Polo - sometimes only idles - and lots of fault codes...
Discussion
Hi,
I’m having a few problems with my ancient old 1.4 VW Polo (X reg 16 valve petrol).
Over the last month, on three occasions it’s started fine, but then won’t rev (can floor the accelerator but it still only idles). I think the idle is a bit rougher than normal.
If I turn it off and on again a few times, it rights itself and then drives absolutely fine.
Each time it’s done this, it’s been running fine prior to the problem occurring. It’s happened on starting from cold, as well as the engine being warm.
I’ve plugged in a basic code reader and got the following:
- Brake switch: implausible signal P0571 [note – brake lights all working]
- Barometric/manifold pressure implausible correlation P1553
- Intake air system leak detected P1504
So far, I’ve cleaned the throttle body (by spraying cleaner into the body while revving engine), checked for any obvious air leaks, tried giving it an Italian tune up, and cleared the fault codes. All seems fine, but then the problem reoccurs a week or so later.
Maybe unrelated, but about 6 months ago I replaced the MAF sensor to try and clear another fault code. This worked for about a week and then the engine management light came back on. It didn’t seem to cause a problem though, drive fine and it passed an MOT with the light on. It was an ECP sensor; I did wish after I’d bought a genuine VAG one. Not sure if there’s any relevance to this new problem and the MAF sensor.
I’m at a bit of a loss now, so would be glad of any pointers. I don’t want to start throwing parts at the problem.
Many thanks
I’m having a few problems with my ancient old 1.4 VW Polo (X reg 16 valve petrol).
Over the last month, on three occasions it’s started fine, but then won’t rev (can floor the accelerator but it still only idles). I think the idle is a bit rougher than normal.
If I turn it off and on again a few times, it rights itself and then drives absolutely fine.
Each time it’s done this, it’s been running fine prior to the problem occurring. It’s happened on starting from cold, as well as the engine being warm.
I’ve plugged in a basic code reader and got the following:
- Brake switch: implausible signal P0571 [note – brake lights all working]
- Barometric/manifold pressure implausible correlation P1553
- Intake air system leak detected P1504
So far, I’ve cleaned the throttle body (by spraying cleaner into the body while revving engine), checked for any obvious air leaks, tried giving it an Italian tune up, and cleared the fault codes. All seems fine, but then the problem reoccurs a week or so later.
Maybe unrelated, but about 6 months ago I replaced the MAF sensor to try and clear another fault code. This worked for about a week and then the engine management light came back on. It didn’t seem to cause a problem though, drive fine and it passed an MOT with the light on. It was an ECP sensor; I did wish after I’d bought a genuine VAG one. Not sure if there’s any relevance to this new problem and the MAF sensor.
I’m at a bit of a loss now, so would be glad of any pointers. I don’t want to start throwing parts at the problem.
Many thanks
Does it idle properly when hot & cold when rolling in neutral? I'd probably change the water temp sensor if there's any suspicion its troublesome (cheap part from ECP + some antifreeze)
https://youtu.be/U0rc6Le3kDU
Plus check all vacuum hoses, main air inlet hose for any splits.
https://youtu.be/U0rc6Le3kDU
Plus check all vacuum hoses, main air inlet hose for any splits.
yeager2004 said:
it’s started fine, but then won’t rev (can floor the accelerator but it still only idles).
I've seen that behaviour when a load sensor failed so that the engine leaned out as the throttle opened. Given the error code you mentioned, I suspect you might be using a MAP sensor for load and perhaps that has failed or got a wiring fault.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff