dan123dbl

I've been trying to tune my truck for months now with no real progress on getting my low end power back. I'll start with saying that I have good power above 2000 rpms and it will put you back in your seat, but anything under 1900-2000 rpms and it will barely get out of it's own way.

I had a 3500lb load in the back of my truck yesterday and I couldn't even make a shift from 2nd to 3rd on a small hill, I had to drop it back into 2nd. And that's with winding 2nd out to 2800rpm before shifting.

Things I have that aren't in my sig are a longer afc slide pin and a stiffer afc spring. I have all my fuel settings counter clockwise to get the least amount of pre-boost smoke. (but I seem to get an excessive amount even when barely putting my foot into it)

I have adjusted my timing from stock to 1/8" bump, to 3/16" and to 1/4". Doesn't help low end smoke or power, just makes the engine louder below 2000rpm. This is with and without the m&h spacer installed.

I have tried turbo settings from 9cm^2 up to 12cm^2 , and it doesn't spool any better even though I'm getting boost instantly. I have pressurised the system up to 30lbs and have fixed all boost leaks with the soapy water test. And the turbo doesn't have any play in the bearings and spins freely.



I'm not sure what else to try, other than assuming my injection pump is worn out and can't support the higher pop pressures of the new 7x10 injectors.


Mpg are also down by 3 since the injector and turbo have been installed. I had a consistent 19mpg average even through winter, and now I'm having a hard time getting 16.

Fuel filter has been changed multiple times, no fuel leaks and not sucking air anywhere. This is over many tanks of fuel so it isn't bad fuel.

j_martin

This sequence is the hardest thing I have found to get my students to learn:

1. You walk up to a running machine and do something to it.
2. The machine now malfunctions.
3. It's what you did.

Always map where you are, and if the response to an action doesn't make sense, do not go forward until you back up to a known place. Otherwise you run the risk of introducing multiple faults.

I might be wrong, but the symptoms you describe would indicate advanced timing at idle. I would put a gauge on it and verify stock timing before I proceeded if it were my project.

dan123dbl

That's usually how I do everything, but this was an exception.

I had my head off doing a head gasket, and while I had downtime I thought it'd be a good idea to do turbo, injectors, seals, and just more than 1 mod at a time. Big mistake


I will try and get a dial gauge and verify stock timing.

Alec

Why (and when) did you put in the long afc slide pin?

When you say you get low speed smoke under acceleration, what color is it?

What are your egt's doing?

How are you controlling the turbo?

I am thinking that you should be able to tune the truck back to the way it was before you did the head, etc., so that basically the only variable is the change in injectors . . .

Interesting tune -- you were going for towing & economy? It all makes sense to me except the injectors, BUT I am not up on how different injectors behave.

j_martin

Dan,
Where did you get the 7x10's?

I threw a set of 7x10's in for awhile. They were pretty snappy, but even at sub stock tune settings I couldn't clean them up Air was supplied by a 60 mm wheel. Auto tranny, held down pretty tight with a Goehrend converter, with stock exhaust side, so spool up was as expected, a bit slow.

I was beginning to get tired of the smoked up camper and boat, and then one dropped out, so I wound up putting stock injectors in on the road. Next run was Denver, so that was pretty frustrating at altitude till I realized that the truck couldn't breathe any better than I could.

I put stocks in. If I change out for a bit more, it'll be +40's. (432 131 837). My son put a set in his W250 and they run real nice.

Not looking for drag racing performance, just getting my 6 tons of recreation gear off the end of the on ramp without getting in anyone's way.

dan123dbl

I put the longer afc slide pin in about a month ago. I put it in for more afc control to limit no boost fueling more.

Egts are fine when up to speed. Doesn't get over 800 accelerating somewhat briskly.

The turbo is controlled electronically. I have it set a certain position, then it starts to open when i reach 20 psi.

The plan was for a quick spooling turbo that'll flow more up top than an he351cw, and the 7x10s are supposed to spool up fast and atomize the fuel better to get better mpg. However, that's all theory from what I have read from other members. On paper my truck should be very clean.

I got my injectors from The Hungry Diesel. For troubleshooting I asked for my stock injectors back, he sent them out right away. But the Canadian post office lost them in transit so I have no baseline to go back to..

Were you using a stock h1c with a 60mm compressor and 16cm housing on it with the 7x10s?

My main goal is to just have very clean low end power. I don't care about racing the truck.

j_martin

Dang it, I hate when that happens.

I was using the stock h1c with a 60 compressor on it. Nice upgrade, gave me quite a bit more boost, especially spooling up.

I think the IP supply pulse at low rpms doesn't have enough snap to utilize the potential of a 7x10's and the result is poor atomization at idle. Mine hazed at idle no matter what I did. Spooling up was black smoke and burning tires if I wasn't careful. At speed cruising was pretty clean, but full throttle, ie hill climbing got pretty smokey. All that was with bone stock IP settings, except idle had to be turned up to run, which is one reason I suspect poor atomization at idle.

They were fun to drive, but hard on trailers and motor oil.

dan123dbl

The difference between our results is that yours would still have power down low, just really smokey. Which I could assume is from the large housing of the h1c with an added 60mm compressor.

Mine will just bog right down if I ask too much out of it down low. Literally like a "bleeeghhh" and belch smoke.

Another thing to add is I can't start out in 2nd gear without the engine stumbling or, again, too much smoke.
This problem seemed to happen when I replaced my injection pump with a used one even on my stock injectors. I think these injectors could be highlighting a problem in my injection pump that wasn't as apparent with more conservative injectors.

j_martin

If you're getting a lot of black smoke, you're getting good fuel. If you aren't getting power, it's burning at the wrong time.

Goes back to pump basic setup and timing.

Alec

Pretty good assessment, in my opinion.


You still haven't given too much detailed rpm, load, smoke, egt, boost info, which I would find interesting . . . but I also would guess that you have a timing problem, with the falling down & belching at low rpm.

One thing you can try: with the truck idling, energize the KSB. If the engine slows down when the ksb advances, your static timing is too advanced. If the engine speeds up, you *might* need to advance your static timing further.

Are you running a Steed controller on your turbo?

dan123dbl

It's definitely burning at the wrong time. I have tried many different timing positions starting at below stock where its hazing too much, and then just advancing it by a 1/16th at a time.

It will probably be best to set it with a dial gauge.. I just have to pick one up.



I will try and get some better info on rpm, load, smoke, egt and boost. Hard to watch everything at the same time. But I can have 10+ psi before 1500rpm, depending on the turbo position.

I am using an arduino with a canbus shield on it. I can control the turbo with a potentiometer or have it run off of my pre-set positions using a boost sensor.

I haven't noticed a change in idle speed when energizing the ksb. I will look again tomorrow.

dan123dbl

Small update..

I have my bd fuel pin turned 180* so I get 0 extra fuel from the afc. I have also turned my power screw down 2 full turns and adjusted my idle back to 850 warm. This has helped a ton with low end smoke, but I'm still hazing dark grey while accelerating with little power.

I am picking up my barring tool tomorrow and will set my truck to stock timing on Sunday morning and go from there.

Is the timing case tdc pin accurate for setting stock timing? I've read a few places that it can be a few degrees off.