fuel pressure shut/off switch

[mrose]

I'm like a lot of guys who has been having fuel pump problems. I was wandering if anyone makes a hobbs switch that would work on the fuel rail that could be wiried to shut the ing. down if a low fuel pressure problem should arise.

I have just finshed a rebuild with serious upgrades and while trying to get my fast system tuned one of the walbros on my new DP set up died. The thought of leaning out scares the hell out of me. Seems like it would be some good insurance!

 

[A2000RICH]

I'm like a lot of guys who has been having fuel pump problems. I was wandering if anyone makes a hobbs switch that would work on the fuel rail that could be wiried to shut the ing. down if a low fuel pressure problem should arise.

I have just finshed a rebuild with serious upgrades and while trying to get my fast system tuned one of the walbros on my new DP set up died. The thought of leaning out scares the hell out of me. Seems like it would be some good insurance!

its a great idea but when you start to build it its pretty complicated because i started to look into this a couple weeks ago----------think about the design goals---------the switch has to be VERY stable and exhibit little hysteresis(this would require something a little more pricey that a normal automotive hobb switch)--------and the really hard part is that it would have to change its set point by tracking the boost (exactly) so the set point would need to change because the fuel pressure changes with boost--------and lastly it would have to respond rather quickly--------i'm working on it but its not quite as simple as it seems-------at least not simple to make an affordable one-------stuff like this is easy if the budget is not so limited by practicality.................RC

 

[mrose]

fuel switch

Richard, keep us posted on your progress.

What kind of money do you think it would take to build it? if you could stay in the 2 to 3 hundred range I thank that would be cheap to save the 13,000 i've got envested in this project so far.

thanks Mike

 

[A2000RICH]

Richard, keep us posted on your progress.

What kind of money do you think it would take to build it? if you could stay in the 2 to 3 hundred range I thank that would be cheap to save the 13,000 i've got envested in this project so far.

thanks Mike

actually i spent a lot of time talking with several of my engineers this weekend about this very subject-------attacking the problem head on is not so simple but when you look at it from a totally different perspective it can actually be done in a practical manner-------this idea could actually enhance the life and reliability of the fuel pump almost degating the need for the device altogether--------i am going to breadboard something up over the Christmas season and see what happens--------stay in touch and if it works i'll give you one of the first ones just for your interest...........RC

 

[mrose]

shut off

Richard; thanks for the reply and help needed to solve and help so many GN owners with the fuel pump problems.

I'm familiar with the PWM (pulse width modulated) fuel systems on late model fords but my engineering skills to make this work with the necessary computer programing is limited to say the least. but its a very workable set-up for the Buick GN. I'm not sure if this was concept you were looking into but I'm very interested in what ever you come up with.
I'll be out of town till after the first of the year so I'll PM you after that.

Thanks Mike Rose

 

[A2000RICH]

Richard; thanks for the reply and help needed to solve and help so many GN owners with the fuel pump problems.

I'm familiar with the PWM (pulse width modulated) fuel systems on late model fords but my engineering skills to make this work with the necessary computer programing is limited to say the least. but its a very workable set-up for the Buick GN. I'm not sure if this was concept you were looking into but I'm very interested in what ever you come up with.
I'll be out of town till after the first of the year so I'll PM you after that.

Thanks Mike Rose

thats exactly what i had in mind--------block off the return line-------monitor the manifold vac/press while servoing the rail pressure by running the pump PWM--------i can easily design and make that-------i believe the pressure could be maintained even more precisely than now and the circuit could either sound an alarm or cut the ign if the pump ever failed to maintain adequate pressure and the pulse width reached 100%..................RC

 

[NCTURBOS]

Why not use a better pump than the current Walbro related issue pump?


K.

 

[A2000RICH]

Why not use a better pump than the current Walbro related issue pump?


K.

thats a great idea----- for now what would that choice be???-------but there is always a better way and i don't have much doubt that this would result in more stable fuel line regulation as well as overall longer pump life------- not to mention always having a safety if/when something goes wrong.............RC

 

[agteacher]

Way-over-my-head!!!!!

thats a great idea----- for now what would that choice be???-------but there is always a better way and i don't have much doubt that this would result in more stable fuel line regulation as well as overall longer pump life------- not to mention always having a safety if/when something goes wrong.............RC

Hey Richard, if you are ever down in MS......stop-by my classroom and "talk-a-while" to/with my students!!!!


MERRY CHRISTmas!!!!

 

[mrose]

thats exactly what i had in mind--------block off the return line-------monitor the manifold vac/press while servoing the rail pressure by running the pump PWM--------i can easily design and make that-------i believe the pressure could be maintained even more precisely than now and the circuit could either sound an alarm or cut the ign if the pump ever failed to maintain adequate pressure and the pulse width reached 100%..................RC

Richard, that would be perfect and for the HP guys you could use the return line for a extra supply line when running the double pumper since no return line would be needed. I'm game for something new this same ol same ol is getting old in my book. Let me know what you come up with, you can e-mail at mrose33293@aol.com

thanks mike

 

[Phoneguy]

thats exactly what i had in mind--------block off the return line-------monitor the manifold vac/press while servoing the rail pressure by running the pump PWM--------i can easily design and make that-------i believe the pressure could be maintained even more precisely than now and the circuit could either sound an alarm or cut the ign if the pump ever failed to maintain adequate pressure and the pulse width reached 100%..................RC

Brilliant. This would be awesome as I just purchased a new stroker motor from RPE and it would be horrible to lose it due to a fuel failure.
I wish I could have made it to your open house.
Subscribed

Bryan

 

[A2000RICH]

Richard, that would be perfect and for the HP guys you could use the return line for a extra supply line when running the double pumper since no return line would be needed. I'm game for something new this same ol same ol is getting old in my book. Let me know what you come up with, you can e-mail at mrose33293@aol.com

thanks mike

i'm working on it------hope to have a prototype breadboarded by weeks end--------anybody want to save me some time and turn me on to a quality pressure transducer that is ok with gasoline ?????..............RC

 

[NCTURBOS]

thats a great idea----- for now what would that choice be???...

I've never had a problem in over 15+ years of using the XP, XP+, or XP+ double-pumper...


K.

 

[A2000RICH]

I've never had a problem in over 15+ years of using the XP, XP+, or XP+ double-pumper...


K.

i haven't either----- i have about a half dozen of them in various cars----some of them go as far back to the original XP that looked like a stock GM pump with the TY-strap around the brush holder right up to the newest that is obviously a modified Walbro and never had a problem------- but for some reason lots of folks don't seem to see that as an alternative-----------for them this could be a solution..............RC

 

[Razor]

i'm working on it------hope to have a prototype breadboarded by weeks end--------anybody want to save me some time and turn me on to a quality pressure transducer that is ok with gasoline ?????..............RC

Rich,
Guess you'll need two transducers. One for fuel and one for vac/boost. Then do a comparator circuit whereby if the tracking changes then you have your issue. These transducers are typically in the 125 range each. And make sure both are the same style. So cost to build the device is in the 300 dollar range.

A cheaper version could be done using a GM 3 bar MAP for the vac/boost. That would cut down on the costs.

I wouldnt cut off ignition, that is dangerous. Alarm is the way.. but this assummes that the person pays attention to the alarm and reacts :/ and maybe ties the output into a solenoid to shut down the wastegate..

HTH

Julio

 

[Razor]

TY-strap around the brush holder

That was the old 307 pump shim trick

 

[Razor]

I'm like a lot of guys who has been having fuel pump problems. I was wandering if anyone makes a hobbs switch that would work on the fuel rail that could be wiried to shut the ing. down if a low fuel pressure problem should arise.

I have just finshed a rebuild with serious upgrades and while trying to get my fast system tuned one of the walbros on my new DP set up died. The thought of leaning out scares the hell out of me. Seems like it would be some good insurance!

If you have an XFI, you can get the "XFI dash" and it has alarms you can setup based on air fuel, or voltage from a sensor(fuel pressure sender)

If you have a classic FAST.. doesnt apply.. but still can add 25% fuel at WOT

 

[agteacher]

i haven't either----- i have about a half dozen of them in various cars----some of them go as far back to the original XP that looked like a stock GM pump with the TY-strap around the brush holder right up to the newest that is obviously a modified Walbro and never had a problem------- but for some reason lots of folks don't seem to see that as an alternative-----------for them this could be a solution..............RC

We bought one from Mr. A, about 2 months ago. NO problems......we are "thinking" about going with another one and DYI a double pumper . New school shop project for the NEW year!!!!

 

[A2000RICH]

Rich,
Guess you'll need two transducers. One for fuel and one for vac/boost. Then do a comparator circuit whereby if the tracking changes then you have your issue. These transducers are typically in the 125 range each. And make sure both are the same style. So cost to build the device is in the 300 dollar range.

A cheaper version could be done using a GM 3 bar MAP for the vac/boost. That would cut down on the costs.

I wouldnt cut off ignition, that is dangerous. Alarm is the way.. but this assummes that the person pays attention to the alarm and reacts :/ and maybe ties the output into a solenoid to shut down the wastegate..

HTH

Julio

the 3 bar map would be ok to monitor the manifold pressure but buying it from an automotive source really makes the cost too high---------300 dollars for sensors kind of puts this in the stratosphere--------i need to find an industrial source and buy them directly-------- something safe for gasoline to at least 100 PSI to monitor line pressure???--------i'm sure i can find something from an industrial source ----i just thought someone might know something offhand............RC

 

[Razor]

the 3 bar map would be ok to monitor the manifold pressure but buying it from an automotive source really makes the cost too high---------300 dollars for sensors kind of puts this in the stratosphere--------i need to find an industrial source and buy them directly-------- something safe for gasoline to at least 100 PSI to monitor line pressure???--------i'm sure i can find something from an industrial source ----i just thought someone might know something offhand............RC

Pretty much any of the SS transducers by Serta, Honeywell, etc will be fine. I have never been able to source an inexpensive transducer. If you come across a MFG, let me know.

I have on occassion through Ebay gotten my hands on a few.. but the issue is not one or two, but to be able and get quantities. Closeouts are very limited.. and once you do scaling, changing the transducer.. will need rescaling.

FWIW, Autometer use to sell an inexpensive fuel pressure guage using an oil pressure sending unit. The problem was over time the senders developed a leak cuasing a recall on the product. The new guages use the transducer style senders, but the cost of the guage went from 70 to over 200

I run the same issue looking for a transducer for methanol.. there is no cheap... for the same safety reasons.

Happy New Year

Julio