posted a while back with a shut down while driving and have been working through the suggestions as i had time/money/patience. Tags are coming due and i have to get it through emissions so I'm back at it. 84 4cyl with manual (typical SE) towed home after it shut off while driving. no fuel spraying at TBI, has gas and appears to have pressure (sprayed fuel when i split the housing to swap the injector head) used a noid light to learn there was no signal to the injector. tonight I swapped the ICM with one i had laying around. now noid light indicates erratic signal, tach jumps around while cranking, noid flashes then stops then flashes a few times and stops. need the next round of suggestions please.
Typically these threads go in the technical section, but are you sure you have a good ICM?
I'm not sure where the FPR sits in relation to the TBI, but you might want to check that. I know nothing about the 2.5, but if there is no buel at the TBI, there shouldn't be at the injectors.
Have you checked the distributor, rotor, and ignition coil?
As you crank the starter, look at the tachometer. It should move up to about 300 to 400 rpm. If it stays on the peg, you have no primary ignition. The components of the primary ignition are the ICM, pick-up coil, distributor magnet, and part of the ignition coil. You can test the ICM at a parts store. The distributor magnet can be inspected for breaks, and here is a simple test for the pickup coil and ignition coil.
as stated, the tach jumps when cranking doesnt stay at one level and is not pegged at the bottom. I'm not sure the ICM is good but it came from a motor i was told ran when pulled. spray is erratic and NOID light doe not indicate a stable signal. so i think the injector is simply reacting to the unstable signal. thoughts on what cold be driving the erratic signal? before i replaced the ICM there was no signal at all.
When the primary ignition is working properly, the tach will be very steady at 300 to 400 rpm when cranking the starter, so I think it would be informative to do those tests. I would start with the pickup coil.
Test, the wires going to the injector, make sure they aren't shorting out any where. I had a 84 that had a broken wire going to the injector, no signs of any insulation brakes. it was just broken inside the wire about 4" from the injector when I started to remove the insulation. Fixed that wire and everything was fine.
Test, Test, Test before throwing parts at a problem.
Edit to add,
"I would rather pound my balls flat with a sledge hammer than hunt down an electrical problem!"
Steve
------------------ Technology is great when it works, and one big pain in the ass when it doesn't
Detroit iron rules all the rest are just toys.
[This message has been edited by 84fiero123 (edited 01-24-2016).]
ok, got a meter and both haynes and chiltons since the distributor in your illustration is not what i have on my 84. makes sense and the PO cut and spliced some wires going from the dist to the coil and/or harness. i spliced into it too when i added an aftermarket tach years ago, it worked for years but something may have turned loose. thinking about it now, when it intermittently sprayed fuel i should have at least gotten a chug from the motor and there was nothing.
update: performed all the tests to pickup coil and primary coil and to the best of my ability they both appear to be good. checked for broken wires and found none. had the ICM from the car and my spare checked and both test good. the testing procedure for the pickup and primary coils used an ohm tester and i am not skilled with electronics but i believe i did it right. mostly challenged by terms like "low setting" "high setting" and "infinite" my meter has different settings so i used 200 for the the low and 2000 for the high. infinite i took to be the same as when the probes are not touching anything, does that sound right?
update: performed all the tests to pickup coil and primary coil and to the best of my ability they both appear to be good. checked for broken wires and found none. had the ICM from the car and my spare checked and both test good. the testing procedure for the pickup and primary coils used an ohm tester and i am not skilled with electronics but i believe i did it right. mostly challenged by terms like "low setting" "high setting" and "infinite" my meter has different settings so i used 200 for the the low and 2000 for the high. infinite i took to be the same as when the probes are not touching anything, does that sound right?
update: performed all the tests to pickup coil and primary coil and to the best of my ability they both appear to be good. checked for broken wires and found none. had the ICM from the car and my spare checked and both test good. the testing procedure for the pickup and primary coils used an ohm tester and i am not skilled with electronics but i believe i did it right. mostly challenged by terms like "low setting" "high setting" and "infinite" my meter has different settings so i used 200 for the the low and 2000 for the high. infinite i took to be the same as when the probes are not touching anything, does that sound right?
That sounds about right. As for other ideas, I am scratching my head on this one.
[This message has been edited by Gall757 (edited 01-25-2016).]
what were we talking about?
