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Discussion Starter #1 (Edited)
Idle suddenly is 1500 rpm, check engine code is P0507. Throttle body butterfly looks good. Seems like a no brainer IACV needs cleaning or replacing.

However, removing the dang thing proved a mightier task than this weekend-wannabe mechanic could perform in one evening.

First off, what bolts/screws do you undo? I found this diagram:
https://www.lotuspartsonline.com/images/parts/lotus/fullsize/ELISEEXIGE415.jpg

On that diagram, the IACV is labeled as #5. However, that is one large composite piece, composed of both metal and the black plastic component going into its side. Usually when a IACV comes out of a GM or most motors I've seen, it's just the little black box you unbolt, which contains the "plunger" or "pintle" or whatever, and that's it. It's barely larger than a D battery. However, in that diagram, they're showing that I might remove the entire metal tray that the little black box is bolted to.

So then I decided to just ignore that diagram and unbolt two gold-colored bolts I found which seem to only hold the black box in place. However, once I got a video camera underneath the throttle body to inspect those bolts, they have a bolt pattern I've never seen before... It's like a 5 point star? Not a hex or torx. I can google more to figure out what that pattern is (I'm clearly inexperienced), but I worried that perhaps this is an indication I shouldn't be undoing those bolts.

And finally - what's the trick for getting under there? Do you remove the whole throttle body? Or do you reach underneath the throttle body and unfasten the IACV without looking? I've been doing this whole thing by recording video with a flashlight to see what's under there and then reach under and feel with my hands.

Finally, bonus points if you know where to buy one of these. They're usually $20 to $35 for any car on the road, and for some reason I'm seeing them for $1,000 for our cars. What in the actual hell, it's a toyota.
(Reference of crazy price: https://www.lotuspartsonline.com/p/Lotus__Elise/IDLE-SPEED-CONTROL-VALVE/62883668/A120E6377S.html)
 

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Discussion Starter #2
After thinking more, I'm going to just remove the throttle body tomorrow. I was reluctant because the bolts on the throttle body are too tight to get off with my 1/4" drive and I was sure it was unnecessary.
 

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It's so much easier to mess with if you remove the throttle body. That will also help with removing the screws.

Sent from my Pixel 2 using Tapatalk
 

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I have two complete throttle bodies at the house I think if you cant find one. FYI search for the part off a 2000 celica GTS.
 

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Discussion Starter #6
Did you verify that there are no vacuum leaks? Did any vacuum hoses pop off or get torn?
I gave a visual inspection but didn't spray anything on in to check for sure.

The high rpm symptom means that air is getting past the TB when it shouldn't, which could be caused by the TB butterfly or the IACV, but I honestly don't see how a vacuum leaks somewhere up the cold air intake, either in the bellows or the air box, could possibly cause this. That's my novice mechanic thinking so I'm zeroed in on the IACV right now.

Thanks man
 

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I gave a visual inspection but didn't spray anything on in to check for sure.

The high rpm symptom means that air is getting past the TB when it shouldn't, which could be caused by the TB butterfly or the IACV, but I honestly don't see how a vacuum leaks somewhere up the cold air intake, either in the bellows or the air box, could possibly cause this. That's my novice mechanic thinking so I'm zeroed in on the IACV right now.

Thanks man
I believe there are 3 vacuum ports on the backside of the butterfly. Check those.
 

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Try this: with the car running, pull off each hose located on the manifold, behind the throttle body, one at a time. If the rpm raises, it's not leaking. If the rpm doesn't change, try plugging the port with your finger. If the rpm drops, that's your culprit.
 

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Discussion Starter #9
That makes perfect sense. I don't know why I wasn't considering those hoses. I'll take a look when I'm back at the car tonight. Big thanks!
 

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Discussion Starter #13 (Edited)
Okay what the heck!

I've got the IACV removed from the throttle body and it is basically two pieces: the metal part and the black plastic electronic part. I don't know the proper terms.

I still don't have access to test/clean the "pintle", or the "little cylinder that slides" because I can't separate the little black plastic part from the metal part. Were any of you able to separate them? I'm including a picture to make it clear. There are some very strange foreign screw heads on the bolts which hold the black plastic piece to the metal piece.

Does yours have these foreign screw heads too? Did you get yours separated?
 

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Discussion Starter #14
I think I've discovered this is a "pentalobe" screw. Is this intended to send a signal to me that I'm not supposed to remove it?
 

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Im not sure why you would spend tooo much time messing with it when you can buy used toyota ones for very little.
 

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Discussion Starter #16
Im not sure why you would spend tooo much time messing with it when you can buy used toyota ones for very little.
I understand they've been found for $130 before shipping... I'd love to save myself ~$140 by spraying cleaner inside this thing.

If that website is out of stock or that purchase doesn't work out, the price goes up quite a bit from there.

Furthermore I'm not sure the IACV is the culprit, I don't feel like throwing money blindly at the problem, and opening it should help me diagnose
 

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Discussion Starter #17 (Edited)
Hmm now that it's out and I can see the part number, search results based on that show some $60 reproduction from China.

UPDATE: After reading reviews, it looks like an unreliable non-oem reproduction. Possibly junk.
 

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Discussion Starter #18 (Edited)
I did end up opening the IACV. Dremel came out and the pentalobe is now a slotted head for Flathead screwdriver.

This was unnecessary - the IACV on this vehicle simply doesn't function like the GM IACVs I'm more familiar with.. all you gain access to is an area that can't get dirty anyhow.

UPDATE for those interested: Idle is corrected and CEL turned off immediately after starting the car and idling correctly. I cleaned the metal components of the iac with throttle body cleaner and the black electrical connection with electrical connection. Was generous with the spray.
 

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