88 MGTE MKIII Mystery Part...

[wuestda]

I bought a MKIII off of eBayMotors a year ago, and LOVE it.
I am currently going over it and doing the usual WasteGate SHIM BOV updates, and came across a part that I do not understand...
Drivers side, Air bypass from Intake manifold back to cold-air intake.
It has 2 coolant lines attached, an electrical harness, a bell housing, and an air pipe. What is this, and should it be open to air flow at all times? I can blow right through the air hose: is this a problem? Is it a valve of some sort?
Bugger of a pain in the ass to remove, because it's lowe mounting bolt is VERY hard to get at, and the lower hose clamps are a bear to reach as well.

Any explanation of it's function and operation would be appreciated!

Thanks!

[SilverMk2]

Sounds like you are describing the ISC (idle speed control) valve. Basically its a electric stepper motor driven air valve. The computer uses it to control the engine idle speed.

[myothersupra]

That's got to be the part he means.

Suggestions...
Unless your stock one's blown, I'd recommend saving the money from the BOV and buying a decent basic EBC instead of bothering with the wastegate shim. You'll spool a lot quicker and actually have control of your boost level too! It's SOOOOO worth every penny. Just don't get one that's overly complicated like the "Profec B Spec 2". The discontinued old school Profec B with the 3 knobs is a much more user friendly controller and I'm sure there are others that are new and just as easy to learn to use.
Plus, the aftermarket BOV will cause stalling when you push the clutch in right after a hard run due to the high level of "metered air" leaving the system unexpectedly.

[wuestda]

Sounds like you are describing the ISC (idle speed control) valve. Basically its a electric stepper motor driven air valve. The computer uses it to control the engine idle speed.
I don't know - what are the coolant lines attached to it for? Also, wouldn't a free passage from manifold back to cold air intake bypass boost?

[wuestda]

That's got to be the part he means.

Suggestions...
Unless your stock one's blown, I'd recommend saving the money from the BOV and buying a decent basic EBC instead of bothering with the wastegate shim. You'll spool a lot quicker and actually have control of your boost level too! It's SOOOOO worth every penny. Just don't get one that's overly complicated like the "Profec B Spec 2". The discontinued old school Profec B with the 3 knobs is a much more user friendly controller and I'm sure there are others that are new and just as easy to learn to use.
Plus, the aftermarket BOV will cause stalling when you push the clutch in right after a hard run due to the high level of "metered air" leaving the system unexpectedly.
Cool - I am new to the turbo market... This Supra is a real barrel of fun. I am hitting fuel cut at present and just Purchased an HKS fuel-cut-defencer for it. I found the gate already shimmed, and I am running 550cc injectors (type unknown). Can you recommend a good source for boost controllers for this beast?

[SilverMk2]

You should really read up on how to modify the engine 1st. It sounds like you don't have a lot of experience with the 7M. The FCD is mostly a waste of money on the 7M. 7Ms don't take kindly to cheap mods and hack jobs. I'd really recommend joining up at supramania.com. They concentrate on MkIIIs specifically, we are mainly MkIIs.

As far as the ISC goes it should be closed at off idle positions. the cooling lines in my opinion are there as an air warmer.

[CJSREDPRA]

The HKS FCD is basically a "band-aid" item & most everyone here dicourages using one!!! There is usually a good reason WHY you are hitting FCO. I'm betting something in the fuel system is causing the motor to go lean.

Yes, we see that you have upgraded injectors. We also see no mention of a upgraded fuel pump...

You need to piece everything together PROPERLY rather than just buying parts left & right.