New project 99 2500hd suburban 6.5TD

[buddy]

There is a large camp of people that upgraded to a TM before they ever paid the bigger bucks for the PCM update. The TM outperforms a stock boost curve for most people, because the PCM cuts boost a lot. But it could waste more fuel if they set their TM too high and were driving with too much boost at empty cruising speeds. Simple solution is to loosen the TM, but then that awesome spooling you had is not as awesome, but alright. When I was using the vac system it would do everything how I wanted it, fast spooling because it held it shut, doesnt give until youre over the programmed boost, and it could be programmed pretty high, but then at a lower fuel rate and cruising RPMs you can program it to cut boost to good cruising levels. Vacuum costs more to maintain, but I liked it better. I only ever had to repair a few vac line cracks, but other have failed pumps which are spendy.

 

[sd455]

Well,

Today I finally replaced the "suspect " PMD. For the short term I mounted the heat sink and PMD on the manifold, basically just wanted to see if replacing it does indeed solve the mystery stalling issue. I managed to get the old one unplugged and fish the wires out without removing the plenum, or anything else for that matter. I made a little hook tool that I looped around the harness before I unclipped it. So now I have a fuel leak somewhere under the manifold or around the IP!!! Drove it home and when I got out noticed a fuel smell, had a look underneath and sure enough...drip,drip. Looks like it could be the feed line from the filter housing,still appears to just have the factory spring clip on it, and looks a little loose. If I remove the line, trim off the end and put a proper hose clamp on I'm hoping it will stop the leak . My question is: How do I bleed the air off from the IP once I re attach the line. My thought was I would try and use the "T" valve and just cycle the LP a few times. Is there a "procedure"?

 

[sd455]

I forgot to mention that I did have a look and I do have the screw on style clutch fan. I cant tell if the airbox is anything special but it does have a larger hole into the fender than my buddys 94.

Also installed a new set of Monroe reflex shocks to replace the originals which had 280,000 kilometers on them. There was a noticeable change but the tires are so bad on this thing that its hard to notice anything other than that. I was at the tire shop and tried a 285 on my H2 wheel....too big for my tastes, so I order a set of 26/70/17 michelins. Just need to find some centre caps and should be set. Will post some updated pics after they are mounted.

 

[buddy]

Its a little more work, but if I were you I would run new lines from the filter to the IP and to the drain valve. Those are always suspect and will cause you grief later. Some of us relocate the filter manager higher up or on the fender or anywhere for easier access. Not necessary but something to consider. And the Feed the Beast mod is something to really consider. WalkingJ designs sells a kit for the FTB, or you can potentially find the pieces for less. I found that their steel IP fitting is the best available, I couldnt find elsewhere. I and some others also have threads for our own versions of the FTB mod. Could also replace all the O rings in the FFM at this time.

 

[sd455]

Its a little more work, but if I were you I would run new lines from the filter to the IP and to the drain valve. Those are always suspect and will cause you grief later. Some of us relocate the filter manager higher up or on the fender or anywhere for easier access. Not necessary but something to consider. And the Feed the Beast mod is something to really consider. WalkingJ designs sells a kit for the FTB, or you can potentially find the pieces for less. I found that their steel IP fitting is the best available, I couldnt find elsewhere. I and some others also have threads for our own versions of the FTB mod. Could also replace all the O rings in the FFM at this time.

i was planning on doing FTB, but need to stop the leak in the meantime. What is the procedure for getting the air out after having the IP feed line off?

 

[buddy]

I would do like you said run the LP out the drain, shut the drain while its pumping. Then, you can take the IP inlet loose, not off, and run the LP, spilling some fuel you could put rags around. Once youre getting good fuel out the hose tighten the clamp on it. No other real way to get air out of the line other than cranking after that. No need to crack an injector line.

 

[DennisG01]

SD: The better airbox, which you likely have (I have it on my '98), would contain a round air filter, not a flat one. The box, itself, mimics the shape of the filter, it's just "flattened out a bit" and not perfectly round.

 

[sd455]

SD: The better airbox, which you likely have (I have it on my '98), would contain a round air filter, not a flat one. The box, itself, mimics the shape of the filter, it's just "flattened out a bit" and not perfectly round.

Ok, so I have the good airbox, and cooling which is awesome. The 1 thing I wish I had is 3.73 gears, the 4.10 will be ideal for towing, but not the best for economy which is my main goal.

I got the wheels and tires on and removed the running boards and all the cheesy GM accessories. I would post a pic but cant figure out how.I'm clicking the rite buttons but its not happening.

On another note I have been reading up on the ATT and wondering if this will be my key to the better mileage? Still not sure about adding the turbomaster to my existing st up. I'm going to head up to see Bill Heath at the end of the month for a new pcm and???

So far I have added LRR tires, changed all fluids and filters,shocks, a thorough cleaning, adjusted front torsion bars to level front end(nose up attitude previously)
3" strait pipe,new LP and new PMD w/heatsink, new shocks and a few other misc items.

Its like a new truck and I love it, but still have the desire to keep tweaking.


I tried again and voila!! Heres a pic

 

[Big T]

Without question you can demonstrably improve the power and performance making it a fun ride. You can do that while preserving the existing rate of fuel consumption. It's been my experience that gains in fuel economy are negligible. There
is virtually no noticeable difference in mileage between 4.10s and 3.73s. I just giving you my honest assessment based on my experience with two Suburbans. My observation is that the guys claiming 20 mpg are all driving 2wd trucks, not 4wd Suburbans. There is a big difference in weight between the two. Your real mileage bench mark should be the 6.5 TD suburban vs the Suburban powered by the 454 or 7.4L gassser. That comparison in fuel economy will only draw extended smiles.

 

[buddy]

Did you end up with 265/70/17 tires? The wheels look good.

255/75/17 tires would actually be a little taller and less wide, but maybe not as common.

 

[sub6291]

That's a nice looking truck...

 

[sd455]

Did you end up with 265/70/17 tires? The wheels look good.

255/75/17 tires would actually be a little taller and less wide, but maybe not as common.

I was not able to find the 255/75 in a tire I liked or in a load range "e" so I ended up going with a 265/75/17 Michelin, which I am very happy with, truck drives beatufully. I am less impressed with the Monroe reflex shocks....well thats half true. The rears are fine, but the fronts seem to be lacking the rebound control required for such a heavy truck so it ends up feeling boaty. Maybe time for some Bilsteins?

 

[sd455]

That's a nice looking truck...

Thanks!! And same to you.

 

[DennisG01]

The 1 thing I wish I had is 3.73 gears, the 4.10 will be ideal for towing, but not the best for economy which is my main goal.

Too bad we weren't closer to each other - I'd swap you my 3.73 's for your 4.10's!

Nice looking wheels!

Bilsteins are the way to go!