This pass weekend, I was doing some compression tests trying to diagnose a possible head gasket leak and did a double-take on the state of my relatively new spark plugs. FJ62 is pretty rough from a cold start, especially under 1500 RPM. There's an occasional popping sound but disappears as it warms up. I suspect it is running rich.
Spark plugs are shown below in reverse order (6-5-4-3-2-1) As you can see in the image, spark plugs seem heavily covered in carbon, especially spark plug 5 and 3. Spark plug 1 however is very clean. I've turned my attention to investigating spark plug 1. I'm also running down the FSM troubleshoot steps for Misfires and Running rich condition. Below are some of the things I've done to troubleshoot and would appreciate any insight or wisdom you guys might have before I end up unnecessarily taking apart the the engine to check injectors and valves, buying new parts, or taking it into the shop.
Misfire Test
I was able to confirm that there was an issue with cylinder 1 by disconnecting the spark plug cable while the engine was running and not hearing any change in idle RPM. Other cylinders saw a notable audible drop in RPM when disconnected.
Swapped Spark Plugs
I've swapped spark plugs 1 and 2 and saw no change in cylinder 1 performance.
Spark Test
I removed spark plug 1 and attached it to the end of the spark cable, grounded it, and ran the engine and I think I was able to get spark on recording. Not sure if it's a good spark or weak spark though. Apologies for the shaky footage as I had to rest the camera on some hoses in the engine bay.
Engine Vacuum
Vacuum is holding at a steady at 21 inHg
Diagnostics Codes
System did not return codes this time around, but in the past I have gotten Code 11 and Code 51.
Ignition Timing
Recently adjusted the timing a few months ago to standard 7º BDTC at idle.
Cold Start Injector
Resistance measured at 3.2 Ω. Within range of specified 2-4 Ω.
Did not measure cold start injector time switch
Fuel Pressure
Did not measure as I do not have gauges.
Did not check fuel pressure regulator.
Injectors
Did not perform sound scope test as I did not have the tool.
Resistance for injector 1 measured at 13.9Ω. Within spec of 13.8Ω.
Spark Plugs
Did not measure gap as they are 2 months old.
Compression Test
Did not measure
EFI Electronic Circuit Check
Have not checked yet, but plan to.
Spark Cord w/ Distributor Cap Resistance
Primary coil is .6Ω
Secondary coil is 12.85 kΩ
I'm turning my attention towards it being something EFI related, but just not certain which part or component. I did noticed that the clip on Fuel Injector 1 connector was cracked and broken. It seems like someone has messed with it before.
Spark plugs are shown below in reverse order (6-5-4-3-2-1) As you can see in the image, spark plugs seem heavily covered in carbon, especially spark plug 5 and 3. Spark plug 1 however is very clean. I've turned my attention to investigating spark plug 1. I'm also running down the FSM troubleshoot steps for Misfires and Running rich condition. Below are some of the things I've done to troubleshoot and would appreciate any insight or wisdom you guys might have before I end up unnecessarily taking apart the the engine to check injectors and valves, buying new parts, or taking it into the shop.
Misfire Test
I was able to confirm that there was an issue with cylinder 1 by disconnecting the spark plug cable while the engine was running and not hearing any change in idle RPM. Other cylinders saw a notable audible drop in RPM when disconnected.
Swapped Spark Plugs
I've swapped spark plugs 1 and 2 and saw no change in cylinder 1 performance.
Spark Test
I removed spark plug 1 and attached it to the end of the spark cable, grounded it, and ran the engine and I think I was able to get spark on recording. Not sure if it's a good spark or weak spark though. Apologies for the shaky footage as I had to rest the camera on some hoses in the engine bay.
Engine Vacuum
Vacuum is holding at a steady at 21 inHg
Diagnostics Codes
System did not return codes this time around, but in the past I have gotten Code 11 and Code 51.
Ignition Timing
Recently adjusted the timing a few months ago to standard 7º BDTC at idle.
Cold Start Injector
Resistance measured at 3.2 Ω. Within range of specified 2-4 Ω.
Did not measure cold start injector time switch
Fuel Pressure
Did not measure as I do not have gauges.
Did not check fuel pressure regulator.
Injectors
Did not perform sound scope test as I did not have the tool.
Resistance for injector 1 measured at 13.9Ω. Within spec of 13.8Ω.
Spark Plugs
Did not measure gap as they are 2 months old.
Compression Test
- 142
- 135
- 137
- 130
- 135
- 134
Did not measure
EFI Electronic Circuit Check
Have not checked yet, but plan to.
Spark Cord w/ Distributor Cap Resistance
- 6.61
- 5.03
- 3.73
- 3.33
- 5.03
- 6.42
Primary coil is .6Ω
Secondary coil is 12.85 kΩ
I'm turning my attention towards it being something EFI related, but just not certain which part or component. I did noticed that the clip on Fuel Injector 1 connector was cracked and broken. It seems like someone has messed with it before.
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