Need a diagnosis

[Satty]

My friend's mom has a Delta 88 with a 307 that she's willing to part with for the right price. That price happens to be less than what a new carburetor would cost me, and as a bonus, I'd get a new AC compressor, radiator and transmission. I took it for a quick spin and it bogs down badly around 30mph. I'm thinking fuel filter or pump. Vapor lock? I only ask because if its a quick, easy fix, I can drive it to the secret lair instead of having to find a trailer or something to tow it with.

BTW: By bogging down, I mean its surging, kinda like its not getting fuel to the carb.

Edited March 6, 2009 by Satty

[Drew Dowdell]

Under slow acceleration or fast or doesn't matter?

After the shift to second I'm guessing?

How is the idle?

[Satty]

Going light on the throttle it bogged down, flooring it killed it. I feathered the throttle, then when it started bogging down, I started pumping the throttle, that kept it from dying, once it got up to about 40 it felt normal until about 55. Hills were an absolute bitch, it almost completely lost power.

It idles fine.

And yes, its in second.

[Drew Dowdell]

Lots of carb cleaner sprayed in the carb and check the vacuum hoses.

Sounds like it could be a fouled jet.

Edit: I'm guessing it's a Quadrajet carb. I'm pretty sure that's the only one they put on the 307.

[Satty]

Yeah, its a Quadrajet. I'm going back down there tomorrow, we'll see what some carb cleaner does and I'll double check all the lines.

[Drew Dowdell]

Make sure while you're under there that the secondaries open at full throttle. Do this with the car off of course.

[SAmadei]

My friend's mom has a Delta 88 with a 307 that she's willing to part with for the right price. That price happens to be less than what a new carburetor would cost me, and as a bonus, I'd get a new AC compressor, radiator and transmission. I took it for a quick spin and it bogs down badly around 30mph. I'm thinking fuel filter or pump. Vapor lock? I only ask because if its a quick, easy fix, I can drive it to the secret lair instead of having to find a trailer or something to tow it with.

BTW: By bogging down, I mean its surging, kinda like its not getting fuel to the carb.

How many miles? If you floor it at a standstill, does it die?

Its my experience that these 307s barely feel like they are seriously bogged down even in good tune. I fiddled with my carb on my '86 Estate wagon to no avail... it was just dog slow, and after it started burning a bit of oil, I felt the engine was just clapped out. I used to have to drive with my foot all the way down just to keep up with traffic, so having it die at full throttle would be REALLY annoying.

Of course, IMHO, these engines go forever because they don't produce enough power to self destruct. I'll also admit that the Estate wagon ran about the same unloaded or overloaded.

Oldsmoboi likely is on to the right track, but I wanted to add...

I would check for a vacuum leak. These had so many miles of dry rotting vacuum lines, it was obscene.

On the fuel side, I would try tapping on the fuel filter housing, then taking it for a spin. If it runs better for a short time, that's your culprit.

Definitely check out the carb linkage... mine used to jam shut and the frigging thing wouldn't start... just made plumes of black smoke. I'd have to stick a screwdriver into the butterflies to get it to open enough to start it... then it would run fine. It was intermittent, and I never could duplicate the problem when I could actually work on it. It normally would only happen twice a year... leaving me stuck in the middle of the Atlantic City Expressway with the hood up stabbing the carb with a screwdriver...

[Satty]

The original owner (my friend's grandmother) bought it in '83 and drove it until she passed a couple years ago, after that her daughter took it. The odometer shows 57k and change, its in too terrible of shape for that to not have rolled. Flooring it at a standstill didn't kill it. I know exactly what 307s feel like, and this sedan felt nothing like my wagon, there is definitely a problem somewhere.

My carb was missing the choke rod, so the choke would stay about halfway open all the time, unless I was going uphill, when it would close completely. Unfortunately that carb, and the decent carb from my other engine, are both gone. Bastards. I'll play with it a bit tomorrow.

[Camino LS6]

Could be a bad accelerator pump in the carb (would need a rebuild).

A clogged cat can also cause those symptoms ( bet its original).

[daves87rs]

I was thinking cat too...

[FloydHendershot]

Cat.

[SAmadei]

A clogged cat will cause it to seriously bog down, but his prime issue he wants to solve so he doesn't have to tow it home is that when he puts his foot into it, it kills or nearly kills the engine. Clogged cat won't cause it to sputter or die.

[Satty]

Maybe on Monday I'll borrow a Tundra for "work purposes" and tow the thing.

[ZL-1]

Maybe on Monday I'll borrow a Tundra for "work purposes" and tow the thing.

Be gentle on the Tundra's frame, be sure it doesn't break

[Satty]

I called in a favor and the car was towed up to the house this afternoon. I just went out and did some of the simple things to see if any of them helped. After I sprayed the carb cleaner, I went ahead and popped the fuel filter off. And I'm thinking that was a large part of my problem, because that filter was an awful, awkward shade of brownish-black like nothing I've ever seen before. 'Twas nasty. So I put the new one in, threw the air filter back on and hit the road. It rund like.....well, it runs like crap, but less like crap than it had. It'll make it up to the secret lair to be dismantled, which is all I really need.

Speaking of cats, the one in the LeSabre is likely near death, I'm thinking about cutting it off and doing without until its time to be inspected.

[Camino LS6]

I called in a favor and the car was towed up to the house this afternoon. I just went out and did some of the simple things to see if any of them helped. After I sprayed the carb cleaner, I went ahead and popped the fuel filter off. And I'm thinking that was a large part of my problem, because that filter was an awful, awkward shade of brownish-black like nothing I've ever seen before. 'Twas nasty. So I put the new one in, threw the air filter back on and hit the road. It rund like.....well, it runs like crap, but less like crap than it had. It'll make it up to the secret lair to be dismantled, which is all I really need.

Speaking of cats, the one in the LeSabre is likely near death, I'm thinking about cutting it off and doing without until its time to be inspected.

Aftermarket cats flow better, are cheaper, and keep you legal.

Just a word to the wise.

[Satty]

Thanks, I'll keep it in mind. When I got the tailpipe put on, the guy suggested I do the cat soon. But since there is nothing flowing through it right now, and wont be for a while, I'll put it off, I have other priorities. Like figuring out how to get the dash apart to replace one of the bulbs and yank the radio.

Ohhh...another bonus I just thought of, I'm pretty sure the telescoping antenna on the donor Olds works, which is sweet 'cause the one on the Buick is 91% gone. Only the base remains.

[Camino LS6]

Parts cars are a good thing!

Try yanking the cat off of the donor and see how it runs then.

Might surprise you.

[2005 EquinoxLS]

My Bonneville has a newer cat. LOrigional plugged up when my grandmother still had it. Mine too though always feels like it is a little suffocated. The 305 in the Caprice doesnt fell quite like this even though that is no powerhouse either.