87 wrangler starting problem - HELP!

Hi Bennett, You need a choke pull-off, number forty at:

And you probably need akit for your carburetor, too. It's not that hard, easiest for me to takeit apart on a card table, with a towel spread out on it to catch thesmall ball bearing valves as the spring from the body. God Bless America, Bill O|||||||Omailto: snipped-for-privacy@aol.com snipped-for-privacy@gmail.com wrote:>

thanks bill - i'll try the choke pull-off!

i have a slight problem with a lack of avail. workspace - nowhere to soak parts, no compressor to blow out ports, etc - also this sucker is soon to be my only vehicle so time is of the essence - all that said: d'ya think its better to attempt to rebuild the carb myself or to by a rebuilt one from NAPA or wherever.. . also any good links for getting rid of this Carter and switching to a Weber? i've seen this mentioned and am curious....

thanks and i'll post and mention whether the choke pull-off replacement has any effect... bennett

Before you start tearing down the carb, check the idle tubes. I'm sure Bill can provide a link. I went through SEVEN carbs on my 87 YJ before I gave up on the 'professionals' and crawled back under the hood.

It has a carb. On the second fast start, you will need to pump the gas like mad to get it going because the POS (piece of sh..) timer choke has opened. Once you wait a bit, the choke closes and it starts back up... The choke opens by how long it has seen 12 volts. It doesn't care how warm or cold the engine 'really' is.

I have never seen the choke pull off Bill mentioned go bad on a Jeep carb.... When they do fail you get a 'stable' high idle that can't be turned down but it won't cause stalling.

I highly recommend a manual choke kit for them. It makes it sooo nice when trying to drive it before it is fully warmed up... Most auto parts stores sell the kits. The heavy duty kit comes with the correct choke replacement parts and is a bolt on unit.

A Carb kit for them is about $20.00 and is easy to do. I recommend you don't take any parts apart that need adjusting unless you have to to clean them.

One thing that can aggravate this is having the gas filter in upside down or having the wrong gas filter in it. The filter has 2 outlets. The center outlet goes to the carb and the top outlet goes to the return line. If the return line outlet isn't at the top, then gas can syphon back to the gas tank or in a shutdown case, get pushed back so it vapor locks or air locks the gas line. If this happens, you can prime the carb with a quarter cup of gas down it's throat and the engine will go vroom. You might have to do it twice to get the pump to pick up the fuel again. It takes a 'lot' of cranking to overcome this vapor lock otherwise, a battery killing 'lot'....

Now to address the idle. First off you will need to see if the carb float bowl and gas tank vent is working. If it is shot, you will have to replace it or disconnect it and drive with lots of gas fumes around while waiting for a new one...

To test it have the engine at idle and trace the PCV line to the back of the carb. There you will find a solenoid thing that can actually be replaced with a T fitting if it isn't functioning and they do fail. (when they fail massive amounts of oil will blow into the air filter)

Off this solenoid or T fitting one line will go way down below the brake booster to a charcoal canister sitting at the bottom of the fender. At idle pinch this line to the canister closed. If the idle changes, the canister purge valve has failed and the canister must be replaced. For temporary set up purposes, you can unplug this line from the canister and block it with a tight fitting bolt so the PCV system is now sealed back up.

If this canister is working ok, then I would suspect the carb has the common problem of plugged up idle circuit tubes. These brass tubes have crimped ends that are too small so they plug up easy. It is recommended to physically ream these ends out because the chemical cleans just won't get them clean. That is why a lot of 'professionally' rebuilt carbs still have blocked up tubes. It is a 'no no' for a rebuilder to physically ream parts so they rely on chemicals and put out crappy rebuilt carbs.

Here is a good site on the idle tube issue:

The tool used can be found at welding supply stores. The small drills or files are used for cleaning torch tips. I can actually pull out the venturi from the top once I remove the choke plate. It will lift up and spin around and pull out past the choke plate pivot bar. Best to do the first time as part of a carb kit and clean up.

When doing the carb clean, pay close attention to the chunk of gas line from the filter to the carb. The U shaped line will hold all kinds of crud that builds up as the vehicle sits and the gas evaporates away. It is often a source for a second bout of plugged up idle tubes that seems to happen just after a carb clean....

If you suspect the brake booster is bad, just unplug it at the booster and block the line to see if the idle gets right.

Hope some of this helps....

Feel free to ask if any of it isn't clear.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

Sounds like you need to deal with the carb.

First thing I'd do is ream out the idle tubes. this can be done on the vehicle. Get a "drill style tip cleaner" at your local welding shop. $8

't be afraid to ream these out a bit oversize, there was a factory tech bulleton out on this. See if the choke is fully closed to start, opensfully when it is warm. Fix as required. You can set the pulloff rate (cool to almost warm rate) later.

Pick up a carb kit based on the number tab on the carb. Inside are instructions for setting the various levers and choke postions. These are very specific to individual models. Maybe someone here can scan the instructions and the spec sheet. Hayes and Chilton manuals only give the general disassembly instructions, not the specs.

Just rebuild it on your kitchen table. It's been done many times before. Just drain the gas before you bring it in!

Make sure your vac lines go where they are supposed to:

Your carb has a motorized mixture control system run off the computer. Pretty problematic. New servo is $120 (!!!), odds are good it is not working correctly. You can look down the carb throat, see the two needles in the bottom shuttling in and out as you move the gas pedal or spray a bit of carb cleaner down the throat. Some of the folks have put the computer to sleep, modify the base of the carb to adjust mixture with the standard mix screws that are currently hidden.

snipped-for-privacy@gmail.com wrote:

thanks Mike - i will attend to the idle tubes today or tomorrow and let you know what happens - i appreciate all the free advice - i'd like to start drivin this thing thru the, soon to be, springtime mud! cheers, bennett

well after a brief moment of triumph it appears that my joy was premature... i removed the venturi cluster and cleaned out the idle tubes, they were in fact dripping at idle and there was quite alot of crud in them and in the 2 screws. i also cleaned out the gas feed line from the fuel filter to the carb just for good measure. since it was nightime by then and i didnt have my jumper cables handy i let it sit till the next day, when happily, it started up - not such a surprise as it reliably starts when cold - but then continued to start up all day long - the idle was high (about 1000rpm sometimes sticking up at around

1500 and blipping the throttle only worked to bring it down about 1/2 the time) and when starting it seemed a bit reluctant for about 1/2 a second but then it would fire right up and run great. no stalls no rough running no hiccups etc. then last night i had a date (uhhh oh...) and of course - no start. she (the jeep that is) had sat for about 3-4 hours at this point so i was surprised (she's supposed to start up and THEN leave me stranded with my date looking on - jealousy is so ugly) anyway i cranked it periodically until the batt ran down then hooked up jumper cables but all to no avail... it didnt even sound like there was any spark at all... i dont think the motor ever even fired once, although it seemed to diesel for about 1/4 second once or twice after about 20 seconds of continuous cranking (didnt want to kill the starter motor). i had a couple of tablespoons of gas left in a gas can, so i tried pouring that into the barrel of the carb - no difference. tried cracking the gas cap and pulling the vent line to the carb float bowl - nope. since it was nightime and i was in clean clothes and had even scraped all the oil out from under my fingernails in anticipation of some serious making out and since - oddly enough - i didnt have a spare spark plug in my pocket, i wasnt able to see if there was in fact any spark at all. today i'm gonna have to wait until i can get someone over to jump me to find out... in the meantime, anyone have any bright ideas about this? i'm beginning to lean toward a problem on the ignition side of things but honestly i have no idea. today i plan to test the coil, and pull the Ignition Control Module and bring it in to NAPA - they say they can test it... i've been trolling some previous posts and there was a very similiar case to mine (averyislandboy, Bob V, from back in Oct 2003 - sorry i dont know how to hotlink here) - his symptoms were similiar if not identical and he apparently resolved them by purchasing a new - what he calls - ECM, by which i take to mean ICM - Ignition Control Module; that is opposed to the ECU - the Electronic Control Unit. i assume he's referring to the ICM based on the implied location of said module, in the engine compartment... (vs ECU in the passenger compartment) and from the details of his post. can anyone clarify this? Bob, you out there? seems to me that if the master brain box - the ECU - was bad the Jeep wouldnt run at all as opposed to intermittently... well i suppose i can take the ICM out and have it tested anyway... i will let all of you know what happens. i am interested to know, Bob if you're still out there - did the problem ever reappear or did the new ICM (ECU?) fix it completely?

thanks for all the help, bennett

PS i am seriously considering pulling the choke circuit as well and replacing it with a manual choke... and when i have the money trashing the Carter and going to a Weber set up. how bout a replacement for the ignition circuit? what's the inside scoop with that?

PPS does the 87 YJ 4.2L have a Crank Position Sensor?

sorry for the barrage of questions... thanks for all your patience. b

Ouch.

Ok, you seem to have more than one thing going on. First off only kicking the idle down about half the time is a linkage thing. Likely the choke linkage pieces and the fast idle cam need some oil. I actually use WD40 on them because it cleans the crud out without leaving too much behind. If I have, I will use carb cleaner on those parts too. That also might indicate a dirty connection on the electric choke not allowing it to open fully.

They even get dirty enough that the choke seizes up. When you checked it to pour in the gas, was the choke closed? It should have been. If not, the linkage needs serious cleaning. They like to seize up right where the choke electric module's shaft comes out.

A bad ignition module can be some of your trouble for sure. When getting one stay far far away from the Wells unit. They come dead in the box more often than they come good. Seriously, they have screwed up something serious in them. If you can find a motorcraft one it would be the best.

At least you have no CPS to worry about...

The coil pickup in the distributor also can go bad. You can check it with a multimeter. It should read between 400 to 800 ohms. Mine was a failed unit at about 415 ohms...

I would be checking the inside of the distributor cap also for crud or carbon tracks. That can affect starting. There also is a bad batch of them on the market. The rotors are too short so they arc out all over the place.

Did you get the carb screws back the same as they were?

One last gotcha is the body ground. There is a wire mesh strap from the rear of the engine head up to the firewall. When it goes ratty the vehicle steals grounds and will do very strange things like not wanting to start. The ignition module needs a ground to run.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

thanks mike - here's an update, first things first: i checked for spark and sure enough, spark is present. cant speak for the strength but she has fire. so next i went and got a new choke pull off and ICM - not too expensive, about $40 from NAPA - when i went to replace the pull off i noticed that the vacuum hose to the pull off from the carb was seriously cracked - i dont mean heat cracks - i mean two big splits, one on either end of the hose where LOTS of air would have been coming thru... AAHA! i thought! the culprit! but no - no start. replaced the ICM - still no start. then i double checked the part # for the pull off with the part # of the carb and lo and behold - it is the incorrect pull off! my Carter BBD is apparently a model 8383 and this pull off is only for models

8338 and 8339... i have since found the correct pull off and will be replacing it tonight or tomorrow so we'll see... an interesting note - when my friend and i were trying to get it to start after replacing both parts, the motor was turning over but still not catching - just like before. on a whim i reached over and manually opened the choke plate - and vroom! she started! she ran great, idled happily at about 700rpm and revved with a healthy roar. i noticed that while she was running, the choke plate stayed at least partially open - held open by the (apparently incorrect) choke pull off which appeared to have vacuum since it was engaged. we turned it off and she restarted again no problem. now after an hour or so - no start, choke plate completely closed - my friend split so i have no one to crank it while i hold the plate open (and no remote starter) so i dont know if i can successfully reproduce the starting procedure... i suppose this is a VERY long way of asking how exactly the choke pull off is supposed to work and whether this could be the ultimate source of the problem (the linkage WAS a bit sticky, cleaned and lubed it up - thanks). sorry this comes out rather stream-of-consciousness, i think better while talking or typing - thinking out loud so to speak... if i had a slightly better idea of how the choke circuit is supposed to work this might be clearer to me...

thanks for all your help, bennett

The hard start was likely the broken vacuum line to the choke pull off. Bill's guess was right. As soon as it sees vacuum it is supposed to open the choke so the engine doesn't flood out. This is critical on hot starts because of that stupid timer choke. If it has time to cool off, then the choke is all the way shut and flood happens. Your old one is very likely just fine. It was only a busted hose.

Once these engines flood, they are pigs to get going.

Once the engine is going, the choke opens so the pull off isn't in the circuit anymore. Unless it is interfering with the choke opening all the way because it is the wrong part....

You can stick a long screwdriver down the carb to hold the choke plate open a bit for starts.

Mike

bobv>

ok. i replaced the pull off with the correct model - they seemed completely identical to me but what do i know? - now when she is cold i notice that the choke plate (butterfly) is partially open and she will start up 90% of the time. HOWEVER - if she doesnt catch, i cannot get her start as per earlier and upon inspection the choke plate is ALWAYS CLOSED. if i then use something to physically hold the choke plate open

- no problem, she will start with a little rough idle for 1-3 seconds probably due to the flooding... so, having replaced the choke pull off, and the vacuum line to the pull off, should i consider replacing the choke thermostat sensor or whatever its called? it would make a nice paperweight i suppose, and i could put a manual choke in... would i have to drill a hole in my dash for that? could this POS be the source of the problem? it sure seems like it since the pull-off doesnt seem to be the one actuating the opening and closing of the plate when i am experiencing this problem... at least she appears to be drivable and will start 'reliably' as long as i have my little piece of wood handy(to prop open the plate). i feel kinda stupid tho and would like to nail this problem so i can move on to all the other issues... exhaust, valve cover leak, wheel alignment, etc etc etc - she's a greedy jealous little bitc... err thing - just like all my girlfriends, no wonder i'm already in love. bennett

PS thanks esp to Mike and Roy for all their time and patience - and kudos to you Bob, got it (at least partially) right on the first guess...

ok. i replaced the pull off with the correct model - they seemed completely identical to me but what do i know? - now when she is cold i notice that the choke plate (butterfly) is partially open and she will start up 90% of the time. HOWEVER - if she doesnt catch, i cannot get her start as per earlier and upon inspection the choke plate is ALWAYS CLOSED. if i then use something to physically hold the choke plate open

- no problem, she will start with a little rough idle for 1-3 seconds probably due to the flooding... so, having replaced the choke pull off, and the vacuum line to the pull off, should i consider replacing the choke thermostat sensor or whatever its called? it would make a nice paperweight i suppose, and i could put a manual choke in... would i have to drill a hole in my dash for that? could this POS be the source of the problem? it sure seems like it since the pull-off doesnt seem to be the one actuating the opening and closing of the plate when i am experiencing this problem... at least she appears to be drivable and will start 'reliably' as long as i have my little piece of wood handy(to prop open the plate). i feel kinda stupid tho and would like to nail this problem so i can move on to all the other issues... exhaust, valve cover leak, wheel alignment, etc etc etc - she's a greedy jealous little bitc... err thing - just like all my girlfriends, no wonder i'm already in love. bennett

PS thanks esp to Mike and Roy for all their time and patience - and kudos to you Bob, got it (at least partially) right on the first guess...

ok. i replaced the pull off with the correct model - they seemed completely identical to me but what do i know? - now when she is cold i notice that the choke plate (butterfly) is partially open and she will start up 90% of the time. HOWEVER - if she doesnt catch, i cannot get her start as per earlier and upon inspection the choke plate is ALWAYS CLOSED. if i then use something to physically hold the choke plate open

- no problem, she will start with a little rough idle for 1-3 seconds probably due to the flooding... so, having replaced the choke pull off, and the vacuum line to the pull off, should i consider replacing the choke thermostat sensor or whatever its called? it would make a nice paperweight i suppose, and i could put a manual choke in... would i have to drill a hole in my dash for that? could this POS be the source of the problem? it sure seems like it since the pull-off doesnt seem to be the one actuating the opening and closing of the plate when i am experiencing this problem... at least she appears to be drivable and will start 'reliably' as long as i have my little piece of wood handy(to prop open the plate). i feel kinda stupid tho and would like to nail this problem so i can move on to all the other issues... exhaust, valve cover leak, wheel alignment, etc etc etc - she's a greedy jealous little bitc... err thing - just like all my girlfriends, no wonder i'm already in love. bennett

PS thanks esp to Mike and Roy for all their time and patience - and kudos to you Bob, got it (at least partially) right on the first guess...

ok. i replaced the pull off with the correct model - they seemed completely identical to me but what do i know? - now when she is cold i notice that the choke plate (butterfly) is partially open and she will start up 90% of the time. HOWEVER - if she doesnt catch, i cannot get her start as per earlier and upon inspection the choke plate is ALWAYS CLOSED. if i then use something to physically hold the choke plate open

- no problem, she will start with a little rough idle for 1-3 seconds probably due to the flooding... so, having replaced the choke pull off, and the vacuum line to the pull off, should i consider replacing the choke thermostat sensor or whatever its called? it would make a nice paperweight i suppose, and i could put a manual choke in... would i have to drill a hole in my dash for that? could this POS be the source of the problem? it sure seems like it since the pull-off doesnt seem to be the one actuating the opening and closing of the plate when i am experiencing this problem... at least she appears to be drivable and will start 'reliably' as long as i have my little piece of wood handy(to prop open the plate). i feel kinda stupid tho and would like to nail this problem so i can move on to all the other issues... exhaust, valve cover leak, wheel alignment, etc etc etc - she's a greedy jealous little bitc... err thing - just like all my girlfriends, no wonder i'm already in love. bennett

PS thanks esp to Mike and Roy for all their time and patience - and kudos to you Bob, got it (at least partially) right on the first guess...

Bob,

It sounds like you need to make a slight adjustment to the linkage or replace it with a manual choke.

Manual chokes usually come with a bracket or can be placed in your dash for a 'cleaner' install.

billy ray did pass the time by typing:

There should be a little adjustment screw that sets how closed the plate can get. If it's not adjusted to give a bit of clearance the butterfly can stick shut and no spring can pull that open. Also check how smooth the bushings are, if they are gummed up it can stick also.

(I'm working off foggy knowlege of the Rochester 4M4 quadrasuck..er quadrajet)

The choke should be almost all the way closed when the Jeep is off. Once you start it, vacuum hits the choke pull off and opens the choke about 1/4" so it gets some air to run rich for cold starting.

Then as the engine warms up or as long as the choke has power to it, the choke will open all the way in less than 5 minutes. It will stay open.

If it is not opening, then the electrical connection on the choke is suspect for a dirty connection. There should be 12 volts there as long as you have oil pressure. If you do not have 12 volts there, then go to the oil pressure sender near the back passenger side of the block and see if the plug is plugged in. The oil pressure sender has a switch that allows power to pass when running. The power goes to the choke and a relay dead center of the firewall in the harness that supplies power to the manifold heater under the carb.

If you do have 12 volts at the choke and it still isn't working, it can be seized up where the shaft comes out of the electric coil unit. That is common or the sucker is dead.

Manual kits come with a bracket you can hang below the dash edge.

Good luck,

Mike

bobv>

Yes, I've vague recollection of using feeler gauges to check the gap but I haven't a clue to what the measurement would be.

I'd be willing to bet that Bill knows....