Nope, nothing to worry about there. Glad it helped you!
DB2 Tuning Guide
- Thread starter Thewespaul
- Start date
Wes,
Thank you for this excellent, easy to understand post.
I had something odd happen. I pulled out the minmaxx rod because it felt a little "chunky" turning it. Turns out a few of the aluminum threads were stripped. I cleaned those off, played with it until I felt it slide back into the governor assembly and bottomed it out. This caused a no fuel issue.
I pulled the top and everything looked ok. Maybe I had bound the governor up. I pulled the rod again, put it back in, set it to original spot and made sure the governor could slide back and forth. Fixed the fueling. In neutral, it would rev to 3300. I need 72 mph, not 67.
I ran it almost all the way in and now it will hit redline of 3800 in neutral. I'll see if I can hit 72 in 3rd now. Fingers crossed.
One question. In the left rear corner, there is a hair spring. Does this ride on top of the minmaxx rod?
Thanks again!
Thank you for this excellent, easy to understand post.
I had something odd happen. I pulled out the minmaxx rod because it felt a little "chunky" turning it. Turns out a few of the aluminum threads were stripped. I cleaned those off, played with it until I felt it slide back into the governor assembly and bottomed it out. This caused a no fuel issue.
I pulled the top and everything looked ok. Maybe I had bound the governor up. I pulled the rod again, put it back in, set it to original spot and made sure the governor could slide back and forth. Fixed the fueling. In neutral, it would rev to 3300. I need 72 mph, not 67.
I ran it almost all the way in and now it will hit redline of 3800 in neutral. I'll see if I can hit 72 in 3rd now. Fingers crossed.
One question. In the left rear corner, there is a hair spring. Does this ride on top of the minmaxx rod?
Thanks again!
More than likely when you reinstalled the rod you got the vent wire under the rod instead of above it which keeps the metering valve from rotating from the fuel shut off position. Once you installed it again you got it in correctly and the pump wasnt bound up anymore. Glad this guide is still helping people out, need to update it when I get some time, got a few more things to get more fuel from these stockers. If you can post a picture of the spring youre seeing I can identify it for you, theres more than a few small springs in these pumps.
Likely so, if you posted a picture it isnt showing up, but that would be where the vent wire is located.
centennial60
Registered User
Wes, I have the adapter to measure transfer pump pressure. Would you be able to give me a quick rundown of what I should be seeing for pressure and the limits of which to not go above?
You need to be able to watch pressures under load, you should have at least 80 psi at wot at max rpms, and no more than 120 psi. If you’re hunting for performance you can go higher. You want it to be above 100 psi to be running well.
centennial60
Registered User
Thanks for those numbers Wes! To tell you guys what I’m doing.. a couple weeks ago I was able to get this truck out on the road (93 f350 dump truck with a late 86 6.9 n/a). It had a couple issues. Under load it smoked white and was low on power. It also acted like the pump stuck at full advance when shifting. Getting back into the throttle after a gear change the engine is very rattly for a split second then goes back to normal. Since I didn’t have the transfer pump pressure tap at that time I blindly increased the transfer pump pressure and it cured my white smoke problem. I should add that prior to this I did advance timing a bit. Didn’t take the time to throw the meter on it but it sounded about right at an idle. That didn’t seem to change the white smoke much. So increasing transfer pump pressure was the cure for the white smoke. Now the advance sticking issue I might try letting some atf soak in the pump for a while. See what that does. I have other pumps I can throw on it as well as a set of injectors that I pressure matched a while back but figured I’d play with this one first.
Adam
Adam
Thats great, glad this info has been useful. With the sticking advance piston, if it doesnt clear up you can pull the pump and remove both the large black hex caps that seal the advance piston bore and slide the piston back and forth while hosing it with brake clean to clean it up and un stick it.
Laine D
Full Access Member
For the minimaxx adjustment, How high will it kick the idle up to before I back it down on the regular idle screw?
Every pump will react differently, typically 50-150 rpm change is normal, anything more and it’s likely adjusted too far.
Detroit80
Full Access Member
Is this the kind of thing that should even be messed with on stock engines? Or in my case, I have a Banks Sidewinder wastegated turbo on what I believe to be an otherwise stock '90 7.3 motor, and stock NA pump/injectors. I didn't put the turbo kit on though, so I don't know if the PO messed with the pump at all before I got it.
I've had the truck for a few years, and am finally getting to the point where I want to go completely through it to get it all tuned the best I can. I recall having issues with high EGT when I took it off the road a year ago, and just started wrenching on it a couple days ago again, so I definitely want to get that worked through first.
But wasn't sure if I should be doing stuff like this pump tuning if I haven't done any other mods or put in bigger injectors?
I've had the truck for a few years, and am finally getting to the point where I want to go completely through it to get it all tuned the best I can. I recall having issues with high EGT when I took it off the road a year ago, and just started wrenching on it a couple days ago again, so I definitely want to get that worked through first.
But wasn't sure if I should be doing stuff like this pump tuning if I haven't done any other mods or put in bigger injectors?
