Georgia Fiero Club Forum

All Things Fiero => Tech Tips, Tech Questions => Topic started by: NoobKevin on August 20, 2019, 05:34:27 pm

Title: High Idle
Post by: NoobKevin on August 20, 2019, 05:34:27 pm
I have the engine running and even with the ecm jumpered the idle remains high. I think I hear a loud sucking sound from under the intake but I have replaced all of the vaccum lines with steel. There is a tube that is attached to the fire wall that appears to have gone from the breather to the engine. Could that be an issue?
Title: Re: High Idle
Post by: GTRS Fiero on August 20, 2019, 06:23:46 pm
There was a tube that went from the front (firewall-side) valve cover, to the air canister.  The recall replaced that with a tube that runs from the front valve cover to the intake tube.  The EGR tube runs from under the intake snorkle to the EGR valve mount block.  That tube likes to leak.
Title: Re: High Idle
Post by: TopNotch on August 20, 2019, 09:49:21 pm
Start your car with the engine cold. Before it has time to warm up, grab the EGR tube and try moving it. if you hear a changing hiss as you move it, you need to replace it. The Fiero Store braided EGR tube is a good replacement.
Title: Re: High Idle
Post by: NoobKevin on August 20, 2019, 10:33:44 pm
The EGR tube is new if it has broken I will be very disappointed. The sucking sound is loud is that normal. Also this engine gets really hot. I was surprised. Why is the radiator not in the rear and what about rear facing venting for the hood to help shed heat?
Title: Re: High Idle
Post by: NoobKevin on August 20, 2019, 10:37:40 pm
The eighties Camaro Z had the Louvered hood. If you have a layer of warm air at the nose and across the front you should also reduce friction and improve aerodynamics.
Title: Re: High Idle
Post by: GTRS Fiero on August 20, 2019, 10:38:03 pm
The EGR system has a lot of gaskets.  Maybe one is not in place.

The intake tube is connected at both the air filter housing and the throttle body, right?  If not, it sounds like Darth Vader on constant inhale.  The breather tube should also be connected to the intake tube.
Title: Re: High Idle
Post by: GTRS Fiero on August 20, 2019, 10:39:06 pm
You can use a length of hose to probe for the source of yhe sound.  A 3-foot section of garden hose works well.
Title: Re: High Idle
Post by: NoobKevin on August 20, 2019, 10:56:26 pm
The intake does sound loud and I love it. I am a noob so I still learning what’s normal. Will be a week or two till I get back to it but my family is impressed that I have dropped the motor and put it back together and it runs.
Title: Re: High Idle
Post by: GTRS Fiero on August 20, 2019, 10:59:35 pm
Absolutely, it is great that you can do that.

FYI, Fiero engine bays get very hot, compared to other vehicles.

Make sure you have a filter on the intake when the engine is running.
Title: Re: High Idle
Post by: TopNotch on August 21, 2019, 10:22:06 am
If your engine is running on a lean mixture because of a vacuum leak, it will run hotter than normal. Your exhaust manifolds will glow red at night. And of course, the vacuum leak causes a high idle.
Title: Re: High Idle
Post by: MikeMac on August 21, 2019, 12:25:36 pm
Congratulations on what you have accomplished! 
Title: Re: High Idle
Post by: Raydar on August 21, 2019, 02:47:48 pm
Congratulations on what you have accomplished!

Second this!

(I still remember the 1st time I pulled an engine from a Fiero and replaced it with another one. My wife was dumbfounded. :D )
Title: Re: High Idle
Post by: NoobKevin on August 25, 2019, 08:00:11 pm
Hi All,

  I did the brake cleaner vacuum check last Thursday and found out that there looks to be an issue at the throttle body. Does the metal tube that inserts into the lower part require an o ring or sealant? I suppose the rubber vacuum boots could be replaced as well.

NoobKev
Title: Re: High Idle
Post by: GTRS Fiero on August 25, 2019, 08:17:45 pm
The intake tube is available from TFS.

There is a grommet at the valve cover.  Metal tube into the lower part?
Title: Re: High Idle
Post by: Fierofool on August 25, 2019, 09:45:58 pm
Yes, the metal tube at the back side, bottom of the throttle body requires an O-ring inside the throttle body.  The metal tube transitions to a rubber hose attached to the lower intake. 
Title: Re: High Idle
Post by: NoobKevin on August 27, 2019, 11:23:54 am
Where can I find a seal for the throttle body connection.
Title: Re: High Idle
Post by: Fierofool on August 27, 2019, 02:01:32 pm
Do you need the gasket or just the O-ring?  I'll be back home after 3:30 and can see what I have.  I'm pretty sure I have a couple of gaskets and I may have an O-ring in my assortment.  I have a loose throttle body that I can use to size it with. 
Title: Re: High Idle
Post by: NoobKevin on August 27, 2019, 02:12:42 pm
I am on the road till Sunday. Is it just a typical O ring or is it specialized?
Title: Re: High Idle
Post by: Fierofool on August 27, 2019, 04:20:55 pm
It's typical.  The O-ring thickness is 0.10 inches.  The inside diameter is 0.542 inches.  I have a couple if you want me to mail one to you. 
Title: Re: High Idle
Post by: NoobKevin on August 27, 2019, 06:19:53 pm
Thanks for the offer I really appreciate it. I am in no hurry. I am driving east in Montana right now just outside of Bozeman so nothing happening with the Fiero.
Title: Re: High Idle
Post by: GTRS Fiero on August 27, 2019, 06:24:40 pm
You lucky guy!  I wish I was in Montana.
Title: Re: High Idle
Post by: Fierofool on August 27, 2019, 09:12:54 pm
PM or email me your address and one will be waiting for you when you get home. 
Title: Re: High Idle
Post by: MikeMac on August 27, 2019, 10:06:25 pm
PM or email me your address and one will be waiting for you when you get home.

Don't send it UPS...
Title: Re: High Idle
Post by: NoobKevin on September 03, 2019, 11:39:17 am
Oring worked. Big Thanks! Idle is around 900 now. There is a voltage issue though. When the radiator fan starts, the idle is drawn down and the engine wants to stall. I am going to check the grounds. Any ideas?
Title: Re: High Idle
Post by: Fierofool on September 03, 2019, 02:15:57 pm
You and MikeMac need to talk.  Both have the same problem.  I keep mine idled at 1000-1100.
Title: Re: High Idle
Post by: GTRS Fiero on September 04, 2019, 08:35:14 pm
I'm curious what would happen if a light bulb was connected in place of the fan.  Would there still be the same drain?  In theory, that would test the wiring.
Title: Re: High Idle
Post by: NoobKevin on September 05, 2019, 08:20:07 am
The same drag on the engine idle occurs when the headlights are turned on. When both lights and fan are on the drag does not double and often if one or the other comes on after the idle has recovered, the drag does not reoccur. This is what got me looking for an idle control issue and not an electrical bug.
Title: Re: High Idle
Post by: GTRS Fiero on September 05, 2019, 05:51:36 pm
Well, you could unplug the IAC to test.  The engine won't run well, and a code will be set, but you can test for any change in the issue.
Title: Re: High Idle
Post by: NoobKevin on September 07, 2019, 09:01:24 pm
IAC swap made a noticeable difference if that helps you at all.
Title: Re: High Idle
Post by: GTRS Fiero on September 07, 2019, 09:03:22 pm
Um...what sort of difference?
Title: Re: High Idle
Post by: NoobKevin on September 07, 2019, 09:07:34 pm
Very good question. Positive difference. Idles better overall, smoother and less variation at the extremes. Adjusts to loads quicker and does not allow the car to approach stalling nearly as far.
Title: Re: High Idle
Post by: GTRS Fiero on September 07, 2019, 09:10:22 pm
So, likely a bad IAC.
Title: Re: High Idle
Post by: NoobKevin on September 07, 2019, 09:46:25 pm
Yes, bad IAC in my case.
Title: Re: High Idle
Post by: GTRS Fiero on September 09, 2019, 06:24:45 pm
Is this issue resolved, now?
Title: Re: High Idle
Post by: NoobKevin on September 11, 2019, 09:31:32 am
Probably. It’s much better but I am thinking the alternator is also suspect. I have moved on to the brakes for now. Found a significant break in the left front line. Stripped the hard line connector at the rubber line so I ordered new rubber lines for both sides up front. I also stripped the bleeder screw on the front right so I ordered a new caliper. Should have done that for the front left. Running out of money though
Title: Re: High Idle
Post by: GTRS Fiero on September 11, 2019, 06:14:47 pm
If the caliper is not damaged, it can be cleaned and re-used.  Less expensive, that way.

You may check if the club has an alternator.