84 Crossfire no injector spray
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84 Crossfire no injector spray
After driving 84 to neighbors, it would not start to come home. Engine would turn over but no fuel spray from injectors. The fuel pump comes on for about 2 seconds and then shuts off when attempting to start. The following is what I have tried: changed fuel filter, injector fuses - OK, continuity from injector to fuses-OK, 12V at injectors when key turned to on position, 12V to hot injector terminals thru fuses and other injector terminals to ground - turned key to on and fuel sprayed from injectors for 2 seconds. "Check Engine" light is on when ignition is "on". I grounded the diagnostic test terminal on the ALCL connector - no code 12 but the "check engine" light flashes. I'm not sure if I am supposed to count the number of times the "check engine" light flashes or if a "12" actually flashes. The manual says to disconnect the white ECM connector. That is easier said than done for a 69 year old guy. Any help would be appreciated.
Thank you, Don
PS I figured out how to count the flashes of "check engine". I only get a code 12.
Thank you, Don
PS I figured out how to count the flashes of "check engine". I only get a code 12.
Last edited by elkprairie; Jul 8, 2022 at 04:07 PM. Reason: Added information
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Did you check for spark?
ECM needs a RPM signal to fire injectors and to fire spark plugs
If no spark, would try ignition module--heat/age related
Ensure "tach" wire is solidly connected to distributor cap--this is signal to ECM
If spark, try and "prime" with raw gas down Throttle bodies--if starts==fuel issue--no start== most likely spark/ignition issue
ECM needs a RPM signal to fire injectors and to fire spark plugs
If no spark, would try ignition module--heat/age related
Ensure "tach" wire is solidly connected to distributor cap--this is signal to ECM
If spark, try and "prime" with raw gas down Throttle bodies--if starts==fuel issue--no start== most likely spark/ignition issue
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I replaced the ignition module - no fuel spray. Poured some gas in the throttle bodies - would not start. Connected and reconnected the tach wire - no help. Are there any more suggestions as to what I could check?
Thank you
Thank you
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
You really need to buy a GM Factory Service Manual (FSM). All the troubleshooting for this issue is in the manual. Do NOT buy the universal C4 ones from Wally World or the auto parts store. You can find either paper or CD copies on eBay.
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FSM is a great suggestion for all !--Good reminder
With the key on--test for 12vDC going into the distributor cap (coil)--the wire next to the tach terminal--test key on and cranking
This is the 12v "ignition on" circuit--required for spark--if no spark--voltage/current is interrupted between battery positive and distributor.
FSM required to troubleshoot components and connections
If power, issue inside distributor (ignition coil--magnetic pick up--trigger wheel (shaft)--ignition coil--rotor/cap--even a bad ground of the distributor, or broken gear/roll pin on distributor shaft--even a bad cam gear--unlikely)--In depth testing found in FSM
With the key on--test for 12vDC going into the distributor cap (coil)--the wire next to the tach terminal--test key on and cranking
This is the 12v "ignition on" circuit--required for spark--if no spark--voltage/current is interrupted between battery positive and distributor.
FSM required to troubleshoot components and connections
If power, issue inside distributor (ignition coil--magnetic pick up--trigger wheel (shaft)--ignition coil--rotor/cap--even a bad ground of the distributor, or broken gear/roll pin on distributor shaft--even a bad cam gear--unlikely)--In depth testing found in FSM
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Installed a new pickup coil in the distributor. Now have spark at plugs. Attempted to start; still no spray from injectors. Checked all connections from distributor to ECM according to FSM. All good. Does anyone have any other suggestions before I spend $$$ for an ECM?
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Will vehicle start if adding fuel in TBI?
ECM issue would be very low on my "list" at this point
Double/triple check wiring and connections (work done)
Are injectors "powered" up?--disconnect and check voltage to injectors (key on)--should be 12v on one of the wires (sorry no diagram for color)
Look in FSM for diagnostic procedure for no injector "triggering/.firing"
Best to monitor the tach signal into the ECM using a lab scope, or graphing DVOM--this will "tell" if tach signal is 'getting to' ECM
ECM issue would be very low on my "list" at this point
Double/triple check wiring and connections (work done)
Are injectors "powered" up?--disconnect and check voltage to injectors (key on)--should be 12v on one of the wires (sorry no diagram for color)
Look in FSM for diagnostic procedure for no injector "triggering/.firing"
Best to monitor the tach signal into the ECM using a lab scope, or graphing DVOM--this will "tell" if tach signal is 'getting to' ECM
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Is there fuel pressure, injectors could fire and not spray if no fuel
Do you hear the fuel pump running w/key on? Should run for about 2 seconds with key on
The oil pressure switch by distributor controls the fuel pump relay when oil pressure rises--is the connector intact on the oil pressure switch?
Do you hear the fuel pump running w/key on? Should run for about 2 seconds with key on
The oil pressure switch by distributor controls the fuel pump relay when oil pressure rises--is the connector intact on the oil pressure switch?
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I put a little gas in each throttle body and the engine fired up. There is 12V at the injectors and the injectors spray fuel for about 2 seconds when the ground side is manually grounded and the ignition turned to start. I have double checked all connections between the distributor and the ecm. I have checked the fuel pump switch and it is working properly. No access to a lab scope to monitor the tach signal, however the dash tachometer shows several rpm while cranking.
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From: Liliha Bakery stuffing my face with coco puffs!
I'm a little miffed that it could be more than 1 issue considering the parts you changed anyhoo..if your TPS is reading more than 2.5v, it will prevent the injectors from firing but I'm thinking it would throw a code for that.
Once upon a time bro's fsc stuck on the side of the road, I could hear the 2 second whirring from the fuel pump but he didn't tell me the fuel gauge was sitting on E!!!
Once upon a time bro's fsc stuck on the side of the road, I could hear the 2 second whirring from the fuel pump but he didn't tell me the fuel gauge was sitting on E!!!
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As the engine starts w/fuel in TBI units--timing close and secondary ignition getting to plugs under compression stroke
As RPM bounces on tach--tach lead connected
Need to determine where the fault is:
ECM firing injectors or no fuel
Do you have a NOID light? If so, install in place of injector--if flashes--ECM getting signal and firing injector--suspect fuel delivery issue
No NOID flash--suspect wiring to ECM, ECM wiring to injectors or ECM
FOR TESTING ONLY
Run Battery + and Batt to fuel pump
Be sure to install a fuse on the Batt + lead--SAFETY first
If starts/runs fuel pump power/ground issue
Can rent NOID lights from local parts house for low $$$ or buy a set--under $50
As RPM bounces on tach--tach lead connected
Need to determine where the fault is:
ECM firing injectors or no fuel
Do you have a NOID light? If so, install in place of injector--if flashes--ECM getting signal and firing injector--suspect fuel delivery issue
No NOID flash--suspect wiring to ECM, ECM wiring to injectors or ECM
FOR TESTING ONLY
Run Battery + and Batt to fuel pump
Be sure to install a fuse on the Batt + lead--SAFETY first
If starts/runs fuel pump power/ground issue
Can rent NOID lights from local parts house for low $$$ or buy a set--under $50
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Finally got engine started. I started checking the 12v to the injectors during start and there was none. I checked the 3A fuses and they were both blown. I had checked them before replacing the pickup coil and they were both fine. Got some new fuses and rented a noid light. Replaced the fuses and plugged in the noid light to the injector harness. Both injectors made noid light flash, Connected the harness to the injectors, turned the key, and varoom!
Thanks to all who responded with advice.
Thanks to all who responded with advice.