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2G Injectors 1 and 4 not firing

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Koda

Proven Member
72
8
Jun 2, 2019
Butler, Pennsylvania
So funny story, my dsm is broke again right when I thought I fixed everything, I have a 1995 eclipse gsx and I recently had problems with what I thought was the ECU , I now realized that the tuned blackbox wasn’t working because two Injectors were not firing , but I also have a stock ECU and the car will run with the stock one in , but smokes from the exhaust and smells like raw gas. I found out injectors 1 and 4 weren’t working whenever I unplugged both of them at the same time and the car stayed running with no change in the idle at all. I unplugged injectors 2 and 3 and the car stalls due to the fuel being cut. I tested the fuel resistor box that is mounted on the fire wall and it read 7.1 ohms on all pins.PLEASE HELP, I have to drive it to storage before winter comes and with all the time I have into it I don’t want it to start rusting because I couldn’t get it there.
 
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Turn your key on, go outside and ground one side of your meter and set the meter for 12v dc range, then unplug each injector connector and one side on each connector should have 12v on it, report back.
 
Turn your key on, go outside and ground one side of your meter and set the meter for 12v dc range, then unplug each injector connector and one side on each connector should have 12v on it, report back.
I tested the dcv on each Connector and I put the black prob on ground and tested All the connectors and every side Of each one had 13-14v
 
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I found out injectors 1 and 4 weren’t working whenever I unplugged both of them at the same time and the car stayed running with no change in the idle at all. I unplugged injectors 2 and 3 and the car stalls due to the fuel being cut.
I think you need to double check this using a different method. A noid light preferably (usually can rent from a parts store for free) or by using a stethoscope and spinning the cas with the power on but engine not running.

I tested the fuel resistor box that is mounted on the fire wall and it read 13-14 volts on pins 1 and 3 , and pins 2 and 3, then it read 7 volts on the both bottom pins and 3.
This is confusing. Can you clarify this at all? Especially with the results you posted next:

I tested the dcv on each Connector and I put the black prob on ground and tested All the connectors and every side Of each one had 13-14v

I got 7.1 ohms on each one of those exactly
 
It would be weird for the 2 outside to be clogged, but have you swapped the injectors around to see if it isnt the injectors that arent working? Like swapping 1&2 and 3&4. I would at least check it, if 1&4 cylinders continue not to work then you know its not the injectors.
 
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I think you need to double check this using a different method. A noid light preferably (usually can rent from a parts store for free) or by using a stethoscope and spinning the cas with the power on but engine not running.

This is confusing. Can you clarify this at all? Especially with the results you posted next:
Yes sorry for the confusion the first time I tested the fuel resistor pins wrong the first time (had the plug upside down so I tested the wrong pins together, ignore the first test )the second test is correct , 7.1 ohms on the resistor box plug... and am I able to spin the cam angle sensor with the cams still on ? And what will I be listening for ?
 
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It would be weird for the 2 outside to be clogged, but have you swapped the injectors around to see if it isnt the injectors that arent working? Like swapping 1&2 and 3&4. I would at least check it, if 1&4 cylinders continue not to work then you know its not the injectors.
I will swap them tommarrow and let you know what they do but I’m confident it is not the injectors that are clogged , I’m still gonna make sure but it was running fine , shut it down and it wouldn’t start back up right, smells like gas and backfires sometimes. It just doesn’t seem like it’s getting enough gas to start up with the tune, but it starts up without the tune , but the injectors don’t work , I’ll upload a video for further Insight
 
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I’m able to unplug those two Injectors with no idle change at all, then unplug either of the two middle and it will stall...
 
am I able to spin the cam angle sensor with the cams still on ? And what will I be listening for ?
Do you have the stock 95 CAS or not? The 95-96 sensor was located under the intake cam sprocket. If you still are using that, you should just use the noid light.
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If you have swapped to a 1G sensor you can take it off the head and spin it and the injectors will click as they are triggered to fire. A stethoscope held on injectors 1 and 4 would tell you whether they were firing.

I shut it down and it wouldn’t start back up right, smells like gas and backfires sometimes. It just doesn’t seem like it’s getting enough gas to start up with the tune, but it starts up without the tune , but the injectors don’t work , I’ll upload a video for further Insight
How are you sure that the injectors are the problem? The cylinders in question share a waste spark ignition coil. Have you eliminated the possibility of the 1&4 ignition coil, both 1&4 plug wires and the signal to fire the 1&4 coil?
 
Do you have the stock 95 CAS or not? The 95-96 sensor was located under the intake cam sprocket. If you still are using that, you should just use the noid light.
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If you have swapped to a 1G sensor you can take it off the head and spin it and the injectors will click as they are triggered to fire. A stethoscope held on injectors 1 and 4 would tell you whether they were firing.


How are you sure that the injectors are the problem? The cylinders in question share a waste spark ignition coil. Have you eliminated the possibility of the 1&4 ignition coil, both 1&4 plug wires and the signal to fire the 1&4 coil?
I replaced the power transistor and the coil pack but I guess I could try another one , maybe since I bought a used one it was bad , I did hold the plugs (with the spark plugs on) against a ground and test for spark and they all had spark , some was just weaker but I checked the gaps on all them and they were at 0.30 , even if I didn’t have spark I thought the injectors would still click at least or I’d hear them ,but tommarrow I’ll take the injectors out and swap them and the coil pack and maybe transistor and see if they are still now working and let you guys know , I appreciate all the help
 
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I mean no offense, but please stop just swapping parts and randomly unplugging stuff. Download the factory service manual and we can help you use it to troubleshoot. Every time you swap a part you introduce another variable into the situation. There's at least a decent possibility that your problem is in a brittle wire that makes intermittent contact or a bad ground or some other problem that is giving you misleading results.

The plug gap is 0.30? Would that be in millimeters or inches? Either way, if that's not a typo, then that needs changed.

All we know at this point is that the engine is probably not firing on cylinders 1 and 4. That could be due to the injectors, but the simplest explanation is usually the right one.
 
I was just saying if you swapped injectors, not to a new set but with different cylinders you can rule out faulty injectors. Just like what you do with RAM in a computer with certain issues and can either find the cause is a bad stick and that stick is causing a no boot in a certain DIMM slot, usually swapping sticks can tell you a lot and it takes no time to do it. If the problem follows to 2&3 then it would most likely be faulty injectors and it is just 3 12mm bolts to check it. It rules out a variable at least.

It smelling like fuel though should be a sign that there is raw fuel not being ignited. It sounds like a spark problem because if the injectors werent firing but 2&3 are then I would think you shouldnt smell any fuel. Sounds like its getting fuel, but not spark or the spark isnt good enough. Could be too much fuel drowning the spark out.

It could be a long laundry list of things.
 
Okay I won’t swap anything out guys And I mean 0.03 inches , and yeah it smells like raw gas so it definitely makes sense that they are working and it’s spark , I’ll download the manual and should I check for spark again ? Can I test the coil pack to find out if it’s good some way ? Or the transistor? And plug wires ? Is there anything else it could be other than those things and bad wires? I have a 1997 ecu and the plugs are in the order 3,2,1,4 on the coil pack and same with the 1998 ecu I have. That is the correct order right ?
 
I mean no offense, but please stop just swapping parts and randomly unplugging stuff. Download the factory service manual and we can help you use it to troubleshoot. Every time you swap a part you introduce another variable into the situation. There's at least a decent possibility that your problem is in a brittle wire that makes intermittent contact or a bad ground or some other problem that is giving you misleading results.

The plug gap is 0.30? Would that be in millimeters or inches? Either way, if that's not a typo, then that needs changed.

All we know at this point is that the engine is probably not firing on cylinders 1 and 4. That could be due to the injectors, but the simplest explanation is usually the right one.
:thumb:


Where’s that f***in emoji where it’s bowing down to someone’s greatness. We need a bow down emoji. Now.
 
If anyone’s willing to help, I tested spark with an inline spark tester and it is a spark problem, cylinders 1 and 4 have no spark the injectors are working so that’s my mistake ( I tested them using a noid light). I tested the coil plug wires and the coil pack and I’m positive they are working, and the spark plugs are brand new so I know they work. What else could this be ? I read on another forum from a guy with the same problem that the cam angle sensor can cause problems so I tested it by starting it up with it unplugged and it still starts up and doesn’t spark on 1 and 4, I’m completely stumped :confused:
 
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Could be either the PTU, the connection between the ECU and the PTU, the connection between the ignition switch and the PTU, or the ECU.

Let's check signal to the PTU first. Make sure there's continuity between ECU pin 10 and PTU pin 7. ECU harness connector:
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If that checks out, then you have to test the PTU. It's a PITA. You need a AA battery and have to check continuity between pins 3 and 8 of the PTU while the negative side of the AA is connected to pin 3 and the positive side is connected to pin 7. PTU connector:
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I'm assuming that you have a 2Ga ECU and have not swapped any pins at the ECU. Otherwise the pin numbers I gave you would be wrong.
 
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Could be either the PTU, the connection between the ECU and the PTU, the connection between the ignition switch and the PTU, or the ECU.

Let's check signal to the PTU first. Make sure there's continuity between ECU pin 10 and PTU pin 7. ECU harness connector:
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If that checks out, then you have to test the PTU. It's a PITA. You need a AA battery and have to check continuity between pins 3 and 8 of the PTU while the negative side of the AA is connected to pin 3 and the positive side is connected to pin 7. PTU connector:
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I'm assuming that you have a 2Ga ECU and have not swapped any pins at the ECU. Otherwise the pin numbers I gave you would be wrong.

It had a 1998 blackbox in it with a tune, I didn’t put the ecu in, I bought it off of a guy in West Virginia who did this all when he owned it. When This problem first started the tach and speedometer also stopped working, I wasn’t sure if it was related or not but now I’m thinking that it might be. Just want a second opinion on that. Because I read the transistor send info to the tachometer and tell the coil pack when to fire
 
Yep, definitely is related. That's the same issue we're hunting down. So it's probably in the wiring harness from the ECU.

I was trying to figure out which wires would be affecting it from the ecu but it’s so hard to track down these wires and grounds to see what’s causing it, and I know it’s not the timing because it was running fine, I shut it down, wouldn’t start back up, no CAS code coming up, I’m at a complete standstill , I’ve tested just about everything, and there has to be a wire on the transistor that controls when the coil pack fires and the tach that I maybe messed up taking the intake manifold off but the whole wiring harness has a plastic cover over it so I don’t think it could have got sliced or cut , it has to be a connection
 
Is the
I was trying to figure out which wires would be affecting it from the ecu but it’s so hard to track down these wires and grounds to see what’s causing it, and I know it’s not the timing because it was running fine, I shut it down, wouldn’t start back up, no CAS code coming up, I’m at a complete standstill , I’ve tested just about everything, and there has to be a wire on the transistor that controls when the coil pack fires and the tach that I maybe messed up taking the intake manifold off but the whole wiring harness has a plastic cover over it so I don’t think it could have got sliced or cut , it has to be a connection
Is there a way to test, to see if the ecu is sending a signal to the PTU for cylinders 1 and 4 to fire ? I think pin 7 & 8 are for cylinders 1 and 4
 
Here's the diagram for the other coil's signal from the PTU in case your car was set up for the 98 ECU:
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And here's the circuit diagram for the whole system:
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Is the
I was trying to figure out which wires would be affecting it from the ecu but it’s so hard to track down these wires and grounds to see what’s causing it, and I know it’s not the timing because it was running fine, I shut it down, wouldn’t start back up, no CAS code coming up, I’m at a complete standstill , I’ve tested just about everything, and there has to be a wire on the transistor that controls when the coil pack fires and the tach that I maybe messed up taking the intake manifold off but the whole wiring harness has a plastic cover over it so I don’t think it could have got sliced or cut , it has to be a connection
Sorry I’m bad with wiring can you explain the diagram to me somewhat,and what I can replace to fix it all or how to trace the wires physically to tell if they came disconnected from somewhere or are damaged ? Like where they connect to start and go through the firewall, if you know and I’ll try to find the colors of them and hunt them down and trace them
 
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Terminals 2 on cps and 1 on the cas both read 0.01v but the other terminals are within spec, both have a black wire coming out of the back into the harness
 
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