camarogirl18

iTrader: (2)

I dont have no signal to the FI using a noide light. Its a 91 RS V6 with 3.1 liter. All fuses are good, all ground wires have ground so what am i doing wrong? Where do I need to start looking from here?

travis401

iTrader: (1)

does the security light come on and stay on when you turn the key?

camarogirl18

iTrader: (2)

no it comes on and then goes off

travis401

iTrader: (1)

alright that shows thats its not a VATS issue. if the injectors arent pulsing then it could be a problem in the ECM, or something as simple as a break in the injector wires. im no good with FI.

camarogirl18

iTrader: (2)

k thanks ill double check the wires. the ECM is new. what is the VATS? I cant remember what it is

travis401

iTrader: (1)

Vehicle Anti Theft System. It reads the resistnce level of the "chip" in your key, and if its right, it sends a signal to the ECM to allow the injectors to pulse (hence why i asked about the security light) and it also grounds the start enable relay, allowing the starter to function.

Apeiron

Do you have spark?

camarogirl18

iTrader: (2)

thanks! im so dumb

would putting a new computer in it have anything to do with it? ive wasted 2 weekends trying to get this thing figured out. im ready to send it to the scrapyard.

camarogirl18

iTrader: (2)

Yep it has spark but no fuel. the distributor, cap, button, wires, plugs are all new.

Apeiron

If the wiring is in order I'd suspect a problem with the injector driver in the ECM.

camarogirl18

iTrader: (2)

is there any way of checking that without having another ECM? i returned the stock ECM for the core charge on the new one already.

Apeiron

The noid light is pretty much the test.

Why did you replace it?

camarogirl18

iTrader: (2)

heres the story:
the car wasnt running right so we were told it was the computer causing it to miss & carry on & not run right. so we replaced the computer & it stilll wasnt running right. later found out it was a blown head gasket so fixed that & put everything back together & in the process replaced the distributor, plugs, wires, button & cap because they all were old & needed replaced. now with all that replaced it wont start cuz theres no signal from the noide light.

Apeiron

Well if it ran before you took it all apart, then it's most likely that you've just put something back together wrong.

camarogirl18

iTrader: (2)

is there anyway of knowing for sure if its the ECM?

ive double checked everything & cant find anything unplugged or broke. ive had the distributor every which way from sunday thinking its the timing off.

if its any help, the car was running sooo bad before the head gasket finally blew that at idle it would shut off in traffic.

deadbird

Unplug the oil pressure switch (by oil filter).
Crank the engine... the fuel pump should run during crank.
If no, the Ecm isn't receiving a reference signal from the dist./ign module. It won't pulse injectors either.

camarogirl18

iTrader: (2)

i tried this & the fuel pump does not run. so does this mean the ignition module is bad or what? not sure where to start next...thanks any & all help is appreciated!

deadbird

There is that chance. The module can operate w/o the ecm (will produce spark).
If you unplug the 4pin connector from the dist, tap (brief contact) the terminal in line with the ppl/wht wire (reference, key on) with +5v (+5 to tps or similar), it should pulse the injectors and cause the pump to run for 2 seconds.

If No, reference circuit is bad.
If yes, ign mod may have failed and not sending ref signal to ecm
If pump runs and no pulse, injector circuit/fuse fail or, ecm driver

camarogirl18

iTrader: (2)

the fuel pump ran for 2 seconds & injectors pulsed. ive tried 2 different ICMs with the same no fuel pulse on crank over. so where do i go from here?

deadbird

From your testing, it seems all the wiring/ECM is in order and working as should but,
the pump doesn't not run during crank (with OPS unplugged), the injectors do not pulse either.

The only other thing that comes to mind is the hall effect pickup in the distributor is bad (a rarity) somehow or, not connected to the ICM except, you said it has spark so, it can not be that either.

With all that working properly, there shouldn't be any issue, even though there is.

All the above is what I checked on my friends '72 truck (w/a 88 TPI) and it was his ECM.

One more for fun, when you key the ignition on, does the check engine light come on ?

camarogirl18

iTrader: (2)

the ses light flashes once & then stays on but theres no codes given.

deadbird

As in zero codes at all, or only code 12 ?

camarogirl18

iTrader: (2)

theres no trouble codes just code 12 but the ses light stays on when switch is on

deadbird

SES should stay on with the key in run position (engine not running).
This is a rather difficult issue. Maybe a smart person will chime in with the answer soon.

The only other thing I could imagine to check is to test the ICM at pinC (ppl/white wire) for voltage during crank using a multi-meter or test light (pinC to ground). You should see a pulsed voltage signal/light while trying to start the engine.

Have you tried/can you get the engine to run using starting fluid ?

camarogirl18

iTrader: (2)

ill have to try testing the ICM at pinC after work.....never tried starting fluid just carbon choke cleaner & wd40 with no luck on either carbon choke cleaner & wd40. Car just wont start. Theres no fuel getting to the cyclinders without an injector pulse.

do you think its the ECM that is junk?

camarogirl18

iTrader: (2)

There is no signal at the purple/white wire when trying to start. Ecm bad or something else?

racerquinny

iTrader: (1)

dont know if anyone said it..i just skipped ahead. id replaced the ign module!! its under the dizzy cap.

deadbird

From my lack of knowledge and with everything you've tried, your testing indicates that you have a(nother) bad ICM.
The ppl/white wire sends a trigger signal to he ECM for fuel and injector control. If this is dead (no signal out from ICM), the ECM will not 'see' the engine as turning and will not run the pump or injectors.

Have the other ICMs you've used been new ? Have you applied new thermal grease each time you've changed the ICM ?

camarogirl18

iTrader: (2)

one is an old one (the one that was on car before head gasket blew) & one is a new one. neither ICM was removed so no need for grease. neither distributor puts out signal to purple wire but both put out spark for plugs.

the two pin plug on ICM, both have 11.76v with key on. cant get no volt/signal to come out on purple/white wire of 4 pin connector. ive tried both distributors (the new & the old one) & still nothing. whats next new ICM??

deadbird

The voltage at the pink wire (two pin plug) should be roughly on par with battery voltage. The same wire powers your coil.

The voltage on the ppl/wht wire pin shouldn't be anything great as it's just a pulse. An LED test light would probably be most ideal. If your multimeter is an autorange, it will never show anything unless it has a Tach range.

At best, which will only be a guess, I would say it's a bad ICM.

The blk/red (four pin) wire is to ECM ground. I don't honestly know if that will affect the ICM sending a reference signal or, not, if that circuit is open (i've never had to test that far).

Apeiron

You can see a small AC voltage on it.

deadbird

Would that be the same range as the pickup coil voltage (.1-.3vac)?
I thought the ICM changed the ac signal from p/u coil to dc (and amplify) to send to the ECM or, have I misunderstood what it's doing (very likely) ?

Apeiron

It'll depend on what kind of meter you're using but on a good one DC pulses will show up as some small AC voltage superimposed on a DC carrier.

camarogirl18

iTrader: (2)

Havent had a chance to fool with car any more these past couple days. Hoping to this weekend. Does anyone have a wiring diagram for the complete car? Im thinking its in the wiring & not on distributor. I took the new one i had gotten for it back to Advance & got another one & it still doesnt work. Send me an email or link please if you got one. Thanks!!

camarogirl18

iTrader: (2)

Soooo....we found a wire that was broke & that the coil was bad, so both of them is replaced. Next problem, why is it getting sooooo much fuel now thru the injectors that its flooding itself so bad that it still wont start????? It wants to start but just wont & smells of raw gas.

travis401

iTrader: (1)

is an injector sticking open?

camarogirl18

iTrader: (2)

I dont think any of them are sticking but is taking everything back apart & physically watching the fuel stop & start the only way to know if their sticking?? sorry for all the dumb questions....but i dont know.

deadbird

Considering the not right guess about the ICM being bad, I hesitate to say much.
One way of observing a stuck injector is watching the fuel pressure. Gauge hooked up, key on to prime, the pressure should rise and stay for a moderate amount of time. Though, a quick bleed off could also show a bad check valve in the pump as well.

I know when I had an injector sticking issue, you could open the throttle blade and hear the gas trickling out of the injector (helps to have a quiet area).

If you pull the injectors fuses, and it still runs (or fires a cyl or two) you probably have a stuck injector.

There is also a remote chance the negative side of one of the injector banks wiring is grounded causing the injectors to run static (always open). If you pull the fuses (no +12v power to them) and it doesn't run, or attempt to run, at all, I would check wiring.

camarogirl18

iTrader: (2)

thank you very much for all your help...got it now

310cid

iTrader: (1)

what color wire was broken and hat was that wire to what was ur problem having same problem flooding crazy and wont start

camarotucker

iTrader: (2)

What was the solution?