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Discussion Starter #1
Brief history: Had timing chain, chain guides and tensioner replaced 4 years ago. Within the same week, I installed the JWT ECU. Went from 27-28 mpg mixed (street and hwy) to about 20-21 mixed.

FF to July 2001: Had clutch replaced...f*cked up mechanic screwed with SOMETHING (STILL haven't figured out what yet) so that both warm and cold idle are screwed up (runs SO rich that it stalls when first starting it and idles low at cold idle (750 RPM) and warm idle (about 600 RPM). At warm idle and 600 RPM w/JWT motor mounts, the thing shakes like a MF!

(BTW: the EGR and other disc-shaped thing next to EGR have been disconnect for about 5 years, so that is NOT part of the problem. I also checked the ECU for codes (5 and 5 - no sensor problems, and have reset the ECU).

Tuesday this week: Took NX to Rosen Autosport in Richmond. Explained the problem and everything I've done to it in the last 3 months to try to fix the idle problem (replaced vacuum lines, PCV valve, O2 sensor, coolant temp sensor, new plugs, wires, distributor cap and rotor), to no avail. After setting the timing (15 degrees), they noticed that the distributor was most of the way to the firewall side of the adjusting slot. Then, we checked the 3 month old plugs (stock NGK platinums); they were already fouled!

Joe at Rosen's theory: The timing chain is off one tooth on the exhaust cam. Basically, the intake and exhaust cams are out of sync with each other! When I ordered a new VC and spark plug gasket and new plugs from Courtesy, I actually got to talk to Brian (from the forum). When I explained to him the problem and possible cause, he told me that 1 tooth off would be something like 20 degrees difference in timing!!!

I'm having them check it next week after the parts come in. I will also have them set the timing, adjust the idle mix, and anything else we can set relating to air/fuel mixture). I STILL think something else is hosed relating to the idle, but after this is fixed, at least I'll be working with a properly timed engine, intake AND exhaust! I'm actually hoping the exhaust cam is one tooth off, now; when fixed, I should get better mileage, a smoother engine, and, hopefully, a bit more power!

If anyone could shed some light on this idle problem, please post it here.

TIA,

al
 

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Man, don't have monkeys work on your car anymore!

As far as the idle goes, having the exhaust cam off a tooth would screw that up as well I believe. I bet if you have them check that out and do a good tune-up you'll be pretty much set. Good luck!
 

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Discussion Starter #4 (Edited)
You might very well be right, subculture; after it gets "fixed", I'll let y'all know what the problem was.

Even with this problem, my car still pulls strong...SOOOO easy to smoke the tires from 3000 RPM. I bought it new w/55 miles on the odometer; I put 15 of them on during my test drive. When the salesman who went with on the test drive told me to take a 30 MPH curve at 55, and I took it at 60, I had him grabbin' for the door handle! That was all it took. I'd read the C&D articles, thought it sounded great, but it looked like ****! After the handling exercise on the test drive....I didn't care WHAT it looked like!

"...I'm in love with my car..." Freddie Mercury
 

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I had my timing chain replaced earlier this year. Car pulls better and no more start up rattle.
The stealer mechanic, who is NO monkey, even shimmed the oil pressure reliefe valve in the oil pump, (which was rebuilt also, new gearset) in order to raise the engine oil pressure. We figured it would be a good idea since the motor had over 100K on it.
Hopefully your monkey replaced the timing chain guides and ALL the sprockets as well.
 

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Discussion Starter #6
I seem to remember him saying that there were a couple of teeth missing, so I'm 99.9% sure that the sprockets were replaced as well.
 

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Discussion Starter #8
It doesn't; the first problem (the timing chain incident) is just a vent, more or less. The second problem still baffles me. Basically, the first problem dropped my mileage from 27-28 combined to 21 combined, but it didn't *smell* rich, so I didn't really think anything of it. Now that it *smells* like a Lawn Boy lawn mower, and sputters, and stalls, it bothers the hell outta me. Especially since before the clutch was replaced, idle was fine, didn't smell, didn't sputter, didn't stall.

As for the 2nd problem, I was wondering about a bad fuel pressure regulator...any thoughts? Might a bad regulator cause my NX to smell like a refinery, especially when cold? :mad:

Any help would be greatly appreciated...TIA!
 

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Discussion Starter #10
Re: rattle - Hey subculture, my bad. He was replying to your post, not mine. I agree about the rattle; that's the sound that prompted the whole chain replacement fiasco in the first place.
 

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That's ok.
Speaking of timing chain rattle, early Altimas have it worse. According to my stealer mechanic, the early Altimas would break timing chain guides on a regular basis. And have had a big problem with leaking front engine seals.
 

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If you are off by 1 tooth, then that is the cause of all the above problems. I had to remove the head on a friend's '94 SE-R, and somehow we had the timing off by 1 tooth, and it idle like doodoo. Its on easy fix if you know your way around a toolbox, but if you have Rosen near you, take it to them. Do you have any kind of repair manual? Haynes or FSM works, but the FSM has a better section related to this.
 

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Discussion Starter #14
Eric, thanx for your reply. I can understand how being 1 tooth off would cause the idle problem. What I DON'T understand is, if this has been 1 tooth off for 4 years, why would I not have had an idle problem until 3 months ago, when the clutch was replaced? A *VERY, VERY, VERY* remote possibility might be that the goof ball that replaced the clutch would have done something to the timing chain. I know that sounds f*cked up, but, again, no idle problem until 3 months ago.

I'm no mechanic, but I understand what the knowledgeable people (Rosen, [email protected], you, others) have told me about being one tooth off, etc. I'm completely baffled by this!

Thanx again for your reply; if you have any more insight, please post here or e-mail me.
 
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