Mysterious engine problem

xs04298 · Feb 18th, 2006, 06:00 PM

89 240sx kae

Ive seen a lot of strange KAE problems, but this one has me miffed...

All i have done to it lately is replace one injector.

Okay here's the lowdown:

a few days ago (prior to the injector problem actually) i noticed the motor wad idling obnoxiously low, around 350-450rpm, it normaly purrsss at 800, great idler. It didnt stumble at all it was just really low, so i adjusted the idler screw down and i had to put it all the way down to get the rpm back to normal, but it seemed to be fine. The next day i get in and the rpm is fine, but all day the motor seemed verry lagy, sluggish. Now today i get in and turn it on the rpm is high, so i undo the idle screw and its running great, but after about 20 min im about to pull into my driveway and it goes back to the 500rpm deal, and the motor gets realllyy slow, even when im trying to rev it its really slugish, and but once again not rough or missing or anything, just really sluggish, i checked the obvious IIAC, Throttle positioning, coolant, and MAF sensors, they all seemed fine, I figure it has to be some kind of sensor somewhere problem, but i'm really not sure which, or how to tell. Any clues?

Thanks

(short version, low idle, adjust idle screw, fix idle, laggy engine, next day high idle, readjust screw, motor runs great, then idle dies again, but motor never once skips a beat, no missfiring/stumbling) very lagy)

**rogoman** · Feb 18th, 2006, 06:18 PM

Check for a sticking EGR valve.

xs04298 · Feb 18th, 2006, 07:59 PM

Hmm..could the fact i dont have the EGR connected to the intake (the connections between the tube and the intake broke, so the EGR is open and the intake is closed, off) but i would think not since its been like that for ever now and ran fine, but EGR valve eh? i'll check it out, is that vacume powered or electric?

**rogoman** · Feb 19th, 2006, 08:32 AM

If the EGR valve is still mounted on the intake manifold, it could cause your problem; it's vacuum powered. Your best bet is to totally remove it and install a blocking plate in place of it.

xs04298 · Feb 19th, 2006, 09:40 AM

The EGR is no longer connected to the intake at all, only the exhaust, where it basicly just runs open into the underhood, i'm gunna check it out today, i'll update.

xs04298 · Feb 19th, 2006, 02:08 PM

Yup, vacume line was cut to the EGR, u guys are good.

zellx2004 · Feb 19th, 2006, 09:01 PM

That's what she said.

xs04298 · Feb 19th, 2006, 09:13 PM

That your line is cut and your underperforming??

:P j/k

bridrive55 · Feb 19th, 2006, 11:36 PM

I hate when she tells me that my EGR line is cut.

Trippen · Feb 22nd, 2006, 07:26 AM

89 240SX SE FB. With 130k Looking to get the emissions working for upcomming test and was wondering. Is the EGR valve normally open or normally closed? As vacume increases does it open? Thanks in Advance

Trippen · Mar 6th, 2006, 12:07 AM

Fixed my issues with the fixing of the egr valve and sooooo many vacume leaks it wasnt funny. Anyhow. I still have a stubling injector which soon will be replacing all the injectors.