KZJ78 1KZ TE misfire at higher revs

[tommi786]

Hi all again - thanks for the continued input.

Paid a visit to the garage. The leaking injector was not really leaking as it was completely dry today. Was properly checked out. The misfire felt better today and the early morning startup was also quicker and smoother. In addition the mechanic could tell immediately from the strong odor in the exhaust fumes that I was burning sothing in addition to diesel and that the bluish grey smoke + strong smell was not oil but most likely kerosene. While I tested it with a clean can of Diesel, there must have been a fair amount additional diesel left in the pump and while I 'used up' around 2 litres of diesel doing the test, most of that I am told would have simply returned to the tank through the return fuel like and I may have actually only burnt up very little of the new diesel (I ran it for about 6 - 7 mins, max 10 mins). I will be draining the fuel out fully and then filling up with hopefully clean diesel along with a good fuel additive to get everything washed through and then see how it goes. I do suspect this is the issue as anything else would have just made the misfire worse and more apparent on the drive particularly in overdrive - there remains no misfire of exhaust visible smoke in drive even when cold.

The alternative problem could be slightly richer mixture but I do not want to change this (if this is a reason) as it drives really well as is with a lot of power. Will live with this without revving the engine when at a standstill.

I will post an update in a couple of day's time.....

 

[Shayne]

Interesting i would have thought kerosene like diesel is just refined oil and kerosene being the more refined it would burn easier than diesel which would not cause a misfire .

If you can get your hands on a high flow air filter try it again and i think you will see a difference .

 

[ValiRom]

Hi all again - thanks for the continued input.

Paid a visit to the garage. The leaking injector was not really leaking as it was completely dry today. Was properly checked out. The misfire felt better today and the early morning startup was also quicker and smoother. In addition the mechanic could tell immediately from the strong odor in the exhaust fumes that I was burning sothing in addition to diesel and that the bluish grey smoke + strong smell was not oil but most likely kerosene. While I tested it with a clean can of Diesel, there must have been a fair amount additional diesel left in the pump and while I 'used up' around 2 litres of diesel doing the test, most of that I am told would have simply returned to the tank through the return fuel like and I may have actually only burnt up very little of the new diesel (I ran it for about 6 - 7 mins, max 10 mins). I will be draining the fuel out fully and then filling up with hopefully clean diesel along with a good fuel additive to get everything washed through and then see how it goes. I do suspect this is the issue as anything else would have just made the misfire worse and more apparent on the drive particularly in overdrive - there remains no misfire of exhaust visible smoke in drive even when cold.

The alternative problem could be slightly richer mixture but I do not want to change this (if this is a reason) as it drives really well as is with a lot of power. Will live with this without revving the engine when at a standstill.

I will post an update in a couple of day's time.....

Hi, i have the same car KZJ 78, and the exact same problem, mine does like missfire when stand still amd rev at 2400 rpm, and i can also here the timing of the injection pump knocking. When the engine is cold is worse and when is hot is better. Have you found your problem ?

 

[Beau]

Have you guys checked the coolant temp sensor? One on the back of the head and ones towards the front. One is for the temp guage and isn't too important, the other for the ECU. Next on the list could also be the crank position sensor located just beneath the starter motor. Both of these can be removed and checked with an Ohm meter.

 

[ValiRom]

Have you guys checked the coolant temp sensor? One on the back of the head and ones towards the front. One is for the temp guage and isn't too important, the other for the ECU. Next on the list could also be the crank position sensor located just beneath the starter motor. Both of these can be removed and checked with an Ohm meter.

I have changed both water temp to ecu, and crank position sensor with new ones. Also checked the air intake temp sensor, and it is ok. The missfire is not bothering me to much, but i have from time to time, a slight vibration at idle, and also at 1000-1200 rpm also a vibration, theese are anoying

 

[ValiRom]

Also have good compresion, new injectors, changed 2 pumps, with both of the pumps the engine behaves the same. All the engine and gearbox rubber mounts are new also. The car drives very well, no smoke, only the two vibrations that upset me

 

[Beau]

hmm that's strange. The engines run pretty smooth for a diesel, especially when compared to the D4D Lump.

I don't think vacuum lines can cause vibration issues but have you checked the lines? Have you also run a clear hose on the return side of the injector pump to see if you're taking in air somewhere

 

[ValiRom]

hmm that's strange. The engines run pretty smooth for a diesel, especially when compared to the D4D Lump.

I don't think vacuum lines can cause vibration issues but have you checked the lines? Have you also run a clear hose on the return side of the injector pump to see if you're taking in air somewhere

Vacuum checked, also i have am amc new head, also egr off and cleaned intake, buterfly workin ok. I did not use a clear hose on the return, i will do this. I did not tryed because in my opinion if i have air, then the engine will vibrate all the time, and it does not but still i will check this

 

[Shayne]

Check the crank breather pipe , i can't be sure because it was a while ago but i think symptoms of a split began with a maddening vibration i could not find the cause of for weeks (maybe months) .

Sods law i was a couple of hundred miles into a 5000 miles round trip when it split enough to make a sound that convinced me my turbo was about to explode !

I patched it up at the roadside and all was good until i started losing oil about 4000 miles later on the return journey , no other noise or symptoms but at the side of the road again i found the same pipe had split at the bottom where it joins the intake .

Patched it up got home replaced the pipe and i haven't thought about it since .