1987 YJ 6 cylinder new Weber 34 carb won't start

defmornahan

New member
Yet another new Jeep owner. Bought this thing from the lady around the corner as my wife's wedding present in April. It's a Laredo and was pretty much stock with a few exceptions:

Most of the pulse air stuff was removed, including the vacuum switches, the little reservoir, both solenoids (the four-wire connector is hanging off the firewall), and the upstream reed valve and vacuum valve. The downstream reed valve is still in place; I just took the vacuum valve off since it had no line, no solenoid, etc. and ducted the reed valve straight to the air cleaner. The upstream pulse air pipe is still mostly there, with the end bent over and not real well pinched off. No vacuum lines were still hooked up to the CTO. The beast has not been Nuttered to my observation.

It's my wife's present, so it's got a column shift automatic and a cruise control (completely nonfunctional). Allegedly a rebuilt engine was put in it around 75,000 ago. It's got just over 200,000 now.

We took it down from Indy to northeast Tennessee to get a hard top and doors off eBay, and it overheated the whole way down and we had to run the heater the whole way back to keep it alive. It started getting very hard to start over the summer and would intermittently die when cold, sometimes three or four times in a 15 minute drive. It also was overheating, and I think the radiator was getting pretty much rusted shut. After taking it a couple of places, I took the dealership's suggestion that a Weber carburetor would do it good, as well as a new intake manifold gasket. As long as I was taking the Jeep apart, I also replaced the radiator at the same time. I also redid the vacuum routing; the only hoses that aren't new or have new plastic ties are the ones to the cruise control, which is teed into the port at the back of the intake manifold along with the 4WD red line (that last according to the tech's advice at the dealership). I unclipped the TVS (?) vacuum switch from the old air cleaner and left it hanging around at the back of the engine (cf. www saragossa net/weber_conv php ) , and I re-added the hoses to the CTO and EGR more or less as he did. I also replaced the old plugs, which looked grateful to retire; they had lots of white to tan deposits on them.

Anyway, last night I finally had Frankenstein put back together and tried to crank it. Turned over, ground it for a while several times, wouldn't start. I had poured about a film bottle's worth of gas into the space between the barrels and the fuel intake on the carburetor. I poured two in, and I think I probably flooded it. I'm not real smart with carburetors; I haven't driven one since I was about 14 or 15 on the farm, I expect. I ground the starter for a while, checked spark at the distributor and at the #2 plug and both wires were sparking. I checked the fuel pump and it was definitely pumping gas, and when I had my wife pump the pedal I could see gas squirting into the primary barrel below the choke. The choke was standing open after she'd popped the pedal, and I think at that point it actually started and ran for ten or twenty seconds at real low RPMs (400 or less, IIRC), then died and wouldn't start again. At some point around that time some smoke also emerged from the air cleaner, so I knew something fun was going on.

I had read mixed reviews about the effectiveness of a fuel pressure regulator, so I hadn't had it in up to that point. I put the fuel regulator back in, but I didn't try starting it again.

Today I took the plugs out and saw that #1 to #3 were black as night with soot, #4 is almost as dark, a little lighter on one side, #5 is dark on one side and kind of bronzy on the other, and #6 is pretty bronzy. All smell like gas. I've got the plugs out and I've stuck a length of virgin vacuum hose down the primary barrel to hold the throttle and the choke open, and I've got a fan blowing on the engine right now and the garage open.

Anyway, hoping that's enough background (!), I'm not sure what to do next.

- Should I pony up for new plugs, or be cheap and scrub the contacts off? I assume I should put some kind of cleaner in the gas to clean the soot out of the cylinders anyway--assuming she ever starts again?

- This differential condition of the plugs has me concerned. Is there maybe a leak on one side or the other of the intake manifold? Which end? I know I had trouble putting the bolts back in on the back end (toward the firewall) and had to use a drill to edge maybe 1/16" off the exhaust manifold to get those bolts in. I tried my best to torque them down but it's fairly absurd trying to get a torque wrench on these beasts, and I think some of them I had to use a U-joint and hope that if I torqued them up a little extra it would be all right (dredging up some vague memories of torque vectors from physics class). I also used this copper gasket spray on the whole affair, intake and exhaust manifold both, whereas the can says exhaust manifold explicitly. Should I take the manifold back off and use some other kind of gasket sealer on the intake manifold?

- Is there anything else obvious I'm missing? Forget Jeeps, I've never worked on anything before this year. I've just got my Chiltons and you guys and the guy at the dealership if I call during the work day...

- If worse happens and this ( www jeepz com/forum/cj-yj-tj-jk/22700-jeep-wont-start html )
is what's wrong (timing chain tore off a couple of sprockets...just shoot me), I assume you need to drain the oil before you take off the timing chain cover? The Chilton's doesn't mention that step, but surely...
 

Ok first off what are the condition of the seals at the carb to intake and at the intake to block thinking something there is causing a leak.
And Try playing with your timing(after marking the current location) and see what results you get.
I went out and bought that mr.Gasket regulator and really don't see a difference. But have it set at 5.
Currentley My set-up consist of this
No lines connected to the weber, choke hoked up, the vac advance open, the egr plugged off, the cto open, the main manifold plugged, both rocker ports open, emissions all open, running dual filter with return going to canister. Do not have kick down hooked to carb(shifts real smooth do feel 1st-2 but have to look at tach for 2-3).

Runs at 900 idle and 600 sitting at a light(in D). Gets between 14 and 18 mpg(Mostly under 60). Which is about what I Got with my 01 tj auto.
Has no spit sputter or whatever. No leaks anywhere. Runs 2500@60(3 speed stock gears).
 
Have you gotten it running more than the initial 10 - 15 seconds? Did the plugs get that black in a 15 second timeframe?

I wouldn't buy new plugs yet, just run a lite sand paper between the contacts.

I would not buy a regulator yet (although they are cheap). I bought one for my old porsche 914 when I went to dual carbs, and they don't seem very accurate. A better investment was an inline fuel pump gauge. I found it at Pep Boys (local auto parts store) for only 3.99 each, and they read up to 20 PSI.

I think you are going in the right direction - you just ended up with too much gas in your engine that first time. Make sure that your carb is bolted down tightly, and there are no air leaks.
 
I appreciate the replies...unfortunately I've had too much life and no Jeep this week. (It was going to happen at some point. Plus my coworker who was going to help me work on it couldn't come.) Yes, the plugs were brand new and now the front four are pretty sooty. It may have run for 30 seconds. The plugs either got black then or while I was grinding the starter all evening or both.

Like I said, I used a copper aerosol spray on the gaskets, so I think I'm going to remove both the manifold and the carburetor and use some of the tube-type gasket sealer on them to hopefully remove air leaks.
 

I appreciate the replies...unfortunately I've had too much life and no Jeep this week. (It was going to happen at some point. Plus my coworker who was going to help me work on it couldn't come.) Yes, the plugs were brand new and now the front four are pretty sooty. It may have run for 30 seconds. The plugs either got black then or while I was grinding the starter all evening or both.

Like I said, I used a copper aerosol spray on the gaskets, so I think I'm going to remove both the manifold and the carburetor and use some of the tube-type gasket sealer on them to hopefully remove air leaks.

With a Weber, make sure that you use loc-tite for the adapter-to-manifold bolts as they have a tendency to back out. You may have a serious vacuum leak somewhere. The black stuff on the plugs is most likely from dumping fuel down the throat and not burning fully (sorry, pointing out the obvious). Not burning properly usually points to ignition. It sounds like you've ruled it already but I would try to get a new/different duraspark module (the box under the washer tank). These go out quite a bit and the issue could be that your not receiving enough spark to run.

Save up to convert to Howell TBI could be another option. 8)
 
Save up to convert to Howell TBI could be another option. 8)

Uh, no...too late now; this is the last fuel delivery infrastructure I'M giving this Jeep ;). I'd be taking someone else's advice and trading up for a 94 or 95 YJ, if not TJ...

I took the manifolds and carb off and used a proper gasket sealant. Unfortunately I stripped the threads on the 12th and last manifold bolt, and it now has an ordinary flat washer instead of the old tall washer to permit the bolt to bite on the remaining good threads at the bottom of the hole in the engine block. I had to get the battery recharged too. I also took the fuel pressure regulator out, and now the engine will start, but it will only run while I have the accelerator down fairly far and the RPMs above about 1000 IIRC. Now my main problem is that I don't know whether to attempt to adjust the carb or do the Nutter and adjust the timing first (!). I THINK that the problem is that there is something wrong with the carb adjustments...as opposed to the fuel pump or the linkages between the accelerator and the carb (seriously, what a Rube Goldberg machine that crap is).
 
I'd say that if you've gotten it to run then the hard part is over. Now you just need to make small adjustments. Don't give up yet!

Do you get any gas in your exhaust, or black smoke? if you can get it running long enough, you may be able to time it, which would be a step in the right direction
 

oh yeah, one more thing - how old is your gas? I once spent 2 months trying to get the fuel injection right on an old porsche - turns out the gas was 2+ years old, and wasn't any good.
 
oh yeah, one more thing - how old is your gas? I once spent 2 months trying to get the fuel injection right on an old porsche - turns out the gas was 2+ years old, and wasn't any good.

Holy cats. That blows chunks. My gas is, at a maximum, 5 months old, and minimum 2 months old. (I last took it on a trip of any length in May or June, and it hasn't run since late July.) I don't know if that's too old.

Meanwhile, I am considering doing the Nutter Bypass. This link seems to be the standard reference: www 4x4wire com/jeep/tech/electrical/jn-ignition99/. But it doesn't really correspond to what I see in my Jeep or in my Chilton. There are indeed a purple and an orange wire (well, black with stripes these colors) coming off the distributor, which turn into actual purple and orange wires past the connector. These feed into the huge omnibus "split loom covering" that crosses the engine compartment along the firewall over to the drivers side. At that point, most of the wires emerge into a plug that I can only imagine is connected to the computer. The purple and orange wires are there. But there is no orange wire going to the ignition module underneath the radiator overflow tank. Rather, the other wires from the omnibus carrier emerge (two green, yellow, black, and light green) and go down to the ignition module. This corresponds to the Chilton wiring diagram. I do notice that these wires split and go to two connectors, and one of these connectors has purple and orange wires coming out the other side.

So, if you're still reading this, anybody, should I get _two_ new wires and splice the purple and orange at the computer port down to the purple and orange beyond that lower connector? I tried to figure out which black, yellow, or green wire connects to the orange and purple wires, but I had no luck.
 
Do you get any gas in your exhaust...?

I believe I was before and may still be now. I'm not sure if the smell of gas in the engine now is from my priming the carb or from the exhaust. Right now the pipe from the exhaust manifold to the cat is hanging on one stud because I didn't put the other back. My friend from work took it off, but couldn't get the other one, and I haven't made myself put that nasty rusty stud back (the nut is rusted fast so the stud itself came out of the manifold).
 

If you're getting gas, or what looks like black soot in the exhaust, then you're running too rich - you should also have black spark plugs.

On the gas front, you should throw some fuel stabilizer in then top off with a gallon or two of gas. It still won't be mixed very well, but should help.

My thought would be to wait on the nutter. I'd try and get it running and idling first. I think that making too many changes at one time will make the problems harder to track down.
 
I'm sure my plugs are still black from flooding it two weeks ago. At this point, for all I know, I'm running too lean.

So I should leave adjusting the timing for later as well, and just fiddle with the carb screws to try to get it to idle?
 
Back
Top