why is the idle so high? Air leak? misadjusted throttle stop screw?

[dnudelman]

why is the idle so high? Air leak? misadjusted throttle stop screw?

Since I can't get it to run long enough when warm, I thought I'd concentrate on that problem first. The throttle top is about 1 screw turn in and and idle mixture about 1 screw turn out from seated. I suppose timing might be a little off as I've never had it idle at 600-800 to check it closely.

[pope]

High idle is a common problem with a bad aux. air valve. Also check that there is not a vacuum leak in the hose going to and from the valve.

[rlux4]

"Seems like something is shutting off the fuel feed."
Are you sure the fuel is shutting off? Put a test light on the green with black wire on the dual relay (goes to fuel pump), see if it looses power at the time the car dies. Have you checked to see if you're getting spark when it dies? You can put an inductive test light on a spark plug wire and see if it looses spark at that time. As far as the cold start valve goes, if everything were working normally, it wouldn't make any difference if it were plugged in or not after the car has warmed up, it's not getting a signal at that point.
You need to determine if the problem of dying is fuel or spark related.
Ron

[launieg]

If you determine it is definitely a fuel related problem, you might want to check the throttle position sensor (switch) as per Brad Artigue's FI Guide or your manual. My understanding is that if it is not adjusted correctly (simple enough with a continuity tester/ohmeter) then it could be telling your ECU to shut off the injectors.

Be careful turning the screws that hold the switch in position - I twisted one off - very easy to do!

[ga.spyder]

Here is a complete troubleshooting guide for the f.i. system.Most of the fuelie guys have downloaded this,it is invaluable.

http://www.wcmotors.com/personal/Fiat%2 ... agnostics/

Craig

[dnudelman]

Thanks to everyone who has contributed to this thread. I appreciate the help.
Here is where I am at today.

1. I cleaned the wires attaching to the coil, set the throttle position switch, fully seated the idle bypass screw, set idle stop screw to contact with throttle plate and then about 1/2 turn in.
2. Car started right up, idled at about 1800 rpm all the way past the point of the radiator fan coming on, the motor did not die. This is good. I shut the engine off.
3. Would not get restart, getting spark. Sort of catches and dies.
4. Let sit for a few minutes, starts right up, continues to run at the 1800 rpm
5. Following a suggestion, I pulled the cold start injector. covered in black stuff but not "dripping wet"
6. Replaced the cold start injector with one out of a Volvo. They bolt right on, but hose size is different.
7. Car restarts right away (it had been sitting about 15 min). Idle still the same.
8. I pull #1 spark plug. Its black and dripping wet.
9. Regarding Idle speed, clamping hoses either end of the aux air valve made no difference.

Thanks,
David

[So Cal Mark]

the plugs shouldn't get wet. Did you pull the plug immediately after shutting off the engine? I'd check all of the plugs for wetness, they could be why the restart is difficult. That would indicate leaking injectors.
Have you checked timing yet? It will be hard with the idle so high, but you really need to get the basics sorted out. You could set the timing staticly as a starting point. Put the engine at tdc, remove the dist cap and turn the dizzy so the tooth on the reluctor is lined up with the pickup unit tooth. If you have the key on, turning the dizzy slightly past the teeth will create a spark.
Do you have a fuel pressure testor and noid light for diagnosing the FI system?

[dnudelman]

SoCal mark said: the plugs shouldn't get wet. Did you pull the plug immediately after shutting off the engine? I'd check all of the plugs for wetness, they could be why the restart is difficult. That would indicate leaking injectors.
A. See next post

Q. Have you checked timing yet?
yes I set it statically but have been monitoring it with a timing light. at 2000 rpm its about 1/2 inch before the 10BTDC mark. If I move the distributor to move the timing back towards the 10 btdc mark while the engine is running at 2000 rpm, I loose the ignition and it dies.

Q. Do you have a fuel pressure testor
A. yes and pressure is about 42 psi

Q. and noid light for diagnosing the FI system?
A. no

[dnudelman]

SoCal mark said: the plugs shouldn't get wet. Did you pull the plug immediately after shutting off the engine? I'd check all of the plugs for wetness, they could be why the restart is difficult. That would indicate leaking injectors.

OK, just went outside and ran a plug test
This time I'm using the volvo cold start injector, not my original fiat CS injector.


1. Started the car, ran it until warm, Idle at 2000 rpm. Shut off the car.
2. Pulled plugs 1, 2, and 3 (4 is such a pita)
3. Plug 1 dry black
4. Tried to re-start the car, could not. Getting spark, almost catches but will not.
5. Pulled plug 1, dry and very black, plug 2 dry and black, plug 3 dry, black but a little whitish on the electrode. Spark plugs are NGK BPR6ES

For those who are wondering I have searched for vacuum leaks by disconnecting the hoses one by one and covering the orifice with duct tape. No luck. I have also examined the afm to intake plenum hose and don't see any cracks.

Thanks
David

[So Cal Mark]

does it hold fuel pressure after shutting off the engine?
Have you checked the coolant sensor resistance throughout the temperature range?

[mdrburchette]

Could it be a faulty oxygen sensor causing it to run too rich?

[rlux4]

Your coolant temp. sensor is the most critical one on the system. The car will run even if the others are unplugged, albeit with poor mileage. A bad coolant sensor would make it either not run, or run very poorly. The resistance ranges for the sensor are 68°= 2,000 to 3,000 ohms; 176°= 250 to 400 ohms. You could get a resistor at Radio Shack in the 300 ohm range and plug it in the temp sensor connector at operating temp, see if it clears up.
Ron