IPSC

Ok I got the car back together today after a LONG spell of not working on it. Everything is plumbed right and she cranks but not start...

I have Spark, tested with a spark plug on the #1 wire.

I have fuel pressure (44PSI) on the rail and I even cracked a line just to be sure and gas squirted everywhere.

On the injector harness I have 12 volts ON BOTH pins of the connector with the ignition switch set to the on position. Shouldn't there be power only on one pin? Here is the weird part when I ohm out the injector connector to ground I have just over 3000 Ohms on each of the two connectors... Shouldn't one of them be straight to ground?

So where to go from here? My fear is that when I had everything apart I somehow damaged the injector harness.

IPSC

theedge

Yes it sounds like you have at least one short.... To test the pins for voltage, youre touching the multimeter ground to a chassis or battery ground correct?

Ideally, one wire should have 12 volts on it with the key in the run position, and the other will be open. The second one should only have a path to ground when an injector is being fired.

IPSC

Yep Measuring from the Injector Connector to a Chassis ground and getting voltage on both pins at the same time.

AHHH so with out the engine idling there is no way to see of the injector is being provided a ground?

RATS ! ! !

Any suggestions on easy trouble shooting before tearing the top of the motor off to get at the harness?

IPSC

theedge

Well you dont have to tear off the top of the motor... Just the black plastic cover over the fuel rail. If its damaged, its damaged at the very ends where the wires go into the connectors. As for troubleshooting.... Is this problem present on one wire or all wires?

IPSC

I have the black plastic injector harness cover over the fuel rail off and there does not APPEAR to be any damage, but I am about to go look at each one very carefully.

I am getting this symptom on both the #2 & #3. I haven't pulled #1 or the #4 but it is a safe bet they are the same way.

Would the speed, reference sensors play into this at all?

IPSC

eclou

I would bet its the reference sensor connectors. Wiggle them and try to start again

Bri Bro

If you are measuring the voltage with the injector connected, it will read 12VDC on both sides. Go get a trouble light and connect one lead to the injector wire that goes to the DME, and the other to 12VDC. When you crank, it should pulse on when the DME sends the ground pulse to the injector to fire it.

IPSC

If the reference sensor is off would I still be getting spark?


I am measuring the voltage with the connector disconnected and the ignition switch in the on position. I will get a light and try that tomorrow.

Can some one show a detailed picture of where the injector harness attaches to the rest of the engine harness?

IPSC

jacksonrw

I had the same problem and ended up buying the Lindsey racing injector harness. It's in route.

jlturpin

Me too. Should be here tomorrow.

blown 944

both sides of the clip get 12 v

the dme pulses the injector by grounding one side.

Has it sat for awhile??If so try tapping on the injectors.

it also may be that the wires right by the clip are deteriorated and the wires are touching. If this happens you may need to reset the system by grounding one side. You can pull back the cover and look at them.

IPSC

So the 12 volts on both pins is normal huh?

It has sat for a while but today we took a fuel injector tester to the injectors and they click back and forth at a high rate of speed.

I tried pulling the boots up from around the injector connectors but they are on there tight, so no luck there.

Ok another thing when I crank the car the tach does bounce slightly. In addition I swapped out the DME relay only to discover one of my SPARE DME relays does not power the fuel pump.

The last time I saw symptoms like this was when my KLR chip was bad...

IPSC

blown 944

I would still make sure that you are getting spark and that the Fuel pump is working that should eliminate S/R sensors.

If that is the case and jsut the injectors are not working I would look at eh injectors and the harness as culprits.

I had a problem that was related to fuel pump not working and it ended up being a shorted O2 sensor blowing fuses.

jacksonrw

got mine today
YAHOOOOOO
On to the club race