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Help me diagnose this one

C

countryguy828

6.5 Lover
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Hey guys, been forever since I have posted. Truck ran perfect for too long...

So I was driving home a couple weeks ago. All of a sudden the motor just got really loud and didn't have hardly any power at all. It did quiet back down some. I parked it and havnt done much to it since.

It is really hard to start gotta crank it 30 seconds to a minute. If you hammer it down once its running it will put out a black cloud like it never has before.

It seems to idle pretty good and I can hold the rpms higher if I want. Heres the bizarre part. Flip the high idle switch and it will run terrible stumbles really bad, just about flops like a fish.

I thought for sure it was lift pump so I checked that today. I unplugged it and everything was exactly the same. Then I jumpered it so it was definatly running opened bleeder dumped fuel all over the place. Then tryed to start again, exactly the same, crank forever then start.

I am at a loss, beginning to think Inj Pump...Maybe computer :/

It has the SES light on but I dont have a code reader and dont really wanna drive it anywhere.

It is a '98 K2500HD F code NV4500
Heath PMD kit mounted to skid plate
Heath Turbo Master
Vacuum pump removed
3 inch downpipe 4 inch exhuast
somewhere around 270,000miles on the clock

For those that remember Goldsburg, it was his old truck

Other known issues, AC clutch not getting power, 4way flashers quit working a few weeks ago, blower motor plug on dash melted several years ago, sometimes left rear turn signal doesn't work and trailer brakes quit working.

I still love the ole truck prefer driving it to the 350 gasser auto.

Thanks for any guesses,
Dave
 
Everything in your "other known issues" list is an electrical problem..... It wouldn't be a far stretch to figure that something electrical is causing your problem now. The SES light is on, so first thing's first, you need to get the codes out of it and see where that leads. Autozone and advance will pull the codes for free. Get the codes from them, then report back to us and we can start diagnosing from there.

When my Optical Sensor filter harness went bad, my truck acted almost exactly as you described your's is acting...... Long crank time, loud rattly engine, huge puff of smoke when it finally did start, and no power at all.....1/2 throttle to maintain 30-35 mph.
 
Hmmmmmmm......... Possibilities......... I am by no means an expert on these things but for what it is worth.
The loud and the black smoke have me thinking turbo related problems. If you have freaking major exhaust leak at the manifolds or in the cross over pipe that could make some noise and also not be providing good gas flow to spin the turbo charger. If the turbo is not spooling up you are getting more fuel than you have air to burn it which could explain your black smoke. Or maybe the turbo itself is toast.
 
Ok guys so last night I was thinking it could be crank sensor so I was looking for other posts about them, gave up kinda quickly...

Decided today that I should dig out that ebay elm327 I bought like 3 years ago that never worked and try again...Did a search for software...Tryed Scantool.net and it said this is a clone and not supported...Tryed PSMSCAN by Palmer Performance. The trial found it and connected BIG SMILE but have to pay to read codes SAD FACE...Then found out Scantool.net V1.13 might work...did lots of searching to find it, uninstalled v1.20 then installed v1.13 connect and codes there for me Oh Ya giggity.

It showed codes p0251 and p0335, cleared codes then p0335 came up again...crankshaft position sensor, looks like I got my diagnosis !!
How bad is crank pos sensor to change and what about the timing?

Just for fun tryed it on the gassy 350 and it showed code p0420 will have to work on that too I guess :/

Thanks guys,
Dave
 
CPS should be on the right side of the timing cover when facing the front of engine. If the engine is dirty do yourself a favour and get some engine degreaser and blast that area good then power wash. There is a bolt holding a clamp which holds the sensor in place.
 
Mudbath said:
CPS should be on the right side of the timing cover when facing the front of engine. If the engine is dirty do yourself a favour and get some engine degreaser and blast that area good then power wash. There is a bolt holding a clamp which holds the sensor in place.
Click to expand...

Agreed.... The wiring will stretch up the driver's side of the timing cover and connect to the rest of the harness near the IP. A CPS really is not "hard" to change, but it can be a little bit of a PIA because of dirt, oil grime, tight spaces, etc.
 
Dave, I emailed this to you, but my first copy dropped a page or 2...

Here is the Diagnostic procedure from the GM manual for P0335
 

Attachments

  • P0335.pdf
    331.8 KB · Views: 18
Thanks guys, I should be able to work on it again Monday, Tommorrow I gotta bale hay and go pick up my camper...Things never end.
 
Sounds like when the optic sensor took a dump in my 96. Real long crank times with lots of coughing, catching, and stalling. Once it did start it loped like crazy, blowing smoke from the pipes. High idle switches didn't work. It would stop the loping idle once i touched the go pedal.

The engine would randomly have this really loud diesel rattle and the truck felt like i was trying to drive with the brake pedal to the floor. No power at all. It would spit out P0251 and P0370 codes at random when this happened as well. Sometimes it would run perfect for a few days with no SES light, and others i couldn't start it without the SES light glowing away.

I honestly thought the IP was bad, and was going to swap it out, until a friend convinced me to follow the codes and check the optic sensor. Sure enough, it was dead to the world.
 
Alright guys here's the story.

Took out the old CPS. It came out fairly easy. Upon inspection there was about a 1 inch crack along the side.

Popped new CPS in, then once I found the bolt that I dropped and put that back in I got in and started it. Started nice and easy rattle a bit for maybe 1 second then smoothed out.

Tryed starting several more times each time was perfect. Tried High idle switch, it ran great.

Then plugged in scanner and reset the code, then keep reading and no more codes came up. Too bad at the end I didn't realize I was sitting on the power cord for the laptop and broke the end off of it, the battery is junk in that laptop.

The important thing is that its all good drove it maybe 50 miles tonight and all was well.

Thanks everyone,
Dave
 
Glad to hear your back up and running.

Dave where are you at, that you're able to make hay? We can't seem to get 2 let alone 3 days without rain here. Everything is up about 3-4 feet and turning brown quick here. Most guys round here haven't got half their 1st off yet. Wheat is only 12-15" high and turning. Not gunna be much straw either. Corn looks like crap...................
 
I am about 25-30 miles Northwest of Dayton around Greenville. We had to fight the rain bad here too. Hay got rained on twice after it was down, Wind blew alot and dried it out and we got lucky. We finally baled yesterday at around 10% moisture. Ended up with about 300 bales on just under 5 acres. Done with hay putting beans in that field now...

Our corn looks like crap its maybe 6 inches high. We are still getting beans put in the ground not having any luck at all this year.
 
We finally got a break up here, no rain since saturday. Put up 600 weds. afternoon. Got more to go today and more friday. Cant really got to far to fast we dont get started till 4:30 due to our "real" job, and there is just 2 of us. The only guys round here that has "knee" corn now is the amish. They can get in the fields a little earlier than us due to the horses vs tractor thing.
 
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