Pre-Pump Mod - Diesel Forum

sail684 · 03-13-2003, 02:08 PM

Did the pre-pump mod today using instructions many have posted on this site. Now I'll just have to wait and see if I notice any difference. Once I removed the quick connect off the pump I could see how the pump might draw some air. Anyway, with new hose and clamps, I know it cannot draw air there now. One of those mods that may or may not help, but sure cannot hurt.

dmftoy1 · 03-13-2003, 02:52 PM

Drive it 30-40 miles and then see what you think. I couldn't hear my tires on the road before I did mine. (with the windows down)

Regards,
Dave

CHPMustang · 03-13-2003, 06:25 PM

We recently performed the in-tank and pre pump mods at the same time which we should have done a week apart so we can tell what is responsible for the positive changes in our Excursion's performance.

I'll assume it's a little of both [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/smile.gif[/img]

BILL

fire1 · 03-15-2003, 07:46 PM

Bill,
What is the verdict on the tank and pre-pump mods? I'm still trying to decide? Mine seems pretty quiet most of the time. Did see a little air the other day, when my tank was less than a quater, in my clear prepump line though. [img]/ubbthreads/images/graemlins/eek.gif[/img] I usually see none. I'd like to hear your results.

Larry M · 03-15-2003, 08:00 PM

sail,

I would recommend in a couple of weeks and then in another month you check the tightness of the worm clamps to ensure you maintain a good seal as the hose relaxes over time unless you used a constant torque or correct spring type clamp.

fire1,

Can you describe what you're seeing in the clear line. If you have the factory in valley system a bubble or so won't hurt, but it can't get out of hand. Also, can you hear any differences in engine sound as the tank drops and you start ot see bubbles/air.

I only posted here since proper attention to the fuel system is really important regardless of what model PSD we have ... mistakes can be costly.

Thanks for you indulgence and intrustion by an outsider,

Larry

fire1 · 03-15-2003, 08:24 PM

Larry M,
I had noticed it was a little louder at idle and a little more cackle than what I normally hear. I noticed this increase after a recent fill up, but from same station as normal. I did not get around to putting the clear line back in until the tank was just below 1/4. I intially saw just a few bubbles "hanging" and releasing from the SS line from the tank. But it got less as the truck continued to run. Checked again later (during day) and saw nothing. That night I checked with a flashlight and could see small "comets" flying by in the line. After a refill of the tank I have seen nothing and the truck seems to be back to "normal". I had also seen .5 to 1 mpg drop recently, but could be my foot causing that. Other than the prepump I am stock fuel system wise.
I appreciate any insight anyone has on this.

CHPMustang · 03-16-2003, 12:17 AM

fire1,it's been about 2 weeks since we've done the mods to ours and I'll say engine noise is down,less engine cackle(noise) and accelerates way better [img]/ubbthreads/images/graemlins/smile.gif[/img]

I'll have to swing out for you to sample the sound and idle of our PSD [img]/ubbthreads/images/graemlins/wink.gif[/img]

BILL

fire1 · 03-16-2003, 02:22 AM

I'd love to hear it somtime. I'd like to see how quiet mine is or isn't compared.

CHPMustang · 03-16-2003, 12:25 PM

You have my number just give me a ring [img]/ubbthreads/images/graemlins/cool.gif[/img]

sail684 · 03-16-2003, 04:31 PM

Haven't run down a tank of fuel yet. It does seem to idle a little quiter. Be driving a lot this next week (son on spring break). We'll see when fuel level gets lower.