you should see them both firing. sounds like 1 still isn't firing. did you try my tapping trick on the injector housing while the engine is running? swap the injector connectors and see if the "working" injector is still firing. could possibly be a connection at injector or ECM, or the ECM itself (failed driver). it's possible 1 injector is bad even though they cleaned them.
I did try tapping the injector housing as suggested, and also originally swapped the connectors as noted in a previous reply. Neither one produced gas out of one injector. The new matched injectors ship Sept 1, so hopefully I can get the by Friday. I did replace the ECM through original diagnosis by the manuals. This did not change anything, so I now put the old ECM (6 years old) back in. Hoping it is the injector.
Also, commenting on Dave's post, I do not have a knock sensor. The *.adx file I got from the sight had it in there, so I am going to remove that and a few things I do not have. this should clean up the data log a bit.
just to cover your bases have you checked for continuity in the injector wires back to the ecm and also to ground?
EDIT: nm you already confirmed swapping the injector plugs which tell me wire integrity and ecm are OK
Hi Tayto, great idea nonetheless to check for continuity. No harm, no foul!!
AAARRGH, as C. Brown would say when trying to kick the football.
New injectors, still one firing. Maybe I was mistaken when I swapped the connectors to the injectors previously. I am starting to question myself.
In the manual Chart A4 "Injector Circuit Diagnosis All Engines". It states to disconnect the distributor 4-way connector and check with a test light for blinking during ignition on.
I am unable to locate such a connector, and if it is the ignition module, I have two connectors with two terminals on each side. I have narrowed it down to looking for the Lt Blu circuit 467, and how to see if I am getting juice to it. My initial thought is to go from the connector about 1' and scrape a bit of insulation off for a quick continuity check at the connector level.
Another question to check the same circuit at D16 on the ECM, is this the connection that plugs directly into the ECM?
Thank you so much for your patience and help.
Hi Tayto,
New injectors, still one firing. Maybe I was mistaken when I swapped the connectors to the injectors previously. I am starting to question myself.
In the manual Chart A4 "Injector Circuit Diagnosis All Engines". It states to disconnect the distributor 4-way connector and check with a test light for blinking during ignition on.
I am unable to locate such a connector, and if it is the ignition module, I have two connectors with two terminals on each side. I have narrowed it down to looking for the Lt Blu circuit 467, and how to see if I am getting juice to it. My initial thought is to go from the connector about 1' for a quick continuity check at the connector level.
Another question to check the same circuit at D16 on the ECM, is this the connection that plugs directly into the ECM?
Thank you so much for your patience and help.
i believe one side is constant key on voltage (RED & WHT) and the other side is on pulsed ground by the ecm (BLUE & GREEN)
I have to check the colors you note for sure. The continuity for both injector circuits to ECM are good. I will check for resistance for both next. Looking at the ignition control module as mentioned. The manual states to check for a reference pulse to ckt 430 (ppl/wht) with ignition on. My ignition module is most likely pre 1990 and only has the two pins per side i.e. a 4 pin ICM. Do you know which wire would supply the reference pulse of the colors you noted? I am unable to find the ppl/wht ckt 430 going to my distributor.
did you try swapping the injector connectors? does the problem move with the connector or stay on the same side?
Picture of a 7 Pin Ignition Module, common for OBD1 EFI System.
dave w
Electronic Spark Control.JPG
I did, and the problem moves with the connector. Meaning injector is good, signal to the other bad.
Thank you Dave, this is what I am looking for. Is this in the 89 or 90 emissions/fuel manual? I only have the B, C and G, W posts on my ICM.4pin.jpg
Using the 4 pin module works for a "Fuel Only" TBI system, meaning no spark control from the ECM.Originally Posted by Dlxman
Likely, if one injector is working, the 4 Pin Ignition Control Module is working fine.
The ECM has two injector drivers, maybe one of the injector drivers is bad?
dave w
Thank you, I was hoping the Ignition Control Module was bad. 3 months ago, I removed it and had it tested at a parts store and it was fine. I also heard that it could be bad and still test fine... (word on the street). I would like to test the circuit as noted in the manuals, but I would only guess which wire is sending the reference pulse. How, or where would I check for an "injector driver"?
BTW, I also believe this is a "fuel only" TBI now that you mention it. This is also a Howell TBI If I have not noted so earlier.
Thank you so much for your time. I have a new ignition control module to add to my parts list.....unfortunately.
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