Running a Passat with air flow metre disconnected

[silverpassat]

Hi

I was just wondering is it ok to run a 02 reg 130 tdi passat with the air flow metre disconnected? I no it will be very slow with this done but is it safe for the engine?

Many thanks for your help.

Matt

[Crasher]

Don't do it!

[silverpassat]

Right o. I won't do it again.

Many thanks.

[Col]

Don't do it!

Why not ?

In an emergancy it will be fine as the ecu would default back to stored values.

Long term though a very bad idea as your car will be as fast as a milk float.

[silverpassat]

BigCol, thank is very useful to know. Yes it was well slow like you say.

The reason I asked about this, was I've just changed my air flow metre, as I had some black smoking issues and after looking on a lot of posts on here it seemed to be a common passat problem. I got a genuine one from VW, I fitted it and it hasn't made any difference. The car still goes well, and starts well. Apart from at very light throttle between about 1000 and 2000 rpm, where it might be not as smooth as normal, and it kicks out a lot of black smoke when it is accelerating at very light throttles, once past around 2000 or so rpm it stops unless you boot it fully (but I would expect that then) I've also cleaned out the egr valve, that was caked up, but no difference. It is just getting embarrassing to drive so I disconnected the air flow metre and all the smoking stopped and it run nice and smoothly, it was just gutless like you said. Not sure what else to do.

[Col]

You need to hook it up and read for fault codes and observe the measuring blocks for the various sensor outputs.

Look at the the vagcom subforum for someone who may be able to help or even set yourself up with it, it will pay for itself if only used once !

Anyway, my guess and it is a guess until you interrogate the ecu and sensors is that your coolant temperature sensor is causing your problem. A very common problem.

What happens is when it goes duff, it fools the ecu into thinking the engine is still cold when it isn't, the ecu in turn up's the fuelling = black smoke.

Like I say, a guess at the moment

[silverpassat]

Thanks for your thought BigCol, I better get hooking it up then :D

I'll let you know what i find.

Many thanks once again for your time.

[silverpassat]

Just a little update, I've went on the ross-tech site and bought the vag software.

I've done a code read and there are no problems engine related, just an air con one that I already knew about.

So with that I decided to take out the injectors for a clean and over haul. I may have found the problem, not sure what you think??

On one of the injectors the very last rubber seal at the base of the injector (the smallest one) has perished and broken down. I'm not to sure how the injectors work yet, being new to it all, but could diesel be passing this in and making the smoke?

Cheers.

[Crasher]

You need seal set 038 198 051 C, 1 set for each injector at £17.81 a set. You also need bolt 038 103 385 A at £2 for each injector as these bolts are a one time only torque plus angle (12Nm plus 270°) stretch bolt and MUST be replaced. To install the “O” rings you must use tool T10056 (this is easy to obtain from a VAG parts department, by law they cannot refuse and if they do, I will supply). When reinstalling, the “O” rings must be coated with G 000 100 grease and the alignment of the injector body relative to the outside surface of the head is absolutely critical with number 1 injector requiring a set of vernier calipers capable of measuring the 333.0-mm distance which has a tolerance of 0.8-mm. If the bolt is not renewed, the “O” rings re-used or the alignment not accurately set, there is a great risk that the injector will come lose in the head and destroy both the head and the injector which is an approx £3000 parts alone problem (genuine VAG prices) should that happen.

[silverpassat]

Hi Crasher thanks for your post that very helpful.

I'm trying to get the injectors looked at before i put them back in the car in case there is a problem with one of them, no one around here seems to want to know! as there are new. Have you any thoughts.

[Crasher]

It is not possible to test PD injectors with the equipment currently available to the aftermarket, the rig required is quite involved and time consuming to set up. Because of this it is more cost effective to fit a set of exchange Bosch injectors if you have doubts about their serviceability.

[silverpassat]

WOW thanks sir that explains the problem i'd had.

what a bugger.

[silverpassat]

Hi just thought I'd give you an up date. I put injectors back and took it to a local diesel specialist to test. And it turns out to be the old EGR valve that has been said on here many a time. The thing I can't under stand is I cleaned it out and got a vacuum on it and it moves up and down nicely so it all looks like it works, the seat also seals, yet when you disconnect the vacuum pipe from it (and block the pipe off) that smoke stops and the car runs normally. how weird. So I'm running around with it disconnected I hope this is ok.

[Crasher]

That sounds like the EGR valve solenoid is stuck open.

[silverpassat]

Yes that makes sence now :) is it ok to run with the egr not connected them would you say?

[Crasher]

It may store a code but thats about it.

[silverpassat]

Nice one thanks.:beerchug:

[Col]

Just to let you know I've been running my Passat PD130 (AWX) for over a year with the EGR vac pipe off and plugged with no adverse effects at all.

It doesn't throw any fault codes either.

[silverpassat]

Thanks for that, glad to hear it:D

[Ben a4]

You need to hook it up and read for fault codes and observe the measuring blocks for the various sensor outputs.

Look at the the vagcom subforum for someone who may be able to help or even set yourself up with it, it will pay for itself if only used once !

Anyway, my guess and it is a guess until you interrogate the ecu and sensors is that your coolant temperature sensor is causing your problem. A very common problem.

What happens is when it goes duff, it fools the ecu into thinking the engine is still cold when it isn't, the ecu in turn up's the fuelling = black smoke.

Like I say, a guess at the moment

Hi all,just jumping on your thread if you dont mind,my A4 1996 tdi keeps losing power,as if the turbo isnt there and is running flat.If i turn it off and on again it runs and pulls well.I have just had the 140k service done and had a new MAF fitted.When the new MAF was fitted and since then when it runs well it is very good.
The temp gauge sits at 70degrees on the gauge(also tested at the garage and was reading the same) so i am wondering if my temp sensor might be faulty.
Any help greatly appreciated,again sorry for jumping on your thread.

Ben.

[Crasher]

Is this a 90 or 110PS engine? I guess it is an AFN 110. Get a fault code read done and this should come up with code 17965.

[caldirun]

the alignment of the injector body relative to the outside surface of the head is absolutely critical with number 1 injector requiring a set of vernier calipers capable of measuring the 333.0-mm distance which has a tolerance of 0.8-mm. .
Is this a slip of the decimal point, thats a mighty big vernier!

[Crasher]

No, it isn't a slip. When I first had to do one, I nearly had heart failure at the price of verniers that would measure that far, nearly £400. I managed to pick up a set used reasonably priced.

[silverpassat]

HI guys. I've been running the egr valve disconnected now for around 1000 miles. The car feels and goes well, I was just wondering, does the egr value help part throttle economy? do you know, as I seem to be down on the town driving, but normally at motorway driving. I'm not to worried, just wondered.

Cheers Matt

[Crasher]

Very slightly.