Hi all vcds values help

[paulmaca]

Hi all wondering if anyone can help with vcds values for a a4 b6 1.9tdi quattro avant 130 please .

Rather than post problem repeated with miltiple solutions ranging from £1.26 to throwing money at problem i was wondering if anyone with more knowledge of VCDS could see with these values what problems you would have to see if anyone can diagnose my problem image 1 is with engine idling and image 2 is after a reset new egr valve (audi part)coolant switch (audi part) thermostat and maf cleaned before both scans thanks in advance

http://www.vwaudiforum.co.uk/forum/attachment.php?attachmentid=25544&stc=1http://www.vwaudiforum.co.uk/forum/attachment.php?attachmentid=25545&stc=1

[Lukenkarl]

Your MAF reading is miles out

[paulmaca]

Hi Lukenkarl ,

First thanks for your input appreciated .Sensor ws cleaned with electricl contact cleaner ,replaced with second hand and also cleaned both bosch both giving same readings and have ebay cheapo that i don't fancy fitting but might be worth trying to see if problem is solved then if works replacing with new original. When your mass air flow sensor goes bad, it cannot react properly to changes in the air entering your engine, so it will provide either too little or too much gas for your airflow, causing issues such as hard starts, rough idle, sluggish throttle response, and pinging. Car runs great starts easy cold and using more fuel and running lean with obviously use of more fuel info below on MAF seems to point to boost leak giving fact both cleaned sensors giving same reading or could wiring to Maf be problem ie if you push voltage metre onto 1 an 3 or 2 and 4 on MAF connector what should voltage be thanks again


What's a MAF and what does it do?

All modern VW, Audi, and TDI use a MAF to help measure air flow. A MAF sensor is one way of directly measuring how much air is passing the MAF sensor and into the engine. Some cars, especially older cars may calculate air flow instead of measuring it by using other air flow sensors and taking into account engine rpm, throttle position, and air temperature. Knowing how much air the engine is getting is important because the car's computer uses this value to know how much fuel to give the engine. If it's giving too much or too little fuel the engine won't run right. This is one reason why it's important to have an airtight intake tract after the MAF sensor. The amount of metered air won't be correct if it's leaking out. Air leaks are called vacuum or boost leaks, see 1000q: boost leak test (http://www.myturbodiesel.com/wiki/boost-leak-tester-leaking-turbo-symptoms-how-to-fix/) for more reasons why this is bad and how to check for it in your turbo car.

A faulty MAF signal will cause the car's computer to give too much or too little fuel. However, a TDI can run without a MAF signal at all, as can many cars. The car computer knows that there is either a nonsense signal or no signal at all, and uses a default value to keep the engine running. The computer takes the engine load and speed, modifies the value for some fuel and engine temperature readings and MAF value, etc., to determine fuel injection timing and metering. A gasoline car will run poorly with no MAF because they have to be within a narrower air/fuel ratio to run smoothly compared to a diesel engine. A diesel will run without the MAF signal but performance will be poor and the engine should feel sluggish.

The MAF sensor on mk3 was a hot wire type sensor. Mk4 and newer use a thin film or hot film MAF.

Never use silicone detailing sprays or silicone products that have not cured near the intake on a running engine. These could deposit on the MAF and contaminate the sensor. For the same reason, the engine air filter has a gasket on it - make sure the gasket is seated during filter replacement or else dirt can damage the MAF.

[Google44]

interesting....I've got the same engine and beside not giving great economy (40-42 at most) I cannot fault it! Same as you I've swapped MAF with the one from another car which was giving 50+ mpg and it made no difference at all. I will be following this thread as I've given up on it some time ago.

[Sam]

paulmaca why have you pasted large sections of text from myturbodiesel and Answers.com into your replies?

I'm very confused.

[Doctle Odd]

You can't clean a MAF and they must be genuine when you buy a replacement

[paulmaca]

To help people understand the MAF and diagnosing it. Some people read forums to solve problems and don't know what MAF is and if reply helps some else's problem then great

[Doctle Odd]

To help people understand the MAF and diagnosing it. Some people read forums to solve problems and don't know what MAF is and if reply helps some else's problem then great

What?

[paulmaca]

Reply was to to mycarsavw hit wrong reply box

[Eshrules]

To help people understand the MAF and diagnosing it. Some people read forums to solve problems and don't know what MAF is and if reply helps some else's problem then great

are you asking for help or not?

[Doctle Odd]

Reply was to to mycarsavw hit wrong reply box

What did he do on you?

[paulmaca]

Problem is car won't start when hot but fine cold ,changed coolant sensor ,checked batter giving 12v fitted new egr ,replaced maf tried cleaning but same values maf sensor because vcds readings and hoping someone can help checking crankshaft sensor ie can this be done in vcds . Is there something that can fail that would give false maf readings thanks

[Google44]

even if you disconnect MAF car should start as normal

[Sam]

To help people understand the MAF and diagnosing it. Some people read forums to solve problems and don't know what MAF is and if reply helps some else's problem then great

Are you asking for help with your MAF or are you helping people with theirs?

[arman123]

Have you checked your starter motor?

[paulmaca]

Yes please problem is car struggles to start hot and cold ,replaced coolant sensor (because originally hot start only) with original part ,checked earth,changed egr ,replaced maf went round with hoses with butane gas to check for air leaks with no change in idle .Not figured way to check starter or mass fly wheel . seems to be not getting enough air and too much fuel comments appreciated >Just started using vcds so not sure how to check ,but appreciate any advice .new values show half air pressure that it should be 25560

[paulmaca]

Hi and thanks arman
was hoping to work from small fix to possible expensive fix .Is there an easy way to check starter

[paulmaca]

Hi MAF isn't faulty chances of 3 giving same readings is surely lottery numbers lol but when disconnected does go into limp mode but no dash warning from any sensor .Is there relay that would cause problems below

[pauldazzle]

Dodgy cam sensor is a common cause of hot starting problems on VAG TDI's.