85 K5 Starting Issues and Fuel Leak
 

I have a 85 K5 that I have been having issues with. It died on me while driving and I went through a whole list of fixes. I changed the distributor and rotor, wires, spark plugs. I had a bit of an exhaust leak at the header, so changed the gaskets there and on the valve covers. Went to change the fuel filter, which is goes into the side of the carb (Roch Quadra Jet E4ME), was stripped badly. I ordered a self-taping fitting from Napa Auto that was supposed to fix the issue. I installed this and immediately had the same leak.

The truck will only start when I depress the accelerator to the floor and keep it there. If I let off it will die and eventually with it depressed it will die. Obviously I am not get enough gas because of the leak.

Does anyone know of a fix or do I need to just get a new(rebuilt) carb? It seems to me that I have a carb problem.

Did you check the fuel line itself? Where it goes through the nut? Does the flared end look like its ok?

I will have to check that but as far as I can tell it's coming from where the part that screws into the carb. That was where I had a small leak before and then when all this went on and I went to change the fuel filter I unscrewed that part from the carb and all the threads came out with it. Then I got the self-taping peice and screwed that in but it didn't seem to set right still. I have used many taps and believe I got it in there straight but like I said it was pretty bad when I got to that point.

When was the last rebuild on your carb? It might be worth it to just get a rebuilt one or send yours out. Or if you plan on getting a new carb anyway you might try some sort of pipe thread sealant.

Got one from Carb Doctors outta Canada. Pretty reasonable price and quick delivery and believe it or not bolted on and no adjustment needed.

https://blazerforum.com/forum/showth...ght=carburetor

I just got the truck a few months ago. As far as I know nothing has ever been done the carb (or anything else). But it was a steal and I knew it was going to be some work. I found a completely rebuilt carb on i-5automotive.com for $305. I am not sure if I want to spend that much though.

Is there any thread sealant I could use being its used on the fuel part? Do you mean like all thread or like pipe sealant?

I "was" thinking pipe dope or thread sealant but in retrospect i'm not sure if that's a good idea without reading the label on a can to see how it reacts to gasoline. Sure would hate for it to deteriorate and make it's way to somewhere it doesn't belong.

Another option might be to pull it off and see if a machine or carb shop can repair it. But for the money probably better to just get a rebuilt one.

I paid $350 for mine and kept the old one as the core was only $25.00US so now I have a $25.00 dollar training tool.:icon_playing:

Another question I had was do you think this could have been the initial problem with it just dying while I was driving. I mean with the carb having some issues.

When I bought the truck it was running ok and did for about a month and a half then it started having problems getting started. I would have to stay on the throttle for a bit till it warmed up a little or it would just die. Then while I was driving in town one day it just died and that was it.

To test you could fill the carb bowl with gas and try starting it. If it starts right up until the bowl is empty then....maybe. But unless the fuel is just pouring out around the fuel line a don't think you'd be losing enough gas to affect it.

You could try letting everything dry and then taping the bejesus out the fuel line to carb connection to contain any leak. It won't be pretty or permanent but might give a clue. But a carb'd engine doesn't really need all that much fuel pressure. I think it's only like 12 PSI. Just enough to keep the fuel bowl at the proper level. When it dies check the fuel level in the carb.

If you can get it running try spraying some carb cleaner around the base of the carb. If it drops the RPMS then you have a vacuum leak at the base of your carb. I'd also check for loose vacuum hoses, clean or replace the EGR valve and AIR system. ( Not sure how this part is done off the top of my head but I have the books for mine I'll do a little research)

I'll try that but I was thinking more along the lines that I am having some issues with the carb itself...not necessarily just with the fuel leak.

Like a float issue or something maybe with the electric choke or mixture control solenoid. Right before it started acting up, I had to get it CA Smogged. They had a helluv a time with that because the check engine control unit behind the dash had a wire running to the computer control and was causing issues.

But they got it smogged and then I started having problems about a month later. So I don't think its the EGR but I will test that. I have checked for some vacuum leaks but not around the base of the carb.

Thanks man for all you info...BTW I can get it started by pushing the accel down all the way but if I take it off it dies and it eventually will die with my foot to the floor (about 30 sec)

No service engine codes though? It could very well be the carb itself or even just a clogged jet or metering rod. A rebuild kit from NAPA is only about $70.00 but if it is electrical that won't help. Are you getting power to the solenoid?


According to the book: No power at the mixture solenoid results in a richer mixture while an energized solenoid would result in a lean mixture. So if it is stuck, it is supposed to move in and out 10 times per second, that could definitely cause the problem.

Also there is a primitive throttle position sensor on there as well that could be causing the problem. Let do some studying and I'll get back to ya.