now to trace a vacuum leak

I got the new cam and lifters installed and even got the beast running (89 XJ, 4.0) and it runs smoother and has more pep ... so far but I
haven't driven farther than around the block.
I won't be taking any longer drives without a recovery vehicle handy.
I have to dig under the dash and into the connections on the vacuum reserve tank behind the bumper to try to find the cause of the fluctuating idle.
I suspect the problem is under the dash as I've not been able to switch from defroster flow to floor flow for two winters now.
Unfortunately, there isn't a diagram of the heater vacuum circuits available online for the 89 XJ that I've been able to find.
I also don't like the look of the vacuum line for the heater water control valve (I also converted from a closed cooling system to an open system while the beast was apart).
Budd
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Budd Cochran wrote:

Will this help? http://www.revbeergoggles.com/temp/88xj%20heater%20system.pdf

On my ZJ I had to use a vac pump (one of those hand held thingies with a gauge) to test lines. Wound up replacing quite a few of the hardlines because they had small cracks. Oddly, the vac harness from Jeep wasn't expensive.
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On 6/20/2015 8:59 AM, DougW wrote:

I have a vacuum line assembly from a '92 in my pile of Jeep stuff but I don't know if it will fit yet.
And the darn thing is still cutting out and stalling so it's back to square one.
Budd
Who truly understands the phrase: (J)ust (E)mpty (E)very (P)ocket ... I'm so broke now I can't afford to sell it . . . . . . .
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Budd Cochran wrote:

About the only thing I'm down to is jumpering the block to the frame. That stoopid ground strap problem.
The other option is a harness issue, and that is an exercise in tracking wires... the biggest PITA of them all.
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On 6/22/2015 6:02 PM, DougW wrote:

. . . . . .

I put a pair of factory ground straps (one saved from a the '92 added in parallel to the factory strap) from the block to the firewall and since the vehicle is a unibody design that should be enough.
I can make another ground cable up from a salvaged sectio9n of # 8 cable from a cheap jumper cable set, if need be.
Wiring????? Oh let's hope not. The vehicle had a lot of bad spots in the harness from rats chewing on it and for a while I used solderless butt connectors to repair them but after the cutting out started I went thru and soldered / shrink wrapped every placed I'd repaired plus a few extra spots.
I even had to replace the connections to the grille surround with flat 4 trailer plugs because they had melted at some time before I got it.
Budd
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On 6/22/2015 9:47 PM, Budd Cochran wrote:
Finally got the vacuum lines tested and the one I thought was bad wasn't.
OTOH, the primary line to the vacuum reservoir leaked so bad I could only salvage about 5" of it and there were 4 other leaks on the reservoir lines.
I routed a length of 1/4" nylon airline from the intake to the reservoir using short sections of the good piece to make connections and cut the leaks out of the smaller hoses and now I have a better idle, all my heater doors function, and I drove the XJ over 5 miles without a single hiccup.
If poor vacuum signals to the MAP sensor, the fuel pressure regulator caused by the leaks in the other lines was causing my grief, I'm a bit ticked off.
Over $300 (not counting the camshaft and kit as it needed replaced) spent because engineers used a dumb design for the vacuum system . . . . . . .
Oy!!!!
Budd
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Budd Cochran wrote:

MAP sensor is fairly important because it controls the fuel via feedback. The one on my ZJ is bloody expensive and kept failing till I gave it a bit more tubing. They put it too close to the engine and it would eventually break the plastic connector.

Indeed!
Hope you fixed it though. Still cheaper than replacing it with another fixer upper. :/
I'm dreading my next repair. Going to have to replace the bushings on the rear links. Eight bushings in the most innacessable locations possible. Got the parts, but I need to find a spot with a lift. Not going to do this on my back like I did with the front.
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On 7/4/2015 3:36 PM, DougW wrote:

I've put a whopping 7 miles on it without a single miss, hiccup, or stalling ... but I ain't holding my breath.
I hated doing the front bushings myself and I'm glad I don't have the rear 4 link suspension for that reason.
While I had it down for the other stuff I converted to an open cooling system instead of the closed system that sent 20% or more of the hot engine coolant thru the pressure bottle (now my overflow tank) and bypassed the radiator and heater cores ... no wonder Renix engines run HOT!!!!
We're looking at a '92 parts XJ (no title) for patch panels but if it is in good enough shape, we may try to get a replacement title and drive it.
Budd
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