I fitted a set off the Isspro Performax guages a while ago (three on pillar & three in dash) and a puzzling thing has recently occured.

Since I fitted the guages, the fuel pressure has always sat very consistantly at 65psi.
On the trip I just done, I looked at the guage at it was off the dial at 100+psi.
I pulled over (roadside) and disconnected the cable from the sender unit and also disconnected it form the processor.
I did this first to see if it was a simple electrical fault. But when I restarted truck, it immediately shot back up to 100+psi.

I then presummed a blocked fuel filter. As I always carry a spare, I changed out the filter. But still no change.

I fitted the guages a few months ago and have never seen a fault, so I presumed it to be a fault in the guage itself or the sender unit for it.
I decided to travel on and keep a close eye on it and the trucks performance. I done approximately 2,000km towing my rough road caravan over all sorts of terrain and never an issue.
If the pressure was indeed 100+psi I would have expected the fuel pump to have given up/over heated, or even a noticable change (for the worst) in fuel consumption haveing run for a further 2,000km.

I just finished the 'In Tank' mod removing the in tank filters and mixing assembly, removing all the quick release fittings on the suction lines and fitting new hoses and double hose clamps and fitting the external pre-pump filter (PITA job in the driveway).
I found a bit of debris in those filters, but not enough to maybe cause the return line to block up thereby increasing the fuel delivery pressure at the fuel bowl. ( I also did the Hutch whilst in there).
Anyway when I primed the system and started the truck there was no change to the indicated fuel pressure at 100+psi.

So the only thing at pressent I can think of is the pressure sender unit is faulty??

I haven't been able to get another guage to x/check the actual pressure. Does anybody have any other ideas on what may cause this? Or have experienced this?

Also any Aussies reading this: Do you know of a ISSPRO agent here in Australia preferably in Adelaide??

Cheers,
Reg.

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Aussie spec Brazilian built 2005 (US 2003) SD 4x4 7.3Ltr Powerstroke: PHP FU2 6 Pos’n Chip, 6 x ISSPRO Promax Guages, AIS Intake, Zoodad, Cowl Hood, AIH Delete, DIY CCV, BTM muffler, MBRP 4” Black Tip, RiffRaff FRx,HPx,OCR, JWVB, ARB Air Lockers Front & Rear, V10 Tranny cooler in series with Stock Tranny cooler, Deep Tranny Pan, ARB Bull Bar, Edge Evo (for PIDs & Codes only), Long Range Fuel Tank, VMS in Dash GPS Street & Off Road Nav, Toyo OPAT AT 305 70R 16”on 10” Rims, Moog Greasable Ball Joints, Tough Dog Steering Stabiliser, HD Rear Suspension & Icon Mini Spring pack front for GVWR (GVM) Upgrade to 5,000Kg.
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More than likely it is a connection issue. On the Performax series the gauge will max if it doesn't get a signal from the sensor. If not I can send you another sensor under warranty without a problem.

 

Clay saved the day again.

 

Clay was right onto this issue of mine

He actually called me here in Victor Harbor South Australia and had a yarn to me about the possible cause and give good sound advice.
Who else but Clay would give this level of service

I found no open circuits in the wiring. Confirmed continuity with muti meter etc.
He even suggested that I swap out the Turbo Boost guage to get confirmation on the defect being wiring or sensor; however I've only fitted a 0-30psi Boost guage. So couldn't actually try that.
I can only think it is a sensor fault?

Cheers,
Reg

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Aussie spec Brazilian built 2005 (US 2003) SD 4x4 7.3Ltr Powerstroke: PHP FU2 6 Pos’n Chip, 6 x ISSPRO Promax Guages, AIS Intake, Zoodad, Cowl Hood, AIH Delete, DIY CCV, BTM muffler, MBRP 4” Black Tip, RiffRaff FRx,HPx,OCR, JWVB, ARB Air Lockers Front & Rear, V10 Tranny cooler in series with Stock Tranny cooler, Deep Tranny Pan, ARB Bull Bar, Edge Evo (for PIDs & Codes only), Long Range Fuel Tank, VMS in Dash GPS Street & Off Road Nav, Toyo OPAT AT 305 70R 16”on 10” Rims, Moog Greasable Ball Joints, Tough Dog Steering Stabiliser, HD Rear Suspension & Icon Mini Spring pack front for GVWR (GVM) Upgrade to 5,000Kg.
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While under load and WOT, does the pressure drop at all? If you see 90-95 psi at WOT then I'd say your FPR is stuck.

I have had both issues happen to me. Bad fuel pressure sending unit that ISSPRO replaced immediately...and then about 6 months later a sticking FPR. When the sending unit was bad the pressure gauge was pegged the entire time, even at WOT. When the FPR was sticking, the gauge would read just over 100 psi until I put the engine under hard load, then the pressure would drop down to about 95 psi or so. I rebuilt the FPR with the Guzzle kit and it's been fine since.

Replacement O-rings for Ford Diesel Engines

 

Maybe I've suffered a seniors moment here...duhh!

I missunderstood what Clay was instructing me by phone yesterday about swapping the Fuel Press Guage with the Boost Guage.

I've been looking at it this morning again and realised that he must have meant to unplug the wiring lumes from Fuel Press Sender Unit' and the 'Boost Press Unit' and plug the Fuel Press wire connector onto the Boost Press sender unit and take the truck for a spin and see if the Fuel Press guage reads the Boost press. This would prove if both the Fuel Press guage and it's associated wireing is ok.
This sounds more lodgical?

Well I did just that, and sure enough when I stood on it a bit (not WOT) I got a 15+psi Boost reading on the Fuel Press Guage.

So this is a clear indication that the Fuel Press guage and it's wiring are ok and that the sender unit is indeed faulty


Clay has a replacement on the way as I write

The mans worth his weight in gold++

Good suggestion on a possible sticking FPR. Something for the memory bank

Cheers,
Reg.


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Aussie spec Brazilian built 2005 (US 2003) SD 4x4 7.3Ltr Powerstroke: PHP FU2 6 Pos’n Chip, 6 x ISSPRO Promax Guages, AIS Intake, Zoodad, Cowl Hood, AIH Delete, DIY CCV, BTM muffler, MBRP 4” Black Tip, RiffRaff FRx,HPx,OCR, JWVB, ARB Air Lockers Front & Rear, V10 Tranny cooler in series with Stock Tranny cooler, Deep Tranny Pan, ARB Bull Bar, Edge Evo (for PIDs & Codes only), Long Range Fuel Tank, VMS in Dash GPS Street & Off Road Nav, Toyo OPAT AT 305 70R 16”on 10” Rims, Moog Greasable Ball Joints, Tough Dog Steering Stabiliser, HD Rear Suspension & Icon Mini Spring pack front for GVWR (GVM) Upgrade to 5,000Kg.

 

Yep...it's happened to me. He was very clear in what he was telling me to do. I just didn't "get it" until the next day when my brain wrapped itself around it for a bit, and sure enough, Clay was right on the money with my problem.

I agree...worth his weight in gold! And what I greatly appreciated was the fact he was having me to first test things that would fix the problem WITHOUT causing me to have to buy anything unless absolutely necessary.