Hello,

I am a new member and found this place when searching for solutions. Purchased truck about a month ago and was told it had problems..understatement.

It wouldn't start at times even after it was just running so I changed the oil, fuel filter, air cleaner. Problem still there. I then changed the lift pump because the truck didn't like high speeds or heavy loads (Fuel Shortage?) problem still there. I also lose my wipers at times..other times when they turn on they set the brake light at a low glow, then high wnen they cycle, then sets the SES light...all goes away when the wipers are turned off.

Checked codes and found 29, 35, 36 FSD? Found this site and read all the posts about simular problems. Then changed the OPS and both coolent sensors. I also found a bad ground wire at the right rear head (PCM Ground?)

The wiper setting the brake light and SES dissapeared but they still take spells of not working.

Truck really runs bad now. I noticed when changing the OPS that one of the connector pins was green and corroded...tried to clean but not sure if it helped. After changing the OPS my pressure readings are much lower...go into the red zone at idle when warmed up...runs about 20psi at 55mph.

I am wondering about the OPS being bad even though it is new. The truck won't start good when cold...acts like it is starved for fuel. When it does start it isn't running on all cyls. After motor is warm you start it up and it runs for about 30 seconds then shuts off. You then need to hold the petal to the floor and crank about 4 times then it takes off and is ok until you shut it off again.

I was sure the FSD was bad because when it stalled, I could pack it in snow and make it start back up and be fine....but that was before the bad ground was fixed....now it just acts like it isn't getting fuel at times.

I know this is alot of info and appreciate everybodys help. I read hundreds of posts to try not to bother members with rehashing of old issues but I still need help.

What really is frustrating is the fact I have a 1991 1/2 ton with a 6.2 at 318,000 miles and it will take me anywhere....the 6.5 I wouldn't trust it to take me anywhere but to the nearest towing yard!-:t

Thanks in advance for your ideas and help.

Bill

UPDATE... I just went outside and checked out a few things like fuses, connectors ect. I removed the fuel filter and noticed that there was only a slight amount of fuel in the bowl. I reinstalled the filter then cracked the bleed screw. I then cranked the engine and fuel came out after purging the air. After this the truck started right up and idled good.

Question? Where is the fuel leaking out of the bowl when the motor is shut off? anybody else have this problem. This truck has went from one problem such as the FSD being faulity (Until PCM Ground Fixed) to no fuel in the filter. The filter bowl leaking down is what I believe is causing my hard starting problem?

Please give me your ideas and thanks in advance.

Bill

did you bleed the filter after you replaced the lift pump? if not that is probably where the air came from. the seal around the filter can cause problems also. let it sit a while and restart the engine then open the bleed and see if the air returned. i have never done it but others here know how to rebuilt the filter housing, seals and stuff. if fuel came out while running then the ops is working, at least then it was. your codes 35 and 36 both point to the injection pump not the fsd when the fsd goes it doesn't set codes. code 29 is a fault in the glow plug relay circuit. wipers are under a recall from gm, as i understand, but if you take the black cover off of the wiper motor housing, pull the board and re-solder all the tabs that go from the harness plug to the board they will(should) work fine again.

DTC35 would be the low fuel empty filter problem.

DTC36 would be the bad ground, and low voltage problem.

DTC29 also indicates low voltage, bad ground.

Oil pressure problem would be corrosion in the connecter, as may well be the rest of the problems.

Disconnect, inspect, clean as necessary all the connectors from the main PCM harness to the various engine and inj pump harnesses.
Possibility disconnect\reconnect will burnish most of the pins.

Any corrosion must be addressed as intermittent\no connection.

Lite corrosion can be cleaned with CLR.

Heavy corrosion requires hydrochloric acid, then soda\water rinse, then hot-water spray-rinse, blow-dry, application of GM wet-service electrical grease, as used in Corvettes, Cadillacs, etc.

Same baby-poop yellow stuff used on tail\clearance\head lites.

Injector pump is dying.
OPS won't power the LP under low psi condition, filling the bowl with air.

Sounds like electrical gremlins to me. Replace your battery grounds, and check the ground strap at the rear of the block where the trans dipstick is bolted on.

There is a TSB on the wiper's, you might even get a dealer to fix it for free since it's saftey related. When I got my truck it was one of the first things I looked for in the carfax(luckily it had already been done).

When I changed my intake I noticed the fuel lines were cracked and leaking where they plug onto the lift pump. So I replaced them. I hope this is where your fuel is leaking out, because it's cheap and easy to fix. Good Luck!!!!

QM can you expand this a little further, I'm not sure I understand what you are saying here that leads you suspect IP, or maybe you typoed the I for an L.
Dry filter bowl would be more leaning to LP or power to it or connections on line from tank sucking air.


Injector pump is dying.
OPS won't power the LP under low psi condition, filling the bowl with air.

CP Cycle I forgot to add welcome to the site, do a search on lift pump or Oil pressure switch (which is where LP power is routed thru) and see what you turn up, I though I had added a thread link for LP troubleshooting in FAQs evidently not.

Take a minute to stroll thru the welcome thread and the FAQs, a lot of good info there for many of the common 6.5 ailments & upgrades.

Hello,

Checked codes and found 29, 35, 36 FSD? Found this site and read all the posts about simular problems. Then changed the OPS and both coolent sensors. I also found a bad ground wire at the right rear head (PCM Ground?)
The truck won't start good when cold...acts like it is starved for fuel. When it does start it isn't running on all cyls. After motor is warm you start it up and it runs for about 30 seconds then shuts off. You then need to hold the petal to the floor and crank about 4 times then it takes off and is ok until you shut it off again.


Thanks in advance for your ideas and help.

Bill
TD,
hard start and code 36 inidictes fuel metering is lagging. Putting in additive may help but not if the armature is excessivily worn.