1.8t engine hesitation

[CraigM]

Hello everyone - I just got a 2001 A3 1.8t sport on Saturday and absolutely love it.

However on 3 occasions today the engine has hesitated when moving off - it is almost like the accelerator is being pressed/released repeatedly until it hits 3000 rpm and it then pulls smoothly.

Does anyone have any ideas what might be wrong - could it be a faulty coil pack??

 

[leespears1]

mine does the same but only in the hihger rpm, above 3500rpm. I was speaking to richa3turbo yesterday and he says its either the turbo, dv or get it chipped and that will smooth out the flat spots.dunno if that applies to the lower end rpm.

 

[pure]

get the dv checked I reckon. When you come off the gas is there a sudden jolt? like some1 is applying the brakes briefly? Could be a stuck / sticky diaphram inside the DV in which case it wo't be building up the pressure it should be doing and causing some probs. Run it into audi and ask them to check the DV to see if it is holding preasure.

They should have a tool, where they insert it into the top hole on the DV and pump some pressure into it. It should build up, if it is knackered it wont.

 

[HTC]

As far as I know this is an indication of a dodgy MAP sensor. Apparently Audi are now changing these on the 80,000 mile services as they are prone to failure.

Don't take that for gospel, just what I have heard. Definately get it checked tho.

 

[excursion]

Welcome aboard!!

Do not get the car chipped, this will only serve to exaggerate the problems you have.

There are a few causes for what you mention - Coolant temp sensor, N75, Recirc valve and plugs.

HTC - Do 1.8T's use a MAP sensor? Where is it?

 

[HTC]

Sorry, might be MAF sensor rather than MAP.

Anyway, the bit after the air filter that works out how much air is entering the engine.

 

[RichA3Turbo]

[ QUOTE ]
HTC said:
Sorry, might be MAF sensor rather than MAP.

Anyway, the bit after the air filter that works out how much air is entering the engine.

[/ QUOTE ]
MAF /ubbthreads/images/graemlins/wink.gif

 

[HTC]

Oops...........cheers!

 

[Katie]

Might just need an 'Italian Tune-up.'

Pootling around in high gears and low revs will gum up the plugs, and you don't know that the car hasn't been used as an around-town shopping car.

A decent run, above 4500 revs and, with Optimax, might blow the cobwebs away.

--
katie.

 

[JamesA3]

I have the very same problem and it has only come about since I had the AmD remap and viper valve fitted, it really is annoying

how can I tell if its my MAF

 

[HTC]

You can log the air mass flow with VAG-COM. Gambba would probably be able to tell you the correct measuring blocks and expected values.

Or try www.ross-tech for more info.

Or take it to you local stealers for them to look at.

 

[JamesA3]

don't really want to take it to the stealers as its been chipped

 

[HTC]

I guess your options would be to find someone in your area with VAG-COM or borrow a MAF sensor from a friends car if you know someone with an audi.

 

[Gambba]

Block 003 will give you 'Air mass in' as well as RPM, and for a standard car at idle (800-900 rpm) you'll be looking for 1.8 - 4.0 g/s. And at 2520 rpm you should have 7.5 - 12 g/s. On a chipped car the latter of the two readings will be slightly higher, but not by much.....can't remeber a figure, but will check.

There are other checks that can be done to check voltage output from the ECU using a multimeter, but these are in conjunction with the diagnostic readings above.

 

[littco]

I had exactly the same problem with my car, It went back to Audi 3 times and each time they said they couldn't find a fault. I was going on Holiday and told the garage that they could have it for a couple of weeks to find and fix, When I picked it up they had change the MAF and since then 6 Months , I have never had the same problem.

I would say it is the Maf

 

[cango_uk]

I picked up my S3 on Saturday, and I love it also, however, the performance is not consistant and am beginning to suspect something is not right with the boost control. Sometimes it pulls like a rocket, other, a rather asmatic 1.8 petrol engine...When the engine is pulling well, there is a distinct "tooosch" when I change gear, and a distinct absence of that when it isn't... could the DV be sticking open?

 

[Gambba]

If you can hear the whoosh noise when releasing the throttle then it's likely that the DV is fluttering due to a diaphragm problem. It's likely the Diaphragm has split or become pouros, which means that boost pressure may be leaking.

So based on what you've said I would replace the DV anyway, as it's cheap and will prove the point, and the latest variant of the 710 in 'N' version is improved.

 

[CraigM]

Thanks for all the replies.

I had the car in the dealers on Friday and they have replaced all the coils and say that should fix the problem.

The engine seems to pull a bit smoother than before, but occasionally it still seems to hesitate slightly.

I will try cleaning the MAF sensor this weekend and see if that makes any difference - can anyone tell me if this is this the right bit to clean on it??

http://www.mcmillan-uk.com/clio/MAF01.jpg

http://www.mcmillan-uk.com/clio/MAF02.jpg

 

[Gambba]

Correct. /ubbthreads/images/graemlins/beerchug.gif

 

[MingBluS3]

Does anyone live near Essex/Herts/Kent at all who has got a VAG-COM?