Print Page - Low Fuel Pressure? Jerky?

Title: Low Fuel Pressure? Jerky?
Post by: jasonlel on February 10, 2006, 01:51:05 PM

Hey guys,

I\'m experience jerky feeling when ever I get positive boost. I\'m very sure is not the ON boost jerk coz it jerk a few times during 0.1 - 0.3. So I did a fuel pressure test and the results is 24psi on idle which is way too low. So I just changed to a new walbro(341) fuel pump and I\'m getting 30/31psi on idle. But I\'m still experiencing jerks during positive boost. Any idea? Fuel filter just change few mths back.

Some extra information
Exhaust temp, degree celsius
On idle: 400
Normal driving:500-600
Hard Drive:>600 ~ <650

Title: Low Fuel Pressure? Jerky?
Post by: rx7veilside on February 10, 2006, 03:13:55 PM

not positive but idle fuel pressure with vac pipe attatched shd be about 3 bar roughly 40psi

Title: Low Fuel Pressure? Jerky?
Post by: jasonlel on February 10, 2006, 05:08:53 PM

So I\'m getting about 30/31psi with a new fuel pump. Could it be the voltage supply to the fuel pump aint sufficient? Or my stock fuel pressure aint working?

Quote from: rx7veilsidenot positive but idle fuel pressure with vac pipe attatched shd be about 3 bar roughly 40psi

Title: Low Fuel Pressure? Jerky?
Post by: Adam on February 10, 2006, 09:02:35 PM

Is this happening when you put your foot down mate???? how much fuel have you got in your tank?

Adam

Title: Low Fuel Pressure? Jerky?
Post by: FD3SNuttah on February 10, 2006, 09:48:25 PM

id get a multi meter and check what voltage you see on the fuel pump? most people check that before buying a pump. still a worthy mod tho!

Title: Low Fuel Pressure? Jerky?
Post by: jasonlel on February 10, 2006, 10:24:45 PM

Yea, going to do just that.... What can I do if the voltage is low?

Quote from: TURBOIINUTTAHid get a multi meter and check what voltage you see on the fuel pump? most people check that before buying a pump. still a worthy mod tho!

Title: Fuel Pump Resistor :(
Post by: jasonlel on February 11, 2006, 10:26:10 AM

At last, my problem solved.

Did a check at fuel pump wiring voltage. Everything is oke. Last resort was to look at the fuel pump resistor. We are not sure how to check if the resistor is in perfect working condition, so we switch to another resistor. But it didn\'t solve the problem. So out of curiosity, I did a voltage check on the wire connecting to the resistor. I\'m getting about 10v+/-. So I guess this is the culprit. It is not powering enought voltage to the fuel pump resistor.

So I by pass the fuel pump resistor and rewire the fuel pump to get 12v from batt source with a relay.

Violaaaaa, problem solved!!!!

*Solving this problem, I too solved another problem at the same time. See link ->http://www.mazdarotaryclub.com/forums/showthread.php?t=22057

Mazda Rotary Club

General => General Technical => Topic started by: jasonlel on February 10, 2006, 01:51:05 PM