T4 stalling every 1000k HELP!

[d4don]

Thankyou in advance for any help. My '01 t4 petrol 2.5 transporter has this odd fault. It will stall briefly under power at any speed, then run ok, then if stopped at lights will idle ok but stall again under power while trying to take off. This will happen a couple of times then run fine for another 800/1000 klm...and then does it again! The problem is always only under power.

What's going on 'ere!!? Have searched threads but haven't been able to pin it down.

Any ideas?? Thankyou...my Preggio driving mate is laughing at me!!

[vwguru]

well, dose this model have the map sensor just after the air filter? if not there should be a vac line running to the ECU, check or replace this hose, but also there is a pice of hose in the ECU housing, these hoses may not be split but may be a bit blocked? also check the throttle body for carbon ect. Any fault codes would also be helpfull.

Any other ideas anyone?????????????

[d4don]

well, dose this model have the map sensor just after the air filter? if not there should be a vac line running to the ECU, check or replace this hose, but also there is a pice of hose in the ECU housing, these hoses may not be split but may be a bit blocked? also check the throttle body for carbon ect. Any fault codes would also be helpfull.

Any other ideas anyone?????????????

hate to seem like an idiot but what does a map sensor look like and where do i find fault codes....and i know what an ECU does but have no idea where it is. I will check these when i find them.

thankyou guru...i really appreciate your help.

[Tombi]

Sounds like a sensor/failsafe issue.

[Silver Caravelle]

Hi there,

Your model has the MAP/MAF sensor (after the aircleaner). It has a metal strip (not heated wire) as the sensor inside the MAP/MAF sensor housing. They tend not affect running to the extent that you describe as it reverts to a defaut value if it is not working properly and should be still be ok under power. You can disconnect the lead to it to check.

I would also suggest checking the coil, as a faulty coil can break down when reaching normal engine temperature. Also check plugs and leads, rotor and distributor cap.

Also doubly check for major vaccum leaks on the inlet side, such as the inlet hose past the MAP sensor, and there is a vacuum hose that comes out of the inlet hose. Also check the brake master cylinder vaccum hose for leaks.

Fuel pump on the way out/ fuel filter partially blocked?

Does it do it when the fuel tank is near empty?

Actual distributor fault?

Check all ECU connections - including earth leads to the body of the vehicle.

Just a few thoughts. It would be worth plugging it into a fault code reader to check for fault codes.

Regards,

Scott

[d4don]

Thanks for the replies. I replaced the dis cap and rotor before the last episode. Just keep looking i guess.

[Silver Caravelle]

Thinking about this further. If it is running perfectly fine the rest of the time, it sounds like a loose electrical connection. Things to check. Earth leads from engine to vehicle body (unlikely), Knock sensors connections on the front lower section of engine block. Check O2 sensor connection (down stream from the exhaust down pipe). Blocked Catalytic converted intermittantly, Fuel pump connections, coil connections and HT lead?

Does the engine stall like the ignition is turned off or just struggle for power?

Cheers,

Scott

[d4don]

Thinking about this further. If it is running perfectly fine the rest of the time, it sounds like a loose electrical connection. Things to check. Earth leads from engine to vehicle body (unlikely), Knock sensors connections on the front lower section of engine block. Check O2 sensor connection (down stream from the exhaust down pipe). Blocked Catalytic converted intermittantly, Fuel pump connections, coil connections and HT lead?

Does the engine stall like the ignition is turned off or just struggle for power?

Cheers,

Scott

It behaves like the ignition is switched off... and if stopped during an episode like a traffic light it will idle ok but refuse to accelerate as if you're turning the key on and off. Then it will behave itself and continue another 500/1000k.

Thanks for the suggestions Scott. Will check as many connections i can get to.

Thanks again,

Don

[Tombi]

Next time your T4 is in for service at the Mornington VW dealership get the mechanics to fault check the bus to see if any fault codes are stored in the memory of the ecu.
Sounds like a faulty sensor, which defaults motor to shut down/limp mode momentarily. If that is the case, I don't think this will show up as faulty code.

Otherwise just keep drivin' it.

BTW how long has this been occurring?


Tombi

[vwguru]

Thanks for the replies. I replaced the dis cap and rotor before the last episode. Just keep looking i guess.

what about the basics air filter, fuel filter and plugs have they all been looked at or replaced? check the coil (behind and below the left head light) are you useing good quality fuel?

[d4don]

Next time your T4 is in for service at the Mornington VW dealership get the mechanics to fault check the bus to see if any fault codes are stored in the memory of the ecu.
Sounds like a faulty sensor, which defaults motor to shut down/limp mode momentarily. If that is the case, I don't think this will show up as faulty code.

Otherwise just keep drivin' it.

BTW how long has this been occurring?


Tombi

Did it once 1500 klm ago and again 500klm ago (last week). I keep driving the thing just hoping the next time it does it i'm not compromised whilst turning right in front of a B double a little ways up the road..

The air and fuel filters were done last service but the coil/transformer does look old and ratty...which doesn't mean its not working properly but i might replace it anyway. I do like the idea of these fault code things though.

[Tombi]

As a relatively cheap option and process of elimination, I would replace the ignition relay located benaeth the interior fuse box( right hand side below steering wheel). There are quite a number of them. Cannot remember which one it is sorry.

[vwguru]

As a relatively cheap option and process of elimination, I would replace the ignition relay located benaeth the interior fuse box( right hand side below steering wheel). There are quite a number of them. Cannot remember which one it is sorry.

it should be the one with 30 stamped on it

[d4don]

it should be the one with 30 stamped on it

I like this idea...i'll replace it. probably have to wait another 500 odd k's to see what happens though.

[d4don]

nearly there

Just an update for those who offered advice and for anyone else who may come across this problem.

The same problem has happened again, three times in the last 3000k, roughly every 1000k. I found the CAT had disintegrated and if i gave it a kicking the car would run ok so i replaced it. Problem solved?...nuh I also made sure the petrol's clean.

The thing stopped completely today and wouldn't even start so i called the racv. Cranking the engine with the coil lead disconnected showed an intermittantly weak or nonexistant spark. The service guy said it wasn't the coil but the module(?) in the dizzy which tells the coil when to spark.

Does this sound right? Car gets trayed to VW Mornington in the morning. Does anyone know if this module(i think that's what he called it) can be replaced instead of a whole dizzy? I'm a bit worried about the $$$$

Thanks again for all the help and advice.