Truck back from shop. What gives???

[Randee of the Redwoods]

$3200 later, Jim Mckay Chevrolet let me have my truck back. Among other things fixed were the headgaskets. Believe it or not, the only difference in driving the truck now and before the work is it heats up faster now(good, too, it's been cold here). Still drives great, but makes fewer noises(new lower pulley). Tranny fluid change when I bought it showed only normal wear for 184k miles on odo. But, one nagging deficiency remains: this thing is a dog up hills, unloaded, on a good day. What gives? I have a full Bill Heath exhaust, no crap trap, pyro temp good, plenty of boost, new air filter(Purolater for now). Everything is working properly. No smog to worry about(see sig). Driving up hills, even just 10* or so, I'll lose more than 15mph. On steeper hills, the tranny will find second to maintain speed. What am I missing here?? This thing clearly needs more sneeze to the snot. Is it because the tranny is slipping maybe? Is it because this is a 4x4 with long bed with crew cab? Is it because this is a weak kneed 6.5TD? Is it because it is officially now 10 years old? I'll be derned if I can put a finger on it since my knowledge is still limited. I'm eyeing some minor performance upgrades(chip, Wickliff injectors, better air filter setup) but would like to make sure everything is now as it should be before going any further. Woody gave it clean bill of health considering the mileage, age, and wear he found on the engine internals. Briscoe Transmissions gave the tranny a passing grade considering the mileage, fluid color, and particles in pan. I don't expect this to be a Dmax or PS, but I was expecting just a bit more oomph.

[moondoggie]

Good Day!

Something ain't right. My pickup pulled our US Cargo SM625TA2 trailer (looks like the US Cargo SM727TA2 (http://www.uscargo.com/uscargo/products/enclosed/snowmate.asp)(click on the colored text), except mine's 6'wide & 25' long) up 10% grades, at least short interstate ones here in the flatlands, in OD with the Gear Vendors Aux. OD engaged, plus 4% larger tires (equivalent to 3.08 gears). I

[Barry Nave]

I'll bet my ex-cab 3500 dully weigh's in more then your. Tool box's and tool's no load is #8200. This truck will fly up hill's in OD at 60 and may drop a few MPH yet it stays in OD.
Your right, What's up?
Even when truck was stock loaded with tools I was happy with my frist diesel,after I got the bug's out from under the hood.
Any chance at all there may be something between the air box,fender,air flow area?
Had a tractor plowing frist of year once and it had no power as I remember. Find a rat nest in the air tube front of the cleaner.
It would be a need to know on timimg and TDC.
Injector? could be.
High miles? NOT, If it run good,start's good and All it is, is low power kind of sounds as if it's not getting enough air but you have boost?
I'll go with timing and fuel flow ;)

[tanker]

Where did they set the timing (offset)? :rolleyes:

[Randee of the Redwoods]

Timing and fuel flow-timing set by dealer after reconstruction. Was set with Tech2. As for screaming at the dealer, I won't be doing that any time soon. As I said, the truck drives exactly like it did before the repairs.
My pump has a green tag on it and there is a "GM Campaign" sticker on the rad cover. It may have had the pump changed at one time.
Throttle response-excellant. Shifting-early, but decisive(firmer with more throttle). Mileage-ok. Travelling to and from work for me is literally up hill both ways. No, really. It's hills in both directions.
So, 2 opinions already and both bad ones at that, too. I'll have that tranny looked at again. I'll also take the truck back to the dealer for "lack of power" and see what comes up. Maybe there is a trouble shooting process they can throw it through that will expose a weak area.
I forgot to mention the truck has factory 4:10's f/r. But it is a dog in my opinion even for that ratio.
Keep the opinions coming. I want to look at all aspects. First up-I'll take out the air filter and drive it. The Purolater filters use a foam "prefilter" element glued to the paper main element. I had speculations this would cause serious restriction, but kept using them anyway.

[Randee of the Redwoods]

Timing-I don't know, but I'll ask. Being a dealer, I'm sure it's wherever the book tells them. Woody did it, so I'm sure it's where he felt it best as a dealer technician.

[GARY PAGE]

Yea something is up. When mine graps OD at 45 shes locked and ready, never comes out after 50 MPH or even slows while unloaded. When towing my 30FT 5th wheel about 9,500 LB in the smokies she maintains 55 to 70 on the interstate and drops back to 3rd on some hills I baby her and let the load do the work on the down hill slides. Put the pedal to the metal and see what comes out!!!

[S\W Off Road]

I'm sure that if you were to put a performance chip in it you would be happy with the results.

[Don Boland]

Randee, I have virtually the same truck, and it used to run like yours does now. I got rid of the stupid air intake stuff in the fender and put in a K&N filter and it did a little better. I added JK's 3 1/2" exhaust without cat, and it did a little better. Then I go smart and put in new injectors at 183,000 miles and whoa! Whole new truck. It doesn't down shift empty going up hills unless I make it cause I want to pass someone. Some thing is wrong even if it does run just like it used too! I have a bunch over 195,000 now so it ain't the miles! It runs pretty strong and can't wait to get a couple more bucks so I can add a chip and boost control and gauges. Still cheaper than a new DMax I can't afford!

DB

94 crew cab dually 6.5td
86 suburban 6.2 with bad head gaskets - runs great even with the problem?

[gmctd]

I'm with Don - timing chain, injectors, and that old green tag pump is probably past the end of its service life - should of had a blue label pump by now.

[Randee of the Redwoods]

Ain't the miles, huh? Seems I may have had the motor figured wrong. After all, I only bought the Chevy because for this model era, they looked better than the Fords.
Woody said nothing otherwise or negative about setting the timing so I'll assume for now the timing set is within spec for the estimated hour life of the motor. It must be ok to at least a small degree since, after all, it DOES drive exactly like it did before.
Since certain other parts of the motor are in question(well, maybe ALL the parts), we'll try injectors first. I'll try and afford the Wickliff set(midrange). Can't afford the hi-po's and my pump could not take them. And I wouldn't want to try since the pump life is also quesitonable. Don Boland: did you put in oem replacements or hi-po jobs?
Tag on pump, I'll check again tomorrow. I THINK it's green, but I could be wrong. I run fuel treatment(antigel, cetan booster, injector cleaner) plus, about 4 quarts of oil have been through the fuel system(recommended by Heath himself). I know how the injectors work. Please explain a worn injector and how it affects performance. Please also explain the part of the pump affected by worn injectors and what part of the pump may also be worn out affecting power output. I'm sucking up all the knowledge I can. Maybe I should change my handle to "SpongeBob".

[gmctd]

Worn pump could mean late inj timing, and insufficient 'pop' pressure.
Worn transfer pump could be starving hi press pump, balancing inj pulse width variation - min fuel = Inj PW short DTC, low pressure = Inj PW long DTC.
Worn injectors could mean minimal fuel atomization, further delaying combustion, with incomplete combustion.
Should be able to see this in Inj Pulse Width variations, cylinder balance\fuel rate tests.
Worn (stretched) timing chain would give erratic timing numbers, late valve timing and inj timing.

It all works toward low power. Mileage has plenty to do with it where precision parts are incolved.

Have your timing and TDC Offset checked for +3.5deg and -.5deg, respectively.

Check out and compare your three pumps - may give you some easy direction.

[ 01-20-2004, 03:20 AM: Message edited by: gmctd ]

[Marty Lau]

I got my 95 on the road again last night YEAH!!!! :D I have 155,000 did the timing chain and gears, (passed on the idler gers) cooling upgrade and glow plugs and injectors , gauges Heath Boost controller and chip. PMD issolator.
I put the standard Bosh new injectors bought them from US Diesel (Gomars) and they check the old ones for me which they said were not working right. They said 5 had poor pattern would spray a nice mist then they would pee a stream. Not only poor fuel burn but could damage pistons. Now I have ONE SWEET ride!!! I pulls 5,000 lbs with 3.42 gears like there is nothing there. So I would change injectors and glow plugs for starts. Now where is that Dodge that passed me this summer!

[Don Boland]

Randee - I got the injectors from DSU in Portland. THey are the stock Bosch in the AC box (go figure?). I had to pick up some other parts and asked for a price and they quoted me $43 and I said load 'em up! Wanted to get the truck back on the road. I have had problems, mostly with cold starts in higher altitudes but a lot of that seems to be settling down. Not sure why really. It has been a little confusing since it runs so darn well, but my pump does have 125k on it. It is a green tagger.

[Randee of the Redwoods]

I paid close attention this afternoon on the way home, and even fell into an oppurtunity to really romp on it. Before I left work, I pulled air filter and ripped of the gauze prefilter. Out of the parking lot, it actually felt different, but it has been very cold, so I was still in high idle. On the usual hills, I drove normal, then pressed it, and kept checking gauges. Maybe this thing is not as bad as I thought. I can hold 3rd up a good hill, and even accelerate in gear for a bit. Any more pedal, and it downs to second, but that's because I'm demanding it pretty much. Even at idle, the motor is rediculously noisy. It literally sounds as if it's going to shake itself to pieces. There's more "marbles in a coffee can" than before it was fixed so I'm wondering if the timing had been advanced before.
I've firmly decided to replace the injectors. They're service life is questionable, so new ones will allow me to eliminate them in future troubleshooting. Only thing now is the ip which I really don't want to get into. I don't have any other vehicles to sell to fund that project. I'll start getting prices on injector replacement tomorrow and make determinations on whether or not I can do it myself(have to find a place to do it, plus how much downtime).
I may have been wrong with EXACTLY how bad it was, but to me, it still feels a bit doggish, like it should have a touch more oomph considering the factory 4:10's. Who knows? Maybe it doesn't have 4:10's in it anymore.
If anyone wants a hands on with this truck, seeing as how it's so popular, drop me a line. You can drive it, listen to it, kick it, prod it, and make your own assumptions.

[dieseldummy]

If the motor sound noisy like a powerstroke, then it may be that your TDC offset has been set to aggressively. I also agree about the intake snorkle, get rid of it. It helps a bunch, good luck. It seems like you get your fair share of trouble :(
Justin

[Barry Nave]

My truck with the DSG gear and -1.75 does sound like a powersmock. Real rattle at cold start but DSG also has a built in addvance of 4 deg.

[Randee of the Redwoods]

Ok, I've been thinking about this a bit. Could maybe just what I THINK I'm feeling is something worn out? Hey, 184xxx miles, you'd be worn out, too. When I accelerate-from a stop, off idle is almost touchy. Hit the gas(diesel?) and the truck rockets forward. As the revs climb as speed increases, a falling off point can clearly be felt. It's just after 2200rpm or so. Not only does it kind of drop off, but after that point, the engine pretty much refuses to rev higher unless I truly demand it. I'm supposing that little glitch is the tranny/engine programming. The last time I accelerated hard, I also noticed the tranny lazily made it's way from 2nd to 3rd. It held mid gear change for at least a full second. Scary. I do know some of what I feel is economy tranny programming keeping the engine at low revs. I also know that trying to compare this truck to my car(380 tq at the rear wheels) is a bit of a stretch. Torque numbers may be similar, but the truck weighs probably 1.8 times my car.
I'm wanting and ready for a chip upgrade, but as I've said before, I want to make sure everything is in good working condition first. No need to hot chip it with a bad ip if you know what I mean.
Injectors may be my last maintainance item. I need to start saving for a tranny rebuild as I'm sure one will be needed eventually.

[markelectric]

I have virtually the same truck, and went thru some of what you are. I went ahead with a chip install ( Heath super ) because the pump was not that old when I bought the truck. When I installed the chip nothing changed. After a good bit of searching I had the pump changed ( Heath pump no PMD, and a remote FSD and cooler )and then unleashed a bunch of power. I annually pull a few loads that can reach 25,000 GCVW and on one of them I smoked a new Duramax that had half the weight and no wind load.

[Jim P]

Randee,

My truck is far from stock and it also has a manual trans. but my power keeps coming on clear up to 3400 when it hits the rev limiter and it is still wanting more. We have a about a half mile hill here that is about a 20% grade. All the locals say that if you can pull the hill empty in high gear, you have a good truck. I topped it in o.d. doing 70 mph.

[Randee of the Redwoods]

Now that's something I know I can't do. My auto won't let me pull full revs to red line climbing hills unless I manually kept it in gear. I'm sure some tranny reprogramming or even a (gulp) rebuild would solve that, but for now, I'm going to focus on ruling out some of the simpler stuff. Since the injectors are questionable, I'll swap in a new set($$$) and see what happens. If there's no change after that(and there @#$*% sure better be), then either this truck truly is working fine or is a lost cause and I shouldn't have bought it. But then again, as I've said before, I don't know the feel of a 6.5TD so I can't tell if it's putting out as it should or not. Wanna test drive it?

[Barry Nave]

Randee
My trany did this even after a rebuild.
Once I installed the Interceptor www.autotransinc.com/intercept.htm (http://www.autotransinc.com/intercept.htm) I was able to incress line PSI and the trans now hooks each gear with out a delay. JK sell's this.
Great product :D