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94 Chevy K2500 6.5 Multiple Codes Present

IdDieselGuy said:
So how do I know which resistor I need to use? Currently have a #7 in there.
Click to expand...

Use the #7. At the end of the day it doesn't matter because it simply doesn't change the fuel much. It does matter to be emissions compliant, but, not at any test we are subject too. A clogged air filter makes more of a difference than the resistor because a clogged air filter has failed me on a smoke measured "snap test" many times. :muted:

I forget emphasis on TOWING near, at and over the limits, in extreme temperatures of 121 degrees, on 7% or steeper grades that go for miles, with an umbrella wedged between the seat and the throttle because the damn cruise kicks out at 16 MPH below the setpoint.

Thus my comments on a specific grade that I refer to as "6.5 killer hill" as it's scattered some 6.5's pretty badly and hurt some other stuff. Yeah, EGT monitoring is a waste of money and unneeded heartburn on this engine. You can see black smoke out the exhaust in your mirror (adjust it, eh) and ECT starting to push over 210 means back it off. With a waste of money EGT gauge I pushed it to a sustained 1550 ECT, towing, on a grade, with minimal smoke, and ECT at 210. All It proved was the turbo didn't melt down and a turbo blanket will indeed burn black where it touches the turbo. Oh yeah, Buddy who was sitting next to me was white as a ghost when I read off the EGT that high because we were in the middle of nowhere while "Busting" the EGT myth. We did turn down the tune because there is no real need to be that hot as it doesn't help power.

My avatar pic burned #8 down just fine for the prior owner with a bad injector and EGT reading normal in the crossover.

Run high EGT on a specific year Cummins 5.9 HO and it can drop a valve seat. So EGT advice is Engine Specific. I would say it's turbo specific as well because the GMx turbo holds so much heat in the engine, but, we ignored 1450 EGT every day 550 miles a day delivering a trailer full of parts all over AZ. This underpowered engine has to work pretty damn hard out here towing. Even unloaded vehicles regularly "Halt and catch fire" on the grades I refer too. They also burn to the ground as fire support is so far away.

Even a stock power setup with everything working means you SHUT IT DOWN at 210 ECT. You are less likely to have trouble in light duty use. Running flatlands or DD grocery getter can hit one go over 210 when something is wrong. Asking for towing or loaded power increses your odds of hitting and going over 210 ECT.
 
Well my ECT never goes over 180/190 but it blows a good amount of smoke if I revv it or get on it while driving. Especially if power shifting. Does that mean my ECT is reading incorrectly and my gauge is wrong?
 
It is wise to put a secondary temp gauge in and put the sensor in the block off of the right rear head or the threaded port of the right rear head.
It very well may be your gauge is accurate. But imo the cost of a gauge and a couple hours to install it- great insurance.
 
I'll look into it for sure. Sometime while driving, my temp gauge will go down to 0 or like 170. Sometimes it does it at idle too after I've been driving for a bit. It doesn't do it all of a sudden, it just gradually does it. It's fine while the truck warms up and stays around 180/190 for awhile then it goes down. Could it be the cold weather? If I open the hood, the temp up under the hood is pretty warm even if the gauge goes down. Could it be a bad ECT? The gauge will usually go back up slowly as well and usually back up to 180/190 if I'm driving for awhile. Also, I'm going to put in that spare pmd I got and see if the code 36 goes away. It doesn't have a resistor in it, but I've got an extra #5 and #9. Does it matter which one goes in it?
 
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IdDieselGuy said:
Well my ECT never goes over 180/190 but it blows a good amount of smoke if I revv it or get on it while driving. Especially if power shifting. Does that mean my ECT is reading incorrectly and my gauge is wrong?
Click to expand...

Overall the focus should be on clearing the code 36 as it may be the cause of the smoke.

Should not generally have smoke on a stock tune. That said you can catch the turbo "asleep" as the engine is fueled assuming the turbo will come around quick. This would be black smoke. I can see a rev between shifts to shift maybe catching the turbo asleep: Are you stomping the go pedal to the floor between shifts?

I forget: Do you have white smoke, blue smoke, black smoke, or white smoke that evaporates quickly?

We have assumed you have checked the intake for restrictions like a clean air filter. If the turbo wastgate is working your converter may be soot plugged.

What resistor does the truck have in it, NOW? Then keep the number as close to that one as possible. As you do not have a resistor trouble code you can use the resistor that's in it now. Otherwise flip a coin...
 
Truck only has white smoke upon startup. Black while driving. Black smoke when I rev the engine or when I get on it. The turbo whistles pretty good though so I know the solenoid and actuator are working. I dont have a converter, my truck is straight piped. And I currently have the #7 resistor in the truck.
 
So just put on the other PMD I got and put in the #9 resistor and started the truck up. Of course, code 36 was alive and well and came back instantly as well as code 29. Everytime I unplug the pmd, it trips a code 29. Not sure why? This pmd got pretty warm though when it was plugged in. I also dont think I have a heatsink on my pmd that's currently mounted on the truck. If I do, it's probably a stainless steel one and not copper. I give up on this now. Im at a loss of what to do.
 
The PMD has to have a heat sink on it. It will not last long without one. Leroy Diesel sells them or you could make your own.

Dont give up on it yet. These trucks are like kids. They drive you crazy sometimes but you can’t help but to love them.
 
Oh I love my truck! It's getting smokestacks here shortly. The extra pmd I just bought last week was zip tied to the egr valve on the truck it was on. Came out of a 94 half ton. It was also upside down and had no heat sink or any kind of mount. Literally just the pmd. The rest of the truck was really ghettoed out so that's probably part of why. It was a seizure by Ada County Sheriff so it must've been left. Anyways, I'm almost positive if the one that's currently on my 94 has a heatsink that its stainless steel instead of copper. From what I've heard or read, only the copper will work with it properly. Is that correct?
 
Thanks for showing that link. I'll just order a heatsink. Both of my PMDs are flight systems. The connector on my 94 is a Delphi, but the shorter connector that goes to the back of the injector pump is different than the end of the Delphi connector. I cant just plug the pmd into that because of the way its shaped. The Delphi harness looks kinda cheap though to be honest. Thinking the smaller connector that connects to the back of the injector pump and hooks to the main pmd harness, is the issue. The main harness for the pmd could also be the issue. Hard to say.
 
So I poured some Stanafyne diesel treatment in the FFM the other night and put in a filter strainer since mine was missing. Code was still there for a bit then went away the yesterday morning at startup. It didnt start hard like normal though. Still smoked white a bit but no hard start and no check engine light upon startup. No intermittent check engine light upon acceleration or deceleration either but the code 36 is still there along with code 29 and now code 15 again. It doesn't start hard anymore in the mornings or after it's been sitting but smokes white a little bit while driving if I get on it or rev it until it's totally warmed up after starting. Last night, truck kept revving really high after I put it into gear almost like it was slipping on wet pavement or skidding but it was dry pavement. It felt like an automatic transmission when it's about to go out. It was really odd. Was doing it all thru driving in downtown Boise last night and then when I got back home to nampa and all lay today its been fine. I just figured maybe the clutch is starting to go or something? Sometimes itll do it too if I really get on it from a stop light and it feels like its laugging power and won't go into gear. Gonna try and replace the ECT since its pulling that code and go from there. Put a 4" straight pipe exhaust on today and that made a huge improvement on sound and gained some horsepower. Was worth the $120 I paid for all the piping. Saved money from buying parts store piping instead of buying the Diamond Eye kit.
 
Sounds like something is dragging now and bad drone and loss of power. I'm thinking exhaust leak. Gonna get some clamps tomorrow.
 
Update: Code 36 with intermittent check engine light is back yet again! (no shocker there!) But only when it's super cold out after first starting the truck. Today and yesterday it only came on intermittently for a few minutes then went away. But its also 30 degrees outside. Should I do another treatment of Stanadyne in the FFM? It went away for almost two days after doing that. (The code was still there to no surprise when jumping the obd1 port but it wasnt tripping the light.) Once I fixed the code 15 for ECT sensor, that's when it started tripping the light for the code 36 again. Not sure why that'd have anything to do with it but at this point I'm honestly pissed off. Any ideas?
 
Yeah but I have a feeling if I replace that it's still gonna be there. I dont have that kinda time or money to replace it either and there's nobody around here with enough knowledge on these trucks to be able to know how to time the engine after the new IP is put in.
 
Where is "around here" anyway?

There are ways to time a new IP including software Leroy sells. Some GM dealers may have "Old School" mechanics around. Stanadyne shops may have the tools and mechanic experience for rent like Perkins Diesel here in Mesa, AZ.

Most on here understand "frugal" and compared to injection equipment cost on modern diesels an IP is cheap. End of they day you got a $4000 4x4 pickup for $750. It runs and drives. Does anyone but you care it has a code? You know what the code is from now at least.

So the IP may fail ... Get AAA or other towing service so that you can have the hook drag it home if needed instead of burning up a starter or attempting to driving a bad running rig home and get towed anyway. No shame in calling for a hook and fixing it with your tools in your garage.
 
I dont have a computer to download the software nor do I know of any GM dealerships around here who'd have an old school guy that would know how to work on these. I've called about it before and two of the dealerships said they've never even had one in their shop. You'd think with idaho being such a agricultural state there would be more mechanics around that know these trucks but there isn't. I'm almost 100% positive it's not the IP. I'm pretty sure its PMD related or something else. I'd have other symptoms if it was the IP. If the IP goes I'll probably just buy another 7.3 IDI Ford like I used to have. That truck was one of the most reliable trucks I've ever had. Had 400k miles on it. Finally took a crap. I dont have time nor money nor enough mechanical knowledge to mess with an IP that's more of a pain in the ass than a newer diesel IP and have nobody know how to time it. The fact that the code 36 went away for almost 3 days after pouring in the additive into the FFM leads me to believe it's a fuel lubricity issue.
 
Not trying to be a jerk, it's just hard to find people around here that know these trucks. I have no problem buying an IP and replacing one myself. Just the timing the engine that's difficult. Gonna be next to impossible to find someone in the boise area who knows how to do that. I work with a guy who has two 6.5s like me, but hes never replaced an injector pump I dont think. I can get a pump from some people locally who have parts for next to nothing. The one junkyard that is big around here sells diesel injector pumps for $80. I know a guy who has a brand new one as well that he would sell cheap cause he ended up pulling the engine. I just dont think the injector pump is the issue. The code 36 only started after i messed with the batteries and pmd.
 
Find a shop that has an OTC genesis scan tool. That tool will show the IP timing. There are actually quite a few independent shops with the OTC scan tool. A shop here lets Me "BORROW" their OTC scanner, even to the extent of bring it to My property so I can put the truck into the garage and work it over in comfort.
I always drop 20 or 30 bucks on him for letting Me borrow the tool and He is way happy with that.
 
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