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Large MPVs -- Ford Galaxy / VW Sharan / SEAT Alhambra: => Ford Galaxy / VW Sharan / SEAT Alhambra => Topic started by: Topsnort on July 15, 2018, 12:43:37 PM

Title: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: Topsnort on July 15, 2018, 12:43:37 PM
Good afternoon all
I wonder if anyone could help with my problem. Galaxy 1.9 TDI AUY 2003. 140k
Symptoms are power tails off under moderate acceleration sometimes. noticeable lower power generally.
I have used a generic scanner and note that the MAP value does not change when applying throttle when running.
There are no DTCs stored and the MIL is off.
Data for the MAF is updating and looks ok to my untrained eye.
I have removed the MAP but wonder if anyone knows the pinout so that I can test it.
I have considered stuck turbo vanes,
restricted fuel filter but think there should be changing data from the MAP
Thanks in advance for any help
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: johnnyroper on July 15, 2018, 08:38:25 PM
If map was not changing I would expect an underboost fault as maf will see incoming air and accelerator position so demand more boost,if the actual was lower than desired it would trigger fault and limp mode.

Check the EGR valve is not clogged with crap and sticking open slightly. Also worth exercising the vnt actuator to make sure it moves freely
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: Topsnort on July 15, 2018, 09:57:22 PM
Thanks for the reply.
The car has gone into limp mode a few times. Restarting exits limp mode. the engine falters at higher RPM and also intermittently under load like coming off a roundabout. Strange that the car goes into limp without setting a fault, unless it is not recognizing the condition. I tried to find the vnt actuator today but it is tucked away. The arm on the EGR is freely moving but that doesnt mean its working. Is it likely that freeing the VNT externally via the actuator will last or should it be stripped to be cleaned? I only ask as We need to use the car to go to France in 3 weeks time 1200 mile trip. Was fantastic last year and didnt miss a beat. Trouble is it doesnt get used enough. Going in to the fuel injection specialist tomorrow to see what they think.
I would have expected some variation in manifold pressure to show via the MAP sensor when throttled even if there was a boost fault. Hopefully I will know a bit more tomorrow.
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: brianh on July 15, 2018, 10:04:31 PM
it may be your diagnostics aren't seeing the data, rather than the sensor not working. Most people here use VCDS for the diesel engines, it might be worth getting hold of a lead if you can as its useful for most other modules on the car as well. I'd suspect if it does it sometimes you'd see the sensor giving readings at least some of the time, rather than nothing?

What diagnostics are you actually using?
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: Topsnort on July 15, 2018, 10:23:17 PM
Hi Thanks for the reply.
The scanner is a Clarke (Machine Mart) handheld unit the live data shows for other sensors. I tried a VAG COM lite which I have for my golf but no go.
I will def get a proper device but am running out of time.
I did expect the value to suddenly jump.  If it is relevant I unplugged the MAP sensor whilst the engine was ticking over and it made no difference to the idle.
Would you recommend a particular VCDS unit?.
Bet its the VNT
Cheers Rob
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: brianh on July 15, 2018, 11:02:27 PM
The VAG com lite should work, but VAG com would be an older version now, using the same drivers which came with the lead you should be able to use VCDS lite from http://www.ross-tech.com/vcds-lite/download/index.php - that should at least be able to talk to the car, not sure how far you will be able to go with visible data though - others more familiar with the diesel versions may be able to help there.

Don't know which would be best out of the full versions for what you want, i've used a hex-can lead for a Golf and could do what was needed between that and VAG-Tacho, I've used the Hex-can lead on the petrol ones, but not had to go further than fault codes using that.

I'd suspect from what you've said that the diagnostics are somehow at fault with that one sensor for whatever reason, I've found a few bits of odd readings that don't work properly for various reasons with certain diagnostics, some will only scan codes but not display live sensor data on some vehicles. It may be something addressed with a software update for the scanner. Don't know of another way of testing the sensor unfortunately.
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: johnnyroper on July 16, 2018, 08:41:34 AM
The egr does not have an arm that part is the anti shudder flap,the egr is the part next to it with the larger vac pipe on. You can only really check by removing it and cleaning the crap out.

If it has gone in limp as you describe it will have logged a boost deviation fault but as Brian suggests it sounds like your diagnostics and not reading it properly. Vcds is the best software to use in my opinion.

As for the VNT which I suspect it is take off the bulkhead extension panel as that will give better access to it,you want to make sure it is on the stop and when you try and move it needs to be smooth and go all way to stop at other end. Also once you can see it start car and the vnt should move from stop all way to other end when sat at idle.

If it is tight/notchy then the mr muscle treatment down egr outlet on exhaust manifold will do the trick. Come back to us if you find vnt at fault and I will explain how to do it as I did mine a couple of times.
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: Topsnort on July 17, 2018, 09:43:37 AM
Looks like I am on the learning curve! As I have little time I have dropped the car into Diesco in Ipswich and am waiting for their findings. Which I am sure will concur with your kind advise. If it were not for the France trip I would be squirting Mr. Muscle down its throat right now.
  I have downloaded the VCDS software as you suggest and I think it should work with my lead. however as the car is not here at the moment cant test it.
  Just to make things more interesting my 08 Relay Van has developed a similar fault also!!
  Great that you are so knowledgeable and helpful. I saw a post on another site the other day and the author was telling the questioner that if he didnt understand how it worked then he shouldnt try to diagnose it. Havent seen any of that on here yet. Will post an update Thanks again
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: johnnyroper on July 17, 2018, 12:51:28 PM
If it turns out to be VNT I would imagine they will quote for a recon turbo?

Mr muscle works a treat problem I have is mrs drives like miss daisy and is scared to get cars on boost..... I switch cars around for going ng to brum/work etc and give Italian tune up keep in lower gear on motorway etc for half hour to get ex gas temps up. Seems to keep on top of it especially now both cars got DPF
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: Topsnort on July 17, 2018, 09:08:56 PM
Right again! VNT sticking near the top of travel, replacement turbo on the way. I hope to keep this car until I dont need 7 seats. The 1.9 TDI engine is one of the best ever designs. after that they have too much tech due to the emission controls.
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: johnnyroper on July 17, 2018, 09:30:50 PM
If you are having a recon fitted so starting with clean slate so to speak,make sure you take it on a decent every week or so at motorway speed in a gear that will keep RPM around 3-3500 to keep things nice and free. 20-30 minutes in 5th at 70-75 should do the trick
Title: Re: Manifold Absolute Pressure Sensor Galaxy 1.9 tdi 03
Post by: Topsnort on July 18, 2018, 09:32:17 PM
Thanks for the advice will do.