Technical Wiring problems

[Jacka]

Hi new member here. I’m having a problem with my 160 hp 11 plate camper van getting a slight misfire around 2000 revs then getting check engine eml light and fuel gauge goes to zero all at the same time. engine has plenty power runs perfect normally I’ve checked loom bend that goes to ecu and it’s had a repair in the past but looks fine the code I get when this happens is injector 1 voltage high it resets while driving no problem but it’s getting more frequent any help please.
Jacka

 

[Anthony489]

Hi Jacka

I agree with you that this sort of intermittent problem is most likely to be electrical.

I suggest the first thing to check are the connectors on the top of all 4 injectors. Each injector has 2 independent wires which go back to the ECU, see attached diagram. If you have an ohmmeter you could also check the coil resistance of each injector with the connector detached. I don't have a spec. figure for resistance but it will be fairly low. The main thing is that all injectors should read pretty much the same. Look at all the connection points for any hint of dulling, blackening or corrosion, and flex/gently pull the wires. Nothing should be under strain when connected. Injectors require a erasonably high electrical current to work, so any shortcomings in the wiring and connectors will upset them.

The second thing to check is the state of the wiring looms, paying particular attention to anywhere they might have chafed under vibration. Favourite weak spots are around the ABS pump and under the nearside headlight unit where the loom is strapped to a steel tube.

The ECU connectors are next on the hit list. If you can, remove each in turn and take a close look. The fact that there is a repair suggests some hanky-panky in the past.

Finally, a check of the various fuses that supply the ECU wouldn't go amiss. I don't mean that they are blown, but sometimes their connections can tarnish. Sometimes just pulling them in and out a few times will clear this away.

I wouldn't be too concerned about the fuel gauge at this point. It relies on data bus communication, which might be lost when the ECU is busy trying to flag an error. There is an outside chance that the connector to the fuel sensor has a problem. It's under a little panel in the floor between the two front seats. The connector is shared with the low pressure fuel pump, but if that dies it would be more likely to give an effect across all injectors rather than just one.

 

[Jacka]

Hi Jacka

I agree with you that this sort of intermittent problem is most likely to be electrical.

I suggest the first thing to check are the connectors on the top of all 4 injectors. Each injector has 2 independent wires which go back to the ECU, see attached diagram. If you have an ohmmeter you could also check the coil resistance of each injector with the connector detached. I don't have a spec. figure for resistance but it will be fairly low. The main thing is that all injectors should read pretty much the same. Look at all the connection points for any hint of dulling, blackening or corrosion, and flex/gently pull the wires. Nothing should be under strain when connected. Injectors require a erasonably high electrical current to work, so any shortcomings in the wiring and connectors will upset them.

The second thing to check is the state of the wiring looms, paying particular attention to anywhere they might have chafed under vibration. Favourite weak spots are around the ABS pump and under the nearside headlight unit where the loom is strapped to a steel tube.

The ECU connectors are next on the hit list. If you can, remove each in turn and take a close look. The fact that there is a repair suggests some hanky-panky in the past.

Finally, a check of the various fuses that supply the ECU wouldn't go amiss. I don't mean that they are blown, but sometimes their connections can tarnish. Sometimes just pulling them in and out a few times will clear this away.

I wouldn't be too concerned about the fuel gauge at this point. It relies on data bus communication, which might be lost when the ECU is busy trying to flag an error. There is an outside chance that the connector to the fuel sensor has a problem. It's under a little panel in the floor between the two front seats. The connector is shared with the low pressure fuel pump, but if that dies it would be more likely to give an effect across all injectors rather than just one.

Thanks Anthony plenty to try cheers
Jacka.

 

[Anthony489]

Here is the diagram that got missed off:

 

[Jacka]

Here is the diagram that got missed off:

Hi Anthony found 2 chafed wires in loom next to injector 1 if it is on the left of engine ? plugs on injectors seem perfect I sealed and insulated the 2 wires and insulated the injector wire put it all back together and it’s much worse makes me think I’ve unearthed the fault??

 

[Anthony489]

Hi

You might think that's a bad result but at least you have made a difference which means you are zooming in on the cause. If you have had any chafing then the finger of suspicion points at ALL the wires, not just the ones that look bad on the outside. It's quite possible to get broken strands inside the plastic sheath due to repeated strain and flexing.

One way to test a wire is to remove the connector from each end, then rig up a testmeter in a "hands free" manner using small sprung probes which can grab onto the relevant connector pins. Switch to an audible ohms/continuity range (i.e. with a bleeper), then work along the loom giving it a good tug and bend and listening for the slightest wavering in the bleep. However, be aware that if a high current feed wire to an injector is down to its last one or two strands, it might "buzz through" OK on the meter but the small extra resistance won't be helping.

A garage might try replacing the whole loom, but that's a long expensive job. DIY is possible with care, remembering that you don't necessarily have to bridge immediately either side of any break. There's nothing wrong with isolating a long bad section and putting in a long new wire starting near the beginning and finishing near the end. I recommend the use of soldered joints and heatshrink sleeving for this. If you have several wires to do, stagger the joints so you don't end up with one big lump. Even if you need to buy all the tools and parts it will still be a lot cheaper.

Happy Hunting !

 

[Jacka]

Hi

You might think that's a bad result but at least you have made a difference which means you are zooming in on the cause. If you have had any chafing then the finger of suspicion points at ALL the wires, not just the ones that look bad on the outside. It's quite possible to get broken strands inside the plastic sheath due to repeated strain and flexing.

One way to test a wire is to remove the connector from each end, then rig up a testmeter in a "hands free" manner using small sprung probes which can grab onto the relevant connector pins. Switch to an audible ohms/continuity range (i.e. with a bleeper), then work along the loom giving it a good tug and bend and listening for the slightest wavering in the bleep. However, be aware that if a high current feed wire to an injector is down to its last one or two strands, it might "buzz through" OK on the meter but the small extra resistance won't be helping.

A garage might try replacing the whole loom, but that's a long expensive job. DIY is possible with care, remembering that you don't necessarily have to bridge immediately either side of any break. There's nothing wrong with isolating a long bad section and putting in a long new wire starting near the beginning and finishing near the end. I recommend the use of soldered joints and heatshrink sleeving for this. If you have several wires to do, stagger the joints so you don't end up with one big lump. Even if you need to buy all the tools and parts it will still be a lot cheaper.

Happy Hunting !

Going to check oms on injectors later in case it’s that cheers Anthony

 

[Jacka]

Going to check oms on injectors later in case it’s that cheers Anthony

Hi Anthony it’s no 1 injector 2/3/4 read 16 on the oms test injector one was .55 now to get it removed holding bolt has snapped already
Jacka.

 

[Anthony489]

Hi Jacka. Injector removal can be quite problematic, to put it mildly. I suggest you read up about it before going further. The holding bolts are long and thin, if they snap off (which they are prone to) it's a specialist job to rectify. To remove injectors, Fiat garages use a hydraulic extractor capable of many tons of force. Not really a DIY job.

 

[Jacka]

Hi Jacka. Injector removal can be quite problematic, to put it mildly. I suggest you read up about it before going further. The holding bolts are long and thin, if they snap off (which they are prone to) it's a specialist job to rectify. To remove injectors, Fiat garages use a hydraulic extractor capable of many tons of force. Not really a DIY job.

Yes Anthony have the guy booked in for Tuesday the holding bolt is a easy fix Fiat recommend turning clamp 180 degrees and use the other bolt there with a support nut need longer bolt tho good to no
Thanks for the help

 

[Jacka]

All sorted was the injector Anthony the water was deep enough to flood injector 1 as my drive is on a slope sealed scuttle now langdale tomorrow cheers

 

[Anthony489]

Glad you got it sorted. Water ingress has been a recurring issue with Ducatos. Not so bad for vehicles in regular use, but if vehicles are parked up with no engine heat or airflow then corrosion sets in.

Fiat acknowledged this at some point by fitting a plastic shield over the top of the engine, this is worthwhile but still doesn't seem to guarantee complete freedom from water sitting in the injector well.

Many owners have improvised better scuttle drainage by adding extra drain tubes. Silicone sealing the scuttle centre joint and the windscreen to scuttle joint also helps.

 

[Jacka]

Glad you got it sorted. Water ingress has been a recurring issue with Ducatos. Not so bad for vehicles in regular use, but if vehicles are parked up with no engine heat or airflow then corrosion sets in.

Fiat acknowledged this at some point by fitting a plastic shield over the top of the engine, this is worthwhile but still doesn't seem to guarantee complete freedom from water sitting in the injector well.

Many owners have improvised better scuttle drainage by adding extra drain tubes. Silicone sealing the scuttle centre joint and the windscreen to scuttle joint also helps.

Yes I’ve sealed the scuttle and mine does have the plastic cover will make another engine cover shortly cheers