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Very rough idle
Thought I would start a new post, if its permitted. There has been some great fault diagnosis on here recenntly, so figured I would chuck it out there and see what happens 
I am currently working my way through a fault (very bad idle) and would love to see what peope come up with. I have been working on this fault for a week, so bear with me.
Symptoms.....idle (with aircon on, with aircon off. Car warmed up and generally after driving for 5 minutes and pulling up to lights etc) is between 1000 and drops to 300. Nearly stalls.
In park, drive, reverse and neutral (all gears..Auto gearbox)
No Check Engine Light.
Misses under load ie put the boot in, car moving.
Have checked and changed vacuum lines. Checked PCV. Changed sparkplugs. Cleaned MAF. Reset ECU. Done TPS reset. Cleaned every electrical connection in engine bay. Secondary throttle butterfly valves present and accounted for...catalytic converter still there. Coolant good, oil good.
Even took it to Nissan who reset TPS and Idle for no result. For free (already done that a few times, but didnt say that) NO fault code recorded. Its been happening for a week....and still no fault code.
I have a coil and MAF coming from OS this week to check for a faulty ignition pack and intake values..
(Nissan want 240 bucks for ONE coil and 290 bucks for a intake sensor...nearly get an engine for the price of 4 coils 8(
What are your thoughts?
I am leaning to Crank sensor, but it could be fuel pump. Or O2 sensor. Or vacuum leak, Or shagged ECU. Or the moon was full on Jan 2nd 1927....anyones guess at the moment
Looking forward to some ideas...going to an independant mechanic on Thurs if I cant fix it, and I will post the results.
Lets see who is closest...gotta make it some fun outta it 
Ps I have also removed the CAI and throttle body spacer. Purely stock intake at the moment...fault still present.
Cheers
---
Dave
02/T30 TI (C)
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5/Sep/2009, 12:19 am
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Re: Very rough idle
Dave,
First 2 questions for you:
1. Has the dealer checked the cat. converter?
2. Have you been monitoring your oil consumption?
I am leaning towards a broken/flaked cat. converter as a faulty crank position sensor would have generated a fault and if it is the cat. converter, you better get that checked pretty quick cause it can lead to a disaster with your engine if these flakes find their way into the engine.
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5/Sep/2009, 12:40 am
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Re: Very rough idle
If everything has been thoroughly looked at , which sounds like it has, I'd put my money on a faulty ECU.
Have you checked the accelerator pedal amd its wiring to the throttle body, maybe its sending a wierd signal that the ECU can't read.
--- Tony X-891c
2008 T31 St
HERE is my X Trail
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5/Sep/2009, 7:40 am
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Re: Very rough idle
I'd pull off the throttle body and give it a good clean (see other posts, unplug wiring first) and then do the throttle closed and idle air relearn.
---
Shawn and Belinda Eggins
2003 STR, K&N, Strut brace, Ground wires, Dunlop LM702's, Tint, Mud flaps, Tow, Nudge, Spots, Mats, Rear scuff plate
http://eggins.synthasite.com/
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5/Sep/2009, 8:24 am
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Re: Very rough idle
Dave,
Ask Village Nissan to re-flash the ECU and upload the software to it again, maybe the maps and software it has got corrupted.
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5/Sep/2009, 8:43 am
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Re: Very rough idle
Yeah. I am leaning that way. They quoted 100 bucks for fault diagnosis...so might get them to run Consult over the whole car and reset everything late next week. The Tech said that the ECU has picked up no faults over the last week though.
Still worth a shot though
---
Dave
02/T30 TI (C)
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5/Sep/2009, 8:47 am
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Re: Very rough idle
Dave, the symptoms don't sound like a crank position sensor failure...
Sometimes you'll experience unusual symptoms for a while before the check-engine light comes on, as happened to me before I found out I had to replace the crank position sensor.
Perhaps a dodgy batch of fuel or crap in the fuel filter?
--- Rich. X-013(c)
'04 S2 ST Auto. Nudge_roofracks_tow_tints_Lightforce_GME_BFG_TBS_home-made-bashplate_50mm-spacer-lift
Click here to see >300MB of photos and videos All For His Glory. |
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5/Sep/2009, 2:55 pm
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