87 YJ 258 Cold start problems (Long)

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

Hmmmm....

Pinhole leak in the gas line on the suction side of the pump is my wild guess.

This will not drip on the ground, but is big enough to empty the gas line by letting air in when it is off.

I would be checking the line visually and be looking for a stain on the pipe. Normally I see it at the back clamp to the frame or at the front clamp to the frame where the rubber hoses hook on.

Mike

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

Jeepster wrote:

Some of my ramblings clipped off.

it is if your serious :) I bought it from the neighbor for $4000Cdn which would be about $3300 US dollars it is a great vehicle in thewarm weather and I have big plans for it next spring.....I just needit to make it thru 1 more winter before I do a major on it. I gave myson my 93 YJ as a grad present, that 93 starts in -30 with out beingplugged 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.

I will take a look for that ..... but would this be a problem that would only appear during the colder weather?

Thanks

Check the rubber lines close.....

Mike

Jeepster wrote:

I got under it tonight with a halogen light and traced the fuel line from the fuel pump back to the tank unfortunatley I didn't find any signs of a leak. A few of the connections were standard hose clamps and others were the stock plier types, I intend to go over and tighen each of the clamps and replace the stock clamps on my next days off.

I'm w>I will take a look for that ..... but would this be a problem that

I had the same problem with my 89 YJ. I too have the same blow-by and valve cover leaks.

Here are a few things my mechanic and I figured out that worked:

1) Put in a paper air filter. The K&N let in too much air and messes with the mixture. Your Dodge dealer set the idle and mixture to factory specs, which is with a paper filter. 2) Check your EGR valve. It should be replaced every 80,000 miles. Make sure you have suction at the EGR valve too. 3) The Air Filter assembly will bend the choke if you put it on too fast. Check to see if it is bent. If it is bend you will notice you have to rev it alot on cold mornings to keep it from stalling, and it will stall at every stop light until it is really warmed up. 4) did you get a rebuilt carb? 1 out of 2 of the rebuilts tend to be bad. Make sure the carb linkage is not greased. They are not meant to be lubed on these carbs. 5) My mechanic told me, that the 258 and carter carb should always use Premium Fuel, and it has helped me since I started using it. When I am near the ocean I need to dump Octane Booster in it just to keep it running. 6) You probably have 2 pipes that run from the cat back into the engine. Make sure these are connected. 7) Make sure your preheater hose is not leaking. 8) After all this, have a mechanic check the choke again.

i replaced my ignition module 2 weeks ago,my 89 Yj 4.2 has been a bear to start for 5 yrs.cut off wouldnt start....it runs great now.

I If it starts fine when you leave a heater under the hood, you can forget about checking for leaks. You have a problem with your choke. Drive it around one evening enough to warm it up. Park it overnight, in the morning (or even better, when you park it) remove the air cleaner so that you can see into the top of the carb. Now, while looking down into the top, move the throttle linkage with your hand. (Give it some gas) You should see the choke plate snap shut. It looks like a little round baffle, blocking the airflow into the carb. If this plate doesn't close when you move the throttle linkage, the choke is not working. If you take off the air cleaner in the morning, be sure not to hit the throttle before you can watch it, or you won't see it when it moves. Good luck, and let us know what you find

Tookie Tookie - Denham Springs, LA

88YJ,"Money Hungry" 4" lift, 33" TSLs, Lock-Rights PosiLock, 4.10s

On Thu, 11 Dec 2003 00:21:23 GMT, tookie snipped-for-privacy@cox.net (Tookie ) wrote: in the morning (or even better, when you park it) remove the air

To be clearer, engine has to be cold again before checking it Tookie - Denham Springs, LA

88YJ,"Money Hungry" 4" lift, 33" TSLs, Lock-Rights PosiLock, 4.10s

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?

Thanks I did some nosing around the EGR valve last night and did notice that it isn't moving when I rev the engine (when warmed up) I have also noticed that the engine seems hot when shutdown these days and this could be an EGR that is stuck closed and not quenching the combustion.

The carb was new/rebuilt I bought it from an after market parts place (NAPA Motor Parts) The furnace tube is new and has no leaks and the flapper in the intake responds as it should.... that was one of my first checks when I started driving this vehicle in the winter. :)

I have recently started running mid grade and it does seem to help maybe I will step it up a notch if the problems persist, I'm hoping the Nutter mod I did tonight helps me with my problem, but either way it seems to have more power. I work for Shell Canada and make gasoline for a living ...... badly tuned vehicles are something our company loves :)

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

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.

when I flick the key over and the stubble it had at idle seems to be>>gone.

No.

Ok .... thanks

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?

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