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How does choke on mid 80s GM V6 VaraJet work?

I've got an '84 Pontiac w/ 2.8L 173CI V6 (really a Chevy V6). The orig choke has been acting up, barely sets on a slightly cool morning and almost immediately opens making the car prone to stalls for about the

1st five minutes.

Picked up a new choke tstat from local parts store thinking bimetal spring was 'tired' - this one stays set waaaaay too long - it could take 30 minutes of driving before it ever opens up fully (and doesn't allows the 2ndaries etc to kick in and having to ride the brakes too much when stopping).

Either the new one is:

A) not properly calibrated (they sold me one that was for ALL 84s and other databases are specific to the part# on the Rochester VJet offering up to 3 DIFFERENT tstats part#s so am suspicious about how 'correct' the tstat is they sold me). That can be easily rectified or it may be 'close enough'...

B) or the wire leading up to the tstat is not working properly. DOes that wire 'heat' the metal spring? I don't see any way for heat to directly apply to the choke spring other than by general ambient engine heat eventually getting there (why it takes 30 minutes to eventually shot off?). If so - What triggers the voltage to teh coil? Does it wait for a minimal temp reached by a sending unit and some sort of logic unit trips voltage to the choke? Does voltage then remain constant for the duration of engine operation to keep the choke open? Is there a logic unit or relay in the mix?

thanks!

Reply to
loadhawg
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"loadhawg" wrote in news:1125761999.263135.19580 @o13g2000cwo.googlegroups.com:

if memory of choke function serves me correct, choke wire is direct feed off of alt. stator. should be B+ anytime eng. running.........that would explain half hour to unload choke.........kjun

Reply to
KjunRaven

All of the electric choke heater I used to see had voltage on them any time the engine was running. Electric choke heaters were used when emission controls became common because electric heat was more reliable and opened the choke faster than exhaust heat (Ford) or intake manifold heat (GM). If the choke is slow opening it is probably not receiving the proper voltage.

Reply to
Mike Walsh

I have a 1984 Chevy Celebrity station wagon with a 2.8L in it and this exact same carburetor that I drive every day. It is the computer-controlled version like yours is.

The behaviour your observing is normal. The choke on these carbs only works to start the car then as soon as the car is started, the choke backs off. Keep in mind that on a cool morning if your choke wasn't functioning at all, you would not be able to start the car. If you can start the car then the choke is (or rather was) working.

Howerver, you should not requre 5 minutes to heat the car up to keep it from stalling out. Mine can stall right after starting if I put it in gear within 5-10 seconds of starting it, but after 30 seconds it will not stall, even though the choke is not on.

Your problem is you have some other fuel problem in your vehicle. I am guessing that you have a bad sensor, perhaps coolant sensor, and the engine computer isn't enriching the mixture enough. After 5 minutes your exhaust has probably hotted up enough to get the O2 sensor running and the engine computer then uses that to adjust the mixture properly. But until the O2 sensor is active the engine computer is running the engine too lean for a cold engine.

You need to buy a engine scan tool and use it. You can buy older model OTC Monitor 2000 devices with the GM software and cabling for your car off Ebay for dirt cheap, and I mean really, really, dirt cheap. Then plug in the scan tool and monitor your engine sensors it should be obvious which one isn't working.

And put the original choke back, obviously.

Ted

Reply to
Ted Mittelstaedt

It sounds like he has a choke pull-off that is not working. The diaphram leaks and allows the choke to work too long.

Reply to
Al Bundy

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