Odd Idle Condition

[Uncle Wally]

Ok Guys,

Update and question on the 94.

Transmission is finally finished. Runs out good. First time I've driven it with the IC and the new injectors. Here's the issue. It seams to be 'loaded' up at idle. Exhaust smells very strong of unburnt fuel. I turn the key, cycle the glows. It pops right off before an entire revolution. Small amount of white smoke (not abnormal from my experience). Glows cycle while idling. A couple of white puffs out the exhuast. None after that. Idles rough and uneven, although it seams like it's hitting on all eight. Idles for a bit to warm things up before I drive it. If I blip the throttle, it stumbles hard. As if it's way to rich. I've not experienced this before. Only change was IC and Injectors. Timing is dead on (-1.75 TDC offset) No codes set. When I road tested it, it's perfectly smooth. The only difference from before is that boost doesn't get as high (I am assuming because the IC added extra volume to the intake tract so it takes longer to get higher boost numbers). I had the engine out to do a lot of the work, so I know that it's not a ground issue. I replaced all the ground wires under the hood and cleaned them all up and used dielectric grease to keep them from corroding.

Any ideas?

Waldo

[Kennedy]

Sounds like something may be restricting the air entry. I had one like this after we did exhaust and crossover install. Piece of rust must have lodged in the turbine wheel. After scratching our heads, it finally popped free.

Basically, while the turbo was "parked" it ran like crap and smoked terribly blue on acceleration.

I've seen a LOT of the turbo inlet ducts folded into the air stream from guys trying to R&R filters without pulling the box also...

[Uncle Wally]

Thanks John,

I'll check all that out again when I can dig into it more. Strange thing, it runs great under power.

I noticed a fuel smell too, and when I crawled underneath to adjust the down pipe so it doesn't hit the bottom of the cab, I noticed that the rubber plug on the #8 injector return wasn't there. A buddy has a spare, so I'll know Wednesday if that would make a difference. Would also explain the terrible fuel mileage this last tank.

Waldo

[Uncle Wally]

John,

I've checked everything in the induction system from air filter to intake. Everything seams as it should be. Turbo spins freely. Air filter is in correctly. No rags or foreign material in I/C or tubes to and from. The whole fuel filter assy was replaced due to a leaking heater element.

Further diagnostics:
- No codes.
- Boost used to peg the 15 psi gauge before the I/C installation, now it only hits 12 psi max (No load behind it - but I am ok with this as I am running stock compression ratio)
- Good fuel flow from the lift pump (as checked by opening bleeder valve on coolant crossover)
- Off Idle stumble that almost kills the engine, then it comes on like gangbusters.

What I replaced while it was down for a while for transmission repairs.
- New ACT Torque converter as you suggested
- Fresh trans rebuild
- I/C
- Fuel injectors
- Large capacity oil pan and pump pickup to go with it

Did your 3/4 ton have an off idle stumble? I believe the only difference in our trucks powertrain would be the turbo, PCM programming and maybe possibly gear ratio. I'm hoping that I am missing something simple. You described your truck as very close to a D-Max in stock configuration. I would say that mine is absolutely not even close. Heck, it can't even keep up to our 3/4 ton burb with an 8100.

Any other idears?

Thanks in advance,
Waldo

[eracers999]

Wally;

It sounds like you need to get on a scanner and see if it is running at the desired timing of 8.5 or what it says. Scanner should verify that stepper motor is alive. Mine will run like this doing a timing learn procedure with the tech1 when you command the stepper motor to the bottom and set base desired timing. Everything down alongside the pump double good??

Kent

[Turbine Doc]

Wally do some further checking, but since my injector replacement I've had similar anomaly at times, extra fuel & stumble slacks off when engine warms up. Boost did go down some with my IC install, but I diled in the TM or JK boost control to get it back up. Would be nice to observe fuel rate while driving, are you chipped, if not may be limited by stock fuel delivery curve.

Oh yeah another thought, my MAP sensor went bad to hi side PCM saw very hi boost and retarded my boost, but that should not effect idle fueling I think you have 2 events happening, but lower boost could be from under fuel HO injectors working against PCM

Did you go to HO injectors, my experience they seem to overfuel some at idle & PCM can't deal with it especially on cold mornings.

I think cold advance is asking for more fuel and the HOs are giving it already and PCM is blind to the mechanical changes to the injectors. Is clack clack at idle more pronounced?? mine is again louder with cold mornings. Does engine smooth out with just a little more throttle say idle up to about 950, mine does when I get in that scenario.

If you didn't go HO never mind all of what I just wrote

[ 12-09-2004, 06:52 PM: Message edited by: tbogemirep ]

[Uncle Wally]

Yes, I picked up a set of John's HO injectors. I am chipped with one of John's TD Max chips with the boost reference portion removed because I am running a larger non-wastegated turbo.

I had a friemd of mine that is a mechanic at the local stealer bring home a tech1 to check everything out. Timing was dead on. No other noticeable problems. He's the diesel guy at this dealership and we've had some pretty good troubleshooting sessions on mine and others rigs. We seem to help out each other fairly well (thanks to this page).

And Yes, diesel rattle is much more pronounced at idle, even very rough at times. I am trying to remember what it was like at 1000 rpm. I did notice that once it's over 1000 rpm and the turbo starts to whistle, it runs flawlessly.

Any more feedback?
Thanks,
Waldo

[ 12-10-2004, 01:34 PM: Message edited by: Uncle Wally ]

[Beedee]

Hey Wally
My $.02 I have had a problem with using too much dielectric grease and loosing grounds because of it. For example, our logging trucks have weight scales on each bunk, if you get too much grease on the pins, the computer gets a wrong reading ( the computers run micro volts and milliamps), the scales work, but the readings are all over the place. Also have the same problem with the ABS system. Just a thought, but if you had too much grease on one of the computer grounds, could it cause a problem ?
One of those places where less is more???
Good luck
Brian

[eracers999]

Wally;

You dont by chance have a straight load of no2 fuel in that thing??

Kent

[Uncle Wally]

More updates,

I changed where I have buying fuel. I also changed my fuel additive back to FPPS.

Preliminary findings:
Seams to run smoother at lower rpm's. EGT's are a touch higher while moving, and a touch lower at idle - I'm not sure if it's just the cold weather or me - but it seamed marginally different. Boost has changed to. I can get up to 15 psi without a load, rugged. The off idle stumble seams to have gotten better and throttle response seams better to.

I'll have to drive a couple tanks of fuel through it to see if this was the problem all along.

My question:
Can the quality of fuel and additives change how these things run that much? The way it drove this morning is livable. The way it drove yesterday before I fueled up was not. Will it make any appreciable difference with a load? I still haven't hooked up the horse trailer yet because I want to insulate the turbo housing before I push the EGT's up. I had issues with the coolant hoses melting before.

Thanks,
Waldo

[Uncle Wally]

Kent,

I have no idea as I was buying fuel in the little podunk town I live in. Last night I filled with #2 at a truck stop off of I-94 and used additive.

BTW - are you running an I/C? Any issues with tires rubbing on your rig? Rear wheel spacers? I was going to change to larger tires here soon as the ones I have on now are marginal for the winter.

[eracers999]

U W:

No intercooler yet.

On a rare occasion while turning i get a touch from the front, i have the suspension in front as low as possible.

With the 255/85/16 tires on it, the rears would touch all the way around just bolting them on so i did some reasearch and found this guy fearless fred who owns Design Deluxe MFG in Van nuys CA.

I pushased a pair of his spacers, 2in deep. Billet aluminum, they bolt on over the inside rim, it pilots itself 2 ways, hub pilot and conicle seat where you bolt it on. Then it has it's own studs that come out for the outside rim, the outside rim is centered on a 4.600 pilot machined on the spacer, so the outer rim needs to go from 4.567 to 4.601, that is the only draw back. Now i have the proper 2in spacing between my tires witch i wouldent have even if i were to switch to a 235/85/16 with no spacer. These spacers run totally true and have no weight limitations, i love em. Cost was around 300 and somthing cant remember. Now i can put whatever tire on that i want.

Kent

[tom.mcinerney]

UW just to remark some of the aberation maybe from a bit of air in injector lines, and time needed for injectors to seat/wear in.
And the fuel may have been big factor.

[Uncle Wally]

Kent,

Do the rear tires stick out from the blister then? I've been tossing around installing taller tires. I've also thought about a 3.73 regear, but I'm going to wait to see what the tires do.

Tom,

How long before I can expect injectors to be broke in - per say. I think alot if it was the fuel, but it still isn't even close to my buddies D-Max in stock Edge mode. I suppose I should get a dern D-Max truck and forget about it! <<laughes>>

Wish I could afford one.

Waldo

[Turbine Doc]

UW
I have 3.73s plenty of pulling power running 265s with 16x8 rims stick out about 1" past fenders. As far as break in of injectors go I'm still waiting for mine to break in, after a year, when I bought mine JK did say there would be more rattle on the bottom, there is, I've gotten used to it by now & don't notice unless I'm in an enclosed garage or car port.

[tom.mcinerney]

Wally-
Can't say, inadequate experience. Suspect first air remnants bleed, then minute harmless particles wear in, then (if all well) the lapped surfaces reach their best fit....

[charliepeterson]

As for Injectors seating I would guess a few hundred miles with cool down cycles mixed in should do it.

Try changing the engine timing. The difference between -1.50 to -1.94 is pretty close but the truck can act differently in sound and performance. You can't go wrong with either setting.

[Uncle Wally]

The timing is at -1.75 at the moment. I tried to set it at -1.95, but then it throws the timing code (88 I think). When I first got it it was at -1.50. I believe I will need to switch to gears to run it @ -1.95.

Waldo

[eracers999]

U W;

The wheels are with in the fenders,

Kent