Knock on Caspers gauge but no retard on XFI??

T

turbogn_231

Member
Joined
Apr 14, 2006
Why would this be happening? I am getting a fair amount of knock reading on the Caspers gauge(first or second yellow light) with no ESC retard on the XFI? Car is breaking up as I reach higher boost levels. Any ideas?
 
I think the first thing I would do is get a log and get it to Cal

Bryan
 
Phoneguy - Tried that
longball - 2.0 and its brand new. Its only been in the car for a month or so.
 
Same thing here,

I took the knock gauge out if the car.


Posted from the TurboBuick.Com mobile app
 
Ok, but at the time the gauge is reading knock the car is breaking up. Cant be coincidence can it? XFI shows nothing(that I can see anyways)
 
Although I believe the xfi ignores knock untill a point, I could not get an exact answer on the fast forums.


Posted from the TurboBuick.Com mobile app
 
turbogn_231 said:
Sorry, didn't realize that there was an ecm section. Maybe a MOD can move it? Or i'll repost in that section.

Ill look into this setting. Where should it be set?



Posted from the TurboBuick.Com mobile app
Click to expand...


no need to be sorry , just that if you post there you'll have a better chance of reaching those that play with XFI

second yellow is under 2 degrees knock and the XFI may very well ignore that
ive heard some say ignore the led knock gauge or get rid of it , well knock is knock and while it can go off due to mechanical things like rockers and such if tuning makes it go away its not mechanical clatter
light knock if the tune isnt corrected or the cause isnt fixed can become heavy knock given different conditions


as far as this thread the opening post and replies really should have been focused on isolating and fixing the breakup issue instead of being concerned why its not showing on the xfi

at what boost level/rpm are you at seeing knock and what timing are you running (i do see cal tune so i would assume its on the safer side around 20)
breaking up could be
ignition related ...a weak coil / bad plug/bad wire/ crank signal
valve train related ....a broken valve spring, bent pushrod or collapsing lifter,
fuel delivery issue.... not enough pump /injector or line for the e85


where is a log of the trouble
 
I attached a datalog from yesterday, from a roll, easing into throttle. Hopefully you can open it.
I am going to try and change the plugs tonight since its an easy cheap thing to try.
 
the resolution is lousy , is this from an internal logger , try logging with laptop
you dont have a fuel gauge hooked up but you are getting a fuel pressure spike when the second pump comes on and its sending you rich
looks like its set at 125 kpa 4psi , might want to move that up to 10psi

not sure what supposed to be in the log but i dont see the breakup and only see it go to 5200
with the combo in sig and the 1.6 rockers it wouldnt surprise me if the valve springs arent enough
 
-Logged with laptop, not sure why resolution was poor. Maybe it was the way it attached or zipped.
-second pump comes on at 8psi. I do get a pressure spike but looks like only 10% correction for a brief period. I didn't think that was too bad. Maybe I'll bump it to 10psi
-I agree, I didnt see anything strange in the log either but I sure can feel it, And the caspers gauge shoots up at the same time(and no retard on the xfi)
-car hasn't seen higher rpms than 5200. (it shifts early)
 
Ok so, took the plugs out and looked at them. They were gapped at .040. Re gapped to .030 and re installed. Car ran MUCH better. I slowly kept turning up boost and logging. Making small fuel adjustments along the way. Changed the second pump to come on a little later. My first 20psi run I had 2 degrees retard on the xfi so I know thats working. The caspers gauge was all over the place, sometimes showing knock other times not, maybe its my downpipe hitting the frame or something. I was able to make a 25psi run with no KR. I guess it most have been the plugs? Maybe the high boost levels blowing out the spark. Thoughts?
So far so good, I'll take it out a little tomorrow and she how it does. Thanks for the help
 
turbogn: "longball - 2.0 and its brand new. Its only been in the car for a month or so".[/quote said:
The release of 2.0 solved the ESC Retard problem in XFI so that's not it.

Sounds like you are getting it straightened out. :)
Click to expand...
 
Cal,
If you're reading this, I'd like to do another dyno tune with you now that my pump issue is fixed. If anyone in the midwest is putting one together, please let me know. I'd be happy to drive a couple of hours to do it again. After driving it the last few days I'm coming to the conclusion that its not near fast enough for me. I don't know if its the tune, combo, or something wrong. Lets get it figured out so I can make upgrades over the winter. I think I 'need' a low 10 sec street car.
 
I shoulda known better, I bought this car thinking it would be 'enough'.............its never enough!!!

Steve, can't go tomorrow but ill try and give you a call back.

Posted from the TurboBuick.Com mobile app
 
You must log in or register to reply here.

Similar threads

BUICKTIME
NEW & USED PARTS: UPDATED LIST AND PRICES… Caspers, VDO, Harland Sharp, Red Armstrong etc...
2
Replies
25
Views
2K
Ttype6
T
jshot
knock on gauge but not scanmaster
Replies
5
Views
807
jshot
jshot
'87 Turbo "T"
No knock
Replies
8
Views
896
'87 Turbo "T"
'87 Turbo "T"
G
NEW to Turbo Buicks - PTE Chip Timing
Replies
7
Views
782
TireFryer
TireFryer
Benny™
Running lean?
Replies
8
Views
1K
Benny™
Benny™
Top