1.4 bar

Phil Rose pjrose at frontiernet.net
Fri Feb 4 18:26:44 EST 2005

At 2:23 PM -0500 2/4/05, Dan Wing wrote:
>Is there a simple list of conditions that give a 1.4 bar boost limit?
>I had an overheat beeping signal despite normal gauge reading and 
>fluid in coolant reservoir.

Those all are classic symptoms of a problem with the 3-pin MFTS 
(either coolant has collected in the connector boot, or an internal 
sensor defect). Remove the connector from the MFTS and determine 
whether or not full boost returns. If yes, and _if_ the rubber boot 
was completely dry, you should replace the MFTS. In any case, leave 
that rubber boot off when you reconnect. Another test for a bad MFTS 
(along with those other symptoms) is if your A/C compressor will not 
run. A bad MFTS disables A/C as well as boost.

>Since I was due for a timing belt (and boy, was I due-- the old one 
>was really loose, and the idler bearing was shot) I had that done 
>and the crank and (leaking) camshaft seals at the same time. The 
>water pump had been leaking, and was replaced.

Wow, you really needed all the bits--I wonder how long it had been 
since the previous timing service?

>  Also, the temp sensor on the back of the head was replaced, the 
>contacts on the sensor on the left side of the engine were cleaned 
>(it was replaced about a year ago)

Which sensor contacts on the left side (driver side?)? If it was the 
MFTS, then that probably confirms the diagnosis--somebody went and 
"fixed it". :-)

>  and the spark plugs replaced. Several deteriorated hoses replaced 
>while accessible, including one from the bypass valve forward to the 
>turbo-- that one had a hole in it.

There is no such hose between the BPV and turbo. Unless you mean the 
wastegate hose, I assume you mean the BPV hose going back to the 
intake manifold.

>The car then ran fine, and had full boost (also better mileage than 
>ever before!) for about 35 miles on the interstate until I witnessed 
>a full-speed roll-over accident ahead of me (really wild) and parked 
>on the shoulder, engine off, to render assistance. No major 
>injuries, thanks to luck and passive restraints.
>Anyway, I was there about 20 minutes, and when I drove off on a long 
>uphill I noticed the car was missing/bucking a little.

You see, no good deed goes unpunished. :-(
The "bucking"--possibly a loose hose clamp (quite possible if the 
shop replaced a bunch of them)? Sounds as though you might have more 
than one problem.

>  And it now it will only make 1.4 bar. I won't be able to get it 
>back to the shop to get the codes dumped (they do only German cars, 
>and work on several other 20V's) until Tuesday, but I wanted to have 
>a list in mind of things for them to check. Obviously, manipulating 
>the plug wires off and on could have led to damage, or I could have 
>a bad sensor connection. Anything else on the list?

Well, there's the ever-popular wastegate frequency valve...a bad wgfv 
defaults the max boost to 1.4 bar.


Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net

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