Fuel Pressure Sensor suggestions

[Cameron]

Hi,

I am unfortunately still chasing my tail on my EFI install and the piece of data I do not have is a reading for fuel pressure.  (the rv still randomly dies and I am not sure if it is fuel going away or something else - but I need to eliminate the fuel going away).

I have tried twice to install a FPS and both failed.  the first one was undoubtedly my fault.  I tried to run 12v power to a 5v sensor which obviously didnt work well.  the second time I bought a 5v step down and a similar sensor to the one I had before.  I started the RV, seemed like it was working correctly then the pressure eventually went to 0 and it never reported again.

both times I just bought a 30psi sensor off amazon that were really fairly reasonable in price (want to say under $20).

at this point, I would love someone to just suggest a combo of stepdown and sensor that should be a 'known good' and take my decision making out of the mix.

suggestions greatly appreciated.

Cameron

[Bruce Hislop]

I have an Auto meter fuel pressure sensor which I installed over 10 years ago.  I used the 5 volt source from the EBL ECM which also powers the MAP and TPS sensors.  I think it was a lot more than $20, more like $100 back then.

Bruce Hislop

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[Bill Van Vlack]

I bought one from Ebay, but this one from Amazon should work:  I bought this 5v supply, also from Amazon.

I bought a separate power supply because I wanted to add more analog points and didn't want to risk hosing the EBL ECM.

You should be able to test the FP sensor by piping it to a regulated air supply, connecting to your 5V supply, and measuring the output voltage.

Fuel Pressure Sensor Specifications:
Material: Stainless Steel
Voltage: 5V
Pressure: 30 psi
Thread Type: 1/8" NPT
Input: 0-30 psi
Output: 0.5V~4.5V linear voltage output. 0 psi outputs 0.5V, 15psi outputs 2.5V, 30 psi outputs 4.5V.
Accuracy: within 2% of reading (full scale).
Thread: 1/8"-27 NPT.
Wiring Connector: Water sealed quick disconnect. Mating connector is included.
Wiring: Red for +5V; Black for ground; Blue for signal output.

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[Cameron]

since those items look indistinguishably similar to the ones I purchased, I am going to try and rig up a test before buying again..

my sensor is just on a T in a straight section of the fuel line.  so, just a 3/8, 1/8, 3/8 brass fitting.  is there some other way I was supposed to mount the pressure sensor?

thanks!

Cameron

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[Bruce Hislop]

Mine is just "T'd" in on the high pressure side as well.

Bruce Hislop

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[Cameron]

hey Bruce, thanks.

when you say 'high pressure side', I assume you mean on the 'bottom leg' of the T?

fuel in------T------fuel out

             |

         FPS sensor

(hopefully my ascii art stayed formatted correctly)

Cameron

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[BruceHislop]

I was referring to the high pressure side of the throttle body (TB) (aka, the input side). The return side of the TB has very a low pressure and we don't really care what that pressure is.

Your diagram of the "T" is correct putting the fuel pressure sensor on the side of the T.

Bruce Hislop

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[James Hupy]

I would caution you, if you are going th make this installation permanent to NOT USE FLEXIBLE HOSE for your commections. I use armoured lines myself. Or, all metal fittings with Gates ethanol resistant lined hose barb fittings with clamps intended for fuel injection high pressure lines. Just what I do.
Jim Hupy
Salem, Oregon

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[BruceHislop]

Jim,
What do you suggest for flexible fuel line jumper hoses between the frame, body and engine (throttle body).

I'm currently using Gates barrier hose (some 30R9 and some 30R14).  I would like to use something more heat resistant where it gets closer to the exhaust and engine heat.

Bruce Hislop

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[Jon Roche]

I would like to see a photo.  

On my install the fuel ports on the tbi pointed downward toward intake.  Was going to be very difficult to use anything but flexible rubber fuel lines.     I have seen some use AN fittings but I am not a big fan of those because they are not easy obtained locally.  

I have metal fuel lines run up to the rear

Firewall.   But then I transition to rubber.  They are ethonal rated EFI rubber fuel line, and if I remember was kinda spendy.   

The good thing is it is all right in your face when ever I open the hatch any issue or deterioration I would see right away.  Hoses are also well away frome exhaust or heat. 

I spent lots of time trying to stay away from rubber lines on this…. But just could not solve the issue of those bends at the tbi and getting things to line up/remove.  

One other reason though for a gm based rochester.  Pressure is only 12psi.    But I guess if it does rupture there would be more flow since it is no longer regulated…

On Jun 18, 2024, at 9:59 AM, James Hupy <james...@gmail.com> wrote:



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[Bill Van Vlack]

I have a fuel pressure sender hard-piped to the Rochester TBI, then this flexible, ss-braided, PFTE kit from there back to the tee that combines pump outputs for each tank.

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[James Hupy]

Gates "BARRICADE" for fuel injection. It is rated for 60psi+. I use the high temperature teflon sleeve material slipped over the hose and secure it in place with metal ty-wraps on each end. I get mine from a friend who has a performance speed shop. Another is Aircraft Spruce in Florida.
Jim Hupy
Salem. Oregon. P.S. also good on speedometer cables near headers.

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[Cameron]

hey Bill,

how important is the amperage of the 12v to 5v stepdown?  the one you have linked above lists a 5 amp output;

DROK® Waterproof Voltage Regulator, 9-35V to 5V 5A DC to DC Buck Converter

but it is out of stock.  any others I am finding look to have a 3A output.

thanks!

Cameron

On Sat, Jun 15, 2024 at 6:34 PM Bill Van Vlack <bill.va...@gmail.com> wrote:

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[bc...@juno.com]

Hope this works, here is my sensor on a carb. EFI similar.
Bruce Roe

[Bill Van Vlack]

Cameron,

 A 3A, 5V power supply should be plenty for any/all sensors you'd ever connect to the EBL ADC inputs.

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[Cameron]

ok, doing some testing.

I have a 30psi sensor that ranges from .5 to 4.5 volts.

I took the sensor off the vehicle and hooked up to a 5v step down and the sensor and saw that it had the expected .5 v current with no pressure.  I then put back on the vehicle and turned on the ignition and still had the .5v.  I then started the engine and on the WUD the pressure went to ~2.1 psi.  I had left the wires exposed on the sensor and tested at the sensor and saw it had .668v.

so, I want to think the sensor is correct and the WUD is correct.  so, the remaining question is - can this thing really run on ~2psi??

thanks!

Cameron

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[Keith V]

It's probably not really 2 psi.

I'd put a known good gauge on it and see what really happening.

That why I have a pressure sensor AND a fuel pressure port on my system!

---

From: gmcm...@googlegroups.com <gmcm...@googlegroups.com> on behalf of Cameron <cbi...@gmail.com>
Sent: Thursday, June 27, 2024 2:56 PM
To: gmcm...@googlegroups.com <gmcm...@googlegroups.com>
Subject: Re: [GMCMH-EFI] Fuel Pressure Sensor suggestions

 

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[Cameron]

thanks Keith,

yeah, I was able to use a local shop's loaner program and found the expected pressure..  not sure why I cant get the darn fps to work..

I dont think this is my issue, but when I mounted the fps, I bought a 3/8 T then reduced one of the 3/8's port's to the 1/8th nps fitting.  that shouldnt be a concern right?  fuel should just fill the cavity and the sensor should read it, right?  or is being slightly out of the flow of the fuel reducing my accuracy?

thanks!

Cameron

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[Keith V]

I think it's a bad sensor.

No The adapter is fine, there is zero flow so no loss of pressure

---

From: gmcm...@googlegroups.com <gmcm...@googlegroups.com> on behalf of Cameron <cbi...@gmail.com>

Sent: Monday, July 1, 2024 10:38 AM

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[Bill Van Vlack]

You said that the 'loaner program' found the 'expected pressure'. Not sure what that means....

But perhaps supplying the original sensor with 12V and then connecting it to the ADC fried the ADC channel.  Have you tried a different ADC channel?

Bill

[Cameron]

hey Bill, 

around 12lbs is the expected pressure for the pumps I have.

yeah, it is a different adc channel. I (believe) the WB sensor is working fine, so I dont think the whole bank is shot..

I have a new sensor I will try to put in and see if it works.  there really is no reason for the one I am using to be damaged though..

thanks for the inputs, they are appreciated!

Cameron

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[Bill Van Vlack]

Can you use air pressure and a regulator or tap water, a shutoff valve, and pressure gauge - along with a voltmeter - to test the output?

Volts	0-30
.5 to 4.5	psi
0.488	-0.09
0.586	0.64
0.684	1.38
0.781	2.11
0.879	2.84
0.977	3.57
1.074	4.31
1.172	5.04
1.270	5.77
1.367	6.50
1.465	7.24
1.563	7.97
1.660	8.70
1.758	9.43
1.855	10.17
1.953	10.90
2.051	11.63
2.148	12.36
2.246	13.10
2.344	13.83
2.441	14.56
2.539	15.29
2.637	16.03
2.734	16.76
2.832	17.49
2.930	18.22
3.027	18.96
3.125	19.69
3.223	20.42

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[Cameron]

Yeah, I just ran out of time this weekend, hoping to get too many things done before taking the rv to do some actual rv’ing!

I’ll report back in a few weeks, when I get back to the vehicle.

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[Tony Cockshutt]

About a month ago I installed a ridiculously expensive Fuel Tech 0-30psi sensor.  Voila!  Since then I've had consistent fuel pressure of 12.5-13psi.  I've driven the coach about 2500 miles and the pressure reading has been correct for the whole time.  

So, my two cheap fuel sensors were expensive garbage.  I know other folks have had success with the inexpensive ones, but both of mine followed the same life cycle.  Started correct and then became intermittently correct, followed by totally and consistently incorrect.  One failed high and the other failed low. I purchased both sensors on Ebay from different sellers.

[Cameron]

Hey Tony,

Wanted to just add to your findings here.  I also broke down and bought a fuel tech sensor and now also have a working fuel pressure sensor.

I have an unopened order of the ‘cheap Chinese model’ if anybody wants it!  

Cameron

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[Paul Ferrigno Jr]

I've finally got a few longer drives under my belt with a cheap Chinese 0-30psi sensor too.  My Winlog gauge is set up to go from 0-30 as well.  The FPS seems to cut out after a certain period of driving, and does not ever recover.  Sometimes I'm left with a permanent reading of 0 psi, sometimes I'm left with the gauge railed at 30 psi. In either case, it sticks for the remainder of the drive.  I've checked it in the WUD, and see the same results.  I'm blaming the cheap sensor, currently.  In the interest of being completely thorough, I'm planning to set up a voltage divider on the end of my sensor connector with a couple 10k resistors that should just set the voltage to 2.5V, and the pressure to 15psi.  I'll do a long drive like that to make sure it isn't SW or ADC related.  

But, I may be in the market for a new FPS. 

Paul (PVFJR)

[Bruce Hislop]

One thing I learned with EFI is the fuel pressure is not smooth and constant.  The injectors opening and closing makes the fuel pressure jitter. Mechanical gauges fail in short order and the internal expansion tube in the gauge have been known to rupture and leak fuel.

A good quality sensor is required to stand up to the "jitter" in this application.

Bruce Hislop

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[gbec...@graestone.org]

Paul,

I see you are using Winlog. Do you happen to know where Winlog saves the Trip information upon exit?

Thanks in advance.

On Nov 18, 2024, at 1:27 PM, Paul Ferrigno Jr <pvf...@gmail.com> wrote:

My Winlog gauge is set up to go from 0-30 as well.

---------

Best Wishes,

George
gbec...@graestone.org

[Bill Van Vlack]

Winlog stores the trip data in the datalog. First, make sure the device is set to be logged:

Select View>Device Configuration, then pull down Dynamic EFI-EBL to find the point to log

 

Then select 'Settings' and check the "Log this field' box.

The location of the datalog is set at 'View>Log Configuration'

To see the values in Excel, you can make a copy of the Log and set the extension to ".csv", then open that file in Excel.

Or, you can view the data in WinLogView by selecting the ".txt" file.

Let me know if you need more info.

Bill

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[Cameron]

Hey Bill,

So, I have been using the datalog function of WUD.  Are you saying to use winlog instead?  I have always just used winlog to view the output of the datalog from WUD..

When I look at the configure logging of winlog, the only com port it gives is com1, my WUD works on com5.  Is there some way to provide more com ports to winlog should that be the better logging option?

Thanks!

Cameron

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[Bill Van Vlack]

Hi Cameron;

 The WUD and WinLog datalogs record many of the same parameters, but both have ones that are unique. WUD records the flags (fan, closed loop for example). WL records the ADC points and the trip meter parameters. I record both and combine them on a spreadsheet and look at them using WinLogView, mostly. The flags have to be changed from 'Y'/'N' to '1'/'0' for WinLogView.

You don't need an additional com port to capture a datalog for WInLog; any parameter that is checked for logging will be logged. I assume you have a serial cable splitter and serial-to-usb cables or adapters to utilize a com port for each program/datalog. That's what I did for a while.

If you're short on physical ports or want just one cable to the laptop, you can use a virtual com port program, Eterlogic, that reads the WUD com port and offers a new virtual port to which both programs can be assigned.  https://eterlogic.com/products.vspe.html

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[Cameron]

Hey Bill,

The EBL came with a usb connection, so it was just a matter of experimenting on com ports before I found the one that fed the WUD.

My question/confusion was in the setup of winlog.  I went into configure logging and there was nothing there, so I added “Dynamic EFI - EBL”.  With that there was a ‘configuration’ option.  That asked for a com port, but all that was available was com1.

Would your suggestion be to use ether logic to split com5 to com1 to feed winlog?  Or am I doing something wrong in winlog??

Thanks!

Cameron

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[Bill Van Vlack]

Are you trying to run WUD and WinLog at the same time? Does the laptop have two open USB ports? If so, and If you have the version of EBL that has a serial connector, you can get a serial splitter and another serial/usb adapter/cable. If you have the later version that just has the phone jack and an adapter cord to USB, you will have to use the software to create virtual points.

If you want to test/run WinLog alone, I think that once you plug in the USB with the ignition on, WL should be able to find the live port and display it as an option on the screen you show.

You can troubleshoot/configure with Device Manager on Windows. If DM doesn't show 'Ports', here's how to make them show:
https://answers.microsoft.com/en-us/windows/forum/all/how-to-identify-com-ports-in-windows10/2591ed8b-805e-4e66-9513-836cdd49ed80

Also, you can ask Google "how does windows assign com port numbers?" for a little more info.

Let me know how you make out.

Bill

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[Keith V]

For what it's worth no EBL has an RS232 output, they all have 5v serial that is converted to RS232 or USB.

Also if you want to split a serial signal a y adapter is a bad idea, it kinda works...

A better choice is a software tool called Com0Com, it can do that. ( and it's free )

Just the opinion of an old software developer

---

From: gmcm...@googlegroups.com <gmcm...@googlegroups.com> on behalf of Bill Van Vlack <bill.va...@gmail.com>
Sent: Thursday, November 21, 2024 5:59 PM

To: gmcm...@googlegroups.com <gmcm...@googlegroups.com>
Subject: Re: [GMCMH-EFI] Fuel Pressure Sensor suggestions

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[Bill Van Vlack]

In my ignorance, I plugged a serial splitter cable assembly into the serial connector that came with my EBL and then plugged two Serial-to-USB cables into the PC to be able to run WL and WUD at the same time. Seemed to work great. I switched to a laptop that only had one available USB port and tried to get com0com to work without success, so I bought the ~$30.00 Enterlogic software - I'm old as well, but it's the software developer part that's amateur at best.

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[James Hupy]

I have been following this thread with a good bit of interest. But, after working on several dozen GMC's with various versions of fuel injection systems, i have only had one coach that gave me fits. It was problems I caused by modifying the engine extensively. The original system without EBL was a literal bi$%# to tune. I had 4 bin files burned by a friend that didn't work as well as I (and the coach owner) liked. So Randy V. was on a road trip, stopped in here for a week and helped me swap out the Original Howell system for an EBL. We updated the bin files and finally got the thing to run without bogging off idle, and going lean at full throttle. I didn't use any software stuff that required special cables other than what Bob R. supplied with the EBL. Didn't see any need for all those printouts or special tables. Keep the fuel/air ratios near the rich side throughout the entire range as a good starting point. Fuel economy? Forgetaboutit. 12,000 pound vehicles with large displacement internal combustion engines are lucky to get 8 mpg on Ethanol laced gasoline. If it starts well, takes throttle without hesitation, and doesn't diesel when you turn off the key, leave the tune-up alone. Get in the drivers seat, look at all America offers through those wraparound windshields, and enjoy yourself.

Jim Hupy

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[Keith V]

Ignorance is bliss they say. Splitters work when they work, good ones work great, some not so great!

---

From: gmcm...@googlegroups.com <gmcm...@googlegroups.com> on behalf of Bill Van Vlack <bill.va...@gmail.com>

Sent: Friday, November 22, 2024 4:06 PM

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