1HDT HDJ81 Misfire

[mudgudgeon]

Just got the Cruiser back it runs great.

Only thing is, it is still creeping up on 1200F egt pretty fast. It has no white or grey smoke and very little black.

That's great news!

Now it's time to learn to tune it

Start reading here

The Official 1HD-T/FT Fuel Pump Mod Tuning Thread

forum.ih8mud.com

There was a couple of guys working through tuning new to them HDJ81s at pretty much the same time. A lot of good info came out of the chat at the time

 

[mudgudgeon]

The tuning thread I linked above started as chat about potential modifications, but has a lot of practical tuning tips on it too.
Starting from the post I linked saves a few days of heavy reading

 

[IanB]

That's great news! The EGT's can be sorted out via tuning easily enough, you need an EGT and boost gauge before you can get started. Read the thread @mudgudgeon posted above, and ask questions before you get started making changes.

 

[AussieHJCruza]

1200f isn't terrible for a 1HDT, I hit 1650 on the dyno after getting a bit carried away with the fuel screw.

(Not reccomending 1650 but you won't hurt anything taking it to 1400f occasionally, but probably a bit much for hours on end)

 

[ubguessin]

That's great news! The EGT's can be sorted out via tuning easily enough, you need an EGT and boost gauge before you can get started. Read the thread @mudgudgeon posted above, and ask questions before you get started making changes.

I have so far adjusted the boost compensator spring to match 14psi of boost, this helped slow the fast ramping of egt's. I have not touched the main fuel screw yet which must be my main issue besides the stock exhaust and air box

 

[AussieHJCruza]

I have so far adjusted the boost compensator spring to match 14psi of boost, this helped slow the fast ramping of egt's. I have not touched the main fuel screw yet which must be my main issue besides the stock exhaust and air box

Lose the stock exhaust first imho, decent drop from a proper 3" dump and 3" exhaust

 

[ubguessin]

Lose the stock exhaust first imho, decent drop from a proper 3" dump and 3" exhaust

I was just waiting to get er back to schedule the appt for a 3" so now I can do that. I should have an airbox and snorkel from Radius Fab hopefully showing up here soon.

I made a slight adjustment to the fuel screw to see what would happen and Its about the same BS. I made a video. I apologize now for some of the commentary.

 

[mudgudgeon]

Provided that your probe is pre turbo, and If that's the highest the EGTs go, you're still within safe limits.
1350f is approx 750c. Widely considered a safe maximum.


To get a better picture of peak EGTs, load it up with a trailer or 500lbs dead weight in the back, find a decent hill.
You want to hit the bottom of the hill at just above idle, in 3rd gear. Stand on the throttle and good it to the floor and watch the EGTs then.
You'll see peak EGTs by loading it up at low RPM, give it a wide open throttle sustained run, uphill etc.

If a 3" exhaust is on the cards, do that before spending much time tuning. It's the single biggest improvement you can make IMO, and will have a big effect on tuning.

If it's well tuned, you can expect to see a puff of smoke out the back of you accelerate hard from life RPM, or when you stab the throttle hard when it's idling.

It's an old diesel, some smoke is to be expected, but not clouds of it, and usually only as it comes onto boost

 

[ubguessin]

Alright so I will have a 3" exhaust installed on the 15th.

I went on a nice 400+ mile round trip this weekend. Travelling west I was able to maintain 70-77mph at 900*-1100*F on a 78*F day. Starting at (4500' Home base - 6500' Midway - 3300' Destination) hills I would end up slowing to about 50mph as EGT's were screaming past 1300 super fast. I maintained about 50mph and 1200f in all large hill climbs

Travelling back home on a 55F day I maintained 1150 -1250F within the same speed 70-77 until I reached about 5000ft and the egt's oddly cooled to the average 1000-1100.

I realized today on a brisk 34 degree morning that my Pyrometer is reading 190*f after the motor had not run for 12 hours.
So I believe that would mean that I could take about 150 degrees off of indicated reading?

 

[AussieHJCruza]

I'd say you could pretty safely assume that, however personally I'd be replacing ASAP because it's not worth being uncertain on something that could kill the engine

 

[Jroc561]

Congrats man, this thing came a long way

 

[ubguessin]

I'd say you could pretty safely assume that, however personally I'd be replacing ASAP because it's not worth being uncertain on something that could kill the engine

I checked with the manufacture and everything is proper with this gauge. No issues with reading temps.

 

[ubguessin]

Alright guys, well im back to this thread because im having more fueling issues. Possibly turbo as well.

The truck has suddenly gotten alot slower on take offs. It runs great in the mornings but afternoon I get halfway home and I have a noticable power loss.

I cannot go 80mph any more as the The EGT's spiked 80mph=1200+F EGT's. Used to be 80mph=800F-1000F

Cold starts in the morning are absolutely terribly smokey white. Like its winter time and truck shakes like crazy (Ordered new glow plugs).

Once warmed up the exhaust takes on more of a blueish color.

I noticed ive been losing my fuel prime when the truck sits and I have a pesky air bubble that keeps popping up. Ive replaced all the rubber fuel lines.
When I prime the fuel line and get the pump hard I hear an ever so faint hissing noise that sounds like it is coming from the IP but no fuel is leaking. The air bubbles are happening at the outflow of the water seperator leading to the fuel filter.

I'm am getting boost creep. And there is a noticeable amount of oil that is masking the bottom of my intake port.
Typically ive noticed in the summer its harder to maintain the 15psi and ive seen it hit 18psi now.
Truck has an intercooler and provent catch can.

All of these symptoms happened so randomly and suddenly I havent been messing with anything.

 

[ubguessin]

 

[roscoFJ73]

It runs great in the mornings but afternoon I get halfway home and I have a noticable power loss.

It could be a symptom your injection pump needs a rebuild. As they warm up and expand, they lose pressure in the plunger and pump head. Common problem on injection pumps with 350000klms +.
And the blue smoke is oil burn. It could be rings or valve guide seals letting oil into the combustion chamber.
Posts like this should include the klms travelled.
Fixing the air leaks in the fuel system must be done first to isolate problems.

 

[ubguessin]

It could be a symptom your injection pump needs a rebuild. As they warm up and expand, they lose pressure in the plunger and pump head. Common problem on injection pumps with 350000klms +.
And the blue smoke is oil burn. It could be rings or valve guide seals letting oil into the combustion chamber.
Posts like this should include the klms travelled.
Fixing the air leaks in the fuel system must be done first to isolate problems.

Pump was rebuilt about 2 years ago.
299k's
Fuel primer head is brand new as well.
Have 6 brand new injectors.

 

[roscoFJ73]

Pump was rebuilt about 2 years ago.

Did you get a list of parts replaced?

 

[ubguessin]

Did you get a list of parts replaced?

Ive been digging for them, I just recall it was a good full rebuild

 

[ubguessin]

So reluctantly somehow my engine has "fixed itself" last night and this morning the motor has run super strong. Very little exhaust smoke. But now has a more audible knocking near idle.

I have put a stethascope to the injectors and #1 seems to be the most noisy at idle. I d I not known what to listen for in terms of good or bad sounds but #1 is obviously different.

 

[ubguessin]

Can anyone chime in on why their are times where I am at a dead stop in the mtns and I have to floor it and black smoke is building everywhere but the truck is barely moving at all...