Factory boost gauge as diagnostic tool?
04-09-2004, 10:21 AM
#1
Instructor
Thread Starter
Factory boost gauge as diagnostic tool?
I read in another post that the stock bbost gauge should read 1 bar with the key on and the car not running, mine reads .75, is that a problem? Also, the speed and reference sensors, my car still has a part throttle hicup around 3000 rpm, so I tried a few items, new TPS, checked for leaks, and the last thing I tried I pulled the sensors one at a time and cleaned the gunk and metal shavings off them and reinstalled them, it is as simple as removing the 10mm bolt, pulling the sensor and reinstalling in reverse order isn't it? Car started and ran the same, still has the 3k part throttle buck.
04-10-2004, 03:35 AM
#3
Three Wheelin'
The .75 reading at idle is present on my car too, that's probably not the problem. As far as your removal and installtation procedure of the speed and reference sensors, it doesn;t sound like you did anything wrong. If you happened to disconnect and reconnect them, you might double check the connections. Even if you didn't remove them completely, the connections are exposed to a lot of heat, and typically crumble when even looked at the wrong way.
. that's way crap!
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04-11-2004, 06:45 AM
#9
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The factory boost gauge is - uh - shall we say "not reliable at all". It's prolly not the speed nor reference sensors, as they when bad make the car unstartable.
The part throttle hickup can be a couple things:
Fuel filter clogging, fual injector clogging
Coil/Wires/Plugs
Wastegate spring sticking a little
Small vacuum leak that gets bigger when you hit boot
Bad trace on the AFM module
I'd look at the last thing first....
HTH!
The part throttle hickup can be a couple things:
Fuel filter clogging, fual injector clogging
Coil/Wires/Plugs
Wastegate spring sticking a little
Small vacuum leak that gets bigger when you hit boot
Bad trace on the AFM module
I'd look at the last thing first....
HTH!
04-13-2004, 07:06 AM
#10
Race Director
What's the air-fuel ratio like at 2750rpm and 3250rpm (before & after) the stumble? Does it change any? If you can datalog the O2-sensor voltage, see if it makes a dramatic change at 3000rpm.
Also what throttle-opening do you have when it revs through 3k? Try 25%, 50%, 75% and 100% throttles through 3k-rpm. Does it happen at all the throttle openings? At 25% throttle, that happens to cross the 2.0v mark, do you have some massaging of the volt-in -> volt-out table? Save all your settings and turn all our ***** to zero adjustments and load up a blank voltage-adjustment table to verify some strange setting isn't in the box.
Also what throttle-opening do you have when it revs through 3k? Try 25%, 50%, 75% and 100% throttles through 3k-rpm. Does it happen at all the throttle openings? At 25% throttle, that happens to cross the 2.0v mark, do you have some massaging of the volt-in -> volt-out table? Save all your settings and turn all our ***** to zero adjustments and load up a blank voltage-adjustment table to verify some strange setting isn't in the box.
04-13-2004, 09:54 AM
#11
Instructor
Thread Starter
Originally posted by Danno
What's the air-fuel ratio like at 2750rpm and 3250rpm (before & after) the stumble? Does it change any? If you can datalog the O2-sensor voltage, see if it makes a dramatic change at 3000rpm.
Also what throttle-opening do you have when it revs through 3k? Try 25%, 50%, 75% and 100% throttles through 3k-rpm. Does it happen at all the throttle openings? At 25% throttle, that happens to cross the 2.0v mark, do you have some massaging of the volt-in -> volt-out table? Save all your settings and turn all our ***** to zero adjustments and load up a blank voltage-adjustment table to verify some strange setting isn't in the box.
What's the air-fuel ratio like at 2750rpm and 3250rpm (before & after) the stumble? Does it change any? If you can datalog the O2-sensor voltage, see if it makes a dramatic change at 3000rpm.
Also what throttle-opening do you have when it revs through 3k? Try 25%, 50%, 75% and 100% throttles through 3k-rpm. Does it happen at all the throttle openings? At 25% throttle, that happens to cross the 2.0v mark, do you have some massaging of the volt-in -> volt-out table? Save all your settings and turn all our ***** to zero adjustments and load up a blank voltage-adjustment table to verify some strange setting isn't in the box.
