Author Topic: 1979 Trans Am now using Holley 0-80555 carburetor, hot hard to start  (Read 38 times)

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Offline chrislynn5

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I had a small shop perform some work for me on my '79 Trans AM and they talked me into replacing my Rochester Q-Jet with the 80555 spread bore carb.

I have several issues:
1.) They said it was the same size as the Q-Jet but even with a thin gasket it pushes my hood up, since the gasket on the blower scoop. Is it the same height?
2.) Most important: I have a real bad issue with hard to start when the engine is hot. The engine runs well at 180-190 degs. But when I park and let it sit, it's hard to start. I have to pump or hold down the gas pedal and there is a strong smell of gas of course.
3.) When I checked the air filter it reeks of gas.
4.) Checking the canister configuration, I'm not sure if the purge is correct? Is it not using the canister. I thought the shop might have done something with it, so I'm trying a vented gas cap. But I can't tell yet as I can't drive it (bad weather).
5.) with the original gad cap (not vented) the garage smells of gas just sitting.

I also had added a fuel pump since I was getting vapor lock issues.

Any help would be appreciated. Pics attached.

Offline chrislynn5

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Re: 1979 Trans Am now using Holley 0-80555 carburetor, hot hard to start
« Reply #1 on: April 15, 2018, 03:16:01 PM »
Canister image

Online Stringer

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Re: 1979 Trans Am now using Holley 0-80555 carburetor, hot hard to start
« Reply #2 on: April 15, 2018, 06:03:33 PM »
If it were me, I would demand the shop put a new Q-Jet on it. If the Q-Jet is set up properly it is a good carburetor. Now as to your problems.

1) The carb is .25 inch higher than stock Q-Jet and I bet the air cleaner sits higher on it as well, causing the whole set up to be off.
2) The carb bowls are too close to the intake and the vehicle is experiencing vapor lock (the fuel in the bowl is boiling off). Hense the strong smell.
3) See number 2
4) They did not match the required port vacuum lines.
5) See number 2 and 4

Get another carburetor. A proper performing Q-Jet can handle up to 850cfm....more than that 650cfm Holley you have on there now, and more that a stock engine will ever need.
« Last Edit: April 15, 2018, 08:11:16 PM by Stringer »

Offline Aus78Formula

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Re: 1979 Trans Am now using Holley 0-80555 carburetor, hot hard to start
« Reply #3 on: April 16, 2018, 05:50:37 AM »
The shop talked you into a Holley? Sounds like you found the limitations of their skills and they still couldn't get it set up, take it elsewhere and replace.