4AGE 16V Bluetop HIGH IDLE

User avatar
BakaBaka
Club4AG Enthusiast
Posts: 86
Joined: Thu Jan 10, 2013 10:08 pm

4AGE 16V Bluetop HIGH IDLE

Postby BakaBaka » Sun Sep 15, 2019 7:26 pm

Car:
'86 Corolla GTS / 4AGE 16V Bluetop.

Mods:
EGR Delete + Hardlines removed (w/ rear intake manifold block off plate)
AW11 Manual Rack conversion
Pod Intake Filter
TRD 4-2-1 Exhaust
Stock bottom and top end.
Keeping TVIS, A/C & Charcoal Canister

Problem:
Car idles at 2500RPM+ constant even after fully warmed (20+ mins @ 80F weather). AFAIK, all vacuum lines have been re-routed correctly regarding the EGR delete. The charcoal canister is connected to the lower port on the (sideways) BVSV at the back of the head. The upper port is routed to port 'C' on the throttle body. Port 'R' and 'E' are plugged on the TB. The ports on BVSV standing vertically at the back of the head are all capped. Port 'N' is connected to the electric idle VSV near the AFM which is Tee'd into the A/C Idle Up Valve. The check valve on the TVIS has been removed and hooked directly into the vacuum diaphragm. The two power steering ports on the IACV are capped.

All vacuum lines has been replaced. I've check all lines for vacuum leaks and did not find any. I've also doused everything intake/vacuum related with carb cleaner and listened for a change in idle and didn't notice anything.

At this point, I have no idea what is causing the high idle issue. My last resort is removing the IACV under the TB and diagnose that under boiling water. If that happens to not be the case, what can cause a high idle issue that isn't vacuum related? Also, not sure if this might be directly related to the IACV, but when I unhook the connector to my TPS, the idle floats between 1500-2000RPM. I faintly remember these two issues correlating with one another. Hopefully, the IACV is the culprit but I wouldn't be able to confirm until a week or two from now since I only have time to work on the car during weekends.

In the meantime, any and all guru'ness appreciated! -Kudos!

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
jondee86
Moderator
Posts: 2646
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: 4AGE 16V Bluetop HIGH IDLE

Postby jondee86 » Mon Sep 16, 2019 12:22 am

You can test the AAV by blocking the hole at about 5 o'clock in front of the throttle plate.

Image

As you most likely have an AFM engine you can't block it temporarily with your finger
while the engine is running. You need to find a rubber plug from an inflateble toy, air
bed or similar, that you can push into the hole to block it off. Replace the intake
ducting and start the engine.

Providing you have not messed with the idle air bypass screw, the engine may be a
little hard to start, and when it does start it will idle low. As it warms up the idle should
slowly rise to normal. If it behaves like this with the hole blocked off, your AAV is not
working. Either the connecting water hoses are blocked or the valve is blocked.

More information and how to clean the valve from the FAQ...
https://www.club4ag.com//forums/viewtop ... 013#p79892
You can test the valve itself by dropping it into a pan oif boiling water and seeing if
the valve opens. That does not necessarily mean that the water flow channel thru the
valve is clear.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

davew7
Club4AG Enthusiast
Posts: 197
Joined: Fri Jun 06, 2014 4:34 am
Location: Michigan

Re: 4AGE 16V Bluetop HIGH IDLE

Postby davew7 » Mon Sep 16, 2019 4:00 am

If you end up removing the valve for testing, then try cleaning the valve with carb/choke cleaner. Some times the valve gets gummed up, and the carb cleaner will free up the valve. As Jondee86 mentioned, verify you have water flow "to" and "from" the valve. If all else fails, you can adjust the wax-stat. Search here for the tool fabrication, to adjust the air flow. Make the adjusting tool pins short per design. It does not require a large adjustment, in my case .025" change made a 400 RPM change.
davew7

User avatar
BakaBaka
Club4AG Enthusiast
Posts: 86
Joined: Thu Jan 10, 2013 10:08 pm

Re: 4AGE 16V Bluetop HIGH IDLE

Postby BakaBaka » Mon Sep 16, 2019 5:27 pm

Thanks Jondee & Dave. Will let you know the results next week.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
BakaBaka
Club4AG Enthusiast
Posts: 86
Joined: Thu Jan 10, 2013 10:08 pm

Re: 4AGE 16V Bluetop HIGH IDLE

Postby BakaBaka » Wed Sep 18, 2019 8:42 pm

There's my problem!

Never been gladder to confirm the AAV/IACV is the culprit. Hopefully this solves my high idle problem.

Image

User avatar
jondee86
Moderator
Posts: 2646
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: 4AGE 16V Bluetop HIGH IDLE

Postby jondee86 » Wed Sep 18, 2019 10:20 pm

Yup... that will do it every time. If you can clean that out and the valve still opens
when dropped in boiling water, you likely couuld JB weld or epoxy glue a stub of tube
in there to get it working. Otherwise, find a replacement, check it works and you
are good to go :)

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

User avatar
BakaBaka
Club4AG Enthusiast
Posts: 86
Joined: Thu Jan 10, 2013 10:08 pm

Re: 4AGE 16V Bluetop HIGH IDLE

Postby BakaBaka » Wed Sep 18, 2019 11:43 pm

Given how hard it is to remove a baked-on hose over time, I've opted with an NPT barb fitting. Another nice surprise is I found a complete TB & AAV tucked under my passenger seat. Gonna test that one instead since it looks way newer (cleaner) and use that if everything checks out. I'll fix this one up and keep it as a spare. :)

User avatar
BakaBaka
Club4AG Enthusiast
Posts: 86
Joined: Thu Jan 10, 2013 10:08 pm

Re: 4AGE 16V Bluetop HIGH IDLE

Postby BakaBaka » Wed Sep 18, 2019 11:44 pm

Image

Image

User avatar
BakaBaka
Club4AG Enthusiast
Posts: 86
Joined: Thu Jan 10, 2013 10:08 pm

Re: 4AGE 16V Bluetop HIGH IDLE

Postby BakaBaka » Mon Sep 30, 2019 11:00 pm

Updated pic of repaired AAV (IACV) using a 1/8" barb fitting. Will update some more if the issue is resolved when I have the chance to put the TB back into place.

Image

sirdeuce
Club4AG Pro
Posts: 694
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 4AGE 16V Bluetop HIGH IDLE

Postby sirdeuce » Tue Oct 01, 2019 8:12 am

Nicely done! I always thought the manufacturers should have used threaded fitting instead of pressed-in tubes. Not that I've had issues with Toyotas in the area, but I've had problems with many other manufacturers, especially German autos. @$!?)*$# Volkswagen!
One shot, one kill.

User avatar
oldeskewltoy
Club4AG MASTER
Posts: 2025
Joined: Wed Jan 09, 2013 4:44 pm
Location: Portland, Oregon

Re: 4AGE 16V Bluetop HIGH IDLE

Postby oldeskewltoy » Tue Oct 01, 2019 9:00 am

sirdeuce wrote:Nicely done! I always thought the manufacturers should have used threaded fitting instead of pressed-in tubes. Not that I've had issues with Toyotas in the area, but I've had problems with many other manufacturers, especially German autos. @$!?)*$# Volkswagen!


along those lines... German Fords too...(Cologne V6 in particular)
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.



Return to “TECH: 4A-GE ENGINE”

Who is online

Users browsing this forum: No registered users and 17 guests