IAC reading 00

[Turbo Keith]

Hello Guys , After the car has been driven and warmed up the IAC will read 00 will its in park idling , I know it says we need to target 10 to 30 but is 00 to low ? My BLM s is also high in park 142 . Does one effect the other ? Thanks for the help and I don't believe I have any vacuum leaks , the car runs super smooth .

 

[Darkstar72]

I'm not a veteran here but a thread reading junkie. I know from all the tuning/BLM threads I have gone through 00 is essentially telling you that the IAC is no longer controlling air flow at idle, all flow is being controlled by the opening of the throttle blade at that point. Need to close up the throttle plate opening with the screw on the drivers side of the throttle body until IAC starts to register something again. Will need then to readjust TPS as well (throttle position sensor).

Plenty of threads out there to find the procedures for adjustment on both IAC and TPS.

 

[Turbo Keith]

I'm not a veteran here but a thread reading junkie. I know from all the tuning/BLM threads I have gone through 00 is essentially telling you that the IAC is no longer controlling air flow at idle, all flow is being controlled by the opening of the throttle blade at that point. Need to close up the throttle plate opening with the screw on the drivers side of the throttle body until IAC starts to register something again. Will need then to readjust TPS as well (throttle position sensor).

Plenty of threads out there to find the procedures for adjustment on both IAC and TPS.

Thank you for the reply , The search tab was giving me fits is why I posted this .

 

[Darkstar72]

I always preface with Non Vet status of the TB community as I've only been involved in these unique cars for like a year and half. I try to gather as much information as I can to really absorb and let it sink in. My only goal is not to make a bad situation worse. The real problem may be, especially with me overthinking shit to death, is making a non-issue a real issue later on by messing with stuff that doesn't need to be messed with.

I myself just happened to have doing a lot of reading on BLM threads for a few weeks dealing a slightly higher than I would like BLM.

Last year I did have to adjust my IAC and TPS as both were high on my previous TR. Not very hard at all...just tedious going back and forth, back and forth, etc.

Good luck man. I hope the BLMs settle down once you get it all adjusted back in spec.

 

[Ttype6]

Need to close up the throttle plate opening with the screw on the drivers side of the throttle body until IAC starts to register something again.
[/QUOTE]Closing the throttle blade will cause the BLM number to rise,but this might not be possible if the throttle is currently adjusted right. I suspect it is.
Along with the low IAC number,we have a high BLM number which means the computer is adding fuel.
High BLM with low IAC usually indicates un-metered air entering the engine. The most likely cause is a hole in the flexible air inlet hose and/or a bad vacuum hose. It can be anything that allows air to enter the engine after the MAF sensor.

 

[ScottHeidinger]

A lot of times the 0 can lead to a stumbling as you come off idle. I would take a minute or two to adjust it since it’s probably only off by a very small amount. The idle speed would also help tell how much it’s off by. If you’re idling higher than programmed rpm then I would adjust it. Blm can be from passenger valve cover breather.


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[Darkstar72]

Scott...can you elaborate on how the open breather on the pass valve cover could cause the BLM issue? Like I said...I'm trying to settle mine down as well and wondering how this might come into play. Thanks.

 

[ScottHeidinger]

I honestly don’t know why but there was a link to a video posted on here about a year ago where someone starts the car with a breather and BLM is around 140. While the car is running they remove the breather and put the stock valve tube to turbo on it and the BLM drops to 128 almost immediately. I don’t have the stock turbo or bell so I can’t do it on mine. I watched it because my BLM is also high at idle and I’ve replaced every vacuum line and zip tied every one of them trying to get it down. I was going to replace my throttle body thinking that the seals where the blade go into it might be leaking but after watching the video I haven’t worried about it. I will try to find it and post a link.


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[3.8L V-8 eater]

Keith,
Do you have a Turbo Tweak chip?? I ask because I have been chasing high BLM's and they were maxed at 160 with Bob's Extender chip...I put in the Turbo Tweak chip an they dropped to 142 and I thought that I had improved the BLM's...Turns out Eric informed me that 142 was at max correction with his chip and it would not add anymore fuel at idle...He said that likely my BLM's were actually higher due to whatever unmetered air was entering the engine...You might be in the same boat and have a bigger BLM problem than you realize

 

[Turbo Keith]

Keith,
Do you have a Turbo Tweak chip?? I ask because I have been chasing high BLM's and they were maxed at 160 with Bob's Extender chip...I put in the Turbo Tweak chip an they dropped to 142 and I thought that I had improved the BLM's...Turns out Eric informed me that 142 was at max correction with his chip and it would not add anymore fuel at idle...He said that likely my BLM's were actually higher due to whatever unmetered air was entering the engine...You might be in the same boat and have a bigger BLM problem than you realize

Yes Sir , I have a TT in both cars

 

[Darkstar72]

I honestly don’t know why but there was a link to a video posted on here about a year ago where someone starts the car with a breather and BLM is around 140. While the car is running they remove the breather and put the stock valve tube to turbo on it and the BLM drops to 128 almost immediately. I don’t have the stock turbo or bell so I can’t do it on mine. I watched it because my BLM is also high at idle and I’ve replaced every vacuum line and zip tied every one of them trying to get it down. I was going to replace my throttle body thinking that the seals where the blade go into it might be leaking but after watching the video I haven’t worried about it. I will try to find it and post a link.


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That’s interesting. It would be simple enough to just remove the breather and tape over it to rule that out.

I only found one questionable vacuum line in my search that I replaced. Noticed a slight change in idle BLM, but nothing drastic.

My next thing to play around with is going back to a stock PCV valve after removing the RJC PCV/check valve. I’ve read those things can whack out BLM too if ran by themselves in place of a standard PCV valve.

If I notice no change with different PCV set ups then I also planned to up the base setting in the Translator to 3% rich.

My BLM readings are all in line otherwise...light throttle, moderate throttle, cruise, etc.

 

[John Larkin]

What TType 6 said, close the throttle blade with the screw on the side of the doghouse that holds the throttle arm open. It's a Torx bit screw, T15 I think? Might have a silver vacuum plug over it. Loosen the screw so the throttle arm moves toward the rear of the engine. The idle RPM will probably drop and then the ECM will try to recover it. Watch your scan tool and see when the IAC values start to rise. After you get some IAC values showing, you will have to reset your TPS all over again. And it will be a dance, you may have to do this sequence a few times to get it right.

 

[Chuck Leeper]

While the car is running they remove the breather and put the stock valve tube to turbo on it and the BLM drops to 128 almost immediately.

That breather is the source of the air being pulled thru the engine, by the PCV system.
If hooked to the inlet bell, there's a different atmospheric pressure seen, vs an open breather.
The original PCV system was calibrated, using the bell source.

 

[Jerryl]

What was the IAC count before it suddenly went to 0, and why do you think it went to 0?

 

[ScottHeidinger]

I went thru everything. PCV valve, vacuum lines, cracks in headers, new Injector O rings and everything else I could find and mine are still high at idle. The only other thing I didn’t replace was the seals on the throttle body. Many people have spent a lot of time trying to figure out the BLM issue. I didn’t think mine was too bad because it never goes over 142 but I learned something new today as I didn’t know that was the limit on Eric’s chips so I will have to find a new throttle body and my passenger exhaust has a crack now so I’ve got to replace it.


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[Darkstar72]

I went thru everything. PCV valve, vacuum lines, cracks in headers, new Injector O rings and everything else I could find and mine are still high at idle. The only other thing I didn’t replace was the seals on the throttle body. Many people have spent a lot of time trying to figure out the BLM issue. I didn’t think mine was too bad because it never goes over 142 but I learned something new today as I didn’t know that was the limit on Eric’s chips so I will have to find a new throttle body and my passenger exhaust has a crack now so I’ve got to replace it.


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Did you ever replace your intake manifold gasket?

I don’t want to just throw stuff at the car and hope it all works out. I’m trying to see if anyone I know has a smoke machine I can borrow to look for leaks that way.

 

[ScottHeidinger]

Haven’t done intake gasket since engine was assembled a couple years ago. I have a few of them here so I will try that too. A lot of the posts I read said people were using propane to find the leaks.


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[Chuck Leeper]

Anyone check the ft of the plenum, under the t/b?
There is no bolt there. A 30 yo alum casting can/will warp.
This too.
A lot of the posts I read said people were using propane to find the leaks.