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Post by beetOls on Jun 8, 2005 0:05:11 GMT 11
What's the default RPM setting for a 4jb1t engine? is it around 750? im having a bit of a problem with my a/c idle up...my rpm is set to around 850 right now and then goes up to 900 to almost 1k when a/c is on...isn't that too high? another problem is rpm gets stuck at 1.250k for around 3 seconds before it goes back to its normal idle setting (850) after revving up(even only up to 2k). now if i lower it down to around 600-750, i hear that hunting sound from the engine which seems like its gasping for breath in regular pattern whcih im pretty sure has something to do with injector (best way i could describe it) but at this setting, a/c idle up goes up and down normally without that getting stuck problem! so, should i stick to my present rpm setting?
hope i explained my prob very well...inputs would be appreciated!
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Post by justin on Jun 8, 2005 9:13:26 GMT 11
I believe its 750rpm for a manual and 850rpm for an auto. J
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Post by geeves on Jun 8, 2005 10:44:57 GMT 11
Aircon revs are about right The low idle/hunting happens on mine as wewll occasionaly mostly when cold Hard to know if its worth worrying about
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Post by Jimmu on Jun 8, 2005 15:43:18 GMT 11
Mine idles at 500 RPM with the air con off.
Is a but low I think as she is not running all that smooth at those revs.
Jimmy.
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Post by geeves on Jun 8, 2005 20:19:13 GMT 11
The way the revs stick could be an issue. Check for a sticking accelorator cable and checjk the engine for blowby by disconecting the 1inch diamiter pipr that attaches to the pipe between the aircleaner and turbo near the inlet manifold . Excess blowby could cause this. What is oil consumption like.
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Post by beetOls on Jun 12, 2005 8:15:24 GMT 11
oil consumption is about normal...the sticking problem usually goes away as soon as the engine reaches its normal temp. (about halfway up)
by the way...is it ok to see oil coming out of the breather? (this is the small pipe that connects from the valve cover to that pipe from the air cleaner...is this another sign of blowby? neighborhood mechanic says its normal and is just caused by worn valve cover gaskets...is this true? thanks for the reply geeves.
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Post by beetOls on Jun 12, 2005 8:21:45 GMT 11
...and also, is it ok to feel the jerking when my a/c turns on? since rpm rises up a bit? or that is too much idle up? i feel that esp when cruising on a particular gear and im not stepping on the accelerator....
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Post by geeves on Jun 12, 2005 9:25:55 GMT 11
for the oil in the breather quesion is how much. Some is common on isuzus but lots is bad. Have a look for threads on oil catch can or breather mod These may help.
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Post by beetOls on Jun 12, 2005 21:45:51 GMT 11
well...there's not much oil in the breather...maybe just enough to make the joint visibly wet...either the clamp just loosened up and is due for replacement or the amount of oil just increased since it was the first time i saw oil coming out of it...will check the oil catch thread...thanks!
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Post by beetOls on Jul 19, 2005 14:50:32 GMT 11
just an update...
tried lowering down my RPM to about 750 but i hear the hunting sound....why is this? it was originally set to 750 (before i had the nozzles and pump cleaned)...i just think that the current setting which is at 850 is too high and when a/c is on...its almost at 1k...but after hours of driving, RPM goes down to normal...very puzzling...
the shop who calibrated my injection pump(new nozzles and injection parts) is willing to have it checked again by running it through their machine again since it should not be hunting at around 750rpm considering its the default
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Post by geeves on Jul 19, 2005 18:10:20 GMT 11
get a compresion test done at the same time but my money would be on pump timing as a guess
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mars
Isuzu Baby
Posts: 4
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Post by mars on Aug 28, 2005 23:53:50 GMT 11
hi
your idle get stuck for 3 seconds because the idle screw is turned in to far
it idles uneven because the set screw at the back of the pump is turned out to far(to lean)
turn in the screw at the back of the pump 1 flat after taking off the cover then let it idle till operating temperature and set the idling screw to between 650 and 750 rpm
if it is not idling smooth turn in the screw another flat and adjust idling if to fast
check if it smokes under load
hope this helps
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Post by beetOls on Aug 31, 2005 14:54:59 GMT 11
hahaha...funny, that's exactly what i did! solve the freakin problem just 2 days ago...now its set to about 750 and maybe 800 with a/c and she's running quiet as ever!
thanks anyway!
just one question though...when you step on the gas pedal, is it normal to feel a little play(like a half inch of allowance) when a/c is off? and none when a/c is on? that's what happened after adjusting the mentioned screw at the back of the pump...i remember it being like that when brand new.
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mars
Isuzu Baby
Posts: 4
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Post by mars on Sept 5, 2005 4:03:25 GMT 11
hi
press down the pedal with your foot and check at the pump that the cable goes up right against the stopper otherwise ajust
the only reason you have a play on the pedal with the aircon off is with the aircon on the vacuum unit on the pump takes up the play on the cable
hope this helps
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