Resolving rough idling almost like 'missing' with 1hz diesel (1 Viewer)

[sunrk]

Since replacing engine mounts I've noticed the motor is idling rough as though it seems to randomly 'missfire' an injector. I've replaced the fuel filter (as I had a new genuine one), so I'm fairly sure there's no air leak into the fuel system at the filter area.

I'm wondering if it's possible that the injector pump timing needs checking? The motor had a rebuilt pump and injectors fitted about 5 yrs ago. In that time I've driven it for about an extra 100 k km's (it's up to over 630 k km's now).

Is it possible that one of the actual injectors is playing up?

Another possibility could be the timing belt being off but when I replaced that (a bit over a yr ago) I made sure the timing marks lined up. If the timing belt was off by one tooth either way, what effect would that have?

As the motor is really old, it's also really worn. I did valve shims last year, so they're unlikely to be the problem unless I stuffed it up (everything was double-checked before and after).

The motor doesn't have a turbo - just a straight non-turbo original (motor never replaced AFAIK) 1hz diesel donk.

 

[mudgudgeon]

1HD-T idle problem - need help!

 

[shocktower]

Idle problems with a diesel can be many things that gassers don't like has it been running that crap B20-30-50 fuels they cause a varnish like effect which screws with metering of fuel and ruins some O-rings which again metering you could have an air leak in the delivery system that you can't see . I am having a similar problem with my Cummins and I'm hunting for it . I hope this helps good luck with your hunt

 

[IanB]

The filter housing/primer pump assembly has been known to wear out and allow air to enter, even with a fresh filter on it. Run some clear hose from the filter housing to the pump and watch for air bubbles to test it.

 

[sunrk]

I have noticed the fuel hose (bit of aftermarket stuff I bought new a while back) isn't fully tight around the outlet port from the fuel filter/primer unit. I replaced the exhaust last week (fitted an aussie made King brown system from pacemaker headers) and when I did a leak test on that, I cannot see any evidence of white smoke at idle.

Once I get a genuine bit of hose I'll replace the aftermarket stuff and maybe try some different hose clamps (not the Toyota ones) and should that not help, I'll go the clear hose route to see if there's air getting in.

 

[sunrk]

Got clear (well translucent) 8 mm hose to try out tomorrow on both sides of the primer housing. I also bought some new Gates 'barricade' hose as the tank side hose (before the primer) is OEM and stiff. The injector pump side hose (after primer) is fairly new but cheapy unbranded auto parts store stuff.