Note... checklist complete in posted thread...

I have a 96 6.5 external pmd.

had the fuel starving thread.. replaced

1. filter
2 lift pump
3. PMD (external) GM supplied.. not Ebay

No real help.

OK.. local garage that does not work on these used a big snapon scanner and here is what we got.

Original scan before a reset.

.

P0205 Eng Shut Off Sel

P0236 boost sensor out of range (had unhooked vac line to waste gate.during observations)

P0251 IP "A" Rotor cam problem

P0370 Timing Ref "A" High RES problem

P 1216 Fuel Sol Response time too short

P0380... long standing glow plug circuit problem... (not part of this)

Reset Codes...

Restarted..

Drove - 500 yards threw codes.. drove about 2 miles and rescanned

NOW....

P0251 Inj Pump "A" Rotor cam problem

"sets when PCM detects missed pump scan signal pulses"


2. some where this was in there...

DTC May set if air enters fuel system -- or hard accel on fuel


P0370 Timing ref "A" High res problem

PCM detects High Resloution Pulses Missed.

PCM activates backup Mode

sympton... poor performance



It also talked about checking voltage on optical sensor and DTC if air entering fuel.

and DTC may set if air entering fuel


OK... where do I start next.





Thanks]Wayne

Looking like IP or PMD issues, yours still on the IP and is that 206k original miles on the IP

But before going there because of big $$$ involved go through the troubleshooting list 1st to eliminate the rest of the low $$$ possibilites

Hi Doc..

PMD is on the fender with a remoe from john kennedy (and yes.. the heat sink).....

To make sure my PMD had not just taken a hike, i went out to local GM dealer (used my cousins shop account) and just replaced the module last night with a direct GM part to make sure that was not in the Equation.... ( i can always keep a spare or ebay it).

GM replaced the IP at about 128K under warranty

updat, about 209.5K on the truck now. No boost foolers or anything other than a big exhaust system and my air box "routed out in the fender well... but other than that.. prefer to play it safe.. it does pretty OK buy itself!!!

I basically run the devil out of this truck... pulls a trailer and runs (ran) great up until Zero hour on Tuesday night... problem did not "creep up at all"...

it just died at a stop sign and then acted like I was out of fuel... could barely do over 2200rpm, give it any throttle and it starved out..

replaced all fuel components and bled the filter and the little T valve (yes, i can see where it runs under the truck and out)... - then replaced lift pump this morning..

still sounds like a cammed up john deer model B tractor loping,, stutters and gives all of the indications that the scan tool said about being in a backup fuel mode... I guess to get it home)

well...actually now to remember, last week it sputtered once going up a local road at about 67-50.. and then tats was all.. nothing since but never thought much of it.. until i just made that statement of no previous symptoms creeping up.. other than that , not a single issue or clue that trouble was pending.

Thanks DOC
Wayne

BTW... what are the Timing Reference High Res problems mean.. is this due to position on the cam??.. timing chain out or stretched.. ???

plan would be to replace all that stuff once it gets tore into (if this is the case..)

and what about the testing of voltage for the optical sensor (where ever that is and how the heck do you get to it.. looks like you got to pull the intake plenum.. would a bad sensor or voltage reference do all of this?

i see P0370 points to the ECM...

that was replaced in California at a GM dealer last march... about 15K on it

. Does the engine Turn over? yes
1a. Does the engine start? yes
1b. Do you have a Wait To Start Light & duration lit. yes

1c. Ambient Condition (temperature outside) 50
1d. Engine Cranking speed (if you have an accurate tachometer). good
1e. Are you experiencing stalling? yes
1f. If Stalling, describe (upon startup only, down the road, hit a bump etc)
down the road... stumble.. now full stall
1g. If Stalling, do you notice loss of dash or instruments?
dasch ok
-note if experiencing stalling,you must indicate PMD location in #24.1.1Lift pump test (http://dieselplace.com/forum/showthread.php?t=39350)- describe results

new lift pump


2.Service Engine Light - on/off/intermittent on
3.Model year 96 6.5 sub 2500
3a. Odometer reading 209k
3b. Miles on major engine components if been replaced (example Injection pump)
injection pump replace at 129K
new PMD ( to check)
new ECM 195K

3c. Indicate the model number on the Injection pump (starts DS4 or DB2......)

not known
4. Have you scanned for engine codes? (varies by pre/post 96) yes/no
yes
p0251
p0370
p0380

5. List exact results on engine codes:
p0251
p0370
p0380

6.Air Filter condition (visual check) good

7.Fuel filter condition (freshly changed or condition unknown)
new

8.Condition of Battery terminal connections (removed, cleaned and tightened)

recent service
8A.Known condition and age of the batteries.

both less than 1,5 years
8B.Are batteries of differing age or are they a matched set?

6 months apart
9.Upon cold start, does the radiator hose get hard quickly? Yes/no

no
10.Upon cold start, do you have excessive white smoke? Yes/no

no
11.Do you have excessive cranking time before the engine starts?

only in real cold weather
12.Have you used the block heater, and does this effect engine starting?

yes.. much better in cold weather not needed above 30deg
13.During hard acceleration, do you have excessive black smoke? Yes/no

no
14.Do you have any unusual exhaust smoke issues?

no
15.Turbo check out (http://dieselplace.com/forum/showthread.php?t=39368)- pass/fail

pass . new turbo and all componets within 2 years Z(sensors, vac pump etc
16.Do you have an EGR on the engine? (An F or an S engine code)

no
17.Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD.

i assume 2500 (6.5 TD 96'
18.Indicate fuel that you are using: Bio-diesel, #2 Diesel, #1Diesel,

#2
SVO/WVO, other
18a. If running a VO setup, indicate details of your conversion (homemade, or packaged system)

19.Are you using any fuel additives? If so, please list.
run diesel conditioner every couple of months on long hauls


20.Please indicate geographic region you are in: (example: Texas or Canada)

mid atlantic maryland
21.Do you have any service history available that might pertain to the problem you are having?

New ECM last year??
22.Please indicate any modifications to the vehicle that might help us diagnose better.

exhaust, thats it
23.Upon unscrewing the fuel cap (http://dieselplace.com/forum/showthread.php?t=42338), do you have a large vacuum formed in the tank? yes/no

no, actually hear air coming out (like under pressure)
24.Location of PMD/FSD (http://www.dieselplace.com/forum/showthread.php?t=39436)? On the pump/remoted over intake/remoted out of engine bay (please specify specifically)

left hand fender behind batter

25.Are ALL glow plugs in proper working order as per this thread (http://www.dieselplace.com/forum/showthread.php?t=39182)?

there are glow issues that show up in really cold weather, get a check circuit code 0380 normal temps it does not effect starting

Looks like the optical reader is having a problem detecting the timing marks on the encoder wheel. It could be trash in the fuel, bubbles in the fuel or intermittent electrical connection to the IP.

I would troubleshoot the fuel problem first: Using clear plastic tubing, temporarily replace the fuel return line coming off the IP. Crank the engine and watch for bubbles. When you finish, don't forget to replace the original hose. I seriously doubt the clear plastic tubing will last a week before the diesel fuel eats a hole in it.

If that proves not to be the problem, unplug and replug all the connectors to the IP.

If you get no joy, inspect for frayed wires coming from the ECM (down below the plastic coolant reservoir) as they emerge through the firewall.

And last, disconnect and clean the grounds connected to the back of the engine on the passenger side.


.

Right, rechecked lift pump.. relay.. lift pump definitely working (voltage good) hear it running (feel it)while engine running and its new, so not electric there.

checked filter assembly again -- clean .. shiny all the way to the bottom of the filter bowl.
re- bleed system..
Ran clear line from IP up and over hood and observed on a 2 mile run... not a single bubble... all clear as can be


OK.. not to your last tip..

OK.. next to take of plenum again and go through all wires - connections.
WD 40 and re-connect.

Thanks you very much for your suppport!!!!

I'll check back after all this is done.

Wayne

OK... replacement injector pump on the way...

Thanks all

I am having exact same problems on Dad's 97 right now...

Codes P0370 and P0251

I have checked everything I can think of including: fuel filter, lift pump, harnesses, grounds, battery connections, new PMD, etc.

My question is this -

I have a spare IP and I am wondering if I can just R+R the optic sensor?

If so, do I have to scribe and lines anywhere or is it just pull out the sensors and swap them?

Thanks!

You can replace the OS in-frame - instructions\pictorial are on the forum here, back several years ago - no more difficult than doing the bump.

There is also a Scandinavian 'site with instructions\pictorial - iirc, that's listed also.

Do a search for Texas Diesel Guy, Quantum Mechanic, Diesel Pro - any one of various member's handles will lead you to one of several threads on that subject - probably should become a sticky, if you find it(them).

Thanks JD....I actually had all of those things bookmarked on my computer but I had to reformat it a few days ago...grr...

I'll start searching...

Found it...

http://www.turbodiesel.no/