cummins fuel problems

[gofshn]

i am not sure on cummins how they route the iol psi safeties, check for a schematic in a chiltons book or haynes amnual and trace out the pattern/ flow of voltage. i do know that simply a dirty battery terminal connection on fords and chevy's will cause a bunch of crazy problems. one day mine would not shift out of second gear, i could restart the engine and it would shift out of second but 20 minutes klater it would not. i cleaned the somewhat dirty terminals at both batteries and haven't had a problem since. also would thriow some crazy obd codes when terminals got dirty.

[flatbottom]

just some info from a trans board I read. I to was going to build up a cummins with the fuel pressure mods and pulse tuning, even thought of piggy back turbos......till I read this.........


LINE PRESSURE & TRANSMISSION LONGIVITY
There seems to be a great deal of confusion about transmission line pressures and how it affects the life of the transmission.

The amount of line pressure you have in the transmission directly relates to how much power the transmission can hold.

Setting up higher line pressure transmissions can be very difficult even for guys like myself who have done hundreds of them

There are many out there that will tell you that you don’t need extra pressure to hold the power. As long as that is a choice you make and understand the consequences.

I am searching for the politically correct term for these so-called transmission technicians and sales people that so ignorantly advocate lower line pressures.

I think I found it, guys giving this type of advice to run lower line pressures are either idiots or don’t understand the first thing about transmissions and the direct relation between line pressure and longevity or cannot set up the trucks to work with the higher pressures.

Let’s look at a stock transmission: line pressures 1999 and earlier Dodge Rams a typical stock dodge ram will have approx 52PSI line pressure at an idle and 105PSI wide open.

2000 + Dodge Rams have approx 58 PSI at an idle, and approx 140 wide open on some trucks. Most range from 115 –120PSI

This is where a lot of guys (customers / technicians) get lost.

Most guys take their mainline pressure readings from the accumulator port and think that is what their pressures are throughout their transmissions.

That is not necessarily true. Take for example if you took a pressure reading of 80PSI in your accumulator port most consumers and technicians assume that they would have 80PSI in the first gear, 3rd gear and the TC lockup clutch as these are the ones that are applied at that time.

If you move the same pressure gauge to your front servo you may be in for a shock.

I have measured some where the pressure was as little as 60PSI. If you have a good solid transmission base the pressure in the front servo and the accumulator should be identical. Keep in mind this is only telling you the integrity of the pressures in first gear and 2nd gear release which is also your third gear apply.

If your pressures are identical chances are your transmission is happy and usually will live a long and healthy life.

If your pressures vary by more than 5 psi you have an internal leak in your transmission.

To check the integrity of the torque converter lockup clutch you should measure your torque converter apply pressure through the cooler line. Most torque converter lockup clutches fail because of internal leaks. Chrysler also gives you a port to measure 4th gear.
Again your 4th gear pressure should measure the same as your accumulator port within 5 psi.

At Diesel Transmission Technology we live and die by the pressure gauge. We pressure test every truck before and after working on it.

Just because you have a higher-pressure valve bodies does not mean you have higher pressures going to your clutch packs and bands in the transmission.

All our hand picked and trained installers I have personally spent time teaching how to use pressures gauges and how to understand the implications of the readings.

BOTTOM LINE IS GUYS, PRESSURES DECIDE HOW LONG YOUR TRANSMISSION IS GOING TO LIVE.

More power you have more pressure you need. The heavier you tow the more pressures you need,

DO NOT BLINDLY FALL PREY TO BELIEVING OTHERWISE. Do some research and your homework.

[homewrecker]

JJ it sounds like your lift pump the model you have is a 5.9 ISB whenever the lift pump doesnt deliver enough fuel it starves the distribution pump of lubrication.Whenever the lift pump stumbles 99 out of 100 times the distribution pump gets wasted and needs replaced.The best thing you can do is put a fuel pressure gauge inside the truck to keep an eye on and at the first sign of a drop replace the lift pump.GOOD LUCK

[Pure Evil Joe]

Blackwell . bad governor pressure sensor or solenoid will give you shift issues. i doubt your trans is jumping in and out of 4th . it is going in and out of lock-up . check the brake switch with a scanner and make sure it is adjusted correctly. driving on the road shakes the pedal and trips the switch i see it alot on dodge vehicles.

[blackwell50]

Blackwell . bad governor pressure sensor or solenoid will give you shift issues. i doubt your trans is jumping in and out of 4th . it is going in and out of lock-up . check the brake switch with a scanner and make sure it is adjusted correctly. driving on the road shakes the pedal and trips the switch i see it alot on dodge vehicles.

I was given some bad info,and put dexron 3 in this tranny against my own knowledge.It was the only thing on the shelf and I had no choice,today I put atf+3 back in it.I drained the TC and cooler to get as much out as possible,the more I drove it the better it got.But now that you mention it and I have gotten over the fact that something is wrong it is going in and out of Torque converter lock up.It is still howling when in gear.When this auto gives it up I was thinking of putting a 5 speed in it.Opinion on that choice.I have done an auto to 4 speed conversion before on a 71 chevelle I used to have,so I know somewhat what would be involved in this.I went from a powerglidw to a muncie m22 in the chevelle.

[WAHOONBOX]

THIS THREAD WAS STARTED JAN 2007

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BUT I CAN CHANGE MY OWN FLAT TIRE!