1985 5.0L HO 5 speed Manual Z28

Hey gents,

My car takes a good 15-20 seconds of cranking after sitting overnight before startup. It is carburated with a cam operated mechanical fuel pump. I have read many different threads on whether or not there is a fuel pump in the tank on these models as well, with no straight answers.
The car is in immaculate original shape with only 10,700 km's needless to say it hasent been jimmy-rigged by anyone wiring wise but I hear no pump when the key is turned on, just a clicking noise under the hood for about 20 seconds then it stops. This is my 2nd iroc since my first was stolen and havent really had much experience with them. I appreciate all feedback!
Thank you!

 

There should not be a pump in the tank for an 85 model year. I believe they started doing that in 87 for the carb cars.

Still what you are experiencing is common on older Quadrajet equipped cars, regardless of make or model, and some carbs in general.

I have had Buicks do that when the gasoline literally evaporated out of the fuel bowls overnight. Then the engine has to crank long enough to fill the float bowls again before it can start. A quick test to do will be before you crank the car up, pop the hood, take off the air cleaner and pump the throttle by hand with the choke open. You will see gasoline squirt out if its in the carb. When I did it, no gas squirted out.

I thought maybe the gas was evaporating out due to some emissions stuff, but that wasn't it. On mine, there was some little plug leaking slightly and allowing all the gas to disappear over night when it was parked. It did not leak to the point of ever seeing raw gasoline anywhere or any other warning signs.

I rebuilt the carb and found some of the little plugs on the base of the carb not doing so hot. I seem to remember epoxying some of those but its been 20 years, so I really don't recall.

Good luck testing to find out!

Also, maybe there is a choke pull off keeping you too choked up?

 

b4 you crank it, slowly push the gas pedal to the floor, release, then crank.

 

I have the same thing with my 86 quadrajet IROC. When It's cold, I push the peddle to the floor 2, sometimes 3 times between cranks before it starts. I don't crank the starter any longer than 3-4 seconds. It's hard on the starter to let it crank longer durations. My carb is rebuilt, and runs great. I don't consider it a problem at all.

 

Definitely wouldn't hear a pump prime with the mechanical pump on the motor. Check for good fuel flow, like what they said, also check for good air flow and good spark. Maybe a timing issue.

 

I rebuilt my Quadrajet and I have the same problem. I wish I could help you. I just assumed I did something wrong on the rebuild.

Cold starts take a while. Warm starts fire right up.

 

quadrajets of all generations are known for leaking well plugs. Earlier models are more of a problem but the later ones can do it to. What happens is overnight the plugs leak and the fuel drains out of the bowl and into the intake. By morning it has evaporated and the bowl is dry. So cranking in the morning has to refill the bowl before it will fire.

The other problem they are known for if the plugs aren't leaking is drain back via the fuel feed. If the seat on the float isn't a perfect seal and the drain back valve in the fuel pump is a little faulty it can siphon the fuel out of the bowl, through the pump, and back to the tank.

Either situation is not a huge deal as many Qjets share these characteristics. Just pump the crap out of it in the morning while cranking as the accelerator pump is the first to get fuel and by pumping the throttle will allow enough fuel in the motor to get it started.

 

KrisW is right on about the leaking aluminum plugs
underneath the Q-jet-i have had a few with that problem
a little epoxy was the fix...Not all 5.0 H.O. have the
auxillary boost pump in the tank,though a 12-83 build
'84 model i examined did have the boost pump-some
also had a little blower under the RH front fender with
a hose to blow on the carb,a 2-84 H.O.Z28 i looked at
had the blower but the blower was '85 dated,so
added by the dealer.L69 H.O.s run hot under the hood
because underhood ventilation is reduced with the
electric fan used on the L69s

 

Aluminum well plugs, that was what I was trying to say, hahahahhahh!

A little epoxy, and its all over with after that. If you go to the auto parts store you can get the Rochester carburetor book in the tech manual section and it will show you the plugs.

Also, take a little time with your service manual and follow these tips, too:

https://www.thirdgen.org/quadrajet

You'll be happy you did!