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Old 09-17-2012, 11:50 AM   #1
JBrassfield715
 
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6.5 cutting out at idle

My buddy has a 6.5 that cuts out at idle, just like a dead miss. The vehilce runs fine and never misses while driving
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 09-17-2012, 11:56 AM   #2
Cumminsfever
 
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Sounds like a pmd failure.

What year truck?
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1999 Dodge Qc Sb Sport black 4x4 auto, p-pump, 35/40& ht3b.
1992 GMC K1500 4bt. Once made 496hp. Always broke.
Now ve-pumped and made 360hp with 12mm pump.

1994 Chevy K1500 3.8 vm i6 idi hx30/hx52
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Old 09-19-2012, 10:07 AM   #3
JBrassfield715
 
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98 i think
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 09-19-2012, 10:49 AM   #4
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Definitely suspect a pmd failure. Also check fuel supply.
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1999 Dodge Qc Sb Sport black 4x4 auto, p-pump, 35/40& ht3b.
1992 GMC K1500 4bt. Once made 496hp. Always broke.
Now ve-pumped and made 360hp with 12mm pump.

1994 Chevy K1500 3.8 vm i6 idi hx30/hx52
Never judge a man's horsepower by his exhaust
 
Old 10-11-2012, 11:58 AM   #5
JBrassfield715
 
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Its actually a 94. it quits surging when you unplug the cranksensor and on a cold start takes a long time cranking to get started but after the first start it hits instantly on hot restarts
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 10-16-2012, 12:21 PM   #6
JBrassfield715
 
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Replaced crank sensor, i would call it more of a miss than a surge, but it still does it and it sputters if u snap the throttle in nuetrual and its a 94
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 10-16-2012, 02:33 PM   #7
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I would definitely say pmd failure. I had one did the same thing pmd will clear it right up.
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Old 10-16-2012, 05:38 PM   #8
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pmd failure in have a 2000 with similure problem but wount crank back. until you un hook the battires
 
Old 10-22-2012, 08:22 AM   #9
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Replaced pmd,same thing still, have also redone a bunch of grounds too and still no change. Could it have anything to do with oil pressure set up? Cause it does it under 1k rpms and when the pressure has dropped to like 20psi on the oil
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 10-22-2012, 09:51 AM   #10
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Oil pressure has nothing to do with the fuel systems on this truck.

There is quite a bit more to those POS pumps other than the PMD. You may also have a faulty speed sensor inside the pump. There is no science to these trucks. Check the following:

Fuel pressure, filter
If you still have a problem, check the injectors, I am sure they have a bit of mileage and could have excessive return.
Finally, pull the pump and get it rebuilt or tested; it can be an expensive test.

Those Stanadyne pumps are garbage. More than 40-50k out of one and consider yourself lucky.

Last edited by raychem; 10-22-2012 at 09:52 AM.
 
Old 10-22-2012, 10:05 AM   #11
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The oil pressure sender controls fuel cut off on these trucks
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 10-22-2012, 09:48 PM   #12
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Quote:
Originally Posted by raychem View Post
Oil pressure has nothing to do with the fuel systems on this truck.

There is quite a bit more to those POS pumps other than the PMD. You may also have a faulty speed sensor inside the pump. There is no science to these trucks. Check the following:

Fuel pressure, filter
If you still have a problem, check the injectors, I am sure they have a bit of mileage and could have excessive return.
Finally, pull the pump and get it rebuilt or tested; it can be an expensive test.

Those Stanadyne pumps are garbage. More than 40-50k out of one and consider yourself lucky.
Quote:
Originally Posted by JBrassfield715 View Post
The oil pressure sender controls fuel cut off on these trucks

What he said. 94-95 6.5's use a POS oil pressure sensor that actually powers teh fuel pump when teh engine is running. 96+ use teh ECM to trigger teh relay. the OPS is a COMMON failure point on OBD1 6.5's. Quick check is to open the water drain while it is idling hot and see if fuel comes out or not. If it stalls then the lift pump is not working and most likely the OPS has failed. Use ONLY an AC DELCO OPS, and I HIGHLY reccomend a relay installed inline to carry the load instead of the OPS.
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95 SUBURBAN to a 01 DURAMAX/ALLISON - The Truck Stop
 
Old 10-23-2012, 12:43 AM   #13
raychem

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Quote:
Originally Posted by JBrassfield715 View Post
The oil pressure sender controls fuel cut off on these trucks
Quote:
Originally Posted by THEFERMANATOR View Post
What he said. 94-95 6.5's use a POS oil pressure sensor that actually powers teh fuel pump when teh engine is running. 96+ use teh ECM to trigger teh relay. the OPS is a COMMON failure point on OBD1 6.5's. Quick check is to open the water drain while it is idling hot and see if fuel comes out or not. If it stalls then the lift pump is not working and most likely the OPS has failed. Use ONLY an AC DELCO OPS, and I HIGHLY reccomend a relay installed inline to carry the load instead of the OPS.
I stand corrected. I looked it up and you guys are right! It has been ages since I work on one. I had a 96 for a few years, hence my comment on the oil pressure. I also mentioned to manually check the fuel pressure. Put a gauge in it. Like you said, if the oil sensor is giving you a problem, zero fuel pressure would be an indication, that or the fuel pump is giving you problems.

Keep us informed.
 
Old 10-23-2012, 10:20 AM   #14
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I tried changing the sender on the block and it didnt change anything but ill try that
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84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 10-23-2012, 04:59 PM   #15
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I cracked it open while running, it didnt die or anything still ran normal beside the miss/surge deal
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87 3+3 shorty k20, 12 valve nv4500 swap, 5x16s, 215 pump, 7mm delivery valves, Valair DD, Fass, S...., maybe to spool


84 C20 6.2 diesel, Short bed, Banks sidewinder td kit
 
Old 03-02-2013, 06:30 AM   #16
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check lift pump is running and has pressure. should be 4-10 psi.
Wire in a relay to take the load off the contacts in the sender for primary power to the pump. Also verify you have power. Most only recommend an AC delco sending unit because some Aftermarket unit omit the contacts for the pump.


check for any fuel leaks. specifically at the filter housing and lines under intake or hardlines running down the back of the block and chassis
.
Change Fuel filter if you have not done so.

Check the air filter.

Check flow of fuel from tank to LP. the socks are known to clog

I installed Napa filter housing and 2 micron filter after the OEM Filter to insure clean fuel to the engine.

Are you dosing the fuel with 2 stroke or other additive to make up for the lack of sulfur for the INJ Pump? If not then do so heavily for a couple takes 2 oz per gallon. after such time use ~0.5-1 oz per gallon of fuel.

Is the PMD located on a cooler in a wind prone area? Do you have a spare to test? If not make sure to get the preferred gray color latest revision.

Rich
 
Old 03-02-2013, 06:39 AM   #17
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Sorry forgot to mention... The issue of hard cold starting:

check the glow plugs individually <1 ohm from plug to block; anymore and they are bad. Most suggest Bosch GPs. Be carefull removing any stock AC plugs. The OEMs are known to swell in the bore. I used vice grips and a small hammer to "gently" remove the 2 which have swelled on me in 3 trucks.

Check the GP relay attachments and wires to each plug. How old is the relay? It's cheap insurance to replace it for ~$30.

How long does the GP light stay on? stock mine was 8-10 seconds on cold days.

Lastly swap PMD to a known good unit.

You might also consider an aftermarket eprom since one of the options is to increase GP time for easier starting.

Rich
 
Old 03-02-2013, 06:58 AM   #18
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Jacob you could do all that or just put a cummins in it. Problem solved lol
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Old 07-01-2013, 07:19 PM   #19
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Quote:
Originally Posted by JBrassfield715 View Post
I tried changing the sender on the block and it didnt change anything but ill try that
You might try disconnecting the coolant sensor then see what it does ?
 
Old 07-01-2013, 07:23 PM   #20
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Make sure you dont have a bad eprom ? I had the same problem on my 94 6.5
 
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