1HD-T idle problem - need help!

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David60series said:
I've thought about a temporary fuel supply but I really need to run it for a while to start getting the problem consistently
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How long do you need to run it for? A 4 litre container would get you 30klms . Is this the same problem you have had since 2013?
 
Probably only need to run it for 15-20m to get it to start playing up really badly.

History:
Got truck in 08 at 240k. Never a pump problem and it was running a pump that was rebuilt at 150k in 02.

Started getting a bit smokey so got pump o/hauled at Rocklea Diesel May 14 at 345k. No end of trouble. Back six times for multiple pump strips until Jan 15. It was never right, but didn't shake like it is now.

March 17 this year it started to shake at idle. Couldn't find an injector problem and compression was perfect so decided to get pump stripped as I still had concerns about it. Turned out they had used a 1hz plunger spring and it had broken and part of it passed through the pump scoring body and head and injectors. We all assumed this was the problem.

Fitted all up and the shake was gone, but to me the idle wasn't as smooth on the exhaust note as it used to be - Especially on cold start. Seemed to be chugging like a petrol engine with a small vacuum leak.

Been flat out since and only five a few thousand km and it's just started to come back.

Does the same through either tank whether it's full or near empty.

If you give it gentle throttle the miss/shake will continue through the rpm but a quick tap will clear it almost instantly until it drops out again.
 
I ran clear hose to injector pump and there were no bubbles to be seen.

It's got me beat. Two different pumps and doing the exact same thing.
 
Had all the pump work been done by the same shop?

Only other thing I can think of is maybe a blockage of the filter screen on the in tank pick up. But it didn't make sense that it's only happening at idle, and doesn't make sense if it's happening on both tanks
 
No after all the trouble with the last pump work I sent it all down to Cooma and did injectors as well.
 
Did either shop give you a list of parts replaced in the pump?
 
Have you talked to the guys at cooma about your issue? Sounds like it's been present to some extent since they reworked it?
 
Yes I've got a parts list. I'll scan and post.

I've called Cooma a few times. Hard for them as they can't see or hear it.

The idle sounded a little bit chugging from day one in a cold start, which I did call and ask about, but other than that it was smooth and perfect. Because I had never had it without ACSD/the old rebuild was so problematic I couldn't say for sure that the idle wasn't just different to what I was used to.

They are good guys though and have spent plenty of time on the phone. It has no other symptoms or problems once you get past idle.

The shake did go away when the pump was refitted (2-3k ago) and it's come back and getting worse by the day. It's quite bad now. You couldn't ignore it. As soon as it's hot it goes bad.

The only other thing that changed while the pump was off was that the valve clearances were corrected. One was down to 0.08mm but they were meant to be in spec the last time they were checked about 30k previously.
 
Interesting. Mine has had exactly the same thing since I first bought it, in 2012. I mentioned it here but it has been discussed quite a bit with Dave2000 (because it was his friend's car prior to me, and they looked at it quite a bit) and discussed on both here and other forums.

the thing about my particular problem was that it only did it once it got hot hot, which was only really in the summer here. I had decided it was probably an injector breaking down when it got really hot, and I would get to it at some point..

But then, my original radiator split in about 2014 and I changed it for a Chinese aluminium one with an (alleged) +40% cooling capacity, and bizarrely enough, since then I have hardly ever noticed it again. Prior to that, it could be a right pain in the arse, if crawling in hot summer traffic.

Nothing else was ever been done to the fuel system since, (apart from a filter change at some point recently) and these days, just occasionally, if it's been turned off hot, but then re-started within 5 or 10 minutes, as it starts the fault is briefly there, but one rev of the throttle clears it, and it's gone again in normal driving.

So I am still thinking it's likely to be some sort of heat-soak injector-y type problem, but my new rad must be holding it a degree or 2 cooler than before and hence masking the issue. Long may that last :)

But lets be honest, I do expect to have to deal with it again at some point..
 
Interesting theory. The problem going away did coincide with with winter and a coolant flush. I guess I can investigate that more at little cost.
 
Governor spring is weak and gets softer when hot.
 
I think from memory all springs were replaced but I will follow up.
 
I found the recent invoice. It does stipulate all springs being replaced.

I'm still searching for reasons why the problem went away after the pump was done and has now come back - this is the only strategy I have in solving it.
 
I know you have probably had the pump off more times than you would want, but I was wondering what would happen if it was placed on a test bench where engine/pump speed could be replicated.
I'm assuming the pump reached the correct specs when it was tested.
I would still try a separate fuel supply at least to isolate the tank and fuel lines.
 
Yes I should def try fuel straight into the filter to rule out everything upstream.

Before the pump was sent down to Canberra it was stripped by another mob here in Brisbane. One of their bosses was very rude to deal with so I decided to go and ask them to collect the pump and pay them for the pull down cost very politely so I could take it somewhere I felt more confit table with. What resulted was the boss walking straight out the back and up ending all his parts boxes into a plastic bag - delivery valves all being mixed up with even the objector bodies etc. couldn't believe it.

Still charged $400 via the workshop that had sent it there whom I sought permission from first to get my pump back. An egotistical, immature tantrum.

What resulted was what I think was a blessing where cooma had to get a new delivery valve set and work through the rebuild part by part - they wanted to get it spot on and were content it was perfect when they sent it back.
 
What an ordeal!
 
Wow. Definitely sounds like getting the pump back from the Brisbane shop was the right thing to do. What a jackass!
 
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