TxDiesel007

Guys

im bored at work so i will give a writeup on my new gauges. I went with the isspros (if you follow my posts yall know) or if you have read up on my sig as of late, yall will see what i got. I had a mechanic friend of mine help me put them in, and he charged me 100 bucks for his time. Not a bad install, and the fuel pressure in the cab was great

Problem with that bein i noticed that my fuel pressure was low. its at 12 PSI at idle, and as i can recall it should be at twice of that. so i need a new overflow valve. I bought the isolator and steel hose and it was a straight forward install, not much harder than i thought. the hard part was actually drillin and tappin the banjo bolt. Nothing a good vice and good tools cannot take care of. Aside from a new overflow valve i get decent pressure. At 70 mph, 2000 rpms and 750-800 or so on the pyro im pushin about 22 psi on teh FP gauge. It is lit and in the middle of the three pillar gauge. Any more suggestions for FP? im open to ideas guys..

Pyro, i had no idea how difficult it was to drill that manifold. I have my probe where it should be, drilled, and tapped at manifold. and WHAT A DIFFERENCE in EGTs. i had a post turbo pyro and would run on average at 70 mph 350-400 on EGTS, at the manifold, WOW!! 850-900 on some points, a difference of 400-500 degrees! GOOD LORD! I did notice that the extra fuel i have pushes that Pyro pretty quickly. overall a good install..

The boost gauge was fairly simple to install, I had enough connections to just use the old ones. I did notice tho that my turbo was wastegated at 32 psi, with a blocked wastegate i can push 44 PSI, and constantly keep it at 40 PSI, so im runnin a blocked gate now. Seems to help alot with spool up. Ill be gettin some pics up soon of my new setup. Just thought id share with u guys...

I seriously think tho, that the FP gauge is well worth it. Its fun to watch as well, and i benefit overall from everything cause now i know what im really running and as accurate as possible...

Funny tho, my old gauges that were "banks" had Isspro behind them. funny aint it?

Thanks guys!

Rick

displacedtexan

I was actually fixing to email or PM you to see how you were liking the new gauges. I love my Isspros. They have tought me a lot about how the engine works, and how hard it is working at any given point. I never would have guessed how much the pyro would fluctuate at 70, I get readings between 525* on long streches of coasting downhill, to 900* on the baby hills we have here...

No suggestions on the FP problem. I'm also wanting a FP gauge now...

We go to close on the house at 4 today!!!!!!!!

infidel

I'm thinking before you replace the lift pump to check for restrictions.
Heater or tank filter, kinked supply line.
If you pinch the rubber return hose with pliers, engine running, and the pressure shoots up over 50 psi the lift pump is fine, OF valve is the problem.

Dr. Evil

Whoa - now thats a great tip !

Theres no harm having a FP guage on a 12V (Im probably gonna install pre and post filter guages)

infidel

Really no need for two, just on the outlet is enough.
Highway warmed up cruising fuel pressure is very consistent until the filter starts plugging (or something else goes wrong.)
Then you know it's time to change the filter. Like any other filter the fuel filter tends to clog up faster and faster once first starts becoming restrictive.
My highway pressure always sits at 32 psi.

Dr. Evil

OK I agree that the prefilter guage is overkill - but I was thinking it will be easier to see when the filter is plugging if you could see the pressure differential across the filter.

Plus, hey, I LIKE guages.

TxDiesel007

Congrats on the house Nick!

more thoughts on my FP gauge, i love it... i love watchin it fluctuate at different throttle levels. and with the isolator i have absolutely no pulsations, it just stays there, but that needle valve is just barely open. Ill get some pics soon of my setup. Im gonna BOMB my gallery again soon enough, and remove some old pics that dont get any views or are just plain outdated.. Trucks gone thru some changes..

Just FYI on the blocked gate. I used a vaccum line plug that came with my posilock kit, a small clamp on there, a long (2.5 inch) 1/4 inch bolt, a washer and two more small clamps to hold it in place. So far no issues and it works great. With my plate at 2/3 forward, 3/4 forward AFC and 3/4 starwheel, i can now limit my boost to about 40 PSI, no more and no less, Smoke is a little less on startup and take off, and im down 4 lbs from a full forward AFC. its amazing what a couple of mm of afc forward can do to a truck...

I can only imagine what fuel ill have with a forward 0 plate, properly adjusted governer arm, and forward AFC and starwheel. Too much smoke for a stocker thats for sure...


Now i need Mr Thompkins info again to order a new OFV...

But ill do that soon enough after i check my LP and what not...

Rick

TxDiesel007

Bill,

Is the higher fuel pressure you are experiencing due to the smaller pumps that your trucks are running? Or it makes no difference....

Rick

12valve

i had a truck here the other day, it made 50 psi at idle! when its suposed to meak 25-30 psi...

why that.... i did not pinch the return line? could it be pinched by itself (clogged?) oh yeah, the truck started very very hard in the morning... about a minute of cranking and cranking... even after priming it!

what could the probl. be? i couldnt help him out!

infidel

Rick, the lift pump and OF valve are the same on both IPs, pressure should be the same.

12 valve, the overflow valve is a ball and spring. Sometimes the ball will wear in one spot till it becomes out of round then will get stuck in the seat preventing little or no fuel from bypassing to the return. Only other cause for the high pressure would be a kinked return line between the engine and tank.

What I've been told is that high fuel pressure advances your timing resulting in hard starting. It does this because the extra pressure causes your injectors to pop off sooner. The opposite is true of low fuel pressure, timing is retarded resulting in less power and poorer mpgs.
My disclaimer: although this makes sense and I was told by a reliable source it just doesn't seem like a +/- 50 psi would make any difference with injection line pressures approaching 17,000 psi.

signature600

Maybe he was thinking of an older rotary pump system...I think high case pressure on those can cause hard starting?!?!

I don't think the P7100 care what you feed it, as long as it's combustable
Chris

12valve

hmmm what signature said, already made sense,,, or i thought i found the problem... ive just never seen 50 psi at idle at a p7100...

when i prime it, the gauge goes up, but it still starts long!

infidel

No, the fellow who told me was referring to a P pump.

signature600

What really kills that theory is the fact that a P-pump makes really crappy pressures at idle anyway?!?! It needs RPM to make good pressure, and make everything just right

I still think he's confused on which pump he's talking about, but I'm not a pump expert by any means
Chris

12valve

But i would still like to know why that high pressure, and why so hord starting...

On these warm mornings over here, sounds just BAD to crank the battery dead each morning... crank over a minute for a cummins?! thats just BAD!

He is a rich guy,,,, he said if it wont work, he'll just go and buy a new CTD anyway!
i would like him to see me pay, after i fix it, if its even possible...

he tows 20 tons often, often a long way! at 80 mph hehe that cummins is under load almost always!

can it be a bad engine? he says it burns a bit oil. and has maybe a little more blowby then normal.