[urq] I'm SO close to giving up...Anyone have a stick of TNT !!

[DGraber460 at aol.com]

In a message dated 4/15/2005 4:53:28 P.M. Mountain Daylight Time,  
John.Chaplen at mercer.com writes:

Ok....basic problem...Under "WOT" and boost the car stumbles...back  off
the throttle just a TAD and car starts pulling strong again...  

What's been done...(not necessarily in this order)

1 New fuel  injectors - all lines checked and cleaned
2 fuel Dist checked, but rebuild  anyways (with increased flow) - all
retested..seems no problem with  flow.
3 Volume test done - Ok'd
4 Pressure test done - Ok'd
5 Back  flow from Exhaust - NP there
6 Checked for the small filter ...no problem  there
7 checked WOT and IDLE switch..all fine there
8 new cap, rotor,  spark plugs and wires...
9 Volt at coil is 13-14 volts
10 all grounds  clean and tested
11 Compression check + - 10psi between all 5 cyl
12  Pulled all 5 plugs, they all look fine, no damage, they all look the
same  too...clean and right color...(bosch tri-electrodes)
13 Swapped ECU with  known good one...still same problem
14 checked Waste gate for torn  diaphragm - no problem there
15 New fuel filters (twice)
16 Boost is NOT  passing 14 psi (chipped by SJM)
17 checked all hoses and removed them, they  are fine.
18 I have backed boost down to less than 9psi still same  symptoms
19 removed full throttle cable (thinking it might be a full  throttle
mode) nope..
20 new and checked the Freq valve for duty cycle  looks correct and can
hear it working
21 rebuilt alternator to make sure  voltage/amps were not a problem
21 car passes DEQ SUPER clean...

I  guess my last question would be that I can think of, are there any
sensors  that might be bad that would put the car into a reduced  timing
mode?

I have had Scott Mockery drive the car, and it's NOT a  fuel cut out
issue (4K cut out).

I just installed a fuel air meter  box Wednesday, but have not had a
chance to run it...but from tests at idle  with running WOT switch, it is
fully enriching as it should do...
and  running and idle it's stoich? (sp)...I will be trying to drive it
this  weekend to see if it's running too lean...But to me at this point I
feel  like it's a timing issue?

(NOTE- I have done all of the above to try to  fix this problem)

Any help would be so much  appreciated!!!



John Chaplen CNE
Mercer Human Resource  Consulting
Portland, OR 97204-3693



As I stated this morning, here is my $.02 .
This has shown why I love this list. All posts have been empirical  evidence. 
A+B=C. Not theory.
My experience over a 4-5 year period resulted in all the changes/fixes you  
mentioned above with equal results. I think (and hope) that the use of an air  
fuel mixture gauge will validate my findings and cure.
I had implemented all of your fixes and ended up going from stumble to flat  
spot at WOT. Partial throttle _always_ seemed to be more fruitful than WOT. I  
have heard this same lament from many other CIS owners.
After much gnashing of teeth etc. I messed with/modified a spare Fuel  
Distributor and my full throttle issues went away. Since these units  can be very 
finicky, I recommend doing this with a _spare_, and not your  original FD. I 
removed the allan head screws adjacent to the fuel lines and  under these caps 
are another set of allen head screws that I believe are a  limiting screw for 
the lifting of the thin metal membrane controlling richness.  I turned these 
screws counterclockwise 1/8 of a turn (45 degrees). I reset the  duty cycle, and 
the car never ran better. For sake of experiment, I later tried  a full 1/4 
(90 degree) turn out and the performance fell away.
Remembering what Phil Payne once stated, that the 3 most important things  
for CIS tuning are 1) fuel pressure, 2) fuel pressure, and 3) fuel  pressure, 
that means mixture. From that line of thought, I changed mixture and  solved my 
issue.
I live and drive at 5k feet, so your results may vary. A lot!
HTH

 
Dennis
Denver