1HD-T idle problem - need help!

[David60series]

Team,

I finally got home long enough to run the truck again.

Started cold OK and ran it for 15km around suburbia at 60km/h until it started to miss and shake at idle.

Took it home and took off inlet hose to filter assembly. Ran hose straight to clean can of fuel eliminating anything upstream of filter - no change. Still shaking and carrying on at idle.

i don't know what to do now except contact the injection shop again and see what they think.

It's a really bad shake and miss so I'm not driving it.

 

[roscoFJ73]

It's got me beat. Two different pumps and doing the exact same thing.

Do you mean 2 completely different fuel injection pumps or feed pumps on the filter head?

Sorry if its been covered before, but has the head ever been inspected? I was wondering if a crack in the head is opening up when it gets hot . I think you mentioned an aluminium radiator seemed to made it better for a while.

 

[Tapage]

Took it home and took off inlet hose to filter assembly. Ran hose straight to clean can of fuel eliminating anything upstream of filter - no change. Still shaking and carrying on at idle.

well then you know the issue it's right there on the IP or the injectors ..

 

[David60series]

Rosco - 2 different IP pumps. This problem surfaced early in the year. After the overhaul where just about every component of the IP was replaced (more so than a normal full rebuild)it went away for 2000km or so and now it's back.

With regards to the head - I actually suspected this originally due to a minor oil leak appearing at the back of the head at the same time but the compression test came up at 470 - 480 in all pots.

But if it's the head; why would cracking an injector Union clear it?

 

[roscoFJ73]

With regards to the head - I actually suspected this originally due to a minor oil leak appearing at the back of the head at the same time but the compression test came up at 470 - 480 in all pots.

Very fine cracks can close up so tight they don't show on compression tests, that's why I was wondering if expansion was reason it was running rough when it was warmed up, somehow allowing coolant into the combustion chamber in small amounts.. But your little trick of blipping the pedal probably wouldn't fix it.

But if it's the head; why would cracking an injector Union clear it?

Another mystery to contemplate.

Has the injection shop observed the warm up and rough running cycle?

 

[David60series]

I sent a video yesterday so hopefully they can have a look.

I'm still finding power down low/off the mark a bit low from 'feel' but whether this is just the factory settings I can't say for sure.

 

[David60series]

Is there any easy way to post a video? I can show you exactly what it's like.

 

[roscoFJ73]

The easiest way is to upload the video to YouTube from your files and then post a link.

I was just watching this, maybe you can get some ideas from it. There is also some great diesel tech advice from an expert for those new to diesels. Make sure you watch part 2

 

[David60series]

Ok thanks. Will give it a shot and watch the video also.

 

[IanB]

Rosco - 2 different IP pumps. This problem surfaced early in the year. After the overhaul where just about every component of the IP was replaced (more so than a normal full rebuild)it went away for 2000km or so and now it's back.

With regards to the head - I actually suspected this originally due to a minor oil leak appearing at the back of the head at the same time but the compression test came up at 470 - 480 in all pots.

But if it's the head; why would cracking an injector Union clear it?

Was the compression test done on a cold or hot motor? If cold, @roscoFJ73 's theory about small cracks opening up only when hot could be the issue. I'd run it till it runs rough, then do the compression test and see what's going on when it exhibits symptoms.

 

[David60series]

I thought the same thing last night. A valid theory, the only glitch being that it went away with the new pump for 2000km or so, then started intermittently and now back full time.

 

[David60series]

The one thing that's changed is ambient temp - the work was done in winter. This could be a factor.

 

[IanB]

So was the compression test done on a cold motor then?

I agree that if it's a head issue, blipping the throttle should have no effect. It's a strange issue for sure. A compression test costs only time though, and might just shed some light on things.

Here's a crazy idea...you said there were bits of a spring sent through the injection pump previously, is there a chance there could be some debris stuck in an injector line or something like that?

 

[David60series]

Pretty sure from memory that that compression test was done cold. I didn't do this myself though.

Yes - the previous pump build used a 1HZ plunger return spring and this broke and passed through the pump and injectors. It is possible I guess that something is in the line.

 

[roscoFJ73]

Surely broken spring parts would be too big too leave the injector pump. They would have to pass through the distributor head and through the injector valves.
Does turning the rpms up with the hand throttle make a difference?

 

[David60series]

The hand throttle - no. Can set idle quite high once the miss arrives and it still persists once the engine is at rest.

Spring - it scored the housing and the head and also the injection nozzles. Hard to believe isn't it?

 

[David60series]

If you apply 'light throttle' the shake follows it thorough the rpm. Only a blip will clear it momentarily.

 

[roscoFJ73]

Yes ,hard to believe. Did they use new injectors?

 

[kevsta]

The one thing that's changed is ambient temp - the work was done in winter. This could be a factor.

indeed, mine won't do it at all (now, with new rad) outside of July / August where ambient is up to 30+ C, and then only occasionally after a hot-stop and quick restart. prior to the new rad it was there every time it was fully warm and we stopped in traffic.

and as that is literally all I did, no other pump or injector touching, I'm certain that in my case it's heat related.

 

[David60series]

Yes ,hard to believe. Did they use new injectors?

Yes the nozzles were scored so had to be replaced.

I've been through a lot with this truck and could buy a new 200 VX for what it's cost me in 10 years but this year has been hard to swallow. Spent $13k and barely a trouble free mile in it.