1991 240sx Rebuilt KA24DE will not come off idle, runs very rich -- bone stock rebuild.
The engine starts really easily, but it sounds like the combustion is really off (kind of an indistinct, furry sound -- not clean and well defined).
Lots of gasoline smell from the exhaust.
It eventually chokes itself to death. I can get it to come slightly off idle by 'feathering' the gas pedal but then it dies.
Distributor timing is set right to where it was before disassembly. Any ignition timing adjustment kills it faster.
Are the internal manifold butterflies maybe not opening up?
Ideas?? Guesses??!?
Thanks in advance for your assistance.
1991 240sx Rebuilt KA24DE will not come off idle, runs very rich
Re: (neverlift)
Yeah neverlift,
Throttle cable is hooked up. And yes, I mean it wont rev when pressing gas pedal.
I drove it into the shop (150 feet) with the spun rod bearing before this in-frame rebuild. It had been sitting for 1 - 1.5 years.
It did this on initial start-up, so I thought well maybe the gas is crap! I used the fuel pump to drain the old gas and dumped in 5 gallons of new gas (minus what tried to pour into my shoe, the new spout design had looked soooo promising too....). Anyhow, this was not the problem. It did run just slightly better. After new fuel, new fuel filter too.
Then I suspected the new Bosch+2 plugs (never needs gapping?? says the box) so I swapped to a new 1mm gapped set of Champion Copper plugs. Same crap!!
I am about to discon the TPS and check the timing ($70 timing light), then recon as recommended in the info on the 240 bible post stuff.
When you say cam timing, do you mean cam/cam relationship or cams to crank? I think both are good or I wouldn't have buttoned everything up.
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Maybe a bypass hose is pinched and not letting the extra fuel at idle return??
Maybe I have a crazy vacuum leak somewhere??
How do the internal butterflies actuate in the manifold?? Could this be jammed or missing an actuator rod?? This acts as a choke, right??
Could the TPS be screwed??
Thanks,Greg
Throttle cable is hooked up. And yes, I mean it wont rev when pressing gas pedal.
I drove it into the shop (150 feet) with the spun rod bearing before this in-frame rebuild. It had been sitting for 1 - 1.5 years.
It did this on initial start-up, so I thought well maybe the gas is crap! I used the fuel pump to drain the old gas and dumped in 5 gallons of new gas (minus what tried to pour into my shoe, the new spout design had looked soooo promising too....). Anyhow, this was not the problem. It did run just slightly better. After new fuel, new fuel filter too.
Then I suspected the new Bosch+2 plugs (never needs gapping?? says the box) so I swapped to a new 1mm gapped set of Champion Copper plugs. Same crap!!
I am about to discon the TPS and check the timing ($70 timing light), then recon as recommended in the info on the 240 bible post stuff.
When you say cam timing, do you mean cam/cam relationship or cams to crank? I think both are good or I wouldn't have buttoned everything up.
*_*_*_*_*_*_*_*_*_*_**_*_*_*_*_*_*_*_**_*_*_*_*_*
Maybe a bypass hose is pinched and not letting the extra fuel at idle return??
Maybe I have a crazy vacuum leak somewhere??
How do the internal butterflies actuate in the manifold?? Could this be jammed or missing an actuator rod?? This acts as a choke, right??
Could the TPS be screwed??
Thanks,Greg
Re: 1991 240sx Rebuilt KA24DE will not come off idle, runs very rich (gthammers)
UPDATE ** ** ** UPDATE
Got it started, running poorly at about 570-670 rpm at idle -- no pedal. I got it to rev a little to about 1200 - 1400 rpm. Still not good combustion smell or sound.
It died and I got it restarted and kept it running with full pedal at about 800 - 850 rpm. I ran it like this while I tried to take the timing. I set the light to +20 degrees (stock for the motor) and got no good readings. I varied the setting on the light up and down and still saw no good reading.
After runing like this for 6 -8 minutes the temp started to climb pretty quickly. The revs went up and it started to sound better (still full throttle position).
Then the hose on the back of the thermostat housing blew off. The temp was only about 2/3 up. That is just a little over std op temp.
Obviously, I shut it down immediately!
BTW: Oil pressure light geos off after cranking or running, so I'm pretty sure its getting lube.
The intake manifold is maybe getting warmer than I might expect from just thermal conduction. Do you think I may be seeing some reverse flow (port reversion?)
Got it started, running poorly at about 570-670 rpm at idle -- no pedal. I got it to rev a little to about 1200 - 1400 rpm. Still not good combustion smell or sound.
It died and I got it restarted and kept it running with full pedal at about 800 - 850 rpm. I ran it like this while I tried to take the timing. I set the light to +20 degrees (stock for the motor) and got no good readings. I varied the setting on the light up and down and still saw no good reading.
After runing like this for 6 -8 minutes the temp started to climb pretty quickly. The revs went up and it started to sound better (still full throttle position).
Then the hose on the back of the thermostat housing blew off. The temp was only about 2/3 up. That is just a little over std op temp.
Obviously, I shut it down immediately!
BTW: Oil pressure light geos off after cranking or running, so I'm pretty sure its getting lube.
The intake manifold is maybe getting warmer than I might expect from just thermal conduction. Do you think I may be seeing some reverse flow (port reversion?)
Re: 1991 240sx Rebuilt KA24DE will not come off idle, runs very rich (gthammers)
OK guys,
Something to watch...
The dumb*** lower chain 'marked' index links were off by one link position. I recovered my old chain and also checked against a couple of other sources of info to be sure of this.
Always count your link positions.
Damn it really sux to drain the sparkling new oil, pull the motor plumbing, motor mounts, raise the engine, pull the pan, pick-up tube, front covers, cam sprockets, idler gear, guides and tensioners, scrape gasket surfaces, realign chains and stuff, clear, reseal, reinstall, replumb... AGAIN!!
Expensive lesson.
Maybe if it wasn't all done between 10:30pm and 5:30am over a few days (after working)........
Something to watch...
The dumb*** lower chain 'marked' index links were off by one link position. I recovered my old chain and also checked against a couple of other sources of info to be sure of this.
Always count your link positions.
Damn it really sux to drain the sparkling new oil, pull the motor plumbing, motor mounts, raise the engine, pull the pan, pick-up tube, front covers, cam sprockets, idler gear, guides and tensioners, scrape gasket surfaces, realign chains and stuff, clear, reseal, reinstall, replumb... AGAIN!!
Expensive lesson.
Maybe if it wasn't all done between 10:30pm and 5:30am over a few days (after working)........
-
edgartheace
- Posts: 368
- Joined: Wed Sep 27, 2006 3:33 pm
- Car: 1993 240sx, 1992 300zx RIP, 1993 300zx 2+2, 1993 Infinti J30t
Re: 1991 240sx Rebuilt KA24DE will not come off idle, runs very rich (gthammers)
I just finished rebuilding my engine too, and the EGR was sticking open for me causing me to have a rough idle and run rich. Check your EGR valve if it still continues after you reset the chain, also dont bother doing all that. just set your engine to TDC take of your valve cover and make sure that the lobes for cylinder 1 are facing away from each other intake in the 9 o'clock position and exhaust in the 3 o'clock position. This will leave your timing spot on.