Diagnostics using the SP & VP combinations

[David Green]

Still learning with these pieces of kit yet. Had a Citreon C3 in today with a customer complaint EML intermittently on. So using SP checked fault codes and found;

P0 204 - Injector Control 2 OC - SC
P0 300 - Random / multiple cylinder misfire detected
P1336 - High combustion misfiring on several cylinders.

Asked customer specifically if any driving conditions were known like loss of power, misfiring etc, customer said no?

So I looked at these codes and asked is it really possible to have a fault on all three circuits?

I decided that I would check the ignition system first using the VP and the flags for the coils operations. The results are shown;

I thought looking at the ignition trace that the number four cylinder was faulty, although i could not notice a misfire. I was also concerned about the number four injector being faulty, or read a code as a fault, so I looked at the wiring diagram which shows that both the injector and the coils share the same power supply. My view at the moment is that the injector is possibly the cause of the fault being seen on the scope with the coils, if for some reason the injector is malfunctioning and the supply voltage is being lost then the coil will also malfunction. I road tested the car and found in my opinion that I thought the car was under powered, but did not misfire. When I spoke to the customer again later, I was advised that a misfire had been noticed

Anyway I advised the customer that given the way the car was running I did not wish to change any parts until I was completely satisfied that a compoent was faulty and contributing to the other circuit. Given Wednesday is a half day for me the car is coming back next week for another play

David

[andybaz]

Hi David, something to ponder on, similar scene,dec 09 peugeot 206 1.4 - codes 203/1336 & 300.
lady had injector replaced 6 months prior to me looking,inj no.3,replugs sparkplug with NGK and spoke with Peugeot, recall due to water ingress into short injector harness, replaced injector harness, inspected washer jet pipe work and washer jet mounting in bonnet,all ok.
Problem persisted.

As the sympton was intermittent and only during wet sessions,we decided, a dealer.
Dealer comments: non gen spark plugs,NEED GEN plugs,coil pack failingand requires a ECU upgrade, little hadr to believe,went with it, 5 months now and no problems.

Car no.2, work mates car, same as above, same problems, GEN spark plugs fitted... still misfire and codes, fitted pattern coil pack, common problem, something about coil pack multiplug being either grey or black ( i'll find out and report back), so coil pack was replaced with GEN and they also upgraded the ECU aswell as add someform of electrical component in the coil pack wiring feed.

Just some views.
Andy

[Dynodave]

Still learning with these pieces of kit yet. Had a Citreon C3 in today with a customer complaint EML intermittently on. So using SP checked fault codes and found;

P0 204 - Injector Control 2 OC - SC
P0 300 - Random / multiple cylinder misfire detected
P1336 - High combustion misfiring on several cylinders.

Asked customer specifically if any driving conditions were known like loss of power, misfiring etc, customer said no?

So I looked at these codes and asked is it really possible to have a fault on all three circuits?

I decided that I would check the ignition system first using the VP and the flags for the coils operations. The results are shown;

I thought looking at the ignition trace that the number four cylinder was faulty, although i could not notice a misfire. I was also concerned about the number four injector being faulty, or read a code as a fault, so I looked at the wiring diagram which shows that both the injector and the coils share the same power supply. My view at the moment is that the injector is possibly the cause of the fault being seen on the scope with the coils, if for some reason the injector is malfunctioning and the supply voltage is being lost then the coil will also malfunction. I road tested the car and found in my opinion that I thought the car was under powered, but did not misfire. When I spoke to the customer again later, I was advised that a misfire had been noticed

Anyway I advised the customer that given the way the car was running I did not wish to change any parts until I was completely satisfied that a compoent was faulty and contributing to the other circuit. Given Wednesday is a half day for me the car is coming back next week for another play

David

I have not seen a citron engine in the USA, but does this vehicle use a coil on plug ignition? or is there a coil pack? If you think the voltage may be dropping out, you could try using the Vantage PRO to graph the voltage feed to the injectors/Coils and run a voltage drop on the vehicles power and grounds. There may be a relay that is feeding the injectors and ignition. If the relay is intermittently cutting out it should be affecting all cylinders not just one cylinder or injector. I have seen a number of USA vehicles that have had coils which will intermittently breakdown and have a misfire when say hot or under load. If you access to a dynamometer you could try monitoring the suspect under load to try to get it to act up. If this vehicle uses COP adapters, It is likely that Snap-on has a COP adapter that can track the misfire. I have found that COP-11 works well on late model vehicles when the ignition control module is built into the individual coil that is over the plug. Attached some pictures of the waveform if you can get the vehicle to act up so we can look at the waveform. Also don’t forget to check the resistance and current ramp of the injectors, if one is partially shorted it may cause some erratic running problems.
Keep us updated, Dynodave

[David Green]

I have not seen a citron engine in the USA, but does this vehicle use a coil on plug ignition? or is there a coil pack? If you think the voltage may be dropping out, you could try using the Vantage PRO to graph the voltage feed to the injectors/Coils and run a voltage drop on the vehicles power and grounds. There may be a relay that is feeding the injectors and ignition. If the relay is intermittently cutting out it should be affecting all cylinders not just one cylinder or injector. I have seen a number of USA vehicles that have had coils which will intermittently breakdown and have a misfire when say hot or under load. If you access to a dynamometer you could try monitoring the suspect under load to try to get it to act up. If this vehicle uses COP adapters, It is likely that Snap-on has a COP adapter that can track the misfire. I have found that COP-11 works well on late model vehicles when the ignition control module is built into the individual coil that is over the plug. Attached some pictures of the waveform if you can get the vehicle to act up so we can look at the waveform. Also don’t forget to check the resistance and current ramp of the injectors, if one is partially shorted it may cause some erratic running problems.
Keep us updated, Dynodave

Hi Dynodave

I tried relentless to upload the picture of the ignition scope graphs I recorded, but to press am struggling. The VP is new to me at the moment because I have not had it long or used it alot to date, also my work colleagues are very negative about vehicle electrics which makes the job so much harder to deal with.

The car in question power wise is flat when driven but does not misfire like engines used to do in the old days, like when a plug lead (wire) failed or the spark plug failed. The problem can be further amplified if the engine management system requires a reprogramme, I had this a few years ago on a Vauxhall which was noisy and flat with no power, after I reprogrammed the ECM, the car was OK, so with the current problem I am a little reluctant at the moment to throw new coil pack and injectors at an engine that runs well but is underpowered.

Will keep you updated and will try to load the graphs if I can.

David

[Dynodave]

You probably have already checked it, but it doesnt hurt to double check a few easy t

This may be redundant, but since you do not have a misfire that you can feel but more of a power loss, have you checked to make sure the fuel pressure and volume looks good. That fuel filter is good, and no restrictions in the air intake? Don’t overlook a possible restriction in the exhaust, ie a partially plugged catalytic converter.
Just want to make sure no possible mechanical issues are overlooked as well as the electrical side.
Thanks for the update, Dynodave.

[greasybob]

Does this vehicle give good, fast scan data? If so what are the fuel trims telling you when the engine feels under powered?

[David Green]

This may be redundant, but since you do not have a misfire that you can feel but more of a power loss, have you checked to make sure the fuel pressure and volume looks good. That fuel filter is good, and no restrictions in the air intake? Don’t overlook a possible restriction in the exhaust, ie a partially plugged catalytic converter.
Just want to make sure no possible mechanical issues are overlooked as well as the electrical side.
Thanks for the update, Dynodave.

Hi Dynodave,

No I did not get that far, I basically checked the ignition system which did not look too good and thought about the injector, but as no miss fire could be heard I took the car for a road test which is where the power loss I thought was present. Not done any further checks yet.

Greasybob.

Sorry never thought to look at live data, but will when the car returns later.

David

[JR-1]

David , might be worth giving the valve timing a once over to rule out anything obvious
Regards
John