Fuel pump circuit
Moderators: jsmcortina, muythaibxr
-
- Super MS/Extra'er
- Posts: 17499
- Joined: Thu Apr 16, 2009 8:08 pm
Re: Fuel pump circuit
If you desolder R19, does the PMP light go off?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: Fuel pump circuit
Here are some pics. I will take out R19 and see what happens
Re: Fuel pump circuit
I removed one side of R19 and PMP is still lit up. Whats next?
-
- Site Admin
- Posts: 39587
- Joined: Mon May 03, 2004 1:34 am
- Location: Birmingham, UK
- Contact:
Re: Fuel pump circuit
Sounds like you have a short-circuit on the transistors.
James
James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
Re: Fuel pump circuit
Q14, Q15, Q20 are showing continuity between 2 legs. All other transistors test ok.
-
- Super MS/Extra'er
- Posts: 2188
- Joined: Sun Aug 31, 2008 4:02 pm
- Location: South Florida, USA
- Contact:
Re: Fuel pump circuit
The "continuity" (actually an ohm or less) is normal. What about Q2? A short between pins 1 and 3 would cause the symptom you're describing.ur2slo wrote:Q14, Q15, Q20 are showing continuity between 2 legs. All other transistors test ok.
Re: Fuel pump circuit
Okay, Im getting 5V coming into R16 when injectors are firing from stim. What should I be getting at FP1? What are the specs of D4?Matt Cramer wrote:Ok, here's the relevant schematic:
First, put it on the Stim and check if there's 5 volts coming into R16 (that's the turn on signal).
-
- Super MS/Extra'er
- Posts: 2188
- Joined: Sun Aug 31, 2008 4:02 pm
- Location: South Florida, USA
- Contact:
Re: Fuel pump circuit
Q2 is switching the connection to ground, so you won't measure any voltage at FP1. D4 is 22V/1W Zener diode. It shouldn't be damaged, but if it is, the fuel pump will remain on indefinitely.ur2slo wrote:Okay, Im getting 5V coming into R16 when injectors are firing from stim. What should I be getting at FP1? What are the specs of D4?
Re: Fuel pump circuit
Im getting 5V at FP1
-
- Super MS/Extra'er
- Posts: 2188
- Joined: Sun Aug 31, 2008 4:02 pm
- Location: South Florida, USA
- Contact:
Re: Fuel pump circuit
With the fuel pump relay connected?ur2slo wrote:Im getting 5V at FP1
Re: Fuel pump circuit
No, that is just with the stim connected.
-
- Super MS/Extra'er
- Posts: 2188
- Joined: Sun Aug 31, 2008 4:02 pm
- Location: South Florida, USA
- Contact:
Re: Fuel pump circuit
Could you repeat this test, but with R16? R19 is for the FIDLE circuit, not the fuel pump relay circuit.ur2slo wrote:I removed one side of R19 and PMP is still lit up. Whats next?
Re: Fuel pump circuit
Hello guys,
I have the same problem with my fuel pump circuit. I measured the voltage at R16 which is 4.85 volt on both sides. I checked R40 which is 1 ohm.
I have no sim and ECU is in a running car. Problem is that for now fuel pump is always on when car is on ignition and i would love to fix it.
Any more checks i can do?
I have the same problem with my fuel pump circuit. I measured the voltage at R16 which is 4.85 volt on both sides. I checked R40 which is 1 ohm.
I have no sim and ECU is in a running car. Problem is that for now fuel pump is always on when car is on ignition and i would love to fix it.
Any more checks i can do?
Re: Fuel pump circuit
I believe the original poster's issue was that his FP wouldn't turn ON; you say yours won't turn OFF. From one of the posts above:Red_bull wrote:I have the same problem with my fuel pump circuit.
I have no sim and ECU is in a running car. Problem is that for now fuel pump is always on when car is on ignition and i would love to fix it.
Remove your D4. If that solves the problem, you need a new one. If it doesn't, check your wiring; make sure the pump is fed from the relay OUT pins, not the IN pin(s).SymTech Laboratories wrote:D4 is 22V/1W Zener diode. It shouldn't be damaged, but if it is, the fuel pump will remain on indefinitely.
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
Re: Fuel pump circuit
Remove the daughter card and check again. If the pump still runs continually, likely a problem in the wiring or driver circuit. If not, a problem with software or the daughter card.Red_bull wrote:Hello guys,
I have the same problem with my fuel pump circuit. I measured the voltage at R16 which is 4.85 volt on both sides. I checked R40 which is 1 ohm.
I have no sim and ECU is in a running car. Problem is that for now fuel pump is always on when car is on ignition and i would love to fix it.
Any more checks i can do?
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
London UK.
MS2 V3
EDIS
Tech Edge O2
London UK.
Re: Fuel pump circuit
Ok now i see my post was a bit messy (sorry i was mega hangover yesterday)
- Pin 37 does not go to ground, but has 5 volt on it when the engine is running (like the first post of the original topic)
- Pin 37 stays as zero when i put ignition on and only comes up when engine is started. No short periode of voltage
- Currently i have the relay switched on ignition and not connected to the megasquirt
Thanks for the reply guys. Do the tips stay the same?
- Pin 37 does not go to ground, but has 5 volt on it when the engine is running (like the first post of the original topic)
- Pin 37 stays as zero when i put ignition on and only comes up when engine is started. No short periode of voltage
- Currently i have the relay switched on ignition and not connected to the megasquirt
Thanks for the reply guys. Do the tips stay the same?
Re: Fuel pump circuit
Yes; do Dave's check first.
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
Re: Fuel pump circuit
But i get the 5 volt when the engine runs. So if i remove the daughterboard i won't be able to start the car.
Is removing D4 the way to go?
Is removing D4 the way to go?
Re: Fuel pump circuit
Pull the daughtercard; do you still have the same malfunction?
THEN pull D4.
THEN pull D4.
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems