Please help! Lb7 has big problems

[kcabbie]

I have been experiencing issues with loss of power/mpg on my lb7. I checked the rail pressure's desired vs. actual and there is a few thousand psi. And I can definitely tell a difference in power.. I tested by raising the fuel regulator in my EFI Live program, to 160*. Desired was 23,xxx K and actual was 20,xxx - 21,xxx K.

So CP3 or FPRV?

Next is the bigger issue I am concerned with. I pulled my oil cap to check blow by and as soon as I pulled the cap off I heard what sounded like a bearing whistling. I feel like it's likely to be the main bearings.. Any suggestions? Is the whistling normal? I don't have time to take this thing out of commission for more than a Sunday. It's my only transport to work. In a month or two I will have a new truck and I can do what needs to be done.


Thanks for any help

 

[chevyburnout1]

Sounds like either failing injection pump or injectors. My bet is on injectors. And that noise I believe is normal. All the Dmax's I've heard have a slight tingy noise when listening inside the oil fill tube.

 

[kcabbie]

Thanks for the reply!

My balance rates are within 2.5 mm3. Also, there is no fuel in the oil, and it never smokes... I really do not want that to be the problem lol

The noise was not there before.. it is a very distinct high pitched grinding sound.. Also I don't have to put my ear up to it. It's like when you pull the cap off it comes out very loud. Is there any oil additives I could try to see if it quietens the noise?

Thanks again for the help

 

[paint94979]

How many miles are on it?

 

[Max Attitude]

My buddy just had to put an injection pump on his LBZ. Truck would not even start on its own. They had to use a little starting fluid so they could diagnose it. The pump was only pumping in the hundreds instead of around 22,000 like you said. I would monitor the flow rate daily and see if it gets worse.

 

[adeso]

get one of these, only way to track noise down...
http://www.autozone.com/autozone/ac...and-Equipment/Automotive-Stethoscope/_/N-26gd
cheap ones seem to work just fine

 

[whitetrash21]

Every dmax I've opened has that tinging sound when the oil filler cap is pulled.

Has the FPRV ever been popped?? Like Nick said, how many miles.

 

[Hot COCOAL]

Is there any pressure coming out of the oil fill? Could the whistle you hear be a pressure leak?

 

[kcabbie]

Hey guys very sorry for the delayed response!

The noise I declared was normal.. Listened to a buddies lb7 and it was there. Seems to be the cheaper water pumps from the parts store, something to do with the gear not being 100% straight.

245,xxx Miles

FPRV Has never been messed with, and CP3 Is stock. There is close to NO blow bye.

We turned up the pressure all the way at set the RPM's to about 1400 and let it sit for a few minutes. After that it ran a LOT better. Would run to 3K again pretty nicely.

My fuel rate went from 2.x to 6-7 at idle. I was told below 8-12 meant your injectors were wore out.

When cruising I randomly feel a distinct roughness come through the gas pedal. It worsens if I cut the ac/heater BLOWER on. Not the compressor.

Thanks for the help guys!

 

[bluecollar]

The cp3 gear is right at the bottom of the fill tube so thats the sound i believe. Also check rail pressure at wot and see if it maintains pressure

 

[kcabbie]

I will hook up the computer and V2 next time I get in it.