help with q-jet - The 1947 - Present Chevrolet & GMC Truck Message Board Network

slow69 · 09-25-2005, 05:43 PM

I recently took all the smog stuff of my 82 blazer and plugged all vacuum lines on qjet except for brake booster, vac advance and pcv valve. I also did the esc disconnect. It is not running right, sounds like it is bogging down, flooding out. Can I run a qjet like this or am I stuck buying another carb?

**swervin ervin** · 09-25-2005, 06:42 PM

If it's the stock Q-jet, which I gather it is, the one thing you have to leave is the connection the temp switch in the thermostat housing going to the dual capacity pump solenoid. The way this thing works is off coolant temp. When the engine is cold, the solenoid receives a signal from the switch as to temp and lets it send extra fuel to the accelerator pump, thus the name dual capacity. After the coolant reaches around 160 degrees or so, it sends the signal to the solenoid and cuts the fuel in half, or like a normal accelerator pump would act. Without this wire hooked to the temp switch, it thinks it's cold all the time and the accelerator pump will be in dual capacity mode all the time, wasting fuel. As far as I know, there is no way around this either except for leaving it hooked up.

This may not be your problem, but it will cause problems like you describe.

slow69 · 09-25-2005, 10:19 PM

thanks swervin,
I will try to connect that back up (with it's 3 or four inlets) and see how it works. Thanks again,
slow69

Slonaker · 09-25-2005, 11:38 PM

Quote:

Originally Posted by slow69

thanks swervin,
I will try to connect that back up (with it's 3 or four inlets) and see how it works. Thanks again,
slow69

The part Swervin is talking about is an electrical conector on the front passenger side of the carb. A wire goes to a temp sensor on the thermostat housing and one other spot, I think. The Doug Roe Rochester book I bought last night says the dual capacity pump was only found on 1985-1986 models, so you might not have it.

Slonaker

slow69 · 09-26-2005, 09:20 AM

ok, the only electical connection i see is for the choke and another on the driver side that doesn't really look like it does anything but I will look again.
Thanks

PHOENIX · 09-26-2005, 03:57 PM

pics?

09-25-2005, 05:43 PM	#1
slow69 Registered User Join Date: Dec 2000 Location: Flagstaff, AZ Posts: 140	help with q-jet I recently took all the smog stuff of my 82 blazer and plugged all vacuum lines on qjet except for brake booster, vac advance and pcv valve. I also did the esc disconnect. It is not running right, sounds like it is bogging down, flooding out. Can I run a qjet like this or am I stuck buying another carb?

09-25-2005, 06:42 PM	#2
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	If it's the stock Q-jet, which I gather it is, the one thing you have to leave is the connection the temp switch in the thermostat housing going to the dual capacity pump solenoid. The way this thing works is off coolant temp. When the engine is cold, the solenoid receives a signal from the switch as to temp and lets it send extra fuel to the accelerator pump, thus the name dual capacity. After the coolant reaches around 160 degrees or so, it sends the signal to the solenoid and cuts the fuel in half, or like a normal accelerator pump would act. Without this wire hooked to the temp switch, it thinks it's cold all the time and the accelerator pump will be in dual capacity mode all the time, wasting fuel. As far as I know, there is no way around this either except for leaving it hooked up. This may not be your problem, but it will cause problems like you describe. __________________ Mike 1985 Chevy C-10

09-26-2005, 03:57 PM	#6
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	pics? __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

09-25-2005, 10:19 PM	#3
slow69 Registered User Join Date: Dec 2000 Location: Flagstaff, AZ Posts: 140	thanks swervin, I will try to connect that back up (with it's 3 or four inlets) and see how it works. Thanks again, slow69

09-26-2005, 09:20 AM	#5
slow69 Registered User Join Date: Dec 2000 Location: Flagstaff, AZ Posts: 140	ok, the only electical connection i see is for the choke and another on the driver side that doesn't really look like it does anything but I will look again. Thanks



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