vacuum...emission and other threads

[kkerem]

Hi all,

Still I have a problem with my chero (89 4.0 at/ac).
First thing, two months ago I broke one heater pipe. There was a valve vith vacuum to close the heating system when the ac is on. Now I got a new pipe with a valve, but I can't find the vacuum line any more. The pipe is under hood next to friewall and it has a vacuum connection. Now, where the vacuum line starts.
Last week I tried to measure my vacuum again, now I am sure that there is some leak in. But I need a vacuum diagram...

Now the most important part. My chero still have a hard start (both cold and hot). When I accelerate slowly, engine misses, when I drive (cruise), engine misses... When I accelerate hard (WOT) engine runs, but I can say that there isn't power as much as it should have. So to be sure, that the vacuum line is not the issue, I unpluged the vacuum line and closed the connector, which controls the 4WD AC/heater system. The idle speed wasn't as high as it was before, but no difference...
Engine stops missing when decelerate and then I accelerate again, or just accelerate. Also I found out that when the engine starts miss, miss and I hold the pedal at the same spot and switch to neutral, it dosn't stop missing, and when I let the engine jerk then it starts to backfire.


From older thread:

I have checked/changed:
TPS (adjusted)
TP cleaned
MAP (new)
O2 sensor (tested... But not sur, was thengine hot enaugh)
Fuel pump (new)
Fuel pressure regulator (tested)
Fuel filter (new)
Vacuum lines (tested - MAP, fuelpressure regulator lines are 100% fine. One leaky line in ac system)
Spark plugs (new)
Wires (new)
Cylinder pressures (tested, equal)

It has disconnected and closed EGR vacuum lines and disconnected EGR solenoid.

??????

 

[Slip Kid]

did you replace the cap and rotor?

 

[kkerem]

Cap seems to be ok, but I haven't check the rotor. I must check them and replace.
Also I didn't say that the resistance of tps is solid...

 

[5-90]

Check and see if your XJ has an underhood emissions sticker (I know they do here, but I don't know about overseas production) - I think it's usually on the driver's side of the upper firewall. If it's there, it should have a vacuum diagram on it.

Also, take a bit to retorque the intake and exhaust manifold bolts - they tend to work loose over time, and that can cause a vacuum leak. If they haven't been doing this long, you probably haven't burned the gasket, and can save it with some wrench work. I've run across this quite often before.

Since you mention emissions, is there an emissions test you've been having trouble with? Or it is just the idle/stumbling part? I just want to have the whole picture here, to make sure I don't miss anything...

5-90