VW Polo 1.4 loses acceleration following timing belt change

polodriver

Standard Member
Car has no history of losing power and engine light has never appeared on the dashboard. Small garage where timing belt was replaced are floundering a bit with the problem. They say they've used the correct timing instructions and the hoses are not crimped. They also say it gets worse when the alternator is disconnected. They put on a new carburettor but that hasn't helped.

They've also rather ominously said they're worried it could be the engine management system. Now it's Xmas they can't get the right level of diagnostics done until 3rd January. In the interim I've hired a car to escape for Xmas.

Would an engine management system just pack up like that? I'm getting good eye contact with the guy working on the car so I doubt anything untoward like dropping the engine has happened. But I realise that if it is the engine management system at fault I'm probably scuppered.

Any help with questions to ask would be greatly appreciated. Maybe I need to go to the car next week (when small garage reopens), turn ignition on and check to see if the engine light comes on on the dashboard.
 

KelvinS1965

Distinguished Member
I bought an Astra 1600 years ago. I'd driven a friend's 1300 and was disappointed when my 1600 didn't seem as quick. I decided to replace the cambelt as it had no history and I was a bit confussed to see that the timing marks didn't line up when I was rotating the engine ready to remove the old belt. Short of it was that it was 1 tooth out and it made a big difference as to how quick it went (pre fuel injection, so very basic engine otherwise no ECU as such). Must have been put on like it as the belt was tight, so not like it had jumped 1 tooth.
 

car-man

Well-known Member
I'm inclined to agree that the cam pulley may be a tooth out.

If the car is an older version, a new carb suggests so, then it will also have a distritbutor and if the cam timing is wrong, the ignition timing will also be wrong.

The car may only have a basic engine management system, more info on the year of the car is needed and whether it does actually have a distributor and plug leads.

If it was fine before the cam belt change, logic dictates something might be wrong with the cam belt job.
 

FZR400RRSP

Banned
I'm amazed it can run at all like this.
Just shows what a low state of tune the 1.4 VW engine is in.
I was given a 1.4SE Golf as a company car once, it was the slowest car I've ever had, and I've had a non-turbo diesel Peugeot!
I'm sure the golf barely scraped 70bhp, in a golf body.....ugh.....
 

polodriver

Standard Member
Thanks loads everyone. The Polo is a 1.4 V reg Dec 1999 101,000 miles. Old I know but since there have been no major problems with it to date (apart from a pedal box replacement) and no signs of rust underneath I was hoping to get another 10-20,000 miles out of it.

I hired a car for Xmas and am now back here in Edinburgh thinking I've got to face the garage and try and work something out. They gave me a £211 quote for the timing belt replacement and have now fitted a new carburettor at £140. They want to get some diagnostics done after 3rd January and I'm wondering who's expected to cover this cost. Them or me? Any ideas? I guess I will happily pay for the timing belt, pulleys and carburettor. But I'm not too happy if I get lumbered with the diagnostics as well.

I don't know if the car is driveable but if it is not I'm tempted to have it towed to a good VW garage and get their opinion. I just feel the small garage is out of its depth and I may not be getting the full story. It may just be some sensors are out because wiring has come adrift somewhere. If this is so will diagnostics show this up?
 

paulyoung666

Distinguished Member
I don't know if the car is driveable but if it is not I'm tempted to have it towed to a good VW garage and get their opinion.

and that is going to cost a minimum of £100 to get done , you shouldnt be needing to throw more money at it , i however appreciate the dilemma you are in ......
 

passatboy

Standard Member
You sound like you are not confident in the work carried out,if the timing belt is out a tooth the car will run smooth but be down on power but if two teeth will be really flat on trying to rev,why have they changed what you say is the carb but is a single point injection unit are they guessing,now going for diagnostics so why change the injection unit without diagnosing it first?.did the car go in running without fault and do they want you to have it back and a bill in poor running order,it might be worth getting a second opinion as the more time and parts are more money.
 

polodriver

Standard Member
Thanks, Passatboy. I think I do need a second opinion and am glad to hear someone else thinks the same. The car went in running without a fault. No loss of power, no warning lights coming up on the dash.

Until I see them on 3rd Jan or afterwards I will not know exactly why they put on a new carb. I'm hoping it has enough power for me to drive it to the VW garage - about 5 miles away. I have breakdown cover if caught out on the road - but I don't want to cause any accidents on the way.
 

passatboy

Standard Member
Its 2011 well almost 2012 most and i mean the majority of garages have diagnostic equipment to hand as vehicles have moved to electronics,your polo is a easy vehicle to work on not like some you can open the bonnet on,if i had changed the belt on your car and then it lacked power i would double check the cam timing firstly and if it was correct i would plug into the diagnostic socket and read off any fault codes if any,any good mechanic would be quick to resolve this,you dont just throw parts at it hoping it will cure the running problem its a process of elimination.there are lots of things that would make a car run poorly but without seeing it cant pass to much judgement.The garage who have your car probably will do all they can to put it right as they dont want a bad name but the cost should be kept down.hope you get it back ok soon....And a happy new year :)..
 

polodriver

Standard Member
Dear All,
My dear old Polo finally had the diagnostics done today. The knock sensor was out. Know anything about knock sensors?

Cheers.
 

paulyoung666

Distinguished Member
polodriver said:
Dear All,
My dear old Polo finally had the diagnostics done today. The knock sensor was out. Know anything about knock sensors?

Cheers.

It basically thinks you have put rubbish fuel in it so therefore restricts the engine power so no engine damage is caused ...
 

polodriver

Standard Member
Ta loads. If there was residue in the bottom of a nearly empty tank might this have set it off? There wasn't much fuel left in the tank when I took it in before Chrissy.
 

paulyoung666

Distinguished Member
polodriver said:
Ta loads. If there was residue in the bottom of a nearly empty tank might this have set it off? There wasn't much fuel left in the tank when I took it in before Chrissy.

Possibly , did you get sorted out ok with the garage ? ..
 

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