Hello,
I have tried searching threads for like problems and mine is acting different.
I have a ’96 - Z28 - T56 – with ~108k on it running great before I started working on it.
I am getting No injector pulse. I have Spark, and there is over 50psi at the fuel rail Schrader.

SECURITY light has been on since I bought it, causing no problems.

Background on what I have done; complete tune up/work done one year ago, new filters, fuel pump, plugs, wires, New TPS (broke when bypassing TB coolant), CAGS disabled W/ resistor installed. Manual cooling fan switch installed. Coolant level disconnected. It ran great with that work done, for 6 months and about 1500 miles.

Then,
About four months ago I started doing a EWP swap, and Cam swap (following shbox’s steps online). I ended up changing a few more things.
The Opti was replaces due to coolant melting (see album for pics, but it still work with that damage). I bought a new ADP Opti online. And I did put red locktight on rotor screws.
The a/c was deleted, switched to a 52mm TB w/ coolant bypassed, Generic CAI installed, CSR EWP installed powered off u/h electrical center w/ relay (front timing cover welded closed),

Things checked so far,
I am getting Spark out to the plugs.
There is system voltage on all the pink leads at the injectors. And I checked wire continuity from injector clips to PCM plug A3,4,5,6 and A19,20,21,22.
Used my PCM safe test probe on ~12volts and checked injector leads with cranking, and got no light.
Coil has 5800 ohms from tower to each terminal.
ICM line has ~12 VDC on A and D, ~3.2 VAC while cranking on B, and C had high resistance to ground (~95ohms).
Opti harness had 5.1 volts on A and B, ~12volts on C, and continuity to ground on D.
Took my ICM to AutoZone and they said they couldn’t test that part number. Neither could O’reilly’s or NAPA.
Manually applied 12volts and ground to injector and it sprayed.
The car will not run on starting fluid sprayed into the TB. It backfired out the intake.

Please let me know what I should check next.
Thanks for all the help and advice.
Eric

 

Go to Rob's page SHBOX.com and read about the VATS. The security system affects both the starter and the Injectors. I think your problem lies there......

Good luck!

 

Hi, Thanks for the reply.
I went to 4th Gen LT1 F-Body Tech-PassKey/VATS and other sites and read all about VATS. It could be VATS if the Theft Deterent Modual(TDM) in the Body Control Modual(BCM) is bad on just the Fuel enableing side. Bacause I still am able to crank the starter. Is there a way to check and see if the BCM is sending the enable sigle to the PCM? (50htz signle?)

Can the optical sensor in the Opti cause the Injectors not to pulse?

 

Any DTCs, even pending?

The Vats can be solved relatively easy, one by tuning it out, or do the resistor mod

The opti-spark does have 2 optical triggers in it. One is a 360 slot high resolution counter the other is a 4 slot low resolution counter. From my understanding it looks at the lo res counter to determined the current cylinder firing. I don't know what would happen if it was not reading the low res counter.

Also the injectors should measure 10ohm~16ohms between leads

 

What does a scan say? There should be a trouble code if the PCM is not getting the fuel enable signal. It can be measured with a meter that has a Hz scale.

 

Thanks Guys.
There were no trouble codes while it was acting up. But its running now. I pulled the water pump and removed the opti cap. with #1 at TDC the rotor was off 60*. I pulled the opti and relized I did install the opti wrong. I didn't think it was possible, but the cam dowel pin was in the bolt relief hole. Im such an a**. Got it started and it has a really high idle. Starts at 1000 and slowly goes up to 4000 untill i shut it off. Also the fuel pump relay is clicking on and off cycling the fuel pump few seconds.
Thanks for the help

 

I'm glad it's now running but a misaligned opti shouldn't give no injector pulse. Something still isn't correct here. I'd recommend doing the VATS bypass to clear that security light and potential problem....

 

Thanks,
I too didn't think timing being off would stop the injector pulses. I guess the optical sensor in the Opti was doing it. It was the only new thing i did to get it running and never had a DTC for it. the only codes were caused by me disconecting things for trouble shooting.
I understand bypassing VATS will turn out the security light. But It has been on the whole time owning the car and it had never caused any problems before. Is it worth it?
Now I need to find out my really eratic idle, and chattering fuel pump relay.

Thanks for all the input.

 

Is it possible the 12V probe wasn't fast enough to detect the pulse. You would need a 'noid light.

 

Swap the fuel pump relay with another relay such as the one from the A/C system you removed. A chattering relay is not a good sign, it could be just the relay, loose contacts, or a bad power/ground for the primary circuit.
Start there for your high idle, perhaps your car is having fuel delivery issues with your pump cutting on/off quickly thus raising the idle.

I would also check for vacuum leaks since you did a TB install. Remember to cap off ALL open ports even if they are for coolant just for good practice and keep crap out of them.

 

Fred,
It could be that the test prob wasn't fast enough. It was just a computer safe one from the auto parts store. But I pulled up the rail and looked for spray. With 12v at the injector and ground wires good back to the PCM. Only when I manualy gave the injector a ground did it spray. So Im pretty sure there was no pulse coming from PCM.

RyanEric,
The relay stopped clicking when I disconected my UltraGauge. So Im not sure what thats about. my other code reader doesn't cause it, but the UltraGauge did when the engine wasnt running.

 

Check if it still clicks with the car running, if it does, sounds like your UG unit has an issue. I read up on those devices and it seems those things are plagued with problems.

http://www.ultra-gauge.com/UltraGauge_Forum/index.php

 

I did run it for a few minutes with it disconected and there was no clicking. The relay was only clicking with ignition on, engine off. And it stopped when I unplugged the UG.

Also with my new TB it seems like the blades are slow to close. are some aftermarket springs weak? Should I add another return spring?

 

Ah, well then maybe it's just eating up a lot of juice with the car off.

Honestly not sure why you changed TB's, I thought I read somewhere around here that the bigger ones are unnecessary and sometimes hurt performance. ?

I'm really uncertain about the return springs, but perhaps you should try swapping on your original TB and check for idle issues again.