LLY: Sticking Regulator??

[SSchmi5519]

I've heard of regulators sticking, but never dealt with one personally, just dealt with bad regs that go straight to max rail..

Very interesting issue here. Truck holds perfect rail on the FIRST wot pass all the way through the gears. Then when you let off, both desired and actual go to ~9k.

Here is where it gets interesting. After this first run, both sitting at ~9k on 0% throttle decal, if you begin to tip into the throttle again desired moves up as it should and actual stays right at that 9k mark.

The only way to get actual to move along with desired again is to slow down under 40mph, where desired drops under 9k. As soon as actual moves even a hair it is good to go again.

Example: you go wide open on the on-ramp of the freeway, get up to speed, and set the cruise. You will cruise at 9k actual indefinitely (with desired jumping around 10-11k, until you slow down to 40mph or so.

I tried blipping the throttle quickly once it is in this condition to try to get actual to move and it stays flatlined at 9k rail.

Exact same issue happened both before and after lift pump.

Any ideas? I cant say ive ever seen or even heard of this.

 

[BobbyBDirtyMax]

Seen a similar thing happen on a LBZ truck about a month ago. Guy brought it to me with his logs and the actual and desired were very odd to me. Truck didn't drive very well at all. After talking and understanding what all he had done to the truck we put in PPE rail fittings, and Race Valves, adjusted and double checked the lift pump and still didn't fix it. I was betting on the regulator all along and after a couple days I put a new regulator in, which he'd just bought new, and problem solved. Some parts are just defective even new. Just to make sure I put the stock rail fittings back in and FPRVs and logs looked great the actual and desired were staying in their ranges correctly. Truck ran better than ever. Not 100% sure this could be your issue but after looking at the regulator I took out the spring inside seemed to be damaged somehow.

 

[SSchmi5519]

Ill screenshot the log and post it up

 

[Chevy1925]

I gotta agree on regulator Steve. It uses voltage to hold it shut. If the gouge or crap that is in it is holding the slide, the spring may not have enough pressure to allow the regulator to open back up to increase rail pressure till you drop below where it's stuck and have the voltage unstick it.

 

[SSchmi5519]

Ok first image you can see actual moving along nicely with desired. Once let off throttle, both desired and actual drop to 9k, except actual stays there until the truck slows way down (where the red arrow is), then begins to move like it should again.

In this second image, you can see actual follows desired again when it goes to WOT, then follows desired down to 9k, and stays there again. The jagged lines are when we were trying to get the actual line to move and it just stays at 9k, regardless of desired, until we slow the truck down and it begins to move again, as seen at the end of the frame.

 

[sweetdiesel]

Steve

Log voltage of fpr and try bumping up the first 3 cells of b1010
Abby doea this quite often.

 

[SSchmi5519]

Steve

Log voltage of fpr and try bumping up the first 3 cells of b1010
Abby doea this quite often.

Do you run a stock regulator? (As opposed to an LBZ reg?)

Funny thing is it does this only after going wide open, otherwise it never sticks there. Is that what you're referring to?

 

[sweetdiesel]

Do you run a stock regulator? (As opposed to an LBZ reg?)

Funny thing is it does this only after going wide open, otherwise it never sticks there. Is that what you're referring to?

Useally run stock lbz regs. I've swapped them so many times its just easier to do that for me.

Has this been modded?

 

[SSchmi5519]

Useally run stock lbz regs. I've swapped them so many times its just easier to do that for me.

Has this been modded?

Nope completely stock LLY truck with LLY cp3 and reg.

 

[SSchmi5519]

Have a new lbz reg in the mail to test out on it, so I guess we will find out if that's the issue or not