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-   -   Why You Need A Fuel Pressure Gauge On The Dash (https://www.rx7club.com/single-turbo-rx-7s-23/why-you-need-fuel-pressure-gauge-dash-1020761/)

cewrx7r1 12-20-12 02:35 PM


Originally Posted by CrispyRX7 (Post 11322398)
Chuck,
Great thread. But I need to correct you. Back in 1999 we also had the infamous PFS Purple Peter Motor Eater.

I had one of those before the PFC came out. One day it gave total fuel cut under boost while in the learning mode in third gear. Scared the shit out of me. Then I bought a reprogrammed ecu.

cewrx7r1 12-20-12 02:39 PM


Originally Posted by tom94RX-7 (Post 11322370)
I was gonna say the same thing, especially with 500+ HP, It's dangerous unless in 4th gear on a wide open highway late at night, That's why I would datalog almost every pull on the street.

For normal dayly driving you are not going to log all the time.
A quick glance once in a while why accelerating is what I have been talking about, not tuning. Because most likely this type of failure will happen when you are not tuning.

tom94RX-7 12-20-12 02:43 PM

And watch the wideband at the same time haha

JhnRx7 12-20-12 04:41 PM


Originally Posted by cewrx7r1 (Post 11322544)
For normal dayly driving you are not going to log all the time.
A quick glance once in a while why accelerating is what I have been talking about, not tuning. Because most likely this type of failure will happen when you are not tuning.

This brings us back to ECU's that are not from 1999. My current ECU has internal logging. I have it setup for conditional loop logging. It automatically starts logging every time throttle is greater than 60% (or any variable you like). The loop logging allows the ECU to re-write over itself until I decide to pull a log. So if I do a pull and notice something wrong I always have the data.

I honestly don't know why so many people stick with the PFC for cars other then sequential cars.

cewrx7r1 12-20-12 05:42 PM

If I was still working instead of being retired with a limited budget, I would replace the PFC. But after 20 years of FD ownership, 13 years of PFC without any problems,
you can say "Chuck is stuck in a rut.". So be it, but my car is better overall than most FDs are.

RCCAZ 1 12-20-12 06:46 PM


Originally Posted by cewrx7r1 (Post 11322695)
If I was still working instead of being retired with a limited budget, I would replace the PFC. But after 20 years of FD ownership, 13 years of PFC without any problems,
you can say "Chuck is stuck in a rut.". So be it, but my car is better overall than most FDs are.

Wow.... so you've been running your current motor for 13 years. How many miles does that equate to Chuck? Has it been trouble free this entire time, or has data logging saved your bacon a few times?

Rob XX 7 12-20-12 08:31 PM


Originally Posted by cewrx7r1 (Post 11322539)
Then by your reasoning only stock gauges are good and all others such as boost are useless. It depends on the location.

Center speaker location which still allows forward level sight.
Maybe some of us have faster eyes/brains.


Originally Posted by cewrx7r1 (Post 11322544)
A quick glance once in a while why accelerating is what I have been talking about, not tuning. Because most likely this type of failure will happen when you are not tuning.

Make up your mind, is it once in a while while accelerating or is it while at full boost?
I said WHILE AT FULL BOOST who can look at everything at the same time.
Of course you can look at anything "once in a while" while at your leisure, at full boost im making sure i shift and i dont crash . Once in a while while accelerating i look at a lot of things

gxl90rx7 12-21-12 07:42 AM

the fuel pressure gauge only verifies your fuel pump, lines, and regulator. A wideband gauge verifies all that and more.. injectors, map sensor, tune, vacuum leaks, etc.

i would rather look at a single gauge that monitors the final product (exhaust AFR). fuel pressure is something you would use for troubleshooting if something went wrong, not as your first indicator. it leaves out a lot of information a wideband can provide

cewrx7r1 12-21-12 04:42 PM


Originally Posted by RCCAZ 1 (Post 11322730)
Wow.... so you've been running your current motor for 13 years. How many miles does that equate to Chuck? Has it been trouble free this entire time, or has data logging saved your bacon a few times?

Just a tad over 50100 miles at 350+ whp untill 2005 when i went single to about 400+ whp.

Here is my recent compressions test done with a calibrated electronic tester.
Front Leading Spark Plug: 129.04/125.39/124.17
Rear Leading Spark Plug: 125.39/121.74/121.74

Engine built by me but rotating parts balanced by Mazda Trix.

cewrx7r1 12-21-12 04:55 PM


Originally Posted by Rob XX 7 (Post 11322807)
Make up your mind, is it once in a while while accelerating or is it while at full boost?
I said WHILE AT FULL BOOST who can look at everything at the same time.
Of course you can look at anything "once in a while" while at your leisure, at full boost im making sure i shift and i dont crash . Once in a while while accelerating i look at a lot of things


The problem is that different cars react differently.

My home built balanced engine with stock ports but port matched and enlarged port runners, port matched manifolds, moded TB, full supporting mods,
etc with an A-Spec GT35R 1.06 kit will hit full boost before 4000 rpm even at 17 psi boost. It also has WI.

Even when I floor the throttle in 2nd or 3rd gear it will hit full boost by 3600 - 4000rpms and hold boost flat all the way to redline.
Thus my max boost is the same as acceleration.
What is so difficult to understand about that?
It was above 6000 rpm that fuel pressure was dropping off.


Can you handle that?

Rob XX 7 12-21-12 07:23 PM

Relax man all i was saying was at full boost who can look at all that, was just making a comment talking about the subject i didnt say your idea was bad or to explain everything. I didnt talk shit to you but You are the one who is saying your eyes and brain are faster which obviously implies i am slow.

Merry christmas to you

Howard Coleman 12-26-12 08:28 AM

"Here is a screen shot of what the engine protection looks like. The reason it is red is because Haltech knows that I do not have a fuel pressure input selected so my settings would be useless here. You can see on the right as C.ludwig mentioned the fuel pressure works off of delta pressure not overall fuel pressure."

post ten caught my eye. in a (more) perfect world the ECU would sense a separation of the fuel pressure from the boost pressure and immediately make an engine saving adjustment.

that's just what post ten is about. very impressive, good job Haltech.

i checked w ViPEC and they alerted me to a parameter entitled "Differential Fuel Pressure."

you simply select it, enter whatever differential pressure value you wish and the computer will react if triggered by switching to another 440 cell ignition map, fuel map or open the WG.

a valuable feature.

howard


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