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The "restification" of a 98 6.5 TD...

Very happy to report with the new tools an IP adjustment now takes about 5 mins. That's with removing the engine cover and upper intake. The fabbed wrench fits nicely on the driver side nut and the upper intake. The angle is just a wee bit off to do a good job on the passenger side but I have a 15mm flex head gear wrench on order that will do that job nicely.

I'm now sitting at -.35 for tdco. I'll run that for a whiel and see how I like it. Truck seems quieter already with no real noticeable diff in power (not by the "butt dyno" at least).

Once the flex head gets here, All an IP timing change will require is disconnecting a few electrical connectors (for room to move) and hooking up the scanner. Nothing else will have to come off.

Life is good....
 
great white said:
Very happy to report with the new tools an IP adjustment now takes about 5 mins. That's with removing the engine cover and upper intake. The fabbed wrench fits nicely on the driver side nut and the upper intake. The angle is just a wee bit off to do a good job on the passenger side but I have a 15mm flex head gear wrench on order that will do that job nicely.

I'm now sitting at -.35 for tdco. I'll run that for a whiel and see how I like it. Truck seems quieter already with no real noticeable diff in power (not by the "butt dyno" at least).

Once the flex head gets here, All an IP timing change will require is disconnecting a few electrical connectors (for room to move) and hooking up the scanner. Nothing else will have to come off.

Life is good....
Click to expand...

That is within stock setting -.25 to -.75 range, IIRC one of the guys back on old site moving from stock TDCO .7 to -1.94 gained 3Hp and 10 pound feet Tq @ rear wheel on a superflow dyno after the resetting of TDCO from just below max factory range.
 
Turbine Doc said:
That is within stock setting -.25 to -.75 range, IIRC one of the guys back on old site moving from stock TDCO .7 to -1.94 gained 3Hp and 10 pound feet Tq @ rear wheel on a superflow dyno after the resetting of TDCO from just below max factory range.
Click to expand...

Could be.

Similar things came be see with advanced timing in a gasser.

But, I'll give up 3 Hp fro a quieter ride.....):h
 
So, after a few days of running with the boost gauge I've noticed a strange trend with the system.

When the truck is stone cold, boost works just fine. Stomp the throttle, boost builds quickly, holds, dips when the shift happens and then goes back up. Steady throttle has the boost slowly dial back until you're running on about 0.5 psi. If the truck stays under load (IE: climbing hills) boost holds around 5 psi. Makes sense, it's how I would build it - power when you need it, economy when you don't.

But once the truck is up to temp, boost seems to just "disappear". The gauge goes negative pressure, and no amount of antics with the throttle can build more the about 0.5 psi.

So, one of two things are happening here:

1. component failure

2. Boost programming is whack

Checking out #1, I first checked vac pump for vacuum. Yup, workin' fine. Damn near tries to pull my finger down the hose!

Next, wastegate diaphragm. Solid as a rock. Open or closed with the port blocked.

So, pull the lines off the actuator/vac switch. It' shot now, so a fault would be present if it's the heat. Connect the pump line to the diaphragm line and sure enough, wastegate slams shut.

Goose the throttle and she builds boost to about 2-5 psi.

So here's the prognosis:

Either the vacuum switch fails once warm (open fault) or the programming doesn't build boost once the engine is warm.

time to get out the multimeter.....

(please, no TM comments. I've already heard them and am well aware of it)
 
interior comes back out today.

I'm planning to sound deadnen the floor with rubber membrane from protecto wrap. It's 1mil thick, self adhesive and plastic backed. No smell what so ever (it's a ruber product)

It also only cost 40 bucks and is 12" x 75 feet. Enough for one full cover of the floor. I'll double it up and get 2mm thickness if I so wish.

Total cost of 40 bucks so far. Should be fairly effective as deadneing is about mass loading and changing resonant frequencies.

We'll see if the old GMT400 platform can be any quieter....
 
I have used ProtectoWrap on both of my doors and it made quite a difference. Would probably do wonders on the floor. Good Stuff.
 
Did some initial testing with the DIC from the bravada with enhanced functions today.

I tapped into the class 2 serial data through the DLC port. I then slaved in 12v+ and 12v Ign plus a ground. The compass sensor and temp sensor were not hooked up and I didn't have a vss input.

The DIC displayed avg, speed gal, instant mpg, etc.

I was curious to see if they were stored values or data reported from the PCM, so I disconnected the Data wire. Sure enough, everything previously reported dropped off to "0" or "E" (error).

DTE (distance to empty) did not display, only returning a "- -" indication. This was expected though. My reading indicates the gas truck PCM receives fuel quantity data from the cluster (or sender, can't remember) and the diesel trucks do not. Fuel quantity remaining, of course, is a fairly important factor when calculating DTE. The Diesel PCM obviously does not calculate it. Once I crack into the strings in the programming, I may be able to patch it to include it. But I'd have to find a way for the PCM to know what the fuel quantity is. The sender and gauge appear to be analog (like the trucks of old) and the PCM would require a digital input, perhaps from a gassers sender slaved into the tank. But, that's waaaaayyyy down the to do list.

Obviously, temp and compass did not function.

I plan to install it slaved below the dash to run testing to see if it is accurate against manual calculations. But, if i understand what I have read correctly, the DIC does no calculations and merely reports what is delivered from the PCM. I can't see engineers :rolleyes5: putting in routines to calculate the above functions without it being needed or accurate for the PCM operations.

I'm pretty sure I can go without the vss signal also as the DIC uses it to adjust the temperature signal to whether the truck is moving or stationary. From what I've been able to ascertain, the DIC doesn't use the input anywhere else.

Early indications are promising for OBDII equipped trucks with class 2 serial data if you want an enhanced DIC in an overhead console.

Time for some field testing......:)
 
Hmm, first test run, no data.

Just "- -".

May have spoke too soon. The PCM may not have the code to communicate with the DIC.

I'll tap into a vss data line for signal, but I'm not holding out much hope for that fixing it....
 
test run #2 with vss signal:

No joy.

Oh well, it doesn't work. The PCm just doesn't have the proper coding I imagine.

At least I'm only out 25 bucks for the unit and now I know.

I'll just wire up my standard temp and compass display.
 
Well, I think I've found the source of the wonky boost action once the truck is warm.

I took it on a 2 hour run down the highway yesterday, it finally lit up the MIL and threw a code I can work with: P0236 Turbo Boost Sensor A Circuit Performance

I went through the system. Good vacuum from the pump at idle (20 psi), good diaphragm (mityvac tested), tested solenoid continuity, operation with 12v and for vent filter clog. All good. Inspected tubing with mity vac, holds good pressure with no drop over 20 mins.

Next, traced the wiring back to the PCM pin, good continuity, pins are clean and make good contact at the sensor.

So, off to buy a boost sensor today.......nothing else left to check! I suppose I could have back probed it for voltages, but it's cooled off now and I don't feel like burning off more fuel to get it hot enough again.

It jibes with the heat related issue also. Once I let the truck cool down, the boost circuit started working as per and the MIL light would stay cleared.

I love the economy, performance and control modern electronics give you over an engine theses days, but troubleshooting has become a real PITA.

Used to be you trace the fault down and change it with a couple wrenches. Now, you trace down the computer codes, trace down everything else in the circuit and then you still have to get out the wrenches and change stuff....and there's no repairing or rebuilding stuf anymore, it's" remove and replace".

Just the way of the world these days I guess.....
 
Crankme69 said:
FYI had a vacuum solenoid on mine that drove me crazy for 2 weeks...it would only fail when it got hot under the hood...just saying.
Click to expand...

Mine tested good when hot with 12V and a mityvac.

But, I'll pick one up when I get teh map sensor today. I'll chuck it in the glove box and if p0236 comes back I'll swap it in.
 
Well, did a little "sniffing around" and came up with a Wells part number for the solenoid. Called the local parts place to see if they could cross reference it. Turns out they had the AC delco one in stock after all, just not listed in their parts breakdown.

40 bucks later I'm swapping it out in the parking lot.

Start up the truck, clear the MIL and what do I see?

No boost.

WTF?

So, I drive it home and start some trouble shooting. I had removed the new Boost sensor and installed the old one because my parts guy said he would take it back for a refund (I'm a good customer!). So I start back probing it.

Sure enough, it fails the voltage test!

So I swap on the new sensor (still had it around) with the old solenoid out of curiosity. Warm it all up to operating temps and what do we see?

Sensor probes good (it should, it's new) but the solenoid now tests bad for continuity! It tested good last time when hot......:skep:

Jebus, I have two parts trying to double team me into madness here!

So, on goes the new solenoid with the new sensor.

Get it all up to running temps and:

Everything finally works!

Just to make sure, I take the truck out on a 1 hour drive and hit every hill that makes her smoke like a WWII destroyer. Lots O' boost, no smoke, EGT's are much better and no codes (pending, history or otherwise).

Well, that was a bit of an ordeal! One intermittent sensor is hard enough to trouble shoot, but two can drive you to drink. Especially when they intermittently fail at different times!

Explains why it was so hard to nail it down.

Still, with 405,000 KM's on the original sensors I can't really complain.

With a new GM-8 Turbo, a new boost sensor and a new solenoid it's good for at least another 100,000 or so I'd say.

Still, I think I'll buy a new vacuum pump and serpentine belt and stick it in the truck somewhere even though it still pulls 20 in/hg at idle. Just in case.



PS: No, I'm not giving up on the vac system. Yes, I've spent 150 bucks and don't have a Turbo Manager. No, I'm not going to buy one. Yes a vacuum pump and belt will probably cost me another 150 bucks. No, I'm still not buying a Turbo Manager. Yes, it's still all subject to failure on the vac system. No, I'm still not buying a Turbo Manager.

There's a few paths I'd still like to explore and a Turbo Manager does not fit into the plan.

There, now we've got all that out of our systems....Feel better? :)
 
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I've often wondered what a Trans Am heat extractor would look like on my old truck. So I grabbed a couple pics of the net and did a quick PS:

13.jpg


Hmmm, don't know how I feel about those right off....

I posted this up because I grabbed a pair in good shape for 20 bucks. May pursue this, may not.

Dunno.

What do you think?
 
great white said:
I've often wondered what a Trans Am heat extractor would look like on my old truck. So I grabbed a couple pics of the net and did a quick PS:

13.jpg


Hmmm, don't know how I feel about those right off....

I posted this up because I grabbed a pair in good shape for 20 bucks. May pursue this, may not.

Dunno.

What do you think?
Click to expand...

... If you plan on cutting the fender to put it in... I'd seriously reconsider.. I talked to Bill about his cold air intake not even a month ago and they did a bunch of testing... that fender actually has a ram air scoop by the passengers side headlight and it pressurizes the fender area (they did manometer tests)... If you cut a hole in it you're releasing that pressure straight back to atmospheric... Ooops!
 
Dylly said:
... If you plan on cutting the fender to put it in... I'd seriously reconsider.. I talked to Bill about his cold air intake not even a month ago and they did a bunch of testing... that fender actually has a ram air scoop by the passengers side headlight and it pressurizes the fender area (they did manometer tests)... If you cut a hole in it you're releasing that pressure straight back to atmospheric... Ooops!
Click to expand...

Yup, it sure does.

It also has a "back wall" to it which can been seen when you take out the air box.

If I were to install these vents, they would be behind the wall forming the intake "plenum" area and allow engine bay air to "vent".

I usually think these things through before a grab the metal shears......

:)
 
what about some sort of scoop that could be mounted in say a running board. You could take advantage of the low press area there and pull air completely thru the engine compartment instead of out just the top part.
 
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