Diesel injectors help needed:

Biker_Mike · Nov 6, 2014

Hi All,

As a non electrical guy I need some serious help regarding a decision that needs to be made.

I am based in South Africa and have a 2009 GM Isuzu KB250 Dteq bakkie/pick-up/truck (whatever you may call it)

My vehicle started giving problems and kicked out a P0652 fault which reads low voltage circuit B. That didnt help any man or beast with finding where the problem lies.

I just had a service done so all filters fuel lines etc... were checked and are clean.

I then took it to a "specialist" for diesel vehicles and he has started to do fault finding by testing parts in the engine. He checked the fuel pump and says its ok. He checked the injectors and he says they are not ok and need to be replaced. the cost of which is R16000. I can get an entire engine for R18000! When I asked him will that sort out the voltage low problem he said I could or it couldnt...

Being in africa I am reluctant to just believe anybody easily as they are most likely trying to just pull a fast move and make a quick big buck. This amount of money is more than an entire months net salary for me.

What I need to know is:
can a faulty injector/s kick out a low voltage circuit problem? Has anybody come across this kind of problem before?

if there is a big possibility that this could be the cause I dont mind changing them but if the problem persists it will be a total balls up which I dont want to fit the bill for for no real reason. As that will basically eat up all available funds I have.

Please help :'(

Thanks guys

garnhamr · Nov 6, 2014

Take it away from them and do a leak off test on the injectors.

http://engine-codes.com/p0652_isuzu.html

plugsandsparks · Nov 6, 2014

I did a quick google and it appears that fault code is given out when the reference voltage for analogue sensor is too low. Now it is not specific which sensor this relates to but this suggests a faulty sensor or wiring is puling the reference voltage down. If the sensor is related to fuel metering like a temp sensor then it would make it run like a dog or simply go to "get home mode" - what is the engine actually doing, does it start, does it smoke, etc etc. I would hold back from blowing all the dosh on new injectors and concentrate on the fault code first. It does not make sense that faulty injectors would cause this fault code. However fault codes can be a bit hard to interpret. It is also very unusual for all injectors to suddenly go at the same time. If it was my car I would use google to get the voltage required on which pin of the ECU for this fault code and the start pulling plugs off sensors, one by one to see if that allowed the voltage to rise to its reference which could be 5V or 12V or something else...lol - You may find then that this code goes but you get another one relating to the sensor that is not giving an output because you have disconnected it. For all of this , of course , you need a code reader.

telectrix · Nov 7, 2014

reminds me of a primastar ( renault trafic in disguise) i once had. main dealer insisted the fault was injectors. ( ecu shutting down fuel pump) after the usual camshaft sensor etc. after having the injectors done, it broke down again. camshaft sensor. then 2 months later, camshaft sensor, then again, so it went to auction.

ruston · Nov 8, 2014

It's a long shot but one of the Isuzu engines from 2003 (and onwards) in the UK had a recall for injectors, a job worth around £2000. check their website you may just be lucky that it is the one fitted to yours. Some injectors are chipped now for delivery and controlled by the ECU, technology gone wild.

Best of luck

Biker_Mike · Nov 10, 2014

Thanks guys. I am trying to source alternative injectors from scrapped vehicles etc... but im still not sure that this is a problem is the fault code problem im getting.

So what is happening is Ill be driving and then suddenly the vehicle will have its engine light shine and then it feels like i have run out of diesel i.e. no power. this will then slow me down to about 20kph. if i stop and hold the clutch the engine will either die or idle very harshly. If a apply the pedal the revs will pick up very slowly and not go more than 1500-2000 revs.

I will switch the engine off and it wont start at all untill when i switch it on and the fuel reserve light shines on. then it will start but it either then has power or no power. 9/10 it wont have power but if it does then it will get me about 200 metres and then the same cycle happens all over.

plugsandsparks · Nov 10, 2014

Crumbs, after all of that you only get one fault code.... Assuming you have good pump pressure, The only thing I can think of that would make the engine behave like that is very high air intake temp. There is an air temp sensor somewhere on the intake manifold, the signal goes to the ECU and if the ecu detects high air temps it can tell the engine to virtually shut down. If the sensor or wiring is faulty I guess you could get that fault code and that behaviour.