What else could it be?

[chevyfan420]

Originally Posted by chevychic

but finally I took it up some hills and got it doing it really good, then got out and checked the underside of my air cleaner and sure enough, there was gas dripping off of it and some sitting on the edge of the carb air horn.

So at least I have a little more to go off of now.

I dont think backfiring will acually blow raw fuel onto the air cleaner. I've seen black soot on the lid, but not raw fuel. Perhaps over-fueling is part of the problem. You said you reset the float level, but did you clean or replace the needle and seat? Also, what type of carb are you running?
If you had a collapsed lifter, then i believe it should pop through the carb constantly.
If you pull your dipstick, wipe the oil on your fingers, and look closely at it under a light for little "shiny's"

Good luck, Jim

[gchemist]

Replace the thermostat with a 180. In Texas, I use a 160!!

[chevychic]

Well there aren't any "shinies" on the dip stick. That's as far as I got today

When I adjusted the float, I checked the needle but didn't replace it. I don't think a new needle came in my rebuild kit. I didn't clean the seat as there was gas in the bowl at the time. What is the best way to clean it?

Actually that brings me to a question. Is it normal for gas to remain in the bowl after the truck has been parked for a bit?

Would it be a good idea to pull the carb and inspect it/clean it out?

I should have my car back on Wednesday so I'll be able to really look at it without worrying about having it driveable for work the next morning.

[79BIG10]

Heather yes it's very likely gas was in the carb when you parked it. I would pull the carb off and take the top off to where the needles and bolws are shown. Take some carb cleaner or brake cleaner (I prefer) to get in there and clean it all out. YOu may need to prime the carb with some fresh fuel after you reinstall the carb.

[89 crew]

Where it is popping out the carb, and tail pipe, I would first get rid of the esc! I despise that system! all it did was mess up a good hei and cause lots of problems! If you want to keep it, check the wire going to the knock sensor. If it is good test knock sensor. after that check distributer cap for tracking, or cracks, check lifters for movement, after that do a compression check to see which valves are burnt. One other thing you might verify is the fuel supply. If the pump isn't doing enough, pluged filter, or if it has a cracked gas line it can cause backfires and all sorts of things. also where it has backfired through carb the air filter will be singed I have seen an air filter cause the popping out tail pipe. Hope those help

[chevychic]

I'll try to get to pulling the carb later this week and cleaning it out. I should have my car back tomorrow or Thursday so I can really dig into this...around the other project I have...decorating my daughter's room while she's visiting her dad in Seattle til next month...It's a surprise for her when she comes back.
Anyways, I'll pull the carb, clean it, and most likely remove the ESC.
Just for kicks, what's the best way to test a knock sensor...not that I'll need it if I'm removing the ESC, but knowledge is power ...until I forget and have to ask again someday....

The air filter isn't singed that I can tell. I've got a K&N that after sitting for awhile was pretty gunked up so I cleaned it real good and did the whole K&N recharge process. The noise was there before and after the treatment but also drove fine for the 2 years this filter was on.

I'm surprised no one has mentioned to check the timing chain. In many of my searches about this issue, I've found a lot of reference to the timing chain causing this sort of problem....what do you think?

If I get so far as to pulling the valve covers to check lifters and doing a compression check, I figure I'll pull the timing chain cover and take a peek to see what type of condition it's in. Might as well since I'll be in the general area anyways.

Although after scratching my head about the gas coming out my carb hard enough to be dripping off the underside of my air cleaner lid, I think I need to start back at the filters and carb before eliminating the ESC and other checks along the way to internal engine problems. It seems to me that something is happening in the fuel system somewhere in line between the tank and the carb. It's not a huge amount of gas, probably about 1/4 teaspoon between what was on the cleaner lid and what had collected on the edge of the air horn. At least this is how it would seem to me. Please let me know if I'm wrong in this thinking.

On a good note, my truck has now had a full tune up within the last month, rebuilt tranny, transfer case and new torque converter in the last 2 years and new frontend and tires within the last 6 months. If I keep it up, I'll have a brand new truck in the next 4 years or so.

[79BIG10]

I know the feeling on a new truck Heather. LOL!! I would eliminate the carb and other stuff you mentioned before the timing chain. This would be easier to do before that. If you need to check the chain you might as well replace it while you're there. Make sure to get a harmonic balancer remover and installer. Don't be like some people and hit it on with a mallet or hammer

[greg0380]

I would get rid of the ESC, it gave me problems on mine after I rebuilt the engine. There is the module behind the glovebox. In your setup the ESC only can retard the timing if the sensor detects knock/pionging. There was an old school way of tapping on the block with a hammer and watching the timing tab with a timing light and see if the timing changed. I have tried this when my ESC was connected and it didn';t work. But I did take a knock sensor to work and hooked it up to an oscilloscope. If you tap the sensor tip you can see the output ring on the scope. I have since replaced the carb with TBI and have funcitoning ESC (it is totally different with the TBI controls) but similar operation. It works as it should now.

The type of ESC you have is a mid step before they went to TBI.

[89 crew]

Greg, You are partially right. the esc system can adjust timing up to 15 degrees either way from where the dizzy is set. That is what gm service manuals I got for mine said. I should have saved the money on the manuals and just installed the hei

[chevychic]

A quick update....I don't have the 4 wire connector to my dizzy....it's only 3 wire and comes from the base of the dizzy to plug into the coil.

I think I'm going to do a compression test before anything else to rule out a burnt valve

The 100+ degree weather here has pretty much kept me from wanting to get out and do anything to it and I probably won't get much done till mid August. I leave a week from Friday for my trip to Alaska.

I'll post back as soon as I know anything more. Thanks for all the great input!!!