Fuel pump channel not grounding.

tom70 · July 29, 2008, 07:47:34 PM

I have problem with my corolla today, I won't bloody start.

So first thing check if the ECU is still alive, it is but the TPS is between 15% and 75% @ off/on throttle (maybe just out of calibration for long time)

Anyway, I hear no fuel pump running so I went on checking the fuel pump relay. Relay is fine (checked by grounding the switch) and fuel pump (checked) is in good health, relay to P259 channel 5 wire (continuety checked).

I have also checked the fuel pump channel on Megatune is the correct one, so it lead me to believe the vems is not grounding it.

Any ideas how to fix it?

tom70 · July 29, 2008, 08:11:35 PM

I have rewire the fuel pump relay channel to P259 channel 1, updated on the Megatune. Still no joy. ??? ???

[email protected] · July 29, 2008, 08:34:42 PM

First off theres something amiss if the TPS has gone out of calibration, unless the TPS is faulty.
Are you still getting a cranking RPM?
Try setting the P259 to channel i5, this will invert the channel so that its on when the car is not cranking.
What wires have you got free on following EC36 pins:

6, 7, 8, 9, 17, 18, 19, 20
or 33 to 35

tom70 · July 30, 2008, 12:34:04 PM

cheers for the reply Rob,

There is no cranking RPM, does register voltage drop during cranking.
Water and air temp at 24deg in a hot day?..mid day?

Tried invert to i5, pump is still not working when it's not cranking.

Wire free on EC36 are: 9 and 35

It was working (driven for 2miles) 10mins before I unplug and replug the vems into the car. I don't think I pulled any wire out since I pay extra caution by pulling the plug head only.

MWfire · July 30, 2008, 02:15:06 PM

p259 is dead.
This happend when analog ground isn't connected to power ground.

tom70 · July 30, 2008, 02:27:53 PM

I think there is more to it since the cranking RPM is not registering as well.

MWfire · July 30, 2008, 02:30:40 PM

When p259 is dead and use vr sensor there is no rpm.
There is many topic related to dead p259 on this forum.

tom70 · July 30, 2008, 02:33:34 PM

Cheers, I got you now.

Let me do a search how to fix it before I ask silly question.

[email protected] · July 30, 2008, 03:12:26 PM

The search you'll find will show you removal of a surface mount component...
The cause of the problem is that the ground cluster's wiring has been compramised :(

Rob

tom70 · July 30, 2008, 03:20:29 PM

Quote from: [email protected] on July 30, 2008, 03:12:26 PM
The cause of the problem is that the ground cluster's wiring has been compramised :(

Sorry, I don't understand technical terms here. Do you mean there some ground wire is not grounding properly?

[email protected] · July 30, 2008, 06:08:28 PM

Its vital that the wire on EC36-pin26 is connected to all the other ground wires at a single point. If 26 becomes disconnected the p259 dies. I've written an explaination of the grounding rules here:
http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide

My concern is that your car has been running for a while quite happily, and suddenly this has happened - which suggests that the wiring has been damaged in some way.

Rob

tom70 · July 31, 2008, 06:33:30 PM

Good and bad news, managed to get the car running by knocking one of the p259 pin out and hard wire the fuel pump.

TPS is wierd though, when I'm on 0min and 255max setting, dial is showing 10% - 75%. TPS wizard is seeing 26min 202max

so I switch to 26min 202max on basic setting, dial is showing 0% - 100%. TPS wizard is seeing 0min 255max.

again, I switch back to 0min 255max, dial is showing 10% - 75%. TPS wizard is seeing 26min 202max....vice versa...

Not the biggest concern, just doesn't make sense.

MWfire · July 31, 2008, 06:41:54 PM

Quote from: tom70 on July 31, 2008, 06:33:30 PM
TPS is wierd though, when I'm on 0min and 255max setting, dial is showing 10% - 75%. TPS wizard is seeing 26min 202max

so I switch to 26min 202max on basic setting, dial is showing 0% - 100%. TPS wizard is seeing 0min 255max.

again, I switch back to 0min 255max, dial is showing 10% - 75%. TPS wizard is seeing 26min 202max....vice versa...

Not the biggest concern, just doesn't make sense.

This is normal.

Clio-wizard · October 14, 2008, 07:19:18 PM

I have a very similar problem with the VEMS on my Clio!! Now and again the ground from the VEMS to the fuel pump relay drops out and I end up with no fuel pump!!

I have also grounded the relay and the pump then works!!

I really am not very good with all this and am learning very slowly but the guy that fitted it isn't being overly helpful as never seems to be avalible ::)

I get the feeling this maybe a problem internally with the VEMS as it is intermitant and I have checked the wiring and software.

If anyone can shed some light on what I can do that would be brilliant :D

[email protected] · October 14, 2008, 09:33:09 PM

Actually the guy who fitted it has been hassling me about it, so he has been trying to sort something out.
And I'll tell you what I told him...
In a nutshell I don't know whats happening, mainly because an intermittent fault is a pain to reproduce and isolate, when the P259 lets go, it does it properly and dies a death from which there is no return, so its a strange problem that you have.
My first suggestion is that we try to use an injector channel to drive the relay.
You'll need to identify a spare Injector channel by looking at the plug and comparing the spare slots with the connector diagrams in the UserGuide, once you've done that post up what you find and I'll take you through the next steps.

News:

Fuel pump channel not grounding.