PMD replaced, now what

[Big Green]

Truck had been missing at times, normally after a hard pull and then shift. Finally got to the point where after I drove it and turned it off it wouldn't restart. No codes. So replaced PMD and truck fired instantly and ran great.

Now to the problem. Still after a hard pull in 3rd or 4th gear (think WOT to 3300 rpm) then shift it still acts like its missing. No smoke, no codes, etc. Grounds are all clean. No strange noises or other symtoms.

Fuel shutoff maybe?

Thanks
Highmile
'95 K2500 6.5td 5spd
200k and working hard

[BrentN]

Have you replaced your fuel filters?

Check the fuel flow coming from your burp line. Search for the exact flow requirements.
If flow is low, 2 items are worth looking at. Filter or the Lift Pump.

Start with the Main Filter on the top of your engine. Check and replace
See if that solves it.

If you still have low flow, replace your lift pump.

Other things to check are:
Pull the inlet line on your Injection Pump and clean the strainer in the pump. Search for this on exact details.

You could have a plugged sock in the tank as well or crud in your lines. But before you go there, go with the simple things first- The Filter.

[racer55]

Have the injectors ever been done?Every 100,000 miles is the accepted rebuild/replace interval.
Does it loose serious power after that hard of a run?Limp mode?
High IAT's could be causing a defuel situation?
What sustained boost levels are you seeing?

[Big Green]

Ok, just an update to answer some of the questions that have been asked....

I bought the truck new in March '95 and it has been maintained. I depend on it to move my 3 horse trailer and pulling hay and other farm jobs. I posted a picture recently with 12k of hay behind it.

Injectors have about 40-50k on them (Kennedy stock replacements)
Injection pump is at about 120k
Remote mount PMD, mounted in front of drivers side battery
Fuel and air filters are new
lift pump and OPS have about 10k on them (checked with filter change)
Gear drive and HO water pump w/dual thermostats
EGT and boost gauges
Kennedy exhaust and chip

With the exhaust and chip under a hard pull I'll see sustained boost levels of 12-13#. Spikes above that particurlarly when it's cold outside are not uncommon. EGT are always well within reasonable, even on a long hard pull it's very uncommon to see more than 750-800 and never see anything over 900.

I doubt that it's a high IAT issue, if that would have been the case it would have shown up this summer when it was 114 degrees here. Now temps are in the 70's.

I should also add that this problem started very suddenly.

thanks in advance.

Big Green

[racer55]

If you were to click user cp at the top of the page and then click edit signature on the left side of that page and post all of that info it would be at the bottom of every post you make and would save a lot of questions from here on out.

I would consider doing a running LP test,could be that the OPS has burned out again-no mention of the OPS relay mod being done?

[Robyn]

Is the issue more common with the fuel tank below 1/2 full ???
If it is ok with the fuel level above 1/2 then the issue is likely the in tank screen bypass valve leaking air.

If it makes no difference in the issue, then install a section of clear plastic hose on the fuel return line from the IP. Loop it up past the wipers and leave the hood on the safety latch so you dont pinch the hose.

Do some runs and see if you get a slug of air bubbles come through.

If air shows, then its got a suction side leak between the lift pump and the tank.

If no air, then I would look at the IP filter harness. This short wire harness pluges into the top of the IP at the rear and has a rectangle shaped black box in it.

The filter can cause a "Fish Bite" symptom. Replacement is the only way to sort this one out.

Check these things and let us know.

Missy

[racer55]

The OS filter can be eliminated with no concern on some trucks,95,96 but is required on some 94's.
The only way to tell for sure is to road test without it and not if any ill effects.

If problems are noted then ferrite core from radio shack placed on each of the OS harness wires has the same RF dampening/absorbing effect as the filter had and is easier to get.

[Big Green]

Robyn,
Fuel level doesn't seem to have any affect one way or the other.

I'm thinking the first, cheapest, and fastest test to run is for air in the return line. Since I am in the rust belt, rusted brake lines and such are not uncommon.

thanks
Big Green

[Big Green]

Finally had time and garage space so got busy on the old truck

Noticed that lift pump would run when starting but after a few minutes it would shut off. Attached volt meter to the wires and full on 13v all the time.

So with the miles and knowing that there was more crud in the bottom of the filter housing that I liked I make the call to pull the entire fuel system short of the injection pump.

Knew that lift pump was bad.... then found loose fuel line on the out side if the filter housing.

SO filter housing clean and lines tight, intake back on, etc. Next up is the lift pump (piece of cake) and pulling the tank to replace the pickup screen.

Big Green

[rapidoxidationman]

Are you still using a dual mass flywheel? If the bearings separating the two sections are going bad and falling out you'll get an out-of-round flywheel which (years ago) the dealer (mis)diagnosed as an engine miss on my 96 6.5 5 speed. Changing to a single mass flywheel solved that problem.

It would show up after a rev and in the beginning would go away after goosing it again with the clutch pushed in. After a month or two (and several more of the ball bearings being thrown loose) the vibration wouldn't go away.

Just something to consider...

[mrwilecoyote]

Finally had time and garage space so got busy on the old truck

Noticed that lift pump would run when starting but after a few minutes it would shut off. Attached volt meter to the wires and full on 13v all the time.

So with the miles and knowing that there was more crud in the bottom of the filter housing that I liked I make the call to pull the entire fuel system short of the injection pump.

Knew that lift pump was bad.... then found loose fuel line on the out side if the filter housing.

SO filter housing clean and lines tight, intake back on, etc. Next up is the lift pump (piece of cake) and pulling the tank to replace the pickup screen.

Big Green
Sounds like you are on the right track. Check the tank pickup assembly very carefully. They tend to rust where it bends into the top thus sucking air and since it's on the suction side you may not see wetness. The the pick up assembly out Plug one end of the tube with rubber cap of some kind and fill a 5 gal pail with water . Put a piece of line on the inlet and put the whole assembly under water and then put about 15 psi of shop air into it and look for bubbles.

[Big Green]

Are you still using a dual mass flywheel? If the bearings separating the two sections are going bad and falling out you'll get an out-of-round flywheel which (years ago) the dealer (mis)diagnosed as an engine miss on my 96 6.5 5 speed. Changing to a single mass flywheel solved that problem.

It would show up after a rev and in the beginning would go away after goosing it again with the clutch pushed in. After a month or two (and several more of the ball bearings being thrown loose) the vibration wouldn't go away.

Just something to consider...

I had mine mis-diagnosed once as well when it was still under warranty. It had a 950-1000 rpm flutter or miss. They replaced about $8k worth of stuff after I told them it was the timing chain. Injection pump, dual mass flywheel, ecm, new wire harness, crank position, etc, etc. Then didn't replace the gasket between the two halves of the intake and cooked the bearings in the turbo... TWICE.

Big Green

[Big Green]

Sounds like you are on the right track. Check the tank pickup assembly very carefully. They tend to rust where it bends into the top thus sucking air and since it's on the suction side you may not see wetness. The the pick up assembly out Plug one end of the tube with rubber cap of some kind and fill a 5 gal pail with water . Put a piece of line on the inlet and put the whole assembly under water and then put about 15 psi of shop air into it and look for bubbles.

I'm actually considering replacing it if it has any rust or signs of pin holes.

Actually after looking at the lines and such under the truck I may just spring for all new lines too.

Big Green

[mrwilecoyote]

If you are replacing the lines don;t get raped by the dealer. You can change the lines over to Pushlok. Russel makes a metric oring x JIC adaptor for both the return and fuel supply. Makes changing the lift pump alot easier too. I'm hitting the sack but I can get part #s tomorrow.

[DWing]

On my 2000 6.5L should I replace the PMD with one of the same color or can I replace a black one with a grey one?
Dave

[mrwilecoyote]

The grey one uses a different connector. Although I have not personally seen it, I have been told you can cut a tab off your existing plug. Black Standynes are no longer produced AFAIK, so the Grey would be your best bet. I would after personal bad experiences, never run any Flight Systems. I'd rather stall on the side of the road then watch my motor do jumping jacks in the engine bay.

[racer55]

The brand of PMD is not a concern,the color however does require some attention.

The grey PMD's have a slightly different connector design and resistor is likewise shaped differently.
This difference can be overcome with a slight trimming though,click the following link and then download the "connector interchange" file:
http://www.kennedydiesel.com/6265techtips.cfm

[greatwhite]

Meh, been running a black Dtech (flight systems) from heath for the last two years with nary a hitch....

[Big Green]

Just an update....

After replacing the lift pump all seemed well so I stopped and did not drop the tank. Judging by the stream of fuel pouring out of the open line when I took the lift pump out the chance of the sock being clogged was zero. Test drove some and it seemed to have cured the issues.

Well the next weekend the kid calls from college and says her old dryer died. Not a problem, head down to the local home store, pick one up, and drive it the 2hrs to her.

On the way home the gremlins returned.

It appears that now that the lift pump actualy works and is pulling some amperage the OPS is just not up to the task.

The new lift pump control harness from Kennedy should be here soon.

Would like to know if anyone has any suggestions on installing the 2nd OPS that comes with the kit. Did you T it into the existing port or tap in somewhere else?

Big Green

[racer55]

IIRC the harness is plug and play?
Will contact John and ask him to advise you in this thread.

[Kennedy]

The harness is quite simple to install provided you have basic skills and understanding. It was originally designed for the Dmax trucks, but will work on anything from a go-kart to a semi so long as it has 12v source and oil pressure. I never did a huge install writeup on this one as it seems most people get lost in the details.


There is a sheet that will be included showing how to plumb the OPS with the included Tee. Most have no problem installing this yet I've had claims that it's impossible to do. The OPS can go anywhere that there is oil under pressure.

[Big Green]

I installed the kit yesterday and so far the truck seems to be 100%. I'll give it a week or so before I know for sure that this corrected my issue

Installing the kit was straight forward. The hardest part was the T into the oil pressure. I elected to put the T in at the orig OPS. Took a bit to get everything positioned so that the new sensor was assessable enough to tighten with an 1-1/16 open end wrench. Once tight I had to tighten the T slightly to gain enough clearance for the wire/plug.

Otherwise the install was very simple. I mounted the relay right above the brake booster and grounded it under on of the windshield wiper motor bolts.

I think I'm really going to like having the manual override for bleeding filters.

Big Green