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Registered
Join Date: Apr 2009
Location: Mass
Posts: 82
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Low Idle
I have an 87 2.5L and am attempting to calibrate my idle as I have a low cold idle (600rpm) and good idle at temp (900 rpm). I just followed the procedure on Clark's Garage and found that when I disable the idle stabilizer my idle increases so after setting the idle at 900 rpm I remove the jumper and idle drops to 500/600 rpm.
Any thoughts? Thanks, Andrew Last edited by fennacf; 06-10-2010 at 06:07 PM.. Reason: Added year.. Thanks John! |
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06-10-2010, 03:01 PM
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Proprietoristicly Refined
Join Date: Jul 2001
Location: ~Carefree Highway~
Posts: 5,833
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Andrew,
It took a couple of minutes to guess you have an '87 (and a mechanic). You could update your User CP? (top of page) You used the Fuel-08 procedure: http://www.clarks-garage.com/pdf-manual/fuel-08.pdf It could be a blocked/dirty ICV/ISV. From under the intake air tube--there is a hose to the ICV/ISV . Shoot some Gumout Fuel Injection-Air Intake and carburator cleaner in the tube with the engine off. If the ilde improves-you have a dirty ICV- You might get better results if you can get the hose off at the ICV/ISV itself. Then, with a straw, spray some more Gumout in. Otherwise you should take it out and clean. If you have good idle at temp, it could be the DME coolant temp sensor when cold. The sensor when cold tells the DME to all fuel during warmup. Or a bad O2 sensor. GL John
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1988 924S, 85,750K ..+ 1987 924S, 154K DD (+15K est. bad odo) |
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06-10-2010, 05:55 PM
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Registered
Join Date: Apr 2009
Location: Mass
Posts: 82
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Thanks for the input John. The car is an 87 and I had just replaced the O2 sensor and the DME temp sensor a few weeks ago. The procedure that I followed is Fuel-08 from Clark's Garage.
http://www.clarks-garage.com/pdf-manual/fuel-08.pdf I recently replaced all vacuum lines on the intake and had cleaned the ICV/ISV when I had the lines out. At the time I had an extra ICV/ISV on the shelf and I grabbed the one that looked to be in the best shape but looks can be deceiving. Is there a procedure for testing this valve? In the mean time I'll pull the current one out and try to see if I can bench test both of my ICV/ISV.. |
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06-10-2010, 06:32 PM
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Proprietoristicly Refined
Join Date: Jul 2001
Location: ~Carefree Highway~
Posts: 5,833
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Well......
Idle Control Valve Testing - Porsche 951 - www.texasblake.com or http://forums.pelicanparts.com/porsche-944-turbo-turbo-s/330312-idle-valve.html This may be of absolutely no value.. Porsche 944 Idle Fluctuations GL John
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1988 924S, 85,750K ..+ 1987 924S, 154K DD (+15K est. bad odo) |
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06-10-2010, 09:08 PM
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Registered
Join Date: Apr 2009
Location: Mass
Posts: 82
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Update.... Temporarily removed the ICV/ISV from the vacuum circuit and capped the intake manifold/intake boot while I look into getting a new ICV/ISV. The car runs and idles fantastically with new life... Can anyone think of any issues that will result from removing the ICV/ISV permanently? Has anyone done this?
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06-16-2010, 06:45 PM
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yarfk
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With the ISV deleted the DME can not control idle speed. On a cold out side temperature day the idle settings you made may not work.
When you turn on the A/C the idle speed will drop because the DME uses the ISV to maintain Idle speed. I think you would be better of finding out what is wrong with the ISV, the ISV hoses, or the ISV wiring. A simple bench check of the ISV is to supply 12vdc to the center pin #2 and then alternately apply ground to pin 1 then pin 3. the ISV should shuttle back and forth passing air then blocking air.
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------Keith------kfray------yarfk------- 87 944 NA stock 116k 06 Honda Ridgeline 83k 10 Vibe 2.4 AWD (Wife's) Retired My week consist of Saturdays and Sundays 
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06-16-2010, 07:13 PM
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Keith's Porsche
