69 replies to this topic

[AlexHillTVR]

Hi all, been having this issue which I've been discussing privately with Joe, who's been massively helpful, but still no joy and it's really starting to grind my gears. It started as an intermittent throttle cutting out issue and now it's rendered my VX motionless. Was wondering if anyone could offer some more wisdom as I'm feeling like I've pretty much exhausted all avenues now!

 

So this is where I am now:

 

On ignition on the throttle body goes through its startup sequence fine. The butterfly can be seen opening 20% with the air intake off.

 

Using my Scanguage I can see that the ignition on procedure throws up both P1635 and P1271. Start the car with both of these codes and I'm rendered with no throttle response.

 

I can then clear these codes with the Scangauge which gives me back the throttle response and the car will rev up fine, with the TPS values visible using the gauge function.

 

Switch the car off and the codes are still absent. Ignition on and they come back, same codes every time now.

 

 

I have checked:

 

Continuity across pins 1-6 of the Black loom of doom connector and all appeared fine to me. Sprayed contact cleaner inside and reconnected along with the same treatment for the blue plug.

 

The throttle body is a second hand one which replaced the original one a few months ago when the problem first arose. This cured the car for about 2 months.

 

I have sprayed contact cleaner into the connector on the pedal and reconnected. 

 

No where seems to show signs of corrosion that I've checked so far! Might set fire to it later as it's doing my head in!

Any help would be greatly received. Beer sent to he who first suggests the ultimate fix for the problem haha

[CHILL Gone DUTCH]

are you saying the issue re appeared with the original throttle body ?

 

are you sc na turbo?

Edited by CHILL Gone DUTCH, 07 January 2017 - 08:21 PM.

[AlexHillTVR]

The issue reappeared with the replacement throttle body after about 2 months of running ok. I have now switched back to the original TB, which wasn't dead, just temperamental, and the issue still remains so I'm pretty sure it's not the TB. Still produces P1271 and 1635 on ignition on which renders me with no throttle. Clear with scanguage and then I can rev it. I'm an NA

[CHILL Gone DUTCH]

have you checked your ecu pins ?

 

it has somthing to do with the 2 pot from the throttle not working in harmony 

[CHILL Gone DUTCH]

do you put your foot on the accelerator when you start the car up ??

[AlexHillTVR]

I haven't cause I need to get hold of a security torx to get the retaining plate off. On my to do list! Don't normally start the car with foot on the accelerator.

[FLD]

Sometimes the terminals in the lod plugs get weak and need replacing. They have a spring tab inside which bends back. Common culprit is the big brown/pink wire (not throttle related) but seems to have some sort of effect. Blue plug is the usual culprit and carries signals from engine. Black plug carries signal from pedal iirc. Sent from my iPhone using Tapatalk

[AlexHillTVR]

Thanks for the info FLD, I appeared to have continuity across the black plug for the wires I tested- yellow, green, blue, black, white & brown as they are the ones which carry the throttle pedal signals. At the beginning of the week I could drive the car but it would still cut the throttle every minute or two, restarting gave control back. After playing with the LOD connectors and the TB connector it now will cut throttle control from startup until I clear the codes. So I'd expect the problem to be with one of those two but there's nothing obvious. Would it be worth scrapping the LOD connectors and soldering then heat shrinking the connections together?

[bladerunner]

Have you tried doing an insulation test on the loom ? You need a special type of tester that will put voltage across the conductors and tell you if there's any breakdown in the insulation, this is indicated by a low resistance reading in ohms. Caution while doing this though as any items sensitive to high voltage would need to be disconnected from the loom ie ecu, throttle assy etc. The cause of insulation breakdown can be chaffing or prolonged heat exposure over time.

[AlexHillTVR]

No I haven't, I only have access to a basic multimeter and I am no auto electrician. Just weird how the pedal will work (in the static situation of revving up on the drive) once I clear the fault codes that get spat out each time the TB goes through startup. Think I'm going to need to get a mobile auto electrician on the case as the car is going nowhere in its current state

[vocky]

I would check the ECU plug pins for corrosion, I have seen that a couple of times.

[AlexHillTVR]

I would check the ECU plug pins for corrosion, I have seen that a couple of times.

Cheers Neil, I'm just waiting for a security torx bit to come in the post so I can get the security plate off. If there is corrosion on the pins is it a dead ECU situation or can the little needles be cleaned up and ECU saved?

[CHILL Gone DUTCH]

It could be the plugs as much as the pins

[AlexHillTVR]

It could be the plugs as much as the pins

Hmm good point... after reading this thread I'm starting to worry that I might need a new loom http://www.vx220.org...ease-new-member

[smiley]

That poor guy had a butchered loom.

Has your's been tampered with also?

 

[AlexHillTVR]

That poor guy had a butchered loom. Has your's been tampered with also?  

Not really, the car was working perfectly up until this happened. Only butchering I have done is exposing a small bit of wire each side of the LOD connectors to check continuity and the same on the wires just before the TB connector.

[smiley]

1271 has also been reported when wiring near the stickshift was exposed/damaged.

But that will be a bit more work to investigate.

Better finalise the TB loom part first.

[AlexHillTVR]

1271 has also been reported when wiring near the stickshift was exposed/damaged. But that will be a bit more work to investigate. Better finalise the TB loom part first.

Thanks smiley, that's another thing to check I guess. I've asked Jez at Back on Track if there's any way of getting it recovered to him. Times like this I wish I had a trailer and a 2nd car!

[FLD]

I had intermittent continuity with mine. It was a nightmare! The plugs should be securely mounted and the wiring fixed each side. Flexing of the wiring with bumps or engine movement cause the weak terminals to loose connection. The terminals are cheap to replace. If you open the plugs and take off the yellow grid you can look into the terminals. You should be able to see if the terminals are 'opened up'. Sent from my iPhone using Tapatalk

[smiley]

 

Drill a few holes, then zipty.