1997 A3 1.8T Sport - WTF?
Discussion
I've had this car a year and for what i paid it hasn't really given me any trouble that i havent been able to sort myself...until now
In the last few months it's developed a fault that causes it to run really lumpy when cold and the whole car rattles and splutters when idling. It has low power and doesnt rev above say 2k RPM so you end up driving like an old lady. After a couple of miles of driving and the engine reaches the mid point on the temp gauge it will start acting normally (Though a friend of mine borrowed it over the weekend and he says it still doesnt feel right once it's warmed up...maybe i'm just used to it?) - This only happens from cold start on a morning, or if it's been stood all day in the car park at work.
A couple of months back i replaced the coolant temp sensor as it was also flashing a "check coolant" warning when starting from cold. no change.
I've also noticed that if you stall it when it's acting funny it can be a bit of a struggle to get it started again and you normally have to turn the key for 5 or 6 seconds before it will fire. No engine management lights or warnings come on at any time through this process, apart from the check coolant message that comes on when it first starts up, this goes away after a minute or so.
Today i was reading some more about it (i need to get rid of it ASAP as i've got a new car on the way) so decided to take the MAF out and give it a clean with some isopropyl. I didnt actually get that far once i'd realised the MAF is screwed on with some stupid star shaped screws so might need to take a trip out tomorrow on the hunt for tools (grr)
This is when i noticed the plug to the left of the MAF housing along the turbo inlet pipe didnt have any wires in it. I then looked underneath and found the wire dangling loose (yellow and green, see pics)- it looks as it they've snapped off as the plug still has bits of wire inside it. see pics, there was a plug in the socket, i'd taken it out before the pics
First of all... what the hell is it, and secondly, could it be the cause of the lumpy running/coolant warnings?
Go easy on me, i'm an IT server nerd and don't claim to know sod all about anything mechanical
Here's the photos. There's one with the engine cover back to too so you can see roughly where i'm talking about
In the last few months it's developed a fault that causes it to run really lumpy when cold and the whole car rattles and splutters when idling. It has low power and doesnt rev above say 2k RPM so you end up driving like an old lady. After a couple of miles of driving and the engine reaches the mid point on the temp gauge it will start acting normally (Though a friend of mine borrowed it over the weekend and he says it still doesnt feel right once it's warmed up...maybe i'm just used to it?) - This only happens from cold start on a morning, or if it's been stood all day in the car park at work.
A couple of months back i replaced the coolant temp sensor as it was also flashing a "check coolant" warning when starting from cold. no change.
I've also noticed that if you stall it when it's acting funny it can be a bit of a struggle to get it started again and you normally have to turn the key for 5 or 6 seconds before it will fire. No engine management lights or warnings come on at any time through this process, apart from the check coolant message that comes on when it first starts up, this goes away after a minute or so.
Today i was reading some more about it (i need to get rid of it ASAP as i've got a new car on the way) so decided to take the MAF out and give it a clean with some isopropyl. I didnt actually get that far once i'd realised the MAF is screwed on with some stupid star shaped screws so might need to take a trip out tomorrow on the hunt for tools (grr)
This is when i noticed the plug to the left of the MAF housing along the turbo inlet pipe didnt have any wires in it. I then looked underneath and found the wire dangling loose (yellow and green, see pics)- it looks as it they've snapped off as the plug still has bits of wire inside it. see pics, there was a plug in the socket, i'd taken it out before the pics
First of all... what the hell is it, and secondly, could it be the cause of the lumpy running/coolant warnings?
Go easy on me, i'm an IT server nerd and don't claim to know sod all about anything mechanical
Here's the photos. There's one with the engine cover back to too so you can see roughly where i'm talking about
Edited by petersLUFC on Monday 8th February 17:38
Escort2dr said:
Err, why not solder the wires back together and see if it cures it?
The wires go in to what looks to be a sealed plug, and theyre snapped right where it enters the sealed block so there's no point i can solder them to. I can't see a way to get the plug open to feed the wires back through into the clamp 
The low coolant warning can be fixed with a new header tank, less than £10.
The rough running sound temp related to me, you say you changed the sensor, is it plugged in properly, was it the right sensor (green four pins IIRC).
Try the car with the MAF connector off. If its better, than as you planned give the sensor a clean, you dont need to remove the tamperproof screws, take the hole thing off, two normal philips screws into the airbox and the big hose clip.
DO all that first. If its no better.
I'm fairly sure that solonid with the broken wires has noting to do with cold start and idle, but if you can find a temp fix just to test will help. Those connectors dont come apart but if your removed the anti backout devise (Coloured plastic u shape) you can use a paperclip to make the pin back out of the connector.
You may have nuked the ECU when the battery terminals were loose, (ECU's dont like to loose there earth when powered up, it can kill them) but that hardly ever happens.
The rough running sound temp related to me, you say you changed the sensor, is it plugged in properly, was it the right sensor (green four pins IIRC).
Try the car with the MAF connector off. If its better, than as you planned give the sensor a clean, you dont need to remove the tamperproof screws, take the hole thing off, two normal philips screws into the airbox and the big hose clip.
DO all that first. If its no better.
I'm fairly sure that solonid with the broken wires has noting to do with cold start and idle, but if you can find a temp fix just to test will help. Those connectors dont come apart but if your removed the anti backout devise (Coloured plastic u shape) you can use a paperclip to make the pin back out of the connector.
You may have nuked the ECU when the battery terminals were loose, (ECU's dont like to loose there earth when powered up, it can kill them) but that hardly ever happens.
Tame Technician said:
The low coolant warning can be fixed with a new header tank, less than £10.
The rough running sound temp related to me, you say you changed the sensor, is it plugged in properly, was it the right sensor (green four pins IIRC).
Try the car with the MAF connector off. If its better, than as you planned give the sensor a clean, you dont need to remove the tamperproof screws, take the hole thing off, two normal philips screws into the airbox and the big hose clip.
DO all that first. If its no better.
I'm fairly sure that solonid with the broken wires has noting to do with cold start and idle, but if you can find a temp fix just to test will help. Those connectors dont come apart but if your removed the anti backout devise (Coloured plastic u shape) you can use a paperclip to make the pin back out of the connector.
EDIT- It started this before the battery thing so i don't think it's related
You may have nuked the ECU when the battery terminals were loose, (ECU's dont like to loose there earth when powered up, it can kill them) but that hardly ever happens.
Managed to figure out it was the N75 boost control solenoid after looking at some engine diagrams, had a google and found this http://uk-mkivs.net/forums/t/283319.aspxThe rough running sound temp related to me, you say you changed the sensor, is it plugged in properly, was it the right sensor (green four pins IIRC).
Try the car with the MAF connector off. If its better, than as you planned give the sensor a clean, you dont need to remove the tamperproof screws, take the hole thing off, two normal philips screws into the airbox and the big hose clip.
DO all that first. If its no better.
I'm fairly sure that solonid with the broken wires has noting to do with cold start and idle, but if you can find a temp fix just to test will help. Those connectors dont come apart but if your removed the anti backout devise (Coloured plastic u shape) you can use a paperclip to make the pin back out of the connector.
EDIT- It started this before the battery thing so i don't think it's related
You may have nuked the ECU when the battery terminals were loose, (ECU's dont like to loose there earth when powered up, it can kill them) but that hardly ever happens.
Will try running without the MAF plug on and see what it's like. So i can just remove the MAF housing itself? Will i be able to get to the MAF and clean it OK?
Edited by petersLUFC on Monday 8th February 20:06
Just been out and unplugged the MAF. Drove it hard from cold and as per usual, it started rattling and lacked power
The strange thing is, if i drive it from cold and keep it off the turbo and let it warm up it's fine. But if you have to get out of a junction quickly or accelerate up to A-road speeds moderately it will start going funny
The strange thing is, if i drive it from cold and keep it off the turbo and let it warm up it's fine. But if you have to get out of a junction quickly or accelerate up to A-road speeds moderately it will start going funny
Trying to figure out how to get the wires back into the connector. Brought the connector into the house so i can see but cant figure out how to get the pieces of wire out so i can attach it to the wires in the car
I've got the blue rubber cable seals out but cant get the wires to budge. I've tried opening the pins from the bottom and pushing up but the wires wont come out. are they soldered in??
I don't fancy buying a whole new cable a from my experience with the audi parts department it's always an expensive affair - plus it looks like the cable disappears around the front of the engine somewhere so re-fitting might be a pain
I've got the blue rubber cable seals out but cant get the wires to budge. I've tried opening the pins from the bottom and pushing up but the wires wont come out. are they soldered in??
I don't fancy buying a whole new cable a from my experience with the audi parts department it's always an expensive affair
- plus it looks like the cable disappears around the front of the engine somewhere so re-fitting might be a painhttp://www.worldimpex.com/assets/partimages/037885...
You see the pirple thing, hook that out so it come out that gap.
Then get a paper clip, bend it into a u shape.
Push the two ends of the paperclip either side of the pin (from the side wear it would plug into the N75) There are two litle cutouts above and bellow each pin.
They're not this shape.[]
but actaully this shape {} thats where you put the paper clip.
This should release the pins retaining tangs and allow the pin to be pushed back out ot the connector, perhaps with a very small screw drive.
You see the pirple thing, hook that out so it come out that gap.
Then get a paper clip, bend it into a u shape.
Push the two ends of the paperclip either side of the pin (from the side wear it would plug into the N75) There are two litle cutouts above and bellow each pin.
They're not this shape.[]
but actaully this shape {} thats where you put the paper clip.
This should release the pins retaining tangs and allow the pin to be pushed back out ot the connector, perhaps with a very small screw drive.
Edited by Tame Technician on Monday 8th February 21:39
Edited by Tame Technician on Monday 8th February 21:40
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