1986 idle much better when checking (not changing) the timing. Why?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It is certainly OK to proceed as planned, but see my concerns, above about your timing situation. I'm not convinced this will end your problems. Is there a GOOD reason for a new IAC?
RACE ON!!!
RACE ON!!!
Instructor
Joined: May 1999
Posts: 206
Likes: 0
From: Lebanon Ohio
Originally Posted by Square
Thanks guys!
The idle adjustment screw on the back of the throttle body still has the cap on it from the factory, so I am not planning on touching that. Please let me know if that is a mistake.
Also, since no one voiced any oposition, I assume that it is ok for me to leave the timing at 8 degrees and proceed with the new IAC install, cleaning, and TPS setting?
Thanks!
The idle adjustment screw on the back of the throttle body still has the cap on it from the factory, so I am not planning on touching that. Please let me know if that is a mistake.
Also, since no one voiced any oposition, I assume that it is ok for me to leave the timing at 8 degrees and proceed with the new IAC install, cleaning, and TPS setting?
Thanks!
If the cap is on it>>>leave it alone>> Only time I ever mess with them is on Forced induction cars or heavily cammed cars where the min idle speed and IAC corrections are not enough to keep the manners in check on the street...I still usually tweak the prom values as well....
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
CFI-EFI : Technically, No, there is not a good reason to relpace my IAC. I just thought it would be easier to replace it than to clean it. If you think I am better off to just clean the one I have and reuse it, then I will do that. If I clean and reinstall, do I have to worry about measuring and adjusting the pintel? I assume that I should use the new O-ring when I reinstall it, yes?
Kenwood : I am still a few lessons away from being able to play with PROM settings.
If I need that, I am afraid that I will need to farm that part out right now.
Kenwood : I am still a few lessons away from being able to play with PROM settings.
If I need that, I am afraid that I will need to farm that part out right now.
Instructor
Joined: May 1999
Posts: 206
Likes: 0
From: Lebanon Ohio
If you have the means its best to replace it... IAC can actually get LAZY if you will and cause problems... Now ones come with the gasket....If you have the TB off its also worthwhile to get a TB gasket set... then you can remove the lower IAC passage and clean it thoroughly...then have fresh gaskets>>>in fact the TB gasket set comes with a new IAC gasket should you choost to reuse tyour stock one...
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Square
CFI-EFI : Technically, No, there is not a good reason to relpace my IAC. I just thought it would be easier to replace it than to clean it.
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Kenwood
WRONG..if the MIN air has been adjusted then the values on the IAC can be manipulated...
Originally Posted by CFI-EFI
There ARE no IAC settings to mess with. The IAC is totally controlled by the ECM. Retract the pintle to prevent damage upon installation, run the self-adjust sequence for the IAC, and you're DONE with the IAC.
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Instructor
Joined: May 1999
Posts: 206
Likes: 0
From: Lebanon Ohio
I was not going off tangent or necessarily mean to>>>but what I was trying to say was Most of the TPI motors that Ive looked at where someone tells me they cant get the idle dialed in correctly 9 times out of 10 Ive found that its because some old schooler thought that turning the throttle blade screw would solve the problems... Thats why I asked if the cap had been poked out..
Should have ended it there.
SORRY
Should have ended it there.
SORRY
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Kenwood
I was not going off tangent or necessarily mean to>>>but what I was trying to say was Most of the TPI motors that Ive looked at where someone tells me they cant get the idle dialed in correctly 9 times out of 10 Ive found that its because some old schooler thought that turning the throttle blade screw would solve the problems... Thats why I asked if the cap had been poked out..
Should have ended it there.
SORRY
Should have ended it there.
SORRY
Originally Posted by Square
Thanks guys!
The idle adjustment screw on the back of the throttle body still has the cap on it from the factory, so I am not planning on touching that. Please let me know if that is a mistake.
Thanks!
Originally Posted by Kenwood
If the cap is on it>>>leave it alone>> Only time I ever mess with them is on Forced induction cars or heavily cammed cars where the min idle speed and IAC corrections are not enough to keep the manners in check on the street...I still usually tweak the prom values as well....
RACE ON!!!
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Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
Hi guys!
Tonight I replaced the IAC and set the TPS to .54 volts. The TPS was reading .47 if I recall correctly. I also cleaned the IAC chamber out with throttle body cleaner, but I did not take it off the throttle body as I did not have a new gasket for it. I did not attempt to set the base idle and I did not short the ALDL connector at any time.
The result are that the car runs the same as it did before (900RPM in gear, 1200 in neutral). I also managed to break something. the vacuum line that comes off the throttle body:
I put some gaffers tape (high quality black duct tape) over the nipple on the throttle body to seal the hole, but the other end is where it basically broke off flush, so I couldn't really put tape on that end. Does anybody know what that is used for?
If you guys have any ideas, I am open, otherwise, I think I may have hit the point where I am better off letting the professionals handle this one.
Tonight I replaced the IAC and set the TPS to .54 volts. The TPS was reading .47 if I recall correctly. I also cleaned the IAC chamber out with throttle body cleaner, but I did not take it off the throttle body as I did not have a new gasket for it. I did not attempt to set the base idle and I did not short the ALDL connector at any time.
The result are that the car runs the same as it did before (900RPM in gear, 1200 in neutral). I also managed to break something. the vacuum line that comes off the throttle body:
I put some gaffers tape (high quality black duct tape) over the nipple on the throttle body to seal the hole, but the other end is where it basically broke off flush, so I couldn't really put tape on that end. Does anybody know what that is used for?
If you guys have any ideas, I am open, otherwise, I think I may have hit the point where I am better off letting the professionals handle this one.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Square
If you guys have any ideas, I am open, otherwise, I think I may have hit the point where I am better off letting the professionals handle this one.
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
I have verified my timing marks. I appreciate what you guys have offered me, and I feel I have done what I can do safely within my current knowledge base. I do not know much about the codes/scanners for this car, nor do I own a scanner right now. Since this is my daily driver, I am more inclined to let someone else handle this piece. I also have a couple of other items that I would like have checked out as well.
Thanks for all your advice. It has helped me learn a lot about my car.
Thanks for all your advice. It has helped me learn a lot about my car.
Instructor
Joined: May 1999
Posts: 206
Likes: 0
From: Lebanon Ohio
You dont need a scanner to get codes on an 86....
All you need is a paperclip and a pen and paper... when the aldl is grounded these SES light will blink codes a you in sequences of 3>>>it always starts with 1 -2 1- 2 1- 2 then if it just keeps blinking 1 -2 then there are no codes>>>but if it starts blinking others you write down the sequence...then take a haynes manual and look it up...
Or you could go to autozone and let them do it for ya..
All you need is a paperclip and a pen and paper... when the aldl is grounded these SES light will blink codes a you in sequences of 3>>>it always starts with 1 -2 1- 2 1- 2 then if it just keeps blinking 1 -2 then there are no codes>>>but if it starts blinking others you write down the sequence...then take a haynes manual and look it up...
Or you could go to autozone and let them do it for ya..
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Square
I have verified my timing marks. I appreciate what you guys have offered me, and I feel I have done what I can do safely within my current knowledge base.
To expand on Kenwood's advice, each code will flash 3 times. After code "12" flashes it's three times, the next code will flash 3 times, and so forth until all the codes have been displayed. When you have run through all the set codes, it will start over with "12" again. That is how you will know you've seen them all. All of this IS in the manual. to reiterate, an evening spent with the book COULD save you a lot of money.
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
Originally Posted by CFI-EFI
Can I ask the method you used to verify the timing marks?
To expand on Kenwood's advice, each code will flash 3 times. After code "12" flashes it's three times, the next code will flash 3 times, and so forth until all the codes have been displayed. When you have run through all the set codes, it will start over with "12" again. That is how you will know you've seen them all. All of this IS in the manual. to reiterate, an evening spent with the book COULD save you a lot of money.
RACE ON!!!
To expand on Kenwood's advice, each code will flash 3 times. After code "12" flashes it's three times, the next code will flash 3 times, and so forth until all the codes have been displayed. When you have run through all the set codes, it will start over with "12" again. That is how you will know you've seen them all. All of this IS in the manual. to reiterate, an evening spent with the book COULD save you a lot of money.
RACE ON!!!
- clean the road grime of the degree indicator
- Hook up the timing light
- disconnect the wire you have to disconnect to check the timing
- check the timing with the motor at normal operating temp.
The timing indicated was 8 degrees BTDC
I am going to order a full gasket set for the throttle body today so I can clean all of it.
I began to look through the shop manual and I tried disconnecting the MAF (one of it's recommendations), but it didn't make a difference.
I am going to spend a few days reading and see if I can figure things out a bit, while I wait for the gaskets to show up. I will also see if I can pull the codes. I will let you know how it goes.
Thanks!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Square
I don't exactly know what you mean by "verifing the timing marks". What I did was:
- clean the road grime of the degree indicator
- Hook up the timing light
- disconnect the wire you have to disconnect to check the timing
- check the timing with the motor at normal operating temp.
The timing indicated was 8 degrees BTDC
- clean the road grime of the degree indicator
- Hook up the timing light
- disconnect the wire you have to disconnect to check the timing
- check the timing with the motor at normal operating temp.
The timing indicated was 8 degrees BTDC
Originally Posted by Square
I began to look through the shop manual and I tried disconnecting the MAF (one of it's recommendations), but it didn't make a difference.
I am going to spend a few days reading and see if I can figure things out a bit, while I wait for the gaskets to show up. I will also see if I can pull the codes. I will let you know how it goes.
Thanks!
I am going to spend a few days reading and see if I can figure things out a bit, while I wait for the gaskets to show up. I will also see if I can pull the codes. I will let you know how it goes.
Thanks!
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
CFI-EFI,
Sorry, I didn't understand what you meant about verifying the timing. What you are saying makes sense. If the timing indicator has moved then it would certainly make a difference. I know on my Supra I-6 I can remove the spark plug and put a dowel in the spark plug hole to make sure that the piston is at TDC. Is there a certain precedure or distance I should be looking to measure in the cylinder to confirm TDC and therefore the timing mark position on the L98?
Thanks!
Sorry, I didn't understand what you meant about verifying the timing. What you are saying makes sense. If the timing indicator has moved then it would certainly make a difference. I know on my Supra I-6 I can remove the spark plug and put a dowel in the spark plug hole to make sure that the piston is at TDC. Is there a certain precedure or distance I should be looking to measure in the cylinder to confirm TDC and therefore the timing mark position on the L98?
Thanks!
Last edited by Square; Sep 23, 2004 at 12:18 PM.