baffled

[superdav95]

Hi all... Recently purchased 1995 burb diesel with 195000 miles. I am pleased with my (new to me) ride and have done some upgrades that have been recomended by those on dtr. I stil have a few more I would like to do of course, money and time permitting. I have been having some issues with dtc code 36 popping up and stalling on occasion. I have tried some of the known cures as mentioned on dtr but to no avail. any help or suggestions would be great and very much appreciated.

Thanks...Dave

 

[gmctd]

Start with the wiring harnesses, incl battery cables, for connectivity - all grounding and termination must be clean and tight, no oxidation\corrosion - battery voltage and power connections must be electrically functional - loads of info on file here vis a vis correcting the various wiring harness problems - low voltage can cause DTC36 - clean up the wiring to start clearing the DTC

 

[Missy Good Wench]

As Mentioned

Check and clean all battery cables ++
The grounds at the battery and the engine.
Check the two grounds that come from the wiring harness and fasten to the RH rear of the intake manifold bolts or water passage cap off stud.

Make sure you have a good braided ground from the engine to the body that is secure and also to the frame too.

Make sure that the Power supply line from the battery to the junction box or distribution center is good and has no corrosion at the cable (battery end)

Make sure you have 14V at the junction/distrib box.

If this is OK thats a good thing.

Now is the PMD remote mounted ??

If not your PMD very well may be the issue with the stalling. (PMD is the little black box on the LF side of the IP down by the manifold)

You need to get a Fresh PMD mounted on a remote cooler either in the grill area or down under on the inside of the front skid pan I below radiator.

Get an extension cable (several vendors offer these)

DTECH make a lovely aftermarket PMD use a number 5 resistor in the PMD socket if you dont know which one is in the old one (Likely not)

The PMD is the one most troublesome item in this electronic injection system.

Keep us posted

MGW

 

[superdav95]

Hey Thanks for responding.

Here is what I have done so far...

I have cleaned all of the electrical connections to the frame and engine that I can find as well as both batteries. I have checked the 15 wire connector behind the fuel filter and cleaned both ends of it. I checked the connectors that plug into the ecm and took note of the "blue" ecm chip in there. It had the following numbers on it.

T&B make.
BXPY
1624
4788

Can anyone tell if this is an orig chip or an "rv" or "race" style chip???

I have also changed the fuel filter and confirmed that the lift pump is functioning. It appears the the IP has been changed out back in 1998 as the date on it states May 28 1998. The pmd has been remotely moved off of the engine intake and attached to a fsd cooler. I have tried 2 other known good pmds to rule it out as the cause as far as I know. I also cleaned the connectors of the harness to the pmd and from the IP itself.

I don't know if this will narrow it down or not but again I am very Thankful for all the help... Really want to be able to drive my truck without fear of next time my wife gets stranded stalled out on the road.

 

[buddy]

Did you remote the PMD or was it there already??

If it was that way before, eliminate the extension and run the PMD on the intake for a while to see if the problem returns.

Also describe the stalling, what occurs, does it start back up right away? This could be caused by air in the fuel lines or bubbly fuel. Are you putting in any additives, which ones?

Verify the LP pressure and drain a jar of fuel out and see if there are water bubbles or excessive air bubbles, or contaminants. You can try running some fuel conditioner with lubricity additive which may help. Make sure you have a fuel cap that says diesel on it, and maybe loosen it up.

I can look up BXPY at home later, but sounds familiar, it would have been the latest release in 1996 for the 95 model year to resolve some driveability issues.

 

[superdav95]

When I bought the truck the pmd attatched the the fsd cooler was bolted to the intake manifold. I had read somewhere that it was not good to place it there due to the heat. I have since moved it to the drivers side firewall still attatched to the fsd cooler. I heard different people say that the intake is best on others say that off the intake is better. I have tried both ways with different pmds still get dtc code 36 even before I get out of the driveway and before the engine is at normal operating temp. I also tried to let the beast warm up for 10 mins before I head out and still get the same code. I am not certain that the stalling is related to the code for sure but to me it seems very coincidental. Lately I have not been taking the truck too far for fear of getting stranded in case it is the IP that is going. My wife has been stranded twice now and each time that I went and restarted it fired right up. Whats funny is that the engine light only comes on over a certain rpms ussually around 1700-2000rpms and the light will stay on if engine kept at this rpm. The engine light will go out right away if I let off the throtle. Almost seems to be pedal related.... Anyway I have also checked for bubbles in the fuel using the clear tubbing idea from the pump and all seems fine. The truck is not driving bad either it is just not reliable with this stalling issue that seems to happen once in a while. When I changed the fuel filter the old one didn't seem too bad. I did not see any water or anything out of the ordinary in the fuel that came out. I do not have a pressure tester to confirm the psi but it seemed to come out of the tube alright. I am using a fuel addittive as well, "Diesel Kleen" by power serivice grey bottle. Hope this narrows it done... Thanks. Dave

 

[buddy]

You should run some 2 stroke oil with your fuel, Power Service doesnt add enough lubricity. Or some SAE30 non detergent oil. 1 quart to a full tank.

It may help your issue if its your IP starting to wear.

and you have no other codes?

 

[Brooklyn Tow]

When I bought the truck the pmd attatched the the fsd cooler was bolted to the intake manifold. I had read somewhere that it was not good to place it there due to the heat. I have since moved it to the drivers side firewall still attatched to the fsd cooler.

PMD is still suspect......Only way to know for sure is switch to "New" or "100% Good" used.

 

[buddy]

Sounds exactly like PMD issue, but he said hes used 2 different PMDs with and without the extension on both. With same results.

But yeah, sounds exactly like a PMD problem.

If there is a filter on the wires to the OS, you can remove that, would be there on a 95 unless PO already removed it.

 

[Rodd]

The fsd needs to be mounted outside the engine compartment. Anywhere in engine bay will be way too hot for it. Most mount theirs inside the front bumper behind the licence plate. It gets air from the two holes in the bumper to keep it cool.

 

[Brooklyn Tow]

If there is a filter on the wires to the OS, you can remove that, would be there on a 95 unless PO already removed it.

Someone post a pic of the OS filter harness/RF AM radio thig a ma jig.


Jim?.....:rolleyes5:

 

[Acesneights1]

You know, I used an extension cable tonight with a PMD on an SS heatsync I got from Ferm. Not bolted down just plugged it in to see if it corrected my problem and 10 mins after the truck was off the cooler and PMD were still very hot. So that give an idea of how much heat they generate.

 

[superdav95]

Buddy, i hear ya on the 2 stroke oil... I think I will do that the next time I make it to fill up. I talked to my mechanic friend and he suggested that it may be the IP timming that might be off slightly. Any thoughts on this???

Acesneights1, I noticed that my pmd got hot after awhile too which leads me to believe that I should put mine somewhere out of the engine bay as well. I don't think that this is what is causing my DTC 36 to show up but could save the pmd down the road.

I looked up what a os filter looks like and from what I can find on the web it looks like a rectagular hard black rubber block about the size of a large eraser with 6 wires that run through it and a connector on either side. Can I just take this off??? Is it possible that this is what is causing my DTC 36 interference??? I'm almost excited to try this tomorow. i will let everyone know... Dave

 

[Mudbath]

Buddy, i hear ya on the 2 stroke oil... I think I will do that the next time I make it to fill up. I talked to my mechanic friend and he suggested that it may be the IP timming that might be off slightly. Any thoughts on this???

Acesneights1, I noticed that my pmd got hot after awhile too which leads me to believe that I should put mine somewhere out of the engine bay as well. I don't think that this is what is causing my DTC 36 to show up but could save the pmd down the road.

I looked up what a os filter looks like and from what I can find on the web it looks like a rectagular hard black rubber block about the size of a large eraser with 6 wires that run through it and a connector on either side. Can I just take this off??? Is it possible that this is what is causing my DTC 36 interference??? I'm almost excited to try this tomorow. i will let everyone know... Dave

A picture is worth a 1000 words.
http://www.heathdiesel.com/P/HDP1559/

A new PMD mounted out of engine compartment is the only sure way to tell. There has been bad cable extensions mentioned before. And most important make sure the black ground wire from PMD harness is still attached to the top of the IP and clean!!!!

 

[Veg_Out]

You should run some 2 stroke oil with your fuel, Power Service doesnt add enough lubricity. Or some SAE30 non detergent oil. 1 quart to a full tank.

It may help your issue if its your IP starting to wear.

and you have no other codes?

Turns out, we all read a study on DTR recently that a bit of B100 Biodiesel is a better lubricant than any additive you can find. It's great stuff.

 

[figment]

I didn't see anything about, the fuel cap, does it say diesel on it or have a D on it? The reason why I'm concerned about it is because after doing all of the above my Tahoe kept stalling, but would fire right back up. I bought a new cap from GM and it quit stalling,(best $13 I ever spent). Gassers seem to require a lot of vaccum in the tank, something to do with emissions I think, where as diesels don't require any. Even if the cap is a diesel cap it may be faulty, mine was. How something so simple can cause such a headache.

 

[superdav95]

Thanks everyone for the responses... Where do a get b100 bio??? Also, anymore thoughts on weather the OS filter can be removed or not???

I don't think that my dtc36 code is heat related as it displays weather it is warmed up or not. I remember testing a known good pmd not too long ago with the 6' extending harness and without it using just the orig one and having the same result. the dtc 36 code would show up right away weather the truck had been running 30 secs or 30 mins. My pmds didn't even get warm untill the truck had been running for 5- 10 mins so I got to think that placement of my pmd and fsd cooler have no bearing on my dtc 36 issue but I could be wrong.

On a side note I am installing a 4' exhaust system from ssdiesel and will let you know how it goes...

Thanks again. Dave

 

[superdav95]

Thanks figment... I will try that and let you know...

 

[buddy]

Just remove the OS filter. If you have any issues afterwards you can get 6 clamp on ferrite bead filters for like $2 each.

 

[superdav95]

Ok... here's an update.

I put the exhaust system system on from ssdiesel which took me about 3hrs. I had to cut off about 3-4" off the final segment of pipe that ends up being the tailpipe. Also had to weld on the orig hangers but I knew I would need to. Went together pretty well except for the 2 stripped bolts on the crossover. We had to drill out the old rusted bolts and put some new ones in. Sounds really good!!! a nice deep tone and it just sounds mean. I like it.

back to my orig problem... I have pulled some new codes; 17, 18, 35. It started running really rough the other day when the engine light came on and could not even get it to run over 1500 rpms. It had no power like it was only running on a few cylinders. I shut it off and waited 5mins and restarted and it ran ok in park and reved up fine untill I put it into drive and did the same thing again with running rough. Could it be that the real problems are finally exibiting themselves now. Any new thoughts on this???

I tried the gas cap thing and it ran it seems to be holding a vacuum alright. I am going to get a new one anyway just in case when dealership re-opens.

Thanks again. Dave.