2019 D-Max 4JJ1 engine Ping

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DamoL
Posts: 2
Joined: Fri May 03, 2024 11:26 am

2019 D-Max 4JJ1 engine Ping

Post by DamoL »

Hi all,
I'm chasing a diesel ping in my 2019 Isuzu dmax. (Definitely a ping and not diesel knock)
Little Background info, I was experiencing light pinging, a flat spot between 1800-2000rpm and general sluggishness so had my car booked in to get the injectors replaced. Whilst replacing the injectors, the mechanic also replaced the SCV on the fuel pump as there was erratic fuel pressures.
Fast forward a couple of days after the injectors were replaced and the ping has come back just as bad and now occurring through the entire rev range, the car idles rougher than normal and lacks the power to get up hills without having to drop down a gear or two.

Things that have been checked:
EGR - had slight carbon build up but was not inhibiting operation, however still cleaned it out and ensure the valve moved freely. No issues with the actuator
CAS - Swapped with one on a running motor with no issues as well as cleaned the plug with no changes
Airbox - Returned to factory box and also swapped the AFM with one that was known working with no changes
Fuel filter - Changed to a genuine filter
Valve clearances are within specs
All readings on the scan tool show within desired specifications
No boost or vacuum leaks - Smoke and pressure test carried out
All plugs have been checked and cleaned on all sensors

I'm hoping someone has experienced this before, or may have more of an understanding into the cause and can provide some advice or direction
mydmax
Posts: 2089
Joined: Sat Oct 12, 2013 8:36 pm

Re: 2019 D-Max 4JJ1 engine Ping

Post by mydmax »

Damol.

What fuel pressure are you talking about. The supply to HIGH PRESSURE pump pressure, ie, LOW, or the Injector pressure in the rail, ie,HIGH injector pressure.
Does the vehicle have a DPF and or A CAT? one or both might be restricted. It may not be an engine fault. Can't see how it can PING unless low quality fuel or contaminated fuel is in there.
I can't see how the CAS, Airbox, EGR, fuel filter, valve clearances can have anything to do with it! Definitely NOT the fuel filter. If it revs up under load it ISN"T ever the fuel filter. Think about it!
The ping if not diesel injection related may be unburnt fuel igniting in the exhaust after the turbo. ie restricted flow. If it is constipated then it will feel sick! Mud WASP buildup in exhaust if been parked for a period!
DamoL
Posts: 2
Joined: Fri May 03, 2024 11:26 am

Re: 2019 D-Max 4JJ1 engine Ping

Post by DamoL »

Hi mydmax,

It was the fuel rail pressures, they now sit stable since the SCV replacement.
The car has a DPF only and a 3" exhaust after the DPF, i checked the differential pressure readings and they don't hint towards any sort of blockage in the DPF
The car is regularly driven on the highway to try and get hot enough/do a burn to mitigate any issues with the DPF

The car has 150,000kms on the clock too
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