still runnung rich 95 tahoe

[adam74]

95 tahoe tbi. have replaced everything except the tps, map sensor and throttle body itself, full tune up. still runs rich especially before warm up. one thing Ive noticed is if it sits for a few days the tb hangs up as if the butterflies catch on something. its not in the cable its in the tb. after it 'uncatches' it wont hang up anymore. also the ses light has come on twice over the past 6 months for the tps which might be the problem? has a slightly rough idle at times but not like a miss. anyone else have this problem?

 

[lesterl]

The Vortecs get carbon buildup in the throttle body, IDK about TBI....

Make shure the map sensor has vacume to it.

How do you know it is running rich? Symptoms? CTS sensor replaced (the one near the thermostat, not the one in the drivers head)?

 

[adam74]

yes replaced the cts. it smells really rich at initial start and the emissions report , which it passed, but still showed running rich. new y pipe with cat and o2 sensor. all vacuum lines are hooked up.

 

[lesterl]

o2 sensor wont do anything with the mix untill it has had some time to come up to temp.

How cold? TBI runs a fuel enrichment program when cold (electronic choking of sorts) as it is a wet manifold and they know alot of the fuel will condense back out of the air.

Compression? Ignition?

 

[adam74]

still showed running rich at normal operating temp when I got it inspected but really bad judging by the smell at start up. hadnt done a compression test. new cap, rotor,plugs and wires

 

[adam74]

when I originally bought it it had a 180 thermostat in it. put the stock 195 in and it helped but not enough I guess

 

[lesterl]

check the injector spray pattern by hooking up a timing light and using the pulses to "freeze frame" the spray pattern, does it look ok?

 

[adam74]

good idea. Ill try that and get back to you. I know theyre supposed to have a perfect 'umbrella' pattern