Injectors not firing
#1
Injectors not firing
Hi,
I have a 2000 Integra LS that has not been started in a year and a half. It was running before. I swapped it and the entire main and engine harnesses, cluster, and ignition switch into a civic... so really it's an Integra in a civic shell.
It has spark, fuel pressure, cranks, but the injectors are not firing. I can't hear any clicking. I unplugged the fuel rail and held the injectors in with tape and cranked - no spray of fuel from the pintles on any of them.
what are the most common connection problems that could cause the injectors to not fire? Or could they all be clogged and stuck from sitting unused for 1.5 years? Please help!! I have searched, but it's still not clear. I have to get the car out of here in two weeks... we are moving.
I have a 2000 Integra LS that has not been started in a year and a half. It was running before. I swapped it and the entire main and engine harnesses, cluster, and ignition switch into a civic... so really it's an Integra in a civic shell.
It has spark, fuel pressure, cranks, but the injectors are not firing. I can't hear any clicking. I unplugged the fuel rail and held the injectors in with tape and cranked - no spray of fuel from the pintles on any of them.
what are the most common connection problems that could cause the injectors to not fire? Or could they all be clogged and stuck from sitting unused for 1.5 years? Please help!! I have searched, but it's still not clear. I have to get the car out of here in two weeks... we are moving.
#2
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Re: Injectors not firing
You left the most important question unanswered, Is the Check Engine Light on?
If the ecu gets signals from the three variable reluctance sensors in the distributor it will always try and fire the coil but many things that cause a check engine light will also effect injector operation. If you have a test light or multimeter check one of the four wires on the injector clips that will all be the same color (most likely yellow with a black stripe or red.) These wires should show +12Vdc with the key turned to the IGN position. If no 12v then it's probably a fuse.
If the ecu gets signals from the three variable reluctance sensors in the distributor it will always try and fire the coil but many things that cause a check engine light will also effect injector operation. If you have a test light or multimeter check one of the four wires on the injector clips that will all be the same color (most likely yellow with a black stripe or red.) These wires should show +12Vdc with the key turned to the IGN position. If no 12v then it's probably a fuse.
Last edited by Tw34k; 04-19-2012 at 06:37 PM.
#3
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Re: Injectors not firing
Check for 12v at the injectors. If you have nothing, I believe they opperate off of a relay, not a fuse. Should be labeled on the underside of your engine bay or under dash fuse box cover.
#4
Re: Injectors not firing
Sorry, forgot to add:
I checked the voltage on the injectors. Main wire has around 12 v, but the other wire (the PCM ground side) has only around 0.04 or even less on all of the injectors, and they are not all the same.
I checked the voltage on the injectors. Main wire has around 12 v, but the other wire (the PCM ground side) has only around 0.04 or even less on all of the injectors, and they are not all the same.
#5
Re: Injectors not firing
You left the most important question unanswered, Is the Check Engine Light on?
If the ecu gets signals from the three variable reluctance sensors in the distributor it will always try and fire the coil but many things that cause a check engine light will also effect injector operation. If you have a test light or multimeter check one of the four wires on the injector clips that will all be the same color (most likely yellow with a black stripe or red.) These wires should show +12Vdc with the key turned to the IGN position. If no 12v then it's probably a fuse.
If the ecu gets signals from the three variable reluctance sensors in the distributor it will always try and fire the coil but many things that cause a check engine light will also effect injector operation. If you have a test light or multimeter check one of the four wires on the injector clips that will all be the same color (most likely yellow with a black stripe or red.) These wires should show +12Vdc with the key turned to the IGN position. If no 12v then it's probably a fuse.
#6
Re: Injectors not firing
And I just went out to try and jump start in case it was my battery that was too weak. Nothing.
OH! but i checked for voltage bouncing on the PCM controlled ground wire of the injector plugs, and they all bounced around some as my wife cranked the engine. I have a digital multimeter, so not easy to tell how much they bounced. It was in the hundreths of a volt.
OH! but i checked for voltage bouncing on the PCM controlled ground wire of the injector plugs, and they all bounced around some as my wife cranked the engine. I have a digital multimeter, so not easy to tell how much they bounced. It was in the hundreths of a volt.
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#9
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Re: Injectors not firing
The power wires for the injectors, [wire that is the same color on all 4 injectors] get their power from the PGM-FI Main Relay, [fuel injector relay] obviously it is turning on because you have power to the injectors and any voltage you are reading on the other lead at each injectors is just the power through the resistance of the injectors coil. the ECU/ECM supplies the injectors with a ground pulse, if there is no ground pulse the injector will not "fire".
The first thing I would do is confirm there is no ground pulse from the ECU/ECM, a noid light is the best for that...
A 12V LED could also be used, or the LED type test light.
If you find there is no ground pulse, you would next check for power at IGP1 and IGP2 at the ECU/ECM, they are also supplied power by the injector relay.
If on the other hand you find a ground pulse then the injectors, "could they all be clogged and stuck from sitting unused for 1.5 years" and you will need to replace them or have them serviced. 94
The first thing I would do is confirm there is no ground pulse from the ECU/ECM, a noid light is the best for that...
A 12V LED could also be used, or the LED type test light.
If you find there is no ground pulse, you would next check for power at IGP1 and IGP2 at the ECU/ECM, they are also supplied power by the injector relay.
If on the other hand you find a ground pulse then the injectors, "could they all be clogged and stuck from sitting unused for 1.5 years" and you will need to replace them or have them serviced. 94
#11
Re: Injectors not firing
Thanks guys. It looks like $50 for a noid light at the local store. I was going to have the injectors flushed tomorrow... May as well flush them first, as it's a good idea to do that anyway for the future health of the motor. Guess we have to wait a day or so then
Is there no other way of seeing a ground pulse? As I said earlier, I held the multimeter to the pin and to the chassis and saw the voltage fluctuating while the engine cranked. Does that confirm the pulse exists?
Is there no other way of seeing a ground pulse? As I said earlier, I held the multimeter to the pin and to the chassis and saw the voltage fluctuating while the engine cranked. Does that confirm the pulse exists?
#13
Re: Injectors not firing
It's not about the money... though renting sounds great! I live in Canada, so we don't have autozone. There may be an equivalent here. It's just that if I am having the injectors cleaned and serviced for $70 bucks anyway, and that will give me the same answer (if pulse, the car will run; if no pulse, the car will not run with clean injectors)... may as well do that first.
#16
Re: Injectors not firing
Ok, so I serviced the injectors myself by backflushing at 20 psi with seafoam and applying 12v, 1 amp across the terminals to click open and shut. They worked perfectly and flow clean.
Car won't start. I am now checking for continuity. I have connection across the shock tower plug to the injectors. Checking from the tower plug to ECM plug now. I fear that this too will show a connection.
So if the ECM is not pulsing correctly, what do I do now?
Car won't start. I am now checking for continuity. I have connection across the shock tower plug to the injectors. Checking from the tower plug to ECM plug now. I fear that this too will show a connection.
So if the ECM is not pulsing correctly, what do I do now?
#17
Re: Injectors not firing
crz, that manual you sent me is for 1998 OBD2.... mine is 2000, which makes it OBD2b. Do you think there is a difference? I am asking because.... pins 1,2,3, and 4, are TOTALLY different in my ECU. Two are unused and two are a completely different colour. I am trying to figure out which 4 could be the injectors now. Looking at a totally different plug which has those four solid colours.
#18
Re: Injectors not firing
So i have had a few episodes of coughing. (The engine, not me). I have been unplugging and wiggling engine harness connectors and the ECM harness into the back of the fusebox, which is coated to the gills with dielectric grease and also had the wires really, really twisted to get them into the fusebox. Battery too drained to try again for a few so will break for lunch.
I just hope the coughing isn't from when I removed the injectors last night... the gas from the fuel rail spilling into the intakes and slowly flowing down into the cylinders.... fingers crossed.
I just hope the coughing isn't from when I removed the injectors last night... the gas from the fuel rail spilling into the intakes and slowly flowing down into the cylinders.... fingers crossed.
#19
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Re: Injectors not firing
Just pull the spark plugs, unplug the PGM-FI Main Relay and the distributor, crank the engine a few times let it sit and the cylinders will "air" out in an hour, then drop in a little oil into each cylinder, crank again a few times, install plugs and crank again a few times, [this will fix things if cylinder walls got "washed" from the gas] reinstall plugs and fire it up. 94
#20
Re: Injectors not firing
- and we're back to cranking but no coughing. I think the battery was running low and the coughing was just from the cylinders fighting back with compression. The plugs are dry, so there is no need to worry about any gas having washed anything. I will try what you suggest, anyway. I had already put one drop of oil in each cylinder - not sure if it is enough.
#21
Re: Injectors not firing
YOU ARE NOT GOING TO BELIEVE WHAT I JUST FOUND!!!!!! A black relay near the PGM-FI relay with a rubber boot on it - was filled to the brim with water from a leak. It rained pretty heavily all yesterday and last night. i had installed it upside down as that was a convenient screw hole in the civic chassis. I cannot believe there was a leak exactly into it. the PGM relay seems ok... now will try to figure out which relay is the wet and shorted one.
EDIT: not a big deal. It was the rear window defogger relay.
fcm: can I just ask - what was the purpose behind doing what you recommend? Did you think the cylinders were flooded?
EDIT: not a big deal. It was the rear window defogger relay.
fcm: can I just ask - what was the purpose behind doing what you recommend? Did you think the cylinders were flooded?
Last edited by b18bcoupe; 04-20-2012 at 02:26 PM.
#22
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Re: Injectors not firing
You had mentioned, "the gas from the fuel rail spilling into the intakes and slowly flowing down into the cylinders" so just as a precaution.
Have you checked if anything else is getting wet from the leak?94
Have you checked if anything else is getting wet from the leak?94
#23
Re: Injectors not firing
I just said that I was afraid that the engine wanting to start was not because my injectors were firing, but was actually because of gas in the intakes. It wouldn't have been a lot of gas in any case.
Is it likely that the apparent firing was caused by this gas from last night's injector removal, or was an injector or two pulsing?
Is it likely that the apparent firing was caused by this gas from last night's injector removal, or was an injector or two pulsing?
#24
Re: Injectors not firing
So... if I am not getting the correct pulse from the ECM, should I look at replacing the distributor? I have read elsewhere that even though there is spark, a bad distributor will not be sending the correct signal, so the injectors will not pulse.
#25
Re: Injectors not firing
crz, that manual you sent me is for 1998 OBD2.... mine is 2000, which makes it OBD2b. Do you think there is a difference? I am asking because.... pins 1,2,3, and 4, are TOTALLY different in my ECU. Two are unused and two are a completely different colour. I am trying to figure out which 4 could be the injectors now. Looking at a totally different plug which has those four solid colours.
Your 10th vin digit will tell you the year. I know "W" is for 1998.
What color are the wires for injectors?
This is what I found: