GU ZD30 Di hesitation & starting issues
Hi all,
So a few weeks back I bought my first GU, engine has had a full rebuild with receipts & about 50,000kms driven since rebuild was done. EGR blocked, 3" echaust fitted and dyno sheets showing boost up to be 18psi I believe on stock boost solenoid.
Now, at first all I had was the usual limp mode from the EGR being blocked as well as the check engine light from the EGR, the boost would spike up to 20psi and be in a limp mode until you let off the accelerator and back on again, it was annoying for long trips on the highway but still driveable. So my plan was to get a HPD manual boost controller fitted to fix the limp mode issues. But I noticed one day that the boost was running slightly lower then when I first bought her, she would only go to around 14psi which I thought nothing of until the boost controller was going to be fitted.
Then after filling up with diesel, around 10 minutes into my drive home I felt a weird jerk/judder in the car almost like all fuel just cut out for s split second then back to normal. Watching the boost gauge, the boost also dropped out too as you would expect so I thought it was a boost problem. It slowly got worse over time becoming a lot more frequent it does it just above 2,000rpm and around 10-13psi of boost, started in 5th gear, now in 4th and 3rd as well but only around those rpms and boost levels. It also took a bit longer to start in the mornings letting out a puff of white smoke I think, not blue.
I took it to a diesel specialist about an hour away as I'm in regional Victoria and they called me the next day and said they scanned the car and got a code for the camshaft position sensor and the injection pump, so they said the issue is definitely the injection pump which they quoted me $5000 to do the job. I don't have that kind of $$ at the moment haha but after doing a bit of research on forums I've read up on MAF voltage causing the same kind of symptoms as well as a blocked fuel filter/air in the lines. I did clean the MAF with MAF cleaner before and it made no difference so while it was at the diesel specialist, I just told them to change the fuel filter for now and see if that makes a difference. So $150 later just for that, the guy called me saying that the car was running alright and didn't notice it playing up again, he also said they took the plugs off the injection pump and sprayed them with contact cleaner and all the codes disappeared aswell?
I was very happy with that as you'd imagine. So I picked it up the next day and it was another hour to drive back home in which it was bound to do the same things if it wasn't fixed. On the way home it drove fine, only jolted/juddered about 4 times max (it would easily do it over 30 times before) so I thought replacing the fuel filter must have done something. I've had it back about a week almost and just been driving it to and from work, 5 mins there and 5 back. It's gone back to doing the same thing as before except this morning it wouldn't start after about 2 minutes of trying, it would crank but not start. I don't have a code reader that can read it. I did call Nissan and spoke to a mechanic for about 5 minutes and he said there's 3 common things to check first before replacing the pump, can't remember what they were off the top of my head but I do remember him saying something about the spill valve?
I'm just wondering if anyone has had the same problems and what they did or their solutions before I spend $5000 on the injection pump and it may not even fix the problem.
Thanks, Ben
