No Injector Signal? - Maintenance and Repair Forum - j-body.org

No Injector Signal? - Maintenance and Repair Forum

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No Injector Signal?

Sunday, February 25, 2007 2:28 PM

I have a '96 2.2L OHV. I'm not getting any injector signal to any of the injectors. I'm getting spark at all 4 plugs. I'm getting reference voltage to the cam position sensor and the sensor is new. Anyone have a clue as to why I'm not getting any injector signal?
Edit: No CEL, No codes.

Edited 1 time(s). Last edited Sunday, February 25, 2007 2:29 PM

Re: No Injector Signal?

Sunday, February 25, 2007 8:11 PM

alont

Could it be this---maybe

http://www.j-body.org/forums/read.php?f=11&i=113856&t=113856

Alont

Re: No Injector Signal?

Sunday, February 25, 2007 9:19 PM

MadJack

I never had any problems with it stumbling or stalling. She was running fine when I parked her, wouldn't start the next time I tried to start her. The grey wire that feeds the injectors 12v + is also the same line that feed the fuel pump(F/P-INJ fuse in fuse panel to the Fuel Pump Relay to pump and injector harness), which is working fine. As stated in the link the inector timing come from the PCM Ground signal to fire the injectors. I will double check the 12v + feed to the harness, to make sure its getting that far. Peviously I had only used a noid light to check for the signal.

Re: No Injector Signal?

Monday, February 26, 2007 7:10 AM

MadJack

I've got the 12v+ to the injector harness.

Re: No Injector Signal?

Wednesday, February 28, 2007 8:37 PM

MadJack

Well it turns out to be a shorted TPS, making the PCM think I had the throttle wide open and i was trying to clear a flooded motor, hence shutting off the injectors.

A good scanner can also identify other faults that aren't throwing error codes. My EGR was stuck at 91%, diluting the cylinder charge. My MAP, A/C pressure, IAT and ECT were all reading high. Turns out a previous battery leaked acid down into the wiring harness beneath the battery tray, causing a voltage bleed through the wires, casing high readings and throwing off the A/F readings and pulling timing (remember most sensors read between 0 and +5v to milli-volt readings). Pull the wire loom from over the harness beneath you battery and check for signs of battery acid in it. If you see any signs of it, wash the wires with a mixture of baking soda and water, to neutralize and flush away the acid.

Re: No Injector Signal?

Thursday, March 01, 2007 4:49 AM

alont

Unbelievable!, but good news that you fixed it.

{If Throttle Position Sensor is over 2.5 volts ECM could be in the "Clear Flood Mode" which may cause the engine not to start.}

Great detective work to identify the original cause of the failure, it sure threw a few sensor readings off.

What Scanner do you use?

Alont

Re: No Injector Signal?

Thursday, March 01, 2007 5:49 AM

MadJack

I can't take the credit for this one, my friends shop owner found it.

As for the make and model of scanner, I didn't pay that close attention to it, but it's a PC based system. Very thorough. I didn't realize I had so many little thing going wrong, till we pulled up the sensor readings screen and saw how many things were reading so high.. Then again, we are talking about a car produced almost 11 years ago, with the original wiring and most of the sensors are original (most of which are working properly).

I learned a bit about trouble shooting electronic systems, something I've never been too good with, I can usually do some basic stuff. The mechanical side is my forte, not electronics. I need some needle tip and clamp leads for my multimeter, the stock tips just don't cut it. Trying to hold the standard tips in place and operate the the ignition switch or move wiring harnesses is impossible, without being clamped or plugged in. A PC based scanner wouldn't hurt either.

Re: No Injector Signal?

Sunday, March 04, 2007 5:39 AM

alont

Thanks for the info, Jack

I saw an advert for a scanner(I thought) for $645 and was immediately interested. Further searching revealed it was a software update for a Snap On scanner system that was somewhere around $8,500!

So I dream on.

Alont

Re: No Injector Signal?

Sunday, March 04, 2007 11:02 AM

Rob

I'm thinking of buying the MODIS, its $10,500 but I can get it, and just pay on it.

I need a good scanner

- 2004 Cavalier - 124k, owned since new

Re: No Injector Signal?

Sunday, March 04, 2007 5:05 PM

MadJack

I've seen a few scanners ranging from about $3K +. Add the O-scope, multi-spectrum gas analyzer, etc.. $10K, easy. I saw the MODIS Elite 6.4 for $7,695.00 but $10,500 ? What is it, your local Snap-On dealer wanting $2,305 to line his pocket?

Re: No Injector Signal?

Sunday, March 04, 2007 5:29 PM

Addicted to meth

I have a PC based scanner. It cost about $135 (includes the cables and a disc). I have found other datalogging programs that are free (but you have to have a cable to access the ECU). These can be really helpful in finding issues. Of course you have to know what you are looking at. If you do not it will not matter. I'm still learning.

FU Tuning

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