87 YJ 258 Cold start problems (Long)

Maybe the experts here might be able to solve a problem with my 4.2 87 YJ, it is a beast to start in cold weather but starts fine after it
has been warmed up. I have had it to the "experts" several times and so far they have solved nothing! When I take it to work I have actually resorted to putting a ceramic heater under the hood, when I do this it usually fires up just fine this has got to be telling me something. (Northern Canada is where I live and it can get quite cold here) Maybe this beast doesn't need to be choked when started? The engine has 250K km on it and experiences some blow by which would be expected, but damn I can still get it up to 130 km/h on the highway and the only oil that it uses is what it blows back or what it leaks out the valve cover.
New Parts I have installed: Starter Carter carb ( 1 month old) Timing chain and gears O2 sensor Battery and starter including new heavy duty 1 guage wires Plugs wires cap and rotor Fuel pump / Fuel filter (vent on top ....considering getting a non vented filter?) PCV valve K&N Air filter Most vac hoses replaced and checked for leaks
Things I have done:
The beast always pinged when the timing was set correctly and I found it was over advancing due to the vac advance being hooked up to manifold vacuum, I switched it over to ported and was finally able to set the timing where I could get some top end out of it. I have set the choke anywhere from fully closed to just cracked open (done when engine had sat over night) The choke appears to be working ok as it will close off when it cools down and slowly open after a successful start. The idle screws were set by the Dodge dealership mechanic and I'm starting to wonder if this might be part of the problem. I checked the carb heater when I had the carb off and I have actually wired it to a switch recently, I turn on the key and switch on the heater for about 2 minutes then try to start....most times this seems to help but I shouldn't have to be doing this. The block heater works and I even installed an inline heater, I realize that the inline doesn't actually circulate because the t-stat will be closed but it does help to get warm air circulating fast. (I did the Chevy heater fan mod on this YJ....best $40 I ever spent)
I'm no mechanic but I do dabble a bit, this vehicle is giving me fits, I have considered several other options like the Nutter bypass or putting in a new Ignition Module but I'm hoping someone here might have some ideas. Here are several things I haven't checked and I'm not sure if they would have any bearing on my problem but here goes.
EGR valve stuck open? Cannister malfunctioning / plugged? Computer?
TIA
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You should just sell it to me really, really cheap! ;-)
Seriously, it sounds like you've tried most options, but there are a few other things worth mentioning. They are probably longshots, but won't cost a lot, if anything, to try.
Have your coil tested to make sure it is putting out the proper voltage, or you may just want to replace it. A little extra spark will have a tendency to ignite a cold air fuel mixture more so than a weak spark, obviously. Also, check for spark when the engine is cold. Pull a plug or use an extra one, and hook one of the plug wires to it. Ground it to the engine and then crank it over. You should see a bright blue spark. If the spark is yellow, then you are not getting enough voltage to the plugs.
I don't know if your carb has the vacuum pulloff for the choke, but most do. Make sure this isn't pulling the choke open while you are cranking the engine over. It shouldn't be, but it is free to check and would cause the engine not to receive enough fuel.
Make sure there is fuel in the carb after sitting overnight. Something may be causing it to siphon back, or possibly drain into the engine. You can do this by operating the throttle while you look down the throttle bores. Do this with the engine off. You should see a steady stream of fuel coming from the accelerator nozzles. If you don't see any fuel, the carb is either draining, or the accelerator pump isn't working properly.
After cranking the engine over in the morning, check to see if the carb is wet or dry in the throttle bores. this could indicate a rich or lean condition while cranking. My guess is that it isn't getting enough fuel which would be consistent with the heater helping to start the engine.
I'm sure Mike and the other guys will have some other more Jeep related possibilities, but these are a few things that may show you where the problem is.
Chris
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Some of my ramblings clipped off.

http://members.shaw.ca/kb57/jeep.htm Here it is if your serious :) I bought it from the neighbor for $4000 Cdn which would be about $3300 US dollars it is a great vehicle in the warm weather and I have big plans for it next spring.....I just need it to make it thru 1 more winter before I do a major on it. I gave my son my 93 YJ as a grad present, that 93 starts in -30 with out being plugged in but has a 4 banger that is quite cold in the winter months.

I forgot to mention that I replaced the coil with a Hi Performance coil last spring but I will check the spark.

It has a vacuum pull off and it doesn't pull off the choke until it has been running for a bit, the pull off and electric choke all came with the new carb so it is all new and appears to be functioning.

This was the reason I changed the fuel pump as I suspected that it might be leaking internally back to the tank, the stream from the bores is strong when I work the throttle linkage. I just changed out the fuel filter a few minutes ago with a non vented type, I just plugged the vent line to the canister... the filter wasn't plugged but it is worth a try.

It gets rich when it doesn't want to start I sometimes have to put the throttle right to floor once it floods to get it to fire. I hate doing this as it will sometimes blow back out the carb and it can't be good for the plugs.

Thanks Chris the spark is something I had no idea about and it is quite possible that the coil is defective even if it is new.
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I decided tonight to do the Nutter bypass on my Jeep today and so far it looks like it might have solved my problems, it starts right up when I flick the key over and the stubble it had at idle seems to be gone. I had the vac advance on ported vacuum already but I did find I had to advance the timing about 2 deg's after the mod, before I did the mod I screwed in the idle screws until it was stalling and then shut it down and unplugged the stepper motor. I did the mod and started it back up it kept stalling of course so I backed the idle screws out 4 turns started it and then cut them back about 1/2 turn, it seemed to idle very well at that point.
Like I said before I'm not a mechanic and carb's are certainly not my forte......
Question >>> As I screw in the idle screws I'm essentially making the mixture richer correct?
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Was it pretty easy to do? Seem like it gives any more power? I can get a used Weber carb pretty cheap, but I want to do the Nutter bypass at the same time. Tookie - Denham Springs, LA 88YJ,"Money Hungry" 4" lift, 33" TSLs, Lock-Rights PosiLock, 4.10s
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It was simple to do. Here is how I wired mine in about 25 minutes.
1.)With the engine idling I screwed in the idle screws at the base of carb (front side) 2.) Engine will want to stall, at this point unplug the stepper motor, then shut the engine down. 3.) Remove the washer fluid bottle (2 nuts) 4.) Remove the Ign. Module that is mounted below it (3 bolts screwed in from tire side of wheel well. 5.) Unplug the Ign. Module (2 plugs) 6.) Cut the orange and purple wires on the harness coming from the Ign Module and connect a wire to each of these. 7.) Run the wires along the firewall over to the distributor, cut the purple and orange wires at the distributor harness ans splice in the new ones. (orange to orange etc.) 8.) If your vac advance is connected to manifold vac you need to reroute it to a ported connection, I used the port from the base of the carb. (located up front most likely with a plug on it right now. 9.) Open up the idle screws about 4 full turns (from fully closed) 10.) Start it up and adjust idle screws and timing as required. 11.) Cleaned up the wire routing and tied it all down 12,) Took it out for a test run with a big grin on my face.
I have more horsepower and it idles a hell of a lot better than before.
http://www.off-road.com/jeep/jnutter1.htm <<<< nutter explains mod http://home.sprynet.com/~dale02/ignmods.htm <<< the mod wiring pics
http://members.shaw.ca/kb57/jeep.htm <<< my ride
On Thu, 11 Dec 2003 02:52:27 GMT, tookie snipped-for-privacy@cox.net (Tookie ) wrote:

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No.
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wrote:

Ok .... thanks
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Just a follow up guys. Since doing the Nutter mod to my Jeep I have found that the thing idles like never before, you would think this engine had 29,000 km's on it and not 297,000 km's. Last night it dipped to -20 Deg C here and I went out this morning pumped it twice to set the choke and cranked it over it didn't fire up right away but on the second crank away it went, with the computer in the loop it would have flooded and I might still be trying to get it to go. It does need a bit of feathering of the gas to get it to a steady idle but I can live with that minor inconvenience.
I did notice that the sol-vac doesn't seem to respond and I was wondering if I should bother to repair this as I thought they were really only needed on automatic transmissions.
Any thoughts on this?
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After Nutter:

This is non-functional after the Nutter. The computer used to use that to raise the idle at starting (~1100 for 30 sec then 900 for 2 min I think). Trash it. I also use a CTO to control timing advance: Manifold vac <155 and ported vac above that. Cost is $20 but well worth it. Grand Wagoneer technology.
Jim
88 Grand Wagoneer 89 Wrangler 00 Grand Cherokee
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On 12 Dec 2003 15:26:39 GMT, snipped-for-privacy@aol.com (Jim Boucher) wrote:

After a bit of Google searching I did come to realization that the sol-vac was now dead.....thanks.
With my limited knowledge on these things I don't quite understand how the CTO could control vac advance.
http://www.off-road.com/jeep/tech/258bbd/images/CTO.jpg
The CTO is a switch isn't?
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Never mind my last post I re-read your post and I think I understand. You use higher vac until you get to 155 deg then it switches your vac advance over to ported when the switch kicks in. Correct?
On 12 Dec 2003 15:26:39 GMT, snipped-for-privacy@aol.com (Jim Boucher) wrote:

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Correct. I removed the coolant temp. sensor that's located at the forward end of the intake manifold. In it's place, I inserted a 155 3-way CTO switch and connected ported and manifold vacuum hoses to the switch; the third connection going to the distributor. After I had done the nutter, it just wouldn't idle nicely when cold using ported vacuum (essensially 0" at idle). Runs like a champ now.
BTW, I like the solenoid idea. I was thinking of doing that for winching operations. Jim
88 Grand Wagoneer 89 Wrangler 00 Grand Cherokee
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On 12 Dec 2003 21:57:31 GMT, snipped-for-privacy@aol.com (Jim Boucher) wrote:

I was playing with the sol-vac and the new switch today and found I can get it to idle anywhere from 900 to 1400 rpm, I just achieve the idle point I want and then flick on the switch. From what I have read the sol-vac doesn't have enough power to open the throttle but it can hold it where ever you set it....... now I have to quit playing with it at stop lights :). I also wired my carb/intake manifold heater to the same switch bank and on the really cold days I can flick it on for a few minutes and get the vapors in the intake nice and warm before starting it. I'm not sure where you live but it can get to -40 Deg C here in Alberta and my vehicle sits out in the open when I'm at work for up to 13 hours, it's my version of a glow plug.
Thanks for the info I might consider trying the cto thing out when I get a chance.
http://members.shaw.ca/kb57/jeep.htm
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Jeepster wrote:

That's neat, never though of that for a 'hand throttle'. I will pass that on to others for sure. I even have my old one kicking around and likely will put it back on.
That would be a great thing to have when the idle tubes plug up and it won't idle for crap but runs good over 1200 rpm or for winching.
I got a manual choke kit from Canadian Tire and put it in mine. That way I can drive away in the real cold without having to 3 foot drive the thing until it warms up. The electric choke is just a plain timer that goes off according to how long it has had 12 volts, no matter the real temp.
I can set a fast idle by pulling on the choke when I have the pedal down where I want it, then letting off the pedal and pushing the choke back in. It stays on the fast idle cam until I blip the gas pedal.
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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wrote:

Yes the choke coming off so quick is a major down fall, it might work in the States but with the weather here it just opens up way to quick.
I have also read somewhere that someone put a reostat on his choke so that he can vary the opening, I thought to myself there is a guy who is thinking.
I looked at the sol-vac not as a useless piece of junk under the hood but as an opportunity. :)
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Jeepster did pass the time by typing:

Hmm..
A thermal switch rigged through the system would work. Get one that is in the correct engine range, say 100F or so then use that to disengange the solinoid. / (NC thermal switch) Fairly simple circuit. IGN>---o/ o------o~~o-.--->sol gnd>----|<|-----------' 12Vled (indicates sol on)
I'd have to reasearch more but I think that's about it. You flip the switch, as long as the ignition is on and the temp is below what the thermal switch is set at, current flows to the solinoid and back to an indicator (12 V LED in this case) possibly even built into the switch.
Soon as it warms up, the thermal switch opens, the sol and led go out. You could actually leave this circuit on since it draws power only when the IGNition is on.
YMMV.
--
DougW



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On Fri, 12 Dec 2003 19:34:29 -0600, "DougW"

I will save this one in my archives also....thanks
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Jeepster wrote:

You are correct, the sol vac is for auto and AC and gets disabled with the Nutter bypass.
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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wrote:

I went and got a switch today and wired the sol-vac to it, when I start it up and want it to rev a bit higher I can tap the gas and flick on the switch. I set it up so that when I do this I get it reving at about 1000 rpm then I can leave it unattended while it warms up, with out fear that it is going to stall on me.
Hell the Solenoid is there I might as well use it. :)
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