Hello,


This is my first time posting to the group, however my brousing around the forum has convinced me that this group is certainly the center of competance on the subject of the 6.5. I'm having some serious issues. Let me begin by explaining what it's doing and what some of the background parameters are:


Mileage-139,000. Dealer replaced complete pump at 132,000 (ouch!). Symptoms: Does not hit on all cylinders as it did before when starting cold (chuggles a little when cold for 5 seconds then idles perfectly). Tip in acceleration cold, the engine shakes like a wet mink. It has flipped the MIL on continuous with a code 711 (trans temp sensor) and 246 (boost pressure). Once warm after 30 min of driving, the manners become much better with only a tiny bit of occasional hesitation, but has little power and the turbo whine is gone.


What I've checked: New air and fuel filters. Batt voltage verified. Vacuum is suspect. The pump is producing 15-18 inches of vac at idle and not much more as RPM increases. I pulled the turbo and verified that it is intact and spinning, however it is producing no boost at all. All vacuum lines are intact. I verified (heat cycled and performed resistance/flow check of the wastegate solenoid).


I notice that the wastegate actuator is not functioning. Is the actuator supposed to "bleed off" vacuum or should it hold it steady?


I may be dealing with multiple problems here. Please let me know your thoughts on the symptoms. Vacuum pump ? or am I chasing ghosts? Help is much appreciated in advance!!!


Jim

You may have a bad wastegate valve. If you have vacuum to it and none to the wastegate that's most likely the problem. Get rid of the vacuum control and buy a Heath diesel manual waste gate controller. Then take the vacuum pump off and replace it with a shorter belt. 96 or newer should use a 100" belt. Earlier models can use the 1993 belt.


I have heard of the pump lines being crossed at the pump on a pump replacement so you might check to make sure they are correct if it developed this problem right after the replacement.

Have your injectors tested.


15-18" at idle at the actuator or before the WG solenoid?

Quantum,


Thank you for the reply. I tested vacuum at the source (capilary tube at the vacuum pump), at the inlet and outlet of the wastegate solenoid, and finally at the wastegate actuator itself. Vacuum at the pump was 15-18 inches. This reading was also found at the other locations mentioned...appearing to indicate that the PCM was driving to allow the maximum possible vacuum. I didn't perform a duty cycle check at the solenoid based upon the fact that the solenoid passes vacuum and is OK electrically. Turbo boost appears to be the least of the problems at the moment. This morning was the coldest yet at 45 degrees and the shaking was highly pronounced...nearly undrivable. Again, it idles perfectly and mostly clears up when hot. Problems "appear" to conincide with replacement of the pump.


Thanks,


Jim

injectors can cause all the rough starting but have you cracked the fuel filter bleed to see if thee's fuel perssure while it's running?


15-18" is low vacuum. Check for dryrot on the rubber hoses coming off the Vac pump.

SHaking when first running cold sounds like glow plugs to me. Check each plug while still in the motor but unplugged using a test light by clipping to a power source and touching the glow plug on the spade where the wire would be connected. You can also check each wire for power by moving the test light clip back to a ground and turn the key to on so the glow plugs cycle.

Did the dealer set the timing correctly when they installed the new pump?

All excellent feedback! I do not know if the dealer set the timing correctly or not. Not to be redundant, but when the pump was first done, it was hot out. I suspected that something wasn't set up right so I insisted that the dealer add my concern to my service record...suspecting that I would be back when it got cold and the problems might become pronounced. The reason that I don't suspect injectors is that they would typically decline in performance gradually, not the dramatic drivability problem experienced presently.


On tap for tonight will be 1) inspection of the vacuum pump lines and 2) verification of fuel delivery and pressure at the inlet to the HP pump. Again, thanks so much for the thoughtful feedback. You all are great and I'm confident that together I can get this thing fixed.


Jim

have you check the glow plugs ? It would be nice to rule those out or in.

Thanks Bowtie. Yes, I did rule these out, at least with respect to the cause of the major drivability problem. No matter how cold, the idle is shaky at first but is glass smooth after a couple of seconds. The big problem is that it will not take any "load" cold, however the idle remains perfect. A comparative to a gasoline engine would be as though you retarded the ignition timing and swapped around a couple of plug wires.


I tested the glow plugs by probing each with a test light, harness connectors detached, then went back and verified that I had power at each of the harness connector terminals also. Additionally, I cleaned each glow plug terminal thoroughly before reattaching the harness connectors.


Thanks,


Jim

there may be some debris in your injector lines. when a dealer replaces the pump, they often loosen junk on the lines and it can get clogged in the injector. this would be a problem for atomization when starting (rough start). because of the low fuel flow rate of a diesel at idle, it may pass enough fuel to run smooth at idle. but when you get into it and demand fuel, the restrictions become an issue and cause a cylinder to miss or at least feel that way. this could be part of your problem. it sounds like you have wastegate issues as well

Any chance the Dealer got the injector lines routed incorrectly? From the pump to each cylinder?


And then the timing issue..


Wastegate - with the engine running and vacuum applied to the vacuum can on the Turbo - you should have real difficulty pushing the lever to open the wastegate.





Good Luck

Once again, I'm overwhelmed by the responses! Referencing the potential for debris in the injectors, I'd speculate that it's unlikely only because warm it will take load very well and smoothly. Concerning the possibility of line misrouting, another good possibility however it runs too well at idle with no perceptible imbalance.


On the wastegate actuator, do I understand it then that applied vacuum should hold the wastegate valve closed so as not to "dump" boost? Should the actuator hold vacuum or bleed it off? In other words, if I exercise it with a Mityvac, should the actuator hold vacuum? Understanding this better might solve a bit of the puzzle.


Thanks,


Jim

That's right, the WG vacuum actuator should hold the pressure from a mightyvac.


That actuator is $300 from the stealer but if you have a PN try www.gmpartsdirect.com (http://www.gmpartsdirect.com) Edited by: quantum mechanic

Update: Based on the responses from yesterday, I verified that the engine will continue to run when the fuel bleed is opened. I ran about a quart of fuel into a container in 3 minutes, engine running normally.


On the possibility of leaks at the vacuum pump, I pulled the pump and verified that the feed tube and outlet line are intact with no leaks. I think we can agree that at 15-18", vacuum is low...and the pump should be replaced. I don't suspect that this moderately low vacuum will affect the MAP or EGR so much as to cause the subject symptom however (anyone want to argue that point, I'm all ears!). It also looks like the wastegate actuator needs to be replaced...what...$300 for a little vacuum can with a rod??? kidding right???


Based on the preliminary and a time crunch (3 little kids with lots of activities and a commute to work, etc...) It went back last night to the stealer that installed the pump. Obviously, I included a list of everything that I'd checked. Fortunately, this is the service operation of a big dealership specializing in truck repair. We'll see! I'll let the group know if it takes another pump!


Thanks, Jim

Update #2: Dealer called this am. New pump on order. Ironically, dealer wanted me to pay $240 to drop and clean the tank. I asked "did the filter show evidence of contamination?" and "did you show that fuel flow is impeded?" Comeback was that GM would not honor this replacement pump unless they performed the cleaning. Asked them to put it in writing...wouldn't; called BS on this...contacted GM and the dealer dropped the idea. Once it's back, I'll pony up for the vac pump and wategate actuator.


Thanks,


Jim

We hear about the stealer telling people they have to pay $500-1000 to clean their fuel system to replace the pump. This must be how they pad thier wallets because GM's reimbursing them for the pump.

Replace it with a TM, you won't need a Vac pump about $85 IIRC, update your sigline so we know what flavor 6.5 you are driving, info allows us to better help out. Spend some time in the FAQs at top of this heading; 3 sites you need to check out www.kennedydiesel.com (http://www.kennedydiesel.com) and www.heathdiesel.com (http://www.heathdiesel.com) www.bankspower,com (http://www.bankspower,com) at both the Kennedy site and Banks some good info on troubleshooting and how a Diesel works info at Banks site.

Thanks gentlemen. I've updated my signiture line, which should show up in this post. (yes...it really is a 1/2 ton 2wd with a turbodiesel...most people challenge this notion and say they never made one).


Jim

I know the feeling supposedly a 1/2T K1500 (4x4) does not exist either, as a 96 one can assume you are out of warranty so we can start doing some mods. For your EGR and vacuum problems they can be done to bypass or eliminate all that stuff unless since you are making this an off road only vehicle http://www.dieselplace.com/forum/smileys/smiley2.gif.


But if you are located someplace that looks for it or will be doing some on road driving subject to federal law that mandates that a L56 must be configured for emissions reduction; we can do some things there also, that will give extra power for off road driving, or reconfigure in about 20 minutes to be on road compliant.


shoot me a PM and we will discuss your options there.

Rough idling when cold does sound like a glow plug issue. The ECM controls this cycle through the coolant switch in the coolant crossover pipe. When the engine is cold try unplugging the switch. The ECM defaults to -40* and increases glow time and cold advance on the Injection Pump. This circuit can and will effect transmission shifts until everything warms up. If this circuit isn't working and the temperature is cold enough you should see lots of white/gray smoke.


When the truck is running you shouln't be able to move the waste gate rod. Vacuum is holding it. These electronic solenoids are known to fail due to heat.Edited by: CharlieP.

CharlieP,


Yes...good thought, however the no-load idle is perfect and starting is only compromised slightly. I should have however validated the operation of the coolant switch and did not. From what you indicate, the switch is normally closed...opening only during extreme cold conditions. It would stand to reason that OBDII would interpret the lack of correlation between CTS and IAT return voltage and the coolant switch status and throw a code or two (mine didn't). As the engine warms, I can still feel the tone of the motor shift slightly as it changes the advance curve.


Thanks,


Jim

Sounds like the diaphram in your WG actuator pot is ruptured, best and most likely cheapest place to get one is from a turbo shop, I know we have dozens of actuators lying around.


I know you said you tested your glowplugs, but I really think you should replace all 8, Delphi preferrably.

Update:


Well, it's been at the steeler for 1wk now. They called yesterday...new pump now installed, however it won't be ready anytime soon. During the call I was informed that the tech "broke" the intake manifold. Thinking this a little odd, I went to the dealer last night to investigate (dealer is 24 hr). Tech broke all the ears off the intake! I asked if he ran the nuts on with a 3/4" impact. They didn't find me amusinghttp://www.dieselplace.com/forum/smileys/smiley32.gif


Jim

what turbo do you have? if you need an actuator, i got one for a gm-8.

Steiner 43511,


I'm uncertain as to the exact model of turbo used. I believe that it's a Borg Warner unit. It is the factory turbo for my 96 6.5. Please PM me with details on the actuator.


Thanks,


Jim

'96 Had the GM-5 with a verticle actuator. It should be the same part.

does anyone have an old bad WG actuator they haven't thrown away yet. I am looking for one to play with a few ideas with.

Folks,


This topic is quickly wrapping itself up. I picked the truck up from the dealer last night, and the 2nd replacement pump fixed the "major" problem. They ended up hanging a new intake on it after the tech broke all the ears of the mounting bolt stantions. I had them pop in a new OPS while it was apart (thanks to the group for this advice)...funny thing, I can hear the pre-pump run now...must have had some voltage drop going on there. I'm generally happy with their work, other than the fact that they left all sorts of sh!t unplugged (AC comp, underhood light, etc), and of course charged me all sorts of nickle and dime BS that I did't authorize (fuel additive, a new filter to replace the one that was a week old, etc.). Now I need to address the rest of the problems pertaining to the turbo:


Would someone in the group (Quantum??) have the correct GM part numbers for the WG actuator, vacuum pump and solenoid. I would really appreciate it. I tried to obtain said from gmpartsdirect site, but they are unresponsive. Once I have the part numbers, I'll just plug in and order from the site.


BTW, I'm going to attempt a repair of the WG actuator diaphragm, which is leaking mildly. I figure that I might be able to inject this high strength flexible bonding adhesive that I have through the vacuum port, apply a minute amount of pressure to force it into the rupture area, then decant out the excess before it sets...nothing to lose if it doesn't work...everything to gain. Will keep the group informed.


Thanks,


Jim

GM PN 199-7227 turbo wg solenoid. $16 dollars gmpartsdirect.

Thanks quantum. That gets me started. What I really need are the part numbers for the WG actuator and Vacuum pump. Anybody out there have those replaced that might have the part numbers. I know that my dealer won't be helpful and I can't get gmparts direct to respond, so I'm really stuck here.


Thanks,


Jim

www.bluridgediesel.com (http://www.bluridgediesel.com) has the vacuum pump for $84 and the actuator for? I've heard tale of a sucessful rebuild with a piece of bicycle tire as the new diaphram. Good luck

If anybody is curious, here's the GM part numbers for the affected parts:


89017558 vaccuum pump
1997227 turbo wastegate solenoid (without vented filter cover)
1997255 turbo wastegate solenoid (with vented filter cover)
12456423 turbo wastegate actuator



Yes...it's still back at the dealer because of the hard start after getting it back with the new pump. We'll see what sort of attempt they pull at somehow pinning it on me. My $$ is on the CTS that they replaced last time (now scanning 30 degrees warmer than actual).


Jim

UPDATE - FIXED!


It's very gratifying when you finally get something sorted out! I owe lots of thanks to the folks on this message board. With the new vac pump, WG actuator, WG solenoid (and of course the new pump) this puppy is singing a new tune. The guidance that I got here allowed me to help the dealer sort out the pump setup issues, and one I figured out that they'd left one of the batteries disconnected, it now starts perfectly too.


Today was the first that I've driven it in almost a month. I did a 450 mile trip pulling my race bike trailer from SE PA to New York and back. I disciplined myself to set the cruise at 60 and managed to pull down 24.0 MPG (aaahhhh the life of 2WD with a diesel!http://www.dieselplace.com/forum/smileys/hihi.gif)


Thanks to all,


JimEdited by: Enduroracer