V5 Underpower, miss-fire, higher fuel consumption, MAF (mass air flow)

Crayfordp

Guest
Just thought I'd leave a quick message about the problems I've had with my V5 and what I did to fix it, just in case anybody else has the same frustrating problem as I did

For about 3 or 4 months the performance on my car had been deteriorating

on an intermittent basis, especially on up hill sections of the motorway, it would max out at 3800rpm in 5th gear but this gradually got worse and more frequent.

on cold starts it would really struggle for the first 5 minutes, at one point it wouldn't do more than 20mph up my street.

I noticed the fuel consumption also dropped below 30-mpg

When stationary, there was always a delay when the engine was revved

I took it to the seat garage who connected the computer up and it came up with mixture fault and a problem with the coolant temperature sensor.

I changed plugs, and HT leads, replaced the fuel filter and put fuel injector cleaner in the petrol tank but it didn't improve things.

Then one day, I though enough was enough and pulled over at the side of the motorway. Finding the MAF sensor on the air inlet pipe (after the air filter), I disconnected it. With quite impressive improvements to performance, not fixed and not back to normal, but definitely better.

That weekend, I replaced the MAF (it has two screws holding it on) and can be done in the car park of your local part shop (I went to French German and Swedish car parts (www.gsfcarparts.com/) and they had more than 60 in-stock as they say they need replacing a lot. It cost about £60 but you get £20 back when you give them the old one back. Car works like a dream now - Back to it's original performance and I'm no longer considering changing it.

I hope that post helps people

Paul
 

pauloliver

Guest
i too had this problem! i ran MAFless for a few days and it really did improve it a bit, although i wouldn't advise doing this for too long, apparently its a pretty common problem with all the vag tdi engines among the range (i know yours was a v5 but i thought its worth mentioning)

i went to a seat garage and got mine for just under 60quid, it was noticeably different in appearance, but fitted fine, my car also ran SO much better, better than when i bought it infact. i was also advised that i should reset the ecu, which basically meant i left it for 30mins with the battery disconnected. i then reconnected it, played with everyhting electric (apparently putting the windows up and down fully tells the ecu when to stop them so that they can smoothly go down by themselves at a touch of a button, rather than holding it?) i then started the car and took it for a spin, maxing out my rev range in every single gear, this apparently helps the ecu again, with air and fuel mixtures i guess, im not quite sure, either way, it ran even better! my 0-60 went from nearly 20seconds with a broken maf, to well below 10 with a fixed one :) and uses less fuel when driving conservatively
 

pingu

The penguin
May 27, 2008
3
0
Thanks for posting that message Crayfordp.

I bought a Toledo V5 a couple of years ago and it has always had a number of running issues: poor for the first 5 minuntes after start up from cold, lumpy idle, underpowered, revs did not drop on depressing the clutch, poor fuel consumpion - all really quite annoying, but still driveable and didn't really deteriorate over time. Seat did not detect the issue and suggested a new ECU for 600 quid - which I wasn't prepared to spend.

Have been on a mechanical roll of late so searched Google and found your post. Popped down to GSF Car parts this morning and picked up a Mass Air Flow Meter - a genuine Bocsh part for 80 quid (60 quid with the exchange) - and the car is like new.

Did not reset the ECU as pauloliver did, but seemed to work anyway - Seat are clearly clueless!

Hope others find these posts!
 

manicmechanic

Guest
I had a similar problem, and after changing 2 MAF's decided to check the wiring - when i removed the multiplug to the ECU, the ECU socket was swimming with water. I got the ECU repaired (£300!) and it still ran awful at first, but its improving all the time - perhaps its relearning its parameters as pauloliver suggests?
 
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