stumped

[Mike Miller]

Another update. Slowly getting things figured out.

I found the wastegate diaphragm very stiff. I could not actuate the WG by 
hand - on my donor cars the WG moves easily by hand. This explains why I was 
seeing so much boost at 1/4 throttle or less.

I sprayed the WG diaphragm liberally with PB Blaster and it has loosened up 
quite a bit. I may swap in a spare WG and see what happens. The car runs 
great to 1.7bar with the stock ECU. When I put in one of my chipped ECUs, I 
get the hard stumble again - but I can make about 2.0-2.1 bar if I very 
gradually ease into the throttle. Using a stiffer spring and different 
spring perches causes the hard stumble even with the stock ECU and it's 
*really* there with the chipped ECU.  This makes me think that the WG is 
still not fully opening when it should. I have run the stiffer spring with 
the chipped ECU in other cars with no issues. I have also replaced the WGFV.

mike


----- Original Message ----- 
From: Mike Miller
To: Bernie Benz
Cc: 200q20V mailing list
Sent: Wednesday, February 24, 2010 4:03 PM
Subject: Re: stumped


UPDATE: I replaced the plugs and it made no difference. Put my inductive 
pick up timing light on each plug wire and watched it fire. # 4 did not fire 
at all. I replaced that wire and it now fires and the car runs better. It 
still misses under load though. Kent suggested looking at the engine when 
running when it gets dark - I'll try that tonight and see what I can (or 
cannot) see.

I still don't understand why boost is comng on so early. I used to see 1.7 
bar max at this altitude - now I see 1.8 at way less than 1/4 throttle. I 
still wonder about a clogged Cat. Bypass valve, MAF, WGFV have all been 
replaced. Chipped ECU removed and replaced with a stock one. None of that 
made any difference - although I replaced those for a _low_ boost problem 
that went away when it started to miss under load.

mike