22 replies to this topic

[pdc]

So I picked up an 86 wagon. It starts up and runs. When I took it on the road, after it was all the way warmed up, it faltered and stopped. If I pumped the pedal a bunch it would start briefly and die out.

So I decided it might be a vac problem and did the devac in the sticky thread. I'm confident I have all the vacuum ports capped and have it done as in that thread. I started it and let it idle for 30 minutes. It was fully warm. I took it on a road test, got about a half mile and the same thing happened.

I am a little baffled as it was fully warmed when i started out this time and was running good for that first little bit. I towed it home and let it cool and it runs again.

Any input as to what would cause this condition? I did do a carb cleaner test around the base and go no positive results of a vacuum leak. I also took the top of the card out and clean the bowl. There was some crap in there.

Edited by pdc, 25 March 2012 - 09:04 PM.

[chedda_j]

sounds like your out of fuel lol.

If it idles fine, and doesn't run very well on the road, the float adjustment might be off.

[pdc]

I checked float level and it is a bit above the halfway point.

Ok I just sprayed again for vacuum leak. It seems maybe there is a leak at the base plate. Can this be cleaned and reused or does it have to be replaced? Do you use any kind of sealant with it?

Would this cause the symptoms I'm getting. Perhaps when heat reaches it and the car is in motion it breaks the seal?

Edited by pdc, 25 March 2012 - 09:06 PM.

[chedda_j]

Ah... it seems odd that it runs good for a bit then it dies. Maybe a little more explanation. Does it run when you punch it? If so, that means that your power valve is working good, spraying gas into the carb through its jet. If it doesn't work under mid to light throttle then it could very possibly be something getting stuck in the carb like the float or the needles. If the car runs good when cold then doesn't run good at all when its warming up it could be something as simple as a fuel filter. Theres a few little tests that you can perform. Id try this first, go and drive the car untill it starts to run like shit, and bring it home, don't go far haha. Then take off the fuel line to the carb, put it into the a water bottle, turn the car over and see how much fluid you get. It should fill the bottle pretty quick. If you turn it over for about 10 seconds, it should give you at least two to three inches in the bottle.

If that works, then you know your carb is getting fuel. Then the problem will probably be internal. There is a little filter inside of the carb as well that you can remove and clean, sometimes that gets filled with junk.

[pdc]

I did the fuel in bottle test earlier. Seems ok. I will try to clean the internal filter. Is it the bigger flathead screw right above wher the fuel line goes in.

Also, if the rubber base plate is damaged, is it possible to get a new one?

[Bubba]

You would need to take the top of the carb off to clean the screen around the float valve seat.

[pdc]

You would need to take the top of the carb off to clean the screen around the float valve seat.

Ok, I already had the top off today to clean out the bowl. I'll try that tomorrow after work. I was just looking at the manual. The rubber base plate is called the insulator. I'm thinking I should remove the carb and try to reseal it the insulator and the insulator to the manifold. Any tips on doing that??

[chedda_j]

You can replace the insulator or you can try to re seal it with rtv silicone.

[pdc]

Picking up some more carb cleaner tonight to do a conclusive vac leak test.

[pdc]

Well I took off carb. Found 2 uncapped places at very bottom back of carb where I couldn't see. Capped 'em and it started up nice. Tested with carb cleaner. I thought this is it, it's gonna run, just fine tuning from here. So off I went to road test, got about a mile and it did the same thing. Rats. I'm out of ideas. No vacuum leaks. Float level is right.

[steamer54]

Just a thought, have you checked the ignition when it is hot? Make sure you have good spark. Another possibility is that the gas tank vent is plugged and preventing the fuel pump from being able to maintain flow.

[chedda_j]

Or cat

[EuphoricBlue]

Have you replaced your fuel filters yet? There should be one in front of the left wheel well, and a small one in the engine bay. Possible it's getting enough flow to idle, but not enough to drive.

[pdc]

Just a thought, have you checked the ignition when it is hot? Make sure you have good spark. Another possibility is that the gas tank vent is plugged and preventing the fuel pump from being able to maintain flow.

I guess driving with the gas cap off would check this.

Have you replaced your fuel filters yet? There should be one in front of the left wheel well, and a small one in the engine bay. Possible it's getting enough flow to idle, but not enough to drive.

I'll check the fuel filters tonight. These ideas make sense because it sure seems like lack of fuel.

Thanks for all the input. I really appreciate it.

[pdc]

Or cat

If these other things dont work I'll loosen at down pipe to make sure excessive backpressure isn't the cause.