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Extremley High Idle after Replacing Head

G

Gunner13

NAXJA Forum User
Location
Ft. Stewart, ga
Hey Guys, ive done some searching, but cant find an answer.

I just got done replacing my head on my 2001 XJ. I replaced with a TUPY head off of a 2002 WJ. Tightened everything up to spec, hooked up all the sensors ( 99% positive) filled up with coolant. not leaking or anything. replaced two upstream o2 sensors. not throwing any codes. I used the pulley from the Tupy head that it came with, could this cause the issue? do I need to remove that and just plug the hole with a bolt?

First start it revved up to about 4k and I turned it off. Did it a few more times and same thing. what can be doing this? vaccum lines? I hooked them all up to the intake manifold. when it gets a little past 4k it will kill itself. I smelled fuel. I released pressure in the fuel rail and it did the same.

Any suggestions?
thanks guys
 
Gunner13 said:
...start it revved up to about 4k and I turned it off. Did it a few more times and same thing.
Click to expand...


It is likely the intake manifold is not fully seated and flush to the head, causing a massive intake manifold air leak. This is a common mistake, the alignment dowel pins are causing the manifold to be slightly cocked at an angle. Check for proper function of the throttle body butterfly valve also.

You will need to remove the intake manifold, clean out the dowel pin holes, and confirm that it is properly seated and flush before you tighten the fasteners.
 
thanks for the quick reply. I will go do this now.

I took off the idler pulley and just tightened the bolt down in there. didn't make a difference.

ill be back shortly with results!
!!!1
 
I'd bet the intake is not seated correctly and it is causing a vacuum leak
Edit
My phone was behind in updating.. I didn't see the same exact reply I gave.
 
didn't crack it. runs great now! Thanks guys!

Well, since I'm already here I might ask well let yall take a stab at this.

when I first got it started, it over heated, causing coolant to spray out of my radiator cap. My coolant reservoir line was clogged. so, I unclogged it, pried the little nubs on the collant cap over, to create a better seal, filled her back up. Now its still over heating, just shooting the coolant out through the reservoir lol. it also went from just over 210 degrees, then shoot up into red super fast, and the check gauges light came on.

I have a brand new thermostat in, idk what else to check. inside the radiator has a lot of brown gunky crap. tomorrow I was going to start with a radiator flush and see what happens
 
You probably have air and not enough coolant in the system, or a malfunctioning thermostat.

The easiest way I've found to fill the system is to remove the upper radiator hose at the thermostat housing and pour coolant into the radiator neck until you see the coolant level rise in the thermostat housing. Then put an extra 1-1.5 quarts in coolant reservoir and it will suck it after a few days.
 
Gunner13 said:
So you're telling me it's supposed to over heat? Just when it starts to, to crank the heater?
Click to expand...
just a pocket of air trapped making it lok like its overheating.

have the heater on right when you start it, turning it on after its hot is too late.

This will help keep an even temp and lessen boil over when the t-stat opens
 
well guys, I made sure she was full today, took it out for its first big test. Temp stayed perfect! I appreciate all the help guys!

I bought this xj for $750. needed a Head, and the A/c Compressor is bypassed.

The heater wasn't blowing hot air, and there is no air coming from the front vents on the dash, only the defrosters. Could the AC compressor cause all this?
 
Gunner13 said:
The heater wasn't blowing hot air, and there is no air coming from the front vents on the dash, only the defrosters. Could the AC compressor cause all this?
Click to expand...

More than likely it is a vacuum leak in the climate control system or where it is fed from the engine.
Anything else vacuum operated affected such as cruise control?
 
I haven't tried cruise control.

I was however wondering, the vaccum lines on the side of the intake manifold, the first one (toward front of vehicle) had a rubber plug inside of it. I took that out and placed it back on the connector. could that have anything to do with it?
 
I would trace out the line from the engine to the ventilation T and over to the cruise control actuator and then to the accumulator ball behind the front bumper to verify there are no obvious leaks such as disconnected lines.....
 
Gunner13 said:
...... there is no air coming from the front vents on the dash, only the defrosters.
Click to expand...

The vent controls a vacuum operated. If there is a vacuum leak, the vents default to defrost. Check the vacuum lines from the vacuum reservoir ball all the way to the dashboard control knobs. Look for split hoses, and dry rotted fittings. The A/C compressor would have no effect on the vents.
 
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