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Lupo GTi jerky when cold


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Hi all.

My 02 GTi runs lovely when warmed up, but for a few minutes when cold it's quite jerky. I've replaced most serviceable engine bits and the only things left are CTS, MAP and lambda.

I can put VAG COM on it but can anyone tell me what to log?

I reckon most likely is lambda and least likely is CTS, but I'd rather not buy a lambda or MAP unless I have to.

Car's done 100k and I reckon the clutch is on the way out as it's a bit fussy on bite but that may be how they are?

Love the car anyway.

Cheers.

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Common thing with em, I posted up a thread when I first got mine and the general consensus was they're all like that when it's cold! Think someone said it depends on the fuel you use but that was quickly stamped on by everyone saying they run theirs on super.

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I think it was MikeM who changed his coilpack\s and leads; said it went away.

Try cleaning the contacts between HT leads and coilpack.

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Oh shhhh ray, I tried that and it didn't help, just meant I had to go without a takeaway that weekend as I'd spent my 'allowance' on car bits!! Grrrrrrrr!!!!!!

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I'll give them a clean and see what happens cheers. An engine that fuels by MAP and lambda rather than MAF is never going to be particularly clean on open loop.

Off topic, Silver which roof rails and roof box is that? It looks awesome.

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Also check for damage to the lamba sensor wires at plug for first lamba, when one of my wires snapped the throttle almost turned to a on off switch when cold.

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Mine never did this, I replaced the pack and leads when I got it and always used vpower. I let it idle for 30 secs before setting off too

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Yeah, check the leads. I don't have a GTI but this sounds exactly like what I was experiencing a few weeks ago. Very juttery in the cold. Would eventually go away when it warmed up. OBD showed up "Misfire on Cylinder 3". 4 new leads and 4 new Spark plugs and my Lupo is driving better than ever :D

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  • 8 years later...

Kangarooing issue solved (by accident):

Needed to replace the Coolant Temperature Sensor on my Lupo GTI as my temp gauge had been playing up intermittently for the last 3-weeks.

Wouldn't you know it, after replacement, not only was the temp gauge now working but no more jerky throttle from cold starts.

Funny that I'm both overjoyed and also annoyed....since I accepted the cold start kangarooing (and second gear workarounds) as a quirk of the GTI, since buying the car 5 years ago and searching high and low online for a fix.

Would be interested to see if this also solves other peoples' issue too (since I notice there are a few users following this thread and it has annoyed me for so long!)

Edited by grogzy
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I was told its because the roots of this engine are in rallying where it would idle higher, whether hot or cold. Mines always done it from day 1, never really been a problem as it's fine once it's done a few miles.....

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I have changed the coolant temperature sensor on my Lupo Gti last week and indeed this seems to have made a noticeable difference in the jerkiness after a cold start. I wonder why though...

What I’ve also done recently, as I was changing the air filter anyway, is clean the throttle body and clear the adaptations with an OBD2 reader thingy. A sticky throttle plate may well cause the engine being jerky as @mk2 has very nicely explained in a different thread about the same topic. 

 

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  • 3 weeks later...
On 12/24/2020 at 11:49 AM, bernd said:

I have changed the coolant temperature sensor on my Lupo Gti last week and indeed this seems to have made a noticeable difference in the jerkiness after a cold start. I wonder why though...

What I’ve also done recently, as I was changing the air filter anyway, is clean the throttle body and clear the adaptations with an OBD2 reader thingy. A sticky throttle plate may well cause the engine being jerky as @mk2 has very nicely explained in a different thread about the same topic. 

I can only guess that an inaccurate temperature reading (below that of the actual coolant temp) may cause the ECU to switch to a higher fuel-to-air ratio when not necessary... This may have a similar effect to the throttle sticking open and then snapping shut after a split second delay ( I may be waaaaay off here 😬).

I'm pretty sure I read that thread some time back, but wasn't sure it would be straightforward to get to. Will look for a guide (with images still working) on how to get to & clean the TB at some point... 🤞

Must also remember to put the injector fuel treatment I bought ages ago (Wynn's IIRC) in the car, for when I run low on petrol and fill up the next time.

And yes, you've reminded me to add that disconnecting & reconnecting the battery after changing the CTS also seems to make a difference - maybe because it clears existing codes or resets something in the ECU perhaps? 🤷‍♂️ I say this because I left something plugged into the 12v ashtray socket over a weekend (after having changed the sensor) causing a flat battery - after a jump start, the car immediately seemed to have a noticeable improvement in overall engine performance/smoothness. 

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20 hours ago, grogzy said:

I can only guess that an inaccurate temperature reading (below that of the actual coolant temp) may cause the ECU to switch to a higher fuel-to-air ratio when not necessary... This may have a similar effect to the throttle sticking open and then snapping shut after a split second delay ( I may be waaaaay off here 😬).

That does make sense. However, shouldn't having a correct temperature reading make more difference when the engine has warmed up, because surely a cold start is a cold start ??

Geting to the throttle body is easy. You need to take the air filter and air filter housing off and there it is...

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On 1/9/2021 at 6:42 PM, grogzy said:

Must also remember to put the injector fuel treatment I bought ages ago (Wynn's IIRC) in the car, for when I run low on petrol and fill up the next time.

I assumed this stuff was snake oil but it did seem to make a difference to my GTI, in fact I'm not sure I've had any jerkiness this winter after having used it around September. Prior to this mine also liked to be a bit jerky in reverse, which given the tightness of my parking spot at home, was rather irritating!

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On 1/10/2021 at 4:01 PM, bernd said:

That does make sense. However, shouldn't having a correct temperature reading make more difference when the engine has warmed up, because surely a cold start is a cold start ??

My thinking is that the "cold start" FTA ratio which the dodgy reading is activating, is only required in a really cold climate (maybe something like -15 or below)... Again, this is all guess work :)

On 1/10/2021 at 4:01 PM, bernd said:

Geting to the throttle body is easy. You need to take the air filter and air filter housing off and there it is...

I'll take a look this weekend or next - Cheers!

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On 1/10/2021 at 9:42 PM, mickster said:

I assumed this stuff was snake oil but it did seem to make a difference to my GTI, in fact I'm not sure I've had any jerkiness this winter after having used it around September. Prior to this mine also liked to be a bit jerky in reverse, which given the tightness of my parking spot at home, was rather irritating!

A friend swears by it, but I haven't yet tested it myself and since replacing the CTS worked for me I'm not sure whether I will be able to notice a difference...at least regarding jerkyness/kangarooing.

I'll report back on whether it improves anything else (responsiveness or smoothness when accelerating maybe?)

Also apologies for the late replies, I've only just found that all Club Lupo notification emails since the beginning of time have been going straight into my google spam folder... 🙈 

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On 1/12/2021 at 6:13 PM, grogzy said:

A friend swears by it, but I haven't yet tested it myself and since replacing the CTS worked for me I'm not sure whether I will be able to notice a difference...at least regarding jerkyness/kangarooing.

I'll report back on whether it improves anything else (responsiveness or smoothness when accelerating maybe?)

Also apologies for the late replies, I've only just found that all Club Lupo notification emails since the beginning of time have been going straight into my google spam folder... 🙈 

I've just remembered actually it did help with responsiveness so you may still benefit. Mine was a little sluggish between 2nd and 3rd and now it's perfectly fine, so much so that I forget it was ever an issue!! 

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10 minutes ago, mickster said:

I've just remembered actually it did help with responsiveness so you may still benefit. Mine was a little sluggish between 2nd and 3rd and now it's perfectly fine, so much so that I forget it was ever an issue!! 

Thanks for the reassurance, fingers crossed I will notice a difference.

Also, even though the directions state the Wynn's should be added along with a full tank of petrol, I've been told the best results are achieved by adding a full bottle to a quarter tank and then after letting it settle get on the M-way and give it a good ragging through the gears.... Not sure whether I should risk it though?... 🤔

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