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S/c Cuts Out On Part Throttle


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#1 ee601

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Posted 30 December 2020 - 02:16 PM

Hello,

 

I have a VX 220 with a Z22SE that has an M62 supercharger fitted and running at what it believe is “stage 2” (245bhp approx).

 

Z22SE with an M62 charger and a Courtenay map. Has been running fine, but lately I’m having serious issues with the engine cutting out and stuttering on part throttle loads.

 

Feathering the throttle is fine, full chat is also fine, but part throttle, from about 20% to 60% pressure it keeps cutting out for half a second or so.  It jolts the car quite violently like I’m a learner driver (!) and then it recovers for a few seconds before it does it again.  Once today, on a test run, I played with the throttle to try and provoke the cutting out by pressing and releasing it quite quickly, and the engine completely cut out and didn’t recover.  Wouldn’t start on the starter motor, not even trying to fire, so pushed the car into a safe place.  Then tried again, and it started (albeit with the stuttering problem still)! 

 

There are no OBD error codes coming up and no EML on the dash.

 

Anyone got any ideas where I should start looking for the culprit?  EGR Cheater fault? TPS? Air intake leak maybe? (I’ve been in there recently fixing the charge cooler water pump...) 



#2 OneYet

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Posted 30 December 2020 - 05:06 PM

TPM, TMP, whatever that Vestra CDI thing is called?

My engine just died when I tried som throttle when my TPM got stuck.

But I don´t think full throttle was an option. It just died on anything but idling and a small feathering. I managed to limp home though.



#3 ee601

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Posted 31 December 2020 - 03:15 PM

Thanks for the suggestion. But I’m not sure what the TPM or TMP is. Only thing I can find on here is TMAP sensor on the manifold as a replacement for the standard MAP sensor. Is that it maybe?

#4 siztenboots

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Posted 31 December 2020 - 04:04 PM

bypass valve 



#5 gertje

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Posted 31 December 2020 - 05:43 PM

Tmap sensor or by pass valve

I have a extra by pass valve

Verstuurd vanaf mijn ONEPLUS A6003 met Tapatalk



#6 OneYet

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Posted 01 January 2021 - 11:30 AM

TMAP, yes!

 

Here is my old thread: http://www.vx220.org...above-4000-rpm/



#7 ee601

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Posted 01 January 2021 - 07:49 PM

Thanks for the comments people..

Interesting development today. Think the problem might be fuel related...?
It started for just a few seconds then died (fuel fumes from running yesterday maybe?) then subsequently only got starter action, no attempt to fire up.

However, spraying carb cleaner into the air intake and spinning the starter simultaneously allowed it to start for just a couple of seconds and then die again..

Could this be fuel? Does the immobiliser cut the fuel feed? However, I do hear what I think is the fuel pump priming when I turn on the ignition...

#8 smiley

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Posted 01 January 2021 - 08:10 PM

If the fuel piping is oem , it should have a little black plastic screw on it.

Remove it, then have someone press start, you put  a small screwdriver in it, and see if fuel starts squerting out.

 

fuelpressure.jpg

 


Edited by smiley, 01 January 2021 - 08:15 PM.


#9 ee601

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Posted 02 January 2021 - 10:23 AM

Thanks Smiley. That’s first job.

#10 paul_mck

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Posted 03 January 2021 - 06:24 PM

Thanks for the comments people..

Interesting development today. Think the problem might be fuel related...?
It started for just a few seconds then died (fuel fumes from running yesterday maybe?) then subsequently only got starter action, no attempt to fire up.

However, spraying carb cleaner into the air intake and spinning the starter simultaneously allowed it to start for just a couple of seconds and then die again..

Could this be fuel? Does the immobiliser cut the fuel feed? However, I do hear what I think is the fuel pump priming when I turn on the ignition...

 

did your battery go flat? mine did this the other day after I replaced my fuel pipes. pump primed, starter spun, wouldnt start. P1614 code (immob fault). Had to disconnect battery, charge it, then reconnect and started straight up.



#11 The Batman

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Posted 03 January 2021 - 06:28 PM

could be the throttle body, i have one you can try and if it fixes it then you can send me some money  :lol:

 

:)



#12 ee601

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Posted 03 January 2021 - 09:19 PM

Update.  Bloody cold out there!!  Fuel pump doesn’t seem to be getting any power and doesn’t prime.  Here’s what we’ve done;

 

On one occasion the fuel line release valve gave a “pffft” after running the starter motor as it released air pressure (but no fuel) when I pressed the valve under the black dust cap down.  Most other attempts have no pressure there.. so I figured the fuel pump is probably not running.

Got under the car and pressed the fuel cutoff switch firmly a few times in case that had reset somehow.  Same result, no fuel pressure.

Tried bridging the contacts for the grey relay in the boot and it started fine, so the fuel pump itself appears to be ok.

Then swapped the grey relay in the boot with the one in the front for headlights, and the headlights still worked fine so assume the grey boot relay is actually ok.

 

I’m wondering if it’s because the fuel pump relay isn’t being triggered to send 12v to the fuel pump somehow?

 

Does anyone know how the immobiliser works. Does it kill the power to the fuel pump?  On one occasion yesterday I tried setting the alarm then un-setting it. Waited for a minute or so and the engine started ok but then died after just a couple of seconds - so I’m wondering if this is a symptom of something (such as maybe getting some fumes from priming but the pump cutting out once the ecu realises the car’s being started while “immobilised”..?

 

The symptoms of this before it completely died were rather like I’d imagine a pcb going dry joint or an electrical connection connecting and then breaking connection for a moment (though when it happened it bore no relationship to going over bumps like a loose wire might do).

 

Any clues there chaps?



#13 ee601

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Posted 03 January 2021 - 09:33 PM

Nope, no flat battery and no error codes. Though I will check codes again now I’ve done all the below. And I’ll try the battery disconnect thing.

 

Thanks..

 

Thanks for the comments people..

Interesting development today. Think the problem might be fuel related...?
It started for just a few seconds then died (fuel fumes from running yesterday maybe?) then subsequently only got starter action, no attempt to fire up.

However, spraying carb cleaner into the air intake and spinning the starter simultaneously allowed it to start for just a couple of seconds and then die again..

Could this be fuel? Does the immobiliser cut the fuel feed? However, I do hear what I think is the fuel pump priming when I turn on the ignition...

 

did your battery go flat? mine did this the other day after I replaced my fuel pipes. pump primed, starter spun, wouldnt start. P1614 code (immob fault). Had to disconnect battery, charge it, then reconnect and started straight up.

 

 



#14 ee601

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Posted 03 January 2021 - 09:37 PM

could be the throttle body, i have one you can try and if it fixes it then you can send me some money  :lol:

 

:)

Thanks for the offer.  Can the throttle body prevent power to the fuel pump? Looks like that could be the root of the problem..



#15 aquilaproejct

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Posted 03 January 2021 - 10:46 PM

Immobilizer works by cutting fuel pump

#16 The Batman

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Posted 03 January 2021 - 10:55 PM

yeah i would check imobiliser controls the pump if you have opcom check it out

 

i got brand new spitfire pumps here aswell :)



#17 TheRealVXed

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Posted 07 January 2021 - 09:00 AM

yeah i would check imobiliser controls the pump if you have opcom check it out

 

i got brand new spitfire pumps here aswell :)

 

Always trying to sell something Joe :lol:



#18 ee601

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Posted 16 January 2021 - 10:16 PM

Ok - sorted now!  It lives!

 

Turns out it was the X2 connector - part of the Loom of Doom.  The pair of electrical connectors that in my case are accessed from the n/s wheel arch.  Should have looked there first I guess!  Fixed by simply taking the 2 connectors apart, spraying them with some switch cleaner, then putting them together and apart a few times to shift any grime in there, and hey presto! Started on the button! 

 

Description:

Initially the problem gradually was the engine cutting out intermittently, and then (maybe an hour’s driving later) dying completely on a test run but starting again after a few minutes wait, and then eventually it was unable to start at all.  We diagnosed that it wasn’t getting any fuel, which strangely was down to a poor / deteriorating connection in the Loom of Doom.

 

 

Just in case anyone has those symptoms in future.. here’s what we did:

  • Check/swap grey boot fuel pump relay.
  • Bridge 2 vertical pins in relay holder, and fuel pump works.
  • Fuel cutoff switch (chassis rail left under engine) reset, then bridged to check function. No change.
  • OpCom check to see ignition key recognised ok. It did show the error B3045 “Anti-theft signal low voltage” but that doesn’t seem related..
  • Loom of Doom - spray with switch cleaner on connectors X2 and X3, and refit.

 

Thanks everyone for the help. I thought I’d post the success here in case anyone has similar symptoms in the future and looking for answers.



#19 kpf1grandprix

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Posted 25 March 2021 - 12:47 PM

Ok - sorted now! It lives!

Turns out it was the X2 connector - part of the Loom of Doom. The pair of electrical connectors that in my case are accessed from the n/s wheel arch. Should have looked there first I guess! Fixed by simply taking the 2 connectors apart, spraying them with some switch cleaner, then putting them together and apart a few times to shift any grime in there, and hey presto! Started on the button!


Description:

Initially the problem gradually was the engine cutting out intermittently, and then (maybe an hour’s driving later) dying completely on a test run but starting again after a few minutes wait, and then eventually it was unable to start at all. We diagnosed that it wasn’t getting any fuel, which strangely was down to a poor / deteriorating connection in the Loom of Doom.



Just in case anyone has those symptoms in future.. here’s what we did:

  • Check/swap grey boot fuel pump relay.
  • Bridge 2 vertical pins in relay holder, and fuel pump works.
  • Fuel cutoff switch (chassis rail left under engine) reset, then bridged to check function. No change.
  • OpCom check to see ignition key recognised ok. It did show the error B3045 “Anti-theft signal low voltage” but that doesn’t seem related..
  • Loom of Doom - spray with switch cleaner on connectors X2 and X3, and refit.

Thanks everyone for the help. I thought I’d post the success here in case anyone has similar symptoms in the future and looking for answers.


Got a pic of the connector you cleaned please. Having similar symptoms today

#20 smiley

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Posted 25 March 2021 - 03:35 PM

stekkersvast.jpg

Blue one iirc.






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