uh oh my shark isn't holding an idle
05-25-2005, 01:56 PM
#16
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really? Any special tools required? I heard there's one for injector harnesses so they don't break on you when removing them. 
I didn't hold onto the 4's but I can buy some more if necessary. Something inside me tells me that swapping platinums back in will correct it. Reason why is because I just read a therad about a guy named Dave on this board (not Big Dave though) saying he had the same exact problem I'm having and putting P 4+'s back in cured it.
I didn't hold onto the 4's but I can buy some more if necessary. Something inside me tells me that swapping platinums back in will correct it. Reason why is because I just read a therad about a guy named Dave on this board (not Big Dave though) saying he had the same exact problem I'm having and putting P 4+'s back in cured it.
05-25-2005, 02:05 PM
#17
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My understanding of that thread was just the opposite, that the +4's were causing the problem...? Oh well, here's an idea! I have +4's (low mileage) in my engine currently and have been wanting to swap them out. If you want we can try putting those plugs in your engine and see what happens. Oh, and no special tools for the intake, just be careful with the harness & inspect it for age/heat related issues.
05-25-2005, 02:17 PM
#18
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I figured it out!!!!!!!!
The reason why the car idle is more stable on platinum 4+ Bosch plugs is because the heat range of the plug! Perhaps the copper is too hot and is causing high NOx levels! The O2 sensor picks up the lean condition and feeds it to the computer to drop the idle and let less air into the engine!
Swapping back in Platinum 4 plugs will cause more CO to buildup in the motor and stabilize the idle by the O2 sensor detecting more concentration of carbon monoxide!!!! Time for a project again and I'm running for platinum 4s for lunch!
Here's the link to Daves' EXACT SAME ISSUE:
https://rennlist.com/forums/showthre...dle+stabilizer
The reason why the car idle is more stable on platinum 4+ Bosch plugs is because the heat range of the plug! Perhaps the copper is too hot and is causing high NOx levels! The O2 sensor picks up the lean condition and feeds it to the computer to drop the idle and let less air into the engine!
Swapping back in Platinum 4 plugs will cause more CO to buildup in the motor and stabilize the idle by the O2 sensor detecting more concentration of carbon monoxide!!!! Time for a project again and I'm running for platinum 4s for lunch!
Here's the link to Daves' EXACT SAME ISSUE:
https://rennlist.com/forums/showthre...dle+stabilizer
05-25-2005, 02:46 PM
#19
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Um, Andy... that's the most 'interesting' theory on O2 sensor operation I've ever heard 
The sensor couldn't care less about the CO level, it detects O2 
Anyway, if the plugs are causing a lean condition, i.e. misfire, you might get a surge as the computer attempts to richen or lean the mixture. Look at it this way, if you are misfiring, the combustion chamber will be full of unburned O2 and raw fuel. The O2 will see this as a 'rich' mixture and the ECU will lean the A/F mixture in response, hence the surging or loping idle. It's my understanding that the +4's exacerbate this problem, but who knows?? I've had a throttle tip-in hesitation ever since I put those things in, so I'm getting rid of them.
The sensor couldn't care less about the CO level, it detects O2 Anyway, if the plugs are causing a lean condition, i.e. misfire, you might get a surge as the computer attempts to richen or lean the mixture. Look at it this way, if you are misfiring, the combustion chamber will be full of unburned O2 and raw fuel. The O2 will see this as a 'rich' mixture and the ECU will lean the A/F mixture in response, hence the surging or loping idle. It's my understanding that the +4's exacerbate this problem, but who knows?? I've had a throttle tip-in hesitation ever since I put those things in, so I'm getting rid of them.
05-25-2005, 02:54 PM
#20
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sorry I have auditing on the mind and can't think about cars for sh*t right now 
I say the same thing as you Bill, which is why it's a mystery as to why this car ran fine with platinum spark plugs before going back to copper. Do you think it could be the age of the MAF sensor and readings? Maybe it's reading that less air should be going into the engine. The surge feels like a misfire too like you said. Maybe it's also just PMSing (but it already did that all over my garage floor), I dunno, but the car's idle was stable before the coppers and that is leading me to switch back to platinums now.
I say the same thing as you Bill, which is why it's a mystery as to why this car ran fine with platinum spark plugs before going back to copper. Do you think it could be the age of the MAF sensor and readings? Maybe it's reading that less air should be going into the engine. The surge feels like a misfire too like you said. Maybe it's also just PMSing (but it already did that all over my garage floor
), I dunno, but the car's idle was stable before the coppers and that is leading me to switch back to platinums now.
05-25-2005, 03:00 PM
#21
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By all means, change the plugs. Your engine may well run better with the platinums for whatever reason. We can do a MAF swap too if that doesn't cure the problem. Also, it never hurts to clean out the idle stabilizer if for no other reason as preventive maintenance. Do one thing at a time though...
05-25-2005, 03:02 PM
#22
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I'm gonna get squirting on the ISV tomorrow since I have school tonight as well as do the plugs. I'll let you know how it works out. This shark is not getting jittery on me again
05-25-2005, 03:53 PM
#23
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Originally Posted by Garth S
No KY for this job - the open port of the 'y' is correct: it leads to a 'Y' type of fitting just over the right valve cover. Inject to the rear hose as it goes under the intake.
Item #12 in Sharkskins pic from his excellent site ....
Item #12 in Sharkskins pic from his excellent site ....
05-25-2005, 04:20 PM
#24
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Originally Posted by SharkSkin
Geez... I wouldn't mind at all if my engine bay looked like that... Thanks for the plug, but I think that's Tony's pic...
I feel better now that that is fixed up ..
05-25-2005, 06:33 PM
#27
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Originally Posted by TheStig
no you don't. 16 more times the worry of a timing belt fracture
05-29-2005, 12:57 AM
#28
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The Platinum 4 plugs smoothened out my idle. The car doesn't hunt what so ever. Now guess what: my freaking water pump gave out on my car and I have coolant puddles below of the front of the engine block to prove it. My luck really sucks lately 
05-29-2005, 11:49 AM
#29
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Just in case, check out the ~ 1" hose ( and gaskets) directly under the top rad hose at the thermostat housing .... leaks here can run down through the front covers.