Cylinder 1,3 and 5 not firing on df200 v6

[padraicbc]

Hi all. I connected Suzuki SDS to my 2008 DF200 and ran the injector-stop/misfire test.

Stopping injectors on cylinders 1, 3 and 5 made no noticeable difference to how the engine ran. Stopping injectors on cylinders 2, 4 and 6 caused a clear drop, so it appears the entire 1-3-5 bank is not contributing properly.

I tested cylinders 1, 3 and 5 with an inline spark tester and the tester flashed on all three cylinders. I then removed the spark plugs. The plugs had a small amount of fuel on them, so fuel appears to be reaching the cylinders. The injectors are new and the injector resistance readings were previously within specification.

The engine starts with some throttle and will continue running, but idle is low at roughly 500–550 rpm. It also struggles under load and will not rev properly. There are no warning alarms or obvious SDS fault codes.

At this stage I appear to have:

• Injector operation/fuel reaching cylinders 1, 3 and 5
• Spark visible on an inline tester
• No contribution from the complete 1-3-5 cylinder bank

I understand the inline tester only confirms that voltage is reaching the plug lead and does not necessarily prove the spark is strong enough under cylinder compression.

My next test will be compression on all six cylinders. Assuming compression is reasonably even, what could cause the whole 1-3-5 bank not to fire properly?

Could this be a shared electrical issue affecting that bank, such as a wiring-harness fault, common power supply, ECU driver, grounding issue, camshaft-position signal, ignition timing issue or incorrect cam timing?

Any suggestions on the most logical tests to carry out next would be appreciated.

 

[99yam40]

knowing the rail pressure is in spec would be good to know

 

[padraicbc]

knowing the rail pressure is in spec would be good to

 

[padraicbc]

I don't have a fuel pressure tester so not in a position to test. The high pressure pump was replaced anout 13 hours ago. I've replaced fuel lines, high/low pressure filters and cleaned the vst. All new injectors in 1,3 and 5 and a decent amount of fuel on spark plug.

 

[cwella]

Hi all. I connected Suzuki SDS to my 2008 DF200 and ran the injector-stop/misfire test.

Stopping injectors on cylinders 1, 3 and 5 made no noticeable difference to how the engine ran. Stopping injectors on cylinders 2, 4 and 6 caused a clear drop, so it appears the entire 1-3-5 bank is not contributing properly.

I tested cylinders 1, 3 and 5 with an inline spark tester and the tester flashed on all three cylinders. I then removed the spark plugs. The plugs had a small amount of fuel on them, so fuel appears to be reaching the cylinders. The injectors are new and the injector resistance readings were previously within specification.

The engine starts with some throttle and will continue running, but idle is low at roughly 500–550 rpm. It also struggles under load and will not rev properly. There are no warning alarms or obvious SDS fault codes.

At this stage I appear to have:

• Injector operation/fuel reaching cylinders 1, 3 and 5
• Spark visible on an inline tester
• No contribution from the complete 1-3-5 cylinder bank

I understand the inline tester only confirms that voltage is reaching the plug lead and does not necessarily prove the spark is strong enough under cylinder compression.

My next test will be compression on all six cylinders. Assuming compression is reasonably even, what could cause the whole 1-3-5 bank not to fire properly?

Could this be a shared electrical issue affecting that bank, such as a wiring-harness fault, common power supply, ECU driver, grounding issue, camshaft-position signal, ignition timing issue or incorrect cam timing?

Any suggestions on the most logical tests to carry out next would be appreciated.

The compression test should be done first and compared across all six cylinders. If compression is even, focus on spark quality and timing since an inline tester only confirms voltage is reaching the plug, not that the spark is strong enough under compression.

Next checks:

Swap coils/components with the good bank if possible
Check ignition timing
Inspect ECU, coil, and harness connections for corrosion or wiring faults
Verify grounds and ECU outputs
Check cam position/timing signals

If compression is good, a common electrical, timing, or ECU-related issue affecting that bank becomes more likely.

 

[padraicbc]

The compression test should be done first and compared across all six cylinders. If compression is even, focus on spark quality and timing since an inline tester only confirms voltage is reaching the plug, not that the spark is strong enough under compression.

Next checks:

Swap coils/components with the good bank if possible
Check ignition timing
Inspect ECU, coil, and harness connections for corrosion or wiring faults
Verify grounds and ECU outputs
Check cam position/timing signals

If compression is good, a common electrical, timing, or ECU-related issue affecting that bank becomes more likely.

Cheers, appreciate the detailed response. I'll have the compression tester tomorrow and report back.

 

[cwella]

Glad to help! Hope the compression test gives you some clear answers. Looking forward to hearing what you find.

 

[padraicbc]

Glad to help! Hope the compression test gives you some clear answers. Looking forward to hearing what you find.

1,3 and 5 ~175 psi. 2,6 ~175psi and 4 around 165.

 

[padraicbc]

I was sure there was fuel getting in as spark plug 1 was wet when I removed after doing the sds tests 2 days ago. I ran the engine for 3 minutes today and immediately checked 1, 3 but they were bone dry. It was very hot here so not sure if that impacted the evaporatiom but I suspect there should still be some unburnt petrol?