Going limp and frustrated!

[ourkid]

I've been driving my Tdi powered Mk2 for a week now and it runs great but i'm getting limp mode after a few miles.I posted over on Mk3 forum but i think maybe this is connected to my mods

Regular is hell,5-6 miles then flashing glow plug light,down to idle with no throttle response then cuts out.Vag com showing Implausible brake light signal and MAF open circuit or short to ground.

I was advised to change the 109 relay - i'm now on my 3rd - still no change

I'm waiting for access to vag com again so that i can properly set the brake switch,but would this cause cut out?

The MAF problem bothers me.I have a Mafless tune.Do i need to still leave the MAF plugged in? (hope not as i've lost it).Can the pins be bridged?

I have no EGR but have left the valve plugged in to avoid a code.It's not connected to anything,would this upset things?

thanks.

How can i update my signature btw? (I'm running a vnt-17)

 

[abctdi]

They now have a pill for that

 

[ourkid]

Ha!

Forgot to say,it's doing this regardless of driving style - fast run or slow cruise!

One more thing.My ECU is inside the car,fixed to the underside of the passenger tray,could it get too hot here?

 

[vwmikel]

The brake light switch could be causing the symptoms that you're experiencing.

If you're throwing a code for the MAF then it would seem you might not have an entirely MAF-less tune. Are you just running it with the default MAF value?

 

[vis-tuning]

we had this with our race car, we found that the car didn't enjoy running cold. If we let it warm up first we then we had no problems. also after help from guys on the forum we had an issue with the boost sensor we were running.

 

[m1ketdi]

The brake light switch could be causing the symptoms that you're experiencing.

If you're throwing a code for the MAF then it would seem you might not have an entirely MAF-less tune. Are you just running it with the default MAF value?

I have looked at the files, the MAF is switched off via the switches and pressure based smoke map has been changed to run properly. So I don't know why it would throw the MAF code.

 

[ourkid]

Thanks Mike,yes a strange one.However i think i have narrowed it down to the brake switch.I realised that If i have a long straight motorway run,it comes on after 5 miles,with short town runs it will last a lot longer.So i'm assuming it doesn't like the pedals being left alone for any length of time.It was flashing this morning again on the way to work.As sonn as i came off the motorway and hit the brake pedal it stopped.I'm hoping to set it up correctly today (or replace the switch).

 

[vwmikel]

I have looked at the files, the MAF is switched off via the switches and pressure based smoke map has been changed to run properly. So I don't know why it would throw the MAF code.

Changing the switches over to reference the MAP sensor instead of the MAF doesn't turn off the trouble codes. Those need to be blocked separately.

 

[ourkid]

Changing the switches over to reference the MAP sensor instead of the MAF doesn't turn off the trouble codes. Those need to be blocked separately.

I'm not bothered about it storing a code as long as it doesn't relate to any running issues.Done using this method,could it flash the glowplug light?

 

[devonutopia]

Is the switch behind the brake pedal up the spout?

 

[G60ING]

Get the vagcom fixed and then you'll be able to see all of the error codes. Yes the brake switches can cause problems. Typically they will caust a flashing glowplug light. I've not had any experiances where the brake switches caused no throttle control. Again I strong suggest that you get the OBD2 port hooked up and then track down a Vagcom cable.

 

[m1ketdi]

Changing the switches over to reference the MAP sensor instead of the MAF doesn't turn off the trouble codes. Those need to be blocked separately.

That would explain the MAF code then, suprised the guy who made the files hasn't changed that too really. Yep definitely not changed checked again.

 

[lowpolo]

my car does this too a quick prod of the brake pedal will clear the gp light for a few minutes then its bak on again, vagcom says the brake signal is implausable, have you wired in the cruise control brake pedal switch thats my next port of call. Hope you get it sorted asap as I know how annoying it is.

 

[G60ING]

I had a flashing GP light and inplausible sign on my Corrado TDi swap. Turned out that the brake light switch on the pedal was worn out. I found out at H20 on a saturday and had advance auto parts order a new one. It arrived on a Sunday by noon and all was fixed.

 

[lowpolo]

but the brake lights work and the gp light goes out after the pedal is depressed surely this shows the circuit works as the ecu is recognising the change in signal?

 

[m1ketdi]

Nope, the cruise switch doesn't turn off when the pedal is released. It goes to 10ohms or close to that. But there is a timer within the ECU before the error will flash up again hence throwing the glow plug light after a certain amount of time.

 

[G60ING]

Not to question you but have you verified that the brake lights do work? When i put together my car I made certain the brake lights worked and then a couple weeks later I had the brake light switch implausible signal issue and I never rechecked my lights. Turns out my lights weren't working.

 

[ThoughtCrime]

Am I the only one who laughed at this title?

 

[ourkid]

ok,got hooked up on VCDS today,

checked measuring blocks in group 6

I'm seeing 001

When i press the brake pedal i get 011
When i let go it returns to 001

Operating the clutch gives 101 (but the first one sometimes stays on for a while until i kick the pedal)
And pressing both clutch/brake together 111

so I'm a bit confused about the last digit staying 1 and it's function?

Just to clarify i have 2 brake pedal switches (both 2 wire).The bottom one for the stoplights is doing it's job ok





UPDATE! - Discovered my clutch pedal was not returning fully.Only by 1/4 inch but enough to fool the switch.This may be down to all the wrestling with it to get it to fit my Mk2 bulkhead.I sorted this and went on a 20 mile run.For the first 12 miles it was fine,However the last 8 were a nightmare,having to stop every half mile to switch off/back on to stop my flashing glowplug light (i discovered also that when it flashes i'm down on power).

So,back home,hooked onto VCDS.....

NO Implausible brake switch fault - so looks like this may be sorted

Still seeing MAF OPEN OR SHORT TO GROUND.



So it looks like i had 2 seperate issues.

i guess it's the MAF issue thats stalling the car?.Although it's not using feedback from the MAF it's still looking for it?
Can i get round this until i speak to my tuner?.I do have a PD150 MAF but it won't fit the plug - i could splice this in but it will just be hanging as i'm not running standard airbox/piping.Or can i bridge the pins somehow?

Thanks for your help so far!

 

[abctdi]

Am I the only one who laughed at this title?

No, see post #2.