'88 YJ 258 ci with carter Hard Warm Start

Bob, it sure sounds like your fuel tank is holding pressure because of a plugged vent or similar problem. You may want to try loosening the filler cap a bit when you park. I had a vehicle do the same thing and it ended up being a plugged vent line. About the only other thing I can think of would be that one of the casting plugs in the carb is leaking fuel. I can't remember if this carb has them in a place where they could leak fuel into the engine or not because it has been ages since I've had one apart, but it is a common problem with the GM Quadrajet carb. the fix for the Q-jet is to simply epoxy over the plugs with a fuel resistant epoxy.

Chris

Please describe your starting regimen to us... the proper way to start a later-model carbureted motor is to pump the gas once fully, then release the pedal. This sets the fast-idle cam and puts a shot of fuel into the bore. It should catch, then run at fast idle until the choke pulloff heats up and you blip the throttle.

Pull a spark plug when in failure mode... see if it is wet. If it is wet, then you are flooded, and you must grind the starter with the throttle pressed fully to the floor to purge the excess fuel. Do not pump the throttle when flooded... you defeat the purpose of grinding the motor. Keep the throttle pressed to the floor, but stop grinding every 20 seconds to allow the starter to cool, for about as long. If your carb is leaking it's fuel into the engine, you should smell raw gas in the oil on the dipstick. Not a good situation for the longevity of your motor.

On the subject of grinding, you can ruin a good starter by grinding it for too long. Starters are not continuous-duty motors, and will give up the ghost if ground for too long (experience here).

Consider replacing the carb... they won't be making them much longer, and yours may be worn out in a way that rebuilding can't help. __ Steve .

You sure sound like you are describing a gas filter that is in upside down or the wrong one.

The stock gas filter has two outlets. The center outlet goes to the carb and the 'top' outlet goes to the return line. If the return line isn't at the top, gas will syphon back to the tank causing a vapor lock on the lines. This makes it a real bugger to start after sitting. If they are side by side, then it depends on the angle you park at.

The filter is also supposed to be horizontal from end to end.

A pinhole leak in the gas line from the pump to the tank can cause the same thing. That is the suction line, so a small leak won't really drip out on the ground, but it will let air into it when it sits. A visual inspection can find that, look for a small wet stain on the gas line, usually close to one of the clamps that holds it to the frame, usually at the back one too...

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

" snipped-for-privacy@yahoo.com" wrote:

I would normally follow the sequence as you described. I'm familiar with the working of the pumper jets and the choke. I don't pump the gas now, because that only contributes to the flooding problem. I've tried holding the throttle open and not even touching the pedal and the not-touching thing works better most days. It's hard to pull the plugs when I'm at work, so I've never been to verify that they are wet when it is doing this. If I do ever hit the pedal, I have to leave the thing for an hour or so and come back at it. I've hooked the battery up on jumper cables to a company vehicle and tried cranking, cranking, cranking (with suitable cooling intervals, I can't say it was 20 seconds, but round about that) with the throttle held wide open. No luck. Then I think maybe I've run it dry and goose the throttle for a little juice. No luck. Then I disperse the not-so-helpful onlookers, pull the jumpers off, go back to my office and wait it out.

If it's the carb, what would be worn out? I'm trying to think what the path for fuel might be. Maybe the metering jets not seated with the throttle closed? They're set to spec so that they don't move until the throttle has moved quite a ways. Any ideas there?

Plugged vent, hmm, interesting idea. That makes some sense, I will definitely give it a try. The next time the old carby is apart (prolly next weekend) I'll check it over for leaks. Thanks.

The problem appeared some months after the fuel filter was replaced. I'm pretty sure it is hooked up as you describe, though I will verify the orientation of the return line.

I assume that the net result would be that the fuel supply side would be dry, but I have plenty of fuel in line to the carb. I'm afraid there's too much actually. I will check, but I have already inspected the line just as a matter of course (i.e., desparation really. I like problems that jump out at you, so I look everything over a couple of times.)

Thanks,

Bob

My 87YJ did that for months. I too went hog wild on rebuilding and adjustments (twice, first by me and then by the dealer who installed a big vacuum leak for me at no additional charge!) It was clearly getting too much gas and manually holding the choke open usually guaranteed success after I've run it a bit or it sat in the warm sun. Went through more than one starter for that reason.

I checked the choke linkage for proper operation many times but it wasn't until I removed the choke I noticed resistance in the linkage on the other side of the carb. Just enough to allow the choke pull off to not remove the choke during starting. A close inspection of the choke shaft showed some oxidation on the shaft in it's bushing.

A healthy dose of carb cleaner on the choke shaft and lots of manual maneuvering to work it in and it was solved. I guess I could have looked into pulling the shaft and buffing it clean but it was working from an external spray. It had reappeared now two more times in the past 12 months. I hit it with gumout again then used silicone spay and worked it feverishly and it's fixed each time. I'm not held to emissions here so I'm giving the carter the boot along with the ignition and computer this winter. These carter's need too much TLC for my liking.

I hope your problem is just as easily fixed with a little gumout!

Cheers!

Perry

87YJ 36X12.5 MT Baja's

snipped-for-privacy@yahoo.com wrote:

Not a hope, the charcoal canister is the vent and the vent for the carb float bowl. When running they can get a vacuum on them if the filter on the bottom of the canister gets plugged, but let it sit for 10 minutes, or crack the gas cap open and away you go. It will 'not' hold a vacuum for very long. Even mud packed like my first one was when I needed a hammer and chisel to get the bugger out.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

I am talking vapor lock.

Carbs just don't work. Been there, done that. My filter was in wrong when I bought my CJ7 and I sometimes had to prime the carb with gas two or three times to get the pump to suck. It will vrooom, then die. Shoot some more gas down the carb and vroom again and maybe it will catch. Sometimes I could get it with out killing the battery so didn't need to prime it. As soon as the starter slowed, a couple tablespoons of gas down the carb and away I went.

Try it, it is a sure check for an air locked gas line.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

" snipped-for-privacy@yahoo.com" wrote:

Aren't the throttle and the pedal the same thing? Or are we misunderstanding each other?

It shouldn't be too hard to pull a plug... if you're under the hood, just pop one out. It's not like my '00XJ, where an entire assembly must come off before you can even see a plug. It does sound like flooding... __ Steve .

I guess it's not so much the pulling the plug as it is remembering to throw the plug wrench into the Jeep, plus that's like admitting defeat up front. I guess I'm so convinced it's flooding I haven't put much priority on it, but you're right about needing to confirm it. Assuming the nature of the problem without direct evidence certainly complicates matters.

I guess I didn't explain my plan well. I left my gas cap off today hoping that would depressurize the fuel system. It didn't work. I'm sitting here now with a dead Jeep outside when I need to be somewhere else. Oh the humanity. . . In addition to that plan I was going to check for leaks in the float bowl. I guess that's still on my action plan list.

My sentence structure sucked, sorry. I meant to say that I've tried to approach the evening startup ritual two different ways. The first is to do the typical, hold the pedal down (throttle open) and crank the crap out of it. The other technique is to not even touch the pedal (throttle closed) and crank the crap out of it. I'm currently scoring more successes by not touching the pedal than if I hold it down.

thanks for patience

FYI, the return line isn't all the way at the top, but it's between 10 and 11 o'lock. Checked it today between botched start-up attempts. I made the mistake of jumping right in and turning it over. That works before 10 am, not after lunch for sure. So I get out lift the cleaner assembly enough to put my rubber hose to work and yowzers if the stupid choke isn't completely closed. It's 83 deg outside! So I put the hose in, jam the pedal down and crank and crank and crank -- not even a cough. So I leave the hose in place with air cleaner off and go check some on some things in the lab and come back 45 minutes later. Again, pedal down (I figured I haven't tried much of this lately and maybe I should revisit it). The first crank it pops once and then dies. Crank, crank, crank. Thinking maybe I've run it dry, I pump once and crank, crank. Twice more, crank, crank, crank. Start smelling gas, so I go back inside to post this message. I'm really freaking out now. It's got to be something simple that I'm missing here. Maybe not. Oh well.

Jut try tossing a 1/8 cup or a couple tablespoons of gas down the carb and see what happens.

If it fires up, you have a hole in the gas line on the suction side of the pump or a dead pump that is letting the gas backflow to the tank or a torn diaphragm on the pump.

Does the oil on the dipstick smell like gas?

Oh, the choke is an electric timer job.

It will be totally closed after 5 minutes and opens according to how long 12 volts has been going to it. Piece of crap actually because it doesn't have a clue how hot or cold the engine really is, just how long it has had 12 volts.

Mike

" snipped-for-privacy@yahoo.com" wrote:

Yeah, I hate those. I have one on my Grand Waggy and I wish I could find a good alternative (with the exception of a manual one).

I went manual, it works great for me up here in Canada. I can leave it set on 1200 or 1500 rpm and drive away. As it 'really' warms up, I drop it down.

Mike

TJim wrote:

Approximately 10/7/03 12:21, Mike Romain uttered for posterity:

Unless you are absolutely certain that there will be no backfiring, take the extra coupla seconds and put the air cleaner back on. So far I have only managed to remove all the hair on my arm and face ignoring this advice... Even if you are certain there will be no backfiring, I'd still suggest it.

LOL!

Damn man, I go sit in the drivers seat to start mine!

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

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