Engine diagnosis help needed

[JZakjeep]

Hello. I am having issues with 91 Wagoneer. It has a rebuilt trans, HEI dist, new spark plug wires, timing chain/gears, new carb, new fuel pump, new fuel sending unit, and emissions taken off. The engine idles fine and revs good. When I drive it and mash ther gas, it makes a loud whooshing sound and has a huge lack of power. No popping, stumbling, or hesitation. just very little power. Any ideas? Thanks.

[REDONE]

There's not enough info to really help point you in a direction. What cam and carb? What emissions is it missing? What was the last change made before the problem started? "Lack of power" compared to before, or compared to a modern vehicle?

I'm hoping it's just a timing/tuning issue, but with so little to go on its really hard to say where to start. Pop back in with some specifics and we'll see if we can point you in a direction!

[JZakjeep]

Thanks. The cam is stock. The carb is a stock 2bbl with the altitude compensator. The smog pump, charcoal canister, air tubes have all been removed. the EGR is still there but not hooked up. As far as last change or upgrade, it has run bad since we got it. I did do a compression check on it and all was good there (I don't remember the numbers but not bad). It had a major vacuum leak at carb base that I fixed and actually runs the best it has ever run right now. I put a vacuum gauge on it the other day and at idle was 18. The emissions were removed when I got it. I installed the HEI, carb, wires, timing chain, etc. I have checked and rechecked my work so many times. Could it be fuel starvation? If it were a timing issue, wouldn't I have more obvious symptoms? I compare the lack of power to other old things I have driven. I am not expecting to pull the front wheels off the ground or anything but I know something is wrong.

[Tatsadasayago]

If the catalytic converter is still installed, I would suggest it may be plugged.

[ghcoe]

If the catalytic converter is still installed, I would suggest it may be plugged.

That is where I was going.

[Tatsadasayago]

That 'Whooshing' sound can be one of two things: Low fuel level in the carb or too much backpressure in the exhaust. It's tough to know for sure without hearing it.

There are different sounds a carb will make that tells you what's going on;

This is a short video clip of a Carter ThermoQuad© being revved until the secondary air valve starts to flutter. You have probably heard this sound in TV and movies when the cops are chasing the bad guys in their Dodge Polaras...

https://www.youtube.com/watch?v=JrchxrKe76I

That's a raspy sound due to the engine not being able to handle the air/fuel charge.

A low moan is usually a sign of a lack of fuel ie; small jets or low fuel level.
This sound can be replicated by disabling the fuel supply and opening the throttle as the carb runs out of fuel. It's a dry moaning sound.

[JZakjeep]

Thanks for the replies. I am going to check fuel delivery and CAT. I will let you know what I find.

[KJ Ryu]

Where is the base timing at? I've noticed that AMCs like quite a bit more advance than most engines. Especially once emissions stuff has been removed.

[JZakjeep]

I went to check the fuel pressure last night and got as far as putting a clear filter in the 1/4 fuel return line. Started it and fuel is flowing through the return line and filling up the filter. I didn't think it would have that much flow.

Update-Fuel pressure is at 5 psi after filter.

[FSJ Guy]

Fuel flow seems decent.

If you SLOWLY push the gas pedal, will it build up power and go fast?

Or does the engine still feel "choked"?