Lets talk FUEL PRESSURE

[kenbronnson73]

Your fuel pressure is fine.look elswhere.the crank relearn is free as long as you have a scanner that can do it and it should be done.Also you can check " cam degree offset" I think its called.on a scanner which should be as close to zero as possible.That is the position of the distributor. To make sure there isnt a big gap between the rotor and cap tower when it sparks.As you all know the distributor position doesn't change timing but it still matters for that reason.Otherwise check Egr valve for being stuck open a little and or maybe a vacuum leak.

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[wingman]

I had endless P0300 on my 2001 6.0 hd, cured with a crank relearn.

its been approximately 10min and the pressure has gone from 50 to 48. Is that bleeding off too quickly?

 

[Manimal]

Well, I drove it last night and the hesitation is gone. I also read on another forum that the new injector spider(MPFI) dont need as much pressure to operate correctly. I will find someone that can do the crank relearn. Thanks for all the help!

 

[Manimal]

OK, I took it to a shop and they hooked up their scanner and found that 3/5 and 6 all had misfires...but #6 was the worst. They did the relearn, but didnt help. He told me that right off idle the misfire cleans up and goes away. He thinks it's a compression issue, like valves or springs.... Any opinions? If not, looks like Im pulling the heads.

 

[Manimal]

Any ideas???

 

[Manimal]

Bump...... When it starts running bad and I shut it off, you can smell fuel.

 

[tom joyce]

Bump...... When it starts running bad and I shut it off, you can smell fuel.

The original post said the plug was fouled and there was build up on it...
Was it fouled by fuel? If so, then it is NOT a fuel pressure issued at all......
Your timing can be off - especially if messed with the distributor. It is impossible tell if the timing is correct without putting it on a scan tool that can observe the timing OR simply buying a clear vortec distributor cap (ebay search "clear 474t").
Install it and observe the spark. The spark should look like a triangle or pyramid when the rotor fires the spark to the cylinder. If it looks like sparks are flying all over the place under the cap (which will be seen by the computer as random misfires) - then adjust your distributer till the spark is a triangle/pyramid....Timing is set at 2000rpm, so it can be tricky....This is exactly what the $15000.00 dealer scan tool does...

If timing is good then I would change the ignition control module. They can be cracked inside, and test good - but when heated up they can cause random misfires. If you change the icm - use Ac Delco ONLY....I found this out the hard way....

http://www.ebay.com/itm/clear-Distr...ash=item33ca91568f:g:Rm4AAOSwQiRUn3KX&vxp=mtr

 

[tom joyce]

Bump...... When it starts running bad and I shut it off, you can smell fuel.

If you smell fuel then it is a spark issue!

 

[Manimal]

I pulled the heads off yesterday...exhaust valves are pretty crusty. But between the cost of gaskets,valve job, I "MAY" end up swapping to a 5.7 Vortec...I posted in the 96-up Vortec Performance section.
It was hooked up on a scan tool and the misfires cleaned up off idle, but at idle #6 was BAD. The mechanic said he thinks its a compression issue..possibly valves.

 

[tom joyce]

I pulled the heads off yesterday...exhaust valves are pretty crusty. But between the cost of gaskets,valve job, I "MAY" end up swapping to a 5.7 Vortec...I posted in the 96-up Vortec Performance section.
It was hooked up on a scan tool and the misfires cleaned up off idle, but at idle #6 was BAD. The mechanic said he thinks its a compression issue..possibly valves.

If it was on a scan tool - then what is the camshaft retard setting?