This old nail is gonna get torched soon

[audiman]

This damn car is still running like a bag of turd. WGFV has been replaced today after Royal Mail let me down along with half the country. Selfish gits, thats another story.

The original WGFV didn't work as it was tested on another car. The new one works on this car and mine now does something different. It is not making boost, still only about 0.8 bar with the spring wound in. The WGFV is venting loads of excess boost to intake, so im assuming that its trying to run low boost. No Fault codes are stored in the ECU, which is handy

It feels like you hit the rev limiter but only when the boost goes past 0.6ish bar. this hits in first at about 3k, but if you accel. gently to even 5k and boost it, it does the same. I have NO leaks as all small hoses have been replaced and the others have all been off to check. I have the IC o ring mod and thats ok. DV valve is new. (have gone back to standard setup not atmos.)

PLEASE PLEASE PLEASE help me. Im getting so pissed off. I had a Saxo nail me today and that has pushed me to drinking again tonight. X10

[Glen Chamberlain]

Hmm, weired not showing any codes especially cos it sounds like the overboost protection routine is taking effect? To replace WGCFV did you umplug or possibly disturbe the MAF? Try cleaning the plug with a bit of brake cleaner or somthing! I know thats what i always say but when i thought i'd tried everything i tried the brake cleaner in the plug and its never falterd since? Its only worked for me so far so iam looking for some one else to try it and succeed!

(silly question but you have definatly got the WGCFV plumbed up right?):

What did it do with the old WGCFV? cos you said it does somthing different now?:

[s2driveruk]

any chance you have blown a hole in one of the pipes since you last checked them??? I'd check any that are not new to be honest...

Sounds like its one thing after another with yours - hopefully you'll have it sorted soon.

Have a few beers and forget about it and just think, once its fixed and that **** in the saxo sees you again, you can nail it and well p*ss him off :nana:

David

[porkkis]

Doesn't the 3B and ABY have some kind of protection against overheating? The ECU lowers boost when it thinks the engine is overheating. Also the a/c compressor is shut down.
I think the multifunction sensor signals this and it might be faulty in this case. The sensor is the 3 or 4 pin one in the external water pipework under the IM.
I also might be completely wrong about this...

[s2driveruk]

Hey Porkkis - where in Finland are you - i was in Helsinki last week on business, as you have the same colour 3b as mine would have been good to see it and have a slide on the fresh snow

Cheers,

David

[Glen Chamberlain]

One additional sensor to check when having low boost problems on the 1991 200TQ 20V, is the Multi-function Temperature sensor which is mounted underneath the intake manifold on the coolant pipe on the side of the cylinder head. It uses a 4 terminal connector which is normally is covered with a protective rubber boot.

The 1991 200TQ 20V and 1992-95 S4/S6 Engines use the same Multi-Function sensor as the 5000/200TQ etc. but it is mounted upside down on the water pipe that connects to the upper radiator hose.

The newer style replacement Multi-Function Sensors will have only 3 terminals as they simplified the internal design of this sensor and eliminated the +12V supply to this sensor.

1991 200TQ 20V: Unfortunately, the 3 terminal version has proven to fail with a "false" overheat signal which will shut off the A/C compressor and send a signal to the 1991 200TQ 20V ECU to lower the boost.


The 1992-95 S4/S6 Engine Control Unit does not use this Multi-Function Temperature Sensor input and will not experience low boost problems from its failure.




This temperature sensor supplies the signal for the dash mounted coolant temperature gauge and can cause intermittent temp gauge operation. In some cases the connector terminals can be corroded and will be causing a poor connection. If the connections are ok, then the sensor is likely defective inside and is causing this intermittent coolant temp. gauge operation. It is very common for the gauge to begin working after this 4 pin connector is removed and installed due to internal sensor connections being moved.


1991 200TQ 20V: This sensor also provides a ground signal from Pin 2 on the sensor to PIN 14 on the ECU if the engine is running too hot (over 247F, 119C) which will reduce the amount of boost the ECU will provide. The Waste Gate (WG) operation is not allowed when this overtemp condition occurs. The BL/G wire (2/R terminal) coming from this sensor should be tested to ensure that it is not grounded. If you remove the connector from the Multi-function temp sensor, pin 2 is the one on the lower right, with the connector end facing you and the connector notch towards the top.

If you suspect the Multi-function sensor is causing the low boost, you should remove the connector from the Multi-function switch and re-do the test. If it works with the connector removed from the Multi-function temp sensor, then the temp sensor is defective and is grounding Pin 2 which will prevent correct operation and this will limit turbo boost output. You should check the wiring between the throttle switch and the ECU as well.


This wire from Pin 2 on the sensor, is also routed to the A/C control head unit which will turn off the A/C if the engine temp. exceeds 247F. The sensor is also connected to the dash mounted warning system and will issue a warning symbol if the engine coolant temp exceeds 247F [1].

I can email the doc if anyone likes cos it all wont quite fit on hear!

[audiman]

So i take it that if I unplug that coolant sensor it should boost OK. I have had problems with the connector on that sensor before, but it was giving me gauge problems. I dont have them at the moment but its got to be worth checking.

So just unplug and the heap should fly??

[Martynf]

Glen,

damn useful doc you have there!! I 'm beginning to wonder about that on mine now.....

I am now positive that I'm low on power (couldn't keep with Pauls S2 today and his is standard!!) and I still have this flat ish spot from 3,800 to 5,000. I changed that sensor only a couple of months ago, so it should be ok, but by coincidense, my AC compressor won't work anymore?? hmmm I wonder.....

Doug gave me a good tip, his S had a similar flat ish spot which turned out to be a leak at the exhaust manifold. I know for a fact i have a slight blow on on of the two front pots, so maybe... that's my cause of the flat spot.

Anyhow.... waffle waffle, can you mail that doc to me please!!

Thanks!
Martyn

[audiman]

but by coincidense, my AC compressor won't work anymore?? hmmm I wonder.....

May just be another leak! Cant imagine that the sensor has ****ed up already.

[porkkis]

Originally posted by s2driveruk
Hey Porkkis - where in Finland are you - i was in Helsinki last week on business, as you have the same colour 3b as mine would have been good to see it and have a slide on the fresh snow

Cheers,

David

220km to Helsinki from here.
Unfortunately I couldn't have offered you a ride as the car is still in the garege without engine..
Next time then.

Tomorrow I'll get the head and after few weeks perhaps it runs!

[porkkis]

http://www.sjmautotechnik.com/20vmfsns.html

[audiman]

Thank you for all your help and tips, will try unplugging that switch today and see if the crate goes better.

If not its going into a field with a box of matches.

[blu_s2]

I can email the doc if anyone likes cos it all wont quite fit on hear!

Glen, I'd like a copy as well. Cheers

[Glen Chamberlain]

i'll mail it when i get home but if anyone wants then its all on the link porkkis has posted above and loads of other cool stuff too!
http://www.sjmautotechnik.com

[S2central.net]

The source doc is also available on Erwin for ****** all money. Tis part of my library !


Cheers,

Paul