electronic problems HELP!!! - Pirate4x4.Com : 4x4 and Off-Road Forum

alkynova · 11-12-2005, 09:49 AM

I have a 95 blazer, 4.3, auto, 4wd. runs fine up to half throttle, then hesitates and bogs down. I replaced to throttle position sensor and noticed something stange--when I measure the resistance directly at the sensor, it ranges from 1.8 at idle up 6.8 at wot, I believe that is an acceptable range. However, when measured through the pigtail, idle is roughly the same, but it tops out around 2.8 (coincidentally at about half throttle). Is this right?, if not how do I go about fixing this problem?
Thanks-- Nick
F.Y.I.-Nearly all ignition components are new as well as the fuel pump and filter.

DSBANHEN · 11-13-2005, 02:35 PM

You should be measuring voltage, not resistance. You should have 5v into the sensor, and approx .5v out at idle, approx 4.3-4.8 at WOT. You can measure this KOEO. If you have more than this into and out of the sensor you will need to determine if the pcm has a bad buffer ckt internally or if the
5v reference is being shorted to voltage somewhere. Good luck DB

tpi_boy · 11-13-2005, 03:43 PM

I agree with dsbanhen, you need to check voltage, you cant measure resistance on a powered up circuit. Is this tbi or mpi? they had both in 95.

s1037s · 11-14-2005, 07:25 AM

How about fuel pressure? Catalytic converter partially plugged? Ck Engine light on? Ck engine light not working? My.02.Hope it helps

11-12-2005, 09:49 AM	#1 (permalink)
alkynova Registered User Join Date: Nov 2005 Member # 57342 Posts: 1	electronic problems HELP!!! I have a 95 blazer, 4.3, auto, 4wd. runs fine up to half throttle, then hesitates and bogs down. I replaced to throttle position sensor and noticed something stange--when I measure the resistance directly at the sensor, it ranges from 1.8 at idle up 6.8 at wot, I believe that is an acceptable range. However, when measured through the pigtail, idle is roughly the same, but it tops out around 2.8 (coincidentally at about half throttle). Is this right?, if not how do I go about fixing this problem? Thanks-- Nick F.Y.I.-Nearly all ignition components are new as well as the fuel pump and filter.

11-13-2005, 02:35 PM	#2 (permalink)
DSBANHEN Registered User Join Date: Dec 2004 Member # 40562 Posts: 50	You should be measuring voltage, not resistance. You should have 5v into the sensor, and approx .5v out at idle, approx 4.3-4.8 at WOT. You can measure this KOEO. If you have more than this into and out of the sensor you will need to determine if the pcm has a bad buffer ckt internally or if the 5v reference is being shorted to voltage somewhere. Good luck DB __________________ You're gonna have that!! 73 K10, lift, lockers, etc, etc, etc.

11-14-2005, 07:25 AM	#4 (permalink)
s1037s Registered User Join Date: Oct 2005 Member # 54549 Location: stae of confusion, Ky Posts: 446	How about fuel pressure? Catalytic converter partially plugged? Ck Engine light on? Ck engine light not working? My.02.Hope it helps __________________ My wife still doesn't know about Pirate4x4.SHHHHH! Sky high!

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11-13-2005, 03:43 PM	#3 (permalink)
tpi_boy Registered User Join Date: Oct 2004 Member # 36845 Location: British Columbia Posts: 123	I agree with dsbanhen, you need to check voltage, you cant measure resistance on a powered up circuit. Is this tbi or mpi? they had both in 95.