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1992wranglersahara 11-27-2010 07:35 PM

Timing or carb? Or...
Hey all -

Comfy? Cozy? Good... cause here goes...

So today I changed out the timing chain and sprockets on my 90 YJ, along with the necessary gaskets/seal. Replaced the water pump with a brand new one, as well as a new thermostat.

This 90 YJ has had the Nutter Bypass performed on it, as well as the Team Rush upgrade.

Prior to installing the new timing chain and sprockets, the timing was set at 8 degrees BTDC at curb idle.

Now, after getting the new chain and sprockets in there, I figured I should check the timing. At idle, the mark was so far off the scale, you had to lean down near the engine compartment just to see how far back it was. It must've been 30 degrees BTDC, if I had to wager a guess. HOWEVER, I realize NOW that when I hooked up the timing light, I failed to disconnect the vacuum advance hose and cap it off. So, I will have to try again tomorrow. I set it to 14 degrees BTDC just to get the Jeeper home.

Now, not for nuthin', but I also had a wicked 100 degree turn in the rubber hose that comes off the fuel pump and into the fuel line. It was also dry rotted. Apparently, that fuel line must've gotten pushed WAY too close to the fuel pump, causing the bend to be soooooo lethal. I bent the fuel line away from the fuel pump about threes inches and replaced that short piece of hose with new. I have been running better with the choke slightly on, so I figure I was lean. Perhaps this kink in the fuel hose added to that???

Also, I have a LOT of oil coming out of the fuel pump area. So much so that you can actually see where it has splashed up onto the distributor cap. I am going to assume that this is the original fuel pump. I will be replacing that next week, as well as any fuel hose I see. Perhaps the fuel pump isn't doing such a great job any more and THAT is causing me to run lean?

I had a wicked ticking coming from the engine compartment and figured, after posting here on WF, that it was the timing chain. That chain was DEFINITELY stretched. Wow, did it have a lot of slack in it, especially compared to the new set I put in.

I guess I am writing in hopes that some of you will take an interest in what's going on and help me get this thing dialed in. When I took it out for a test drive after putting in the new chain and sprockets (and before re-setting the timing), there was a good deal of low-end bearing noise, especially around 2000 RPM with no load being put on the engine (I was deliberately NOT accelerating). Once I set the timing to 14 degrees BTDC, that noise was mostly gone (how happy was I?!!?). I may even be a quart or two or oil low, actually, being that I am losing so much oil near the fuel pump.

What do I want?...

I have owned three Jeeps, so believe me - I know I do not have a Honda Prelude on my hands here. I know this is not a performance vehicle.

That being said, I want what I know it SHOULD have... power, no knocking/pinging/ticking/bearing noise and a smooth idle.

Of note: I also installed a MC2100 carb in there last year. I bought it from the guy who rebuilds them and sells them on Ebay.

If anyone would like to chime in and offer some sage advice to get this thing dialed in, I am all ears.

My plan right now?...

1) Top off the oil
2) Re-set the timing, doing it correctly this time, to 8 degrees BTDC
3) Install all new spark plugs, correctly gapped
4) Install a new fuel pump

Thanks everybody -

mcgyver1467 11-27-2010 08:05 PM

Sounds to me like you got the timing off.

sppfields 11-27-2010 08:45 PM

I agree, your timing being off causes the knock. your fuel pump diaphram is busted causing the oil leak. sounds like you have a good plan with everything you said.

1992wranglersahara 11-28-2010 03:29 PM

I'll give an update tomorrow on the situation. Thanks for chiming in, guys.

1992wranglersahara 11-29-2010 01:51 PM

Re-did the timing. Got the idle at 750-800 and set the timing to 8 degrees BTDC. Idle is smooth :-) However, my low-end noise is there when there is no load on the engine :-( I am going to replace the fuel pump next, since it is leaking oil. Maybe it is causing my low-end noise, who knows... We shall see.

Topped off the oil, too, so I am full on that. My oil pressure looks fine. When I am shifting up through the gears, my pressure goes from 10 to 40 on the gauge. I was at 25 when I was running at 1500 RPM, so I think I am getting good oil pressure. It would appear that I am not getting the low-end ticking from low oil pressure.

1992wranglersahara 11-29-2010 08:54 PM

Another update
Installed the new fuel pump. My oil leak issue should be gone now.

Still getting the low end noise. I am thinking I am looking at rod noise.

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