Author Topic: TBI running rich at 25mph  (Read 12928 times)

Offline 1MCP7.3/87GMC

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Re: TBI running rich at 25mph
« Reply #15 on: November 17, 2011, 11:09:15 AM »
All I need is a paper clip? Before testing I ran 91 octane a few tanks before did a full tune up and that did include a new air cleaner. Also would a scan tool be something auto zone or oriely would rent or are they relatively cheap and buying it be better?
1984 Chevy Silverado 2wd swb (311hp 350) El Diablo Rojo
1975 Chevy Scottsdale 4wd swb  silver slug 350 tbi
1987 GMC Sierra 4wd lwb 350 stock replacement

Offline Captkaos

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Re: TBI running rich at 25mph
« Reply #16 on: November 17, 2011, 01:02:25 PM »
You just need a paperclip in the AB slot to pull the codes.

For getting the other info, use this:
http://winaldl.joby.se/

This is mine:
http://forum.73-87chevytrucks.com/smforum/index.php/topic,7711.msg47384.html#msg47384

Offline Tazman

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Re: TBI running rich at 25mph
« Reply #17 on: November 18, 2011, 06:25:04 AM »
I bought mine scanner at Checker for 29 bucks,very good investment.
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God BLESS AMERICA

Offline JesseC

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Re: TBI running rich at 25mph
« Reply #18 on: November 22, 2011, 11:56:32 AM »
I'm just throwing out a suggestion.
 
Are you running headers? If so, the factory oxygen sensor is not self heated, meaning it only reaches operating temp by way of exhaust heat. Sometimes the headers place the sensor to far to reach optimal temp. This along with the fact that your running a lower temp stat could be the issue. A 3 wire O2 sensor will fix this. One wire for the factory hook up, one negative, and one switched power source.

my 2 cents.
JesseC
1987 GMC R10

Offline 1MCP7.3/87GMC

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Re: TBI running rich at 25mph
« Reply #19 on: November 22, 2011, 10:16:20 PM »
Running factory manifolds and the temp is only the 180 because it smoged cleaner then the 195 did.
1984 Chevy Silverado 2wd swb (311hp 350) El Diablo Rojo
1975 Chevy Scottsdale 4wd swb  silver slug 350 tbi
1987 GMC Sierra 4wd lwb 350 stock replacement

Offline SAATR

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Re: TBI running rich at 25mph
« Reply #20 on: November 23, 2011, 09:11:45 AM »
You really need to check fuel pressure KOEO, KOER, and KOEO with the return line blocked.  This will give you a good idea of the health of your pump, regulator, and injectors.  Barring any issues there, I would say it could be a bad TPS or MAP sensor causing the ECM to miscalculate load percentages.   Without any datastream info to back it up, it's just shots in the dark though.