Pennock's Fiero Forum
  Technical Discussion & Questions
  Swapped TB's, Now something's up. Puzzling

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
Swapped TB's, Now something's up. Puzzling by 87FieroSport
Started on: 10-05-2013 07:58 PM
Replies: 16 (216 views)
Last post by: 87FieroSport on 10-08-2013 01:46 PM
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-05-2013 07:58 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
So my old TB had the idle screw cap removed.
Tried to reset it, but the screw is jammed tight,
So I bought a capped TB from Hardpact.

I swapped them today.

Before: idle @1200 warm, shift to neutral while driving, idle dropped to 1200 from 3000 range.

Now: idle quirky. 2000 startup, 1500 warm, if I turn it off and on, I can get to 1200 again.
Shift to neutral at 2500rpm, went to 2000rpm only.

I have no loss of power,
Everything is normal it seems. Why the weird reading?

I am positive all vac lines are back in place.
IP: Logged
PFF
System Bot
katatak
Member
Posts: 7136
From: Omaha, NE USA
Registered: Apr 2008


Feedback score:    (8)
Leave feedback





Total ratings: 82
Rate this member

Report this Post10-05-2013 09:21 PM Click Here to See the Profile for katatakSend a Private Message to katatakEdit/Delete MessageReply w/QuoteDirect Link to This Post
IAC Sticking?
IP: Logged
PatrickTRoof
Member
Posts: 547
From: Baltimore, MD, USA
Registered: May 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-05-2013 09:23 PM Click Here to See the Profile for PatrickTRoofClick Here to Email PatrickTRoofSend a Private Message to PatrickTRoofEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm having similar problems.
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-05-2013 09:24 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
I wouldn't be able to tell if its sticking honestly.
Maybe I'll swap IACs from my old TB to my new one
IP: Logged
PatrickTRoof
Member
Posts: 547
From: Baltimore, MD, USA
Registered: May 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-05-2013 09:26 PM Click Here to See the Profile for PatrickTRoofClick Here to Email PatrickTRoofSend a Private Message to PatrickTRoofEdit/Delete MessageReply w/QuoteDirect Link to This Post
I swapped IACs and it didn't help much.
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-05-2013 09:26 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
It does hunt a little bit, 100-200rpm from 1200-1400 Inoticed every once in a while at lights
IP: Logged
PatrickTRoof
Member
Posts: 547
From: Baltimore, MD, USA
Registered: May 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-05-2013 09:31 PM Click Here to See the Profile for PatrickTRoofClick Here to Email PatrickTRoofSend a Private Message to PatrickTRoofEdit/Delete MessageReply w/QuoteDirect Link to This Post
How is your throttle response? Is it good or does it hesitate like crazy?
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-05-2013 09:37 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well I only drove it for 10mins tonight.
Before the swap, I noticed it'll hesitate to 2K rpm highway and city, if I press more it'll jump to 4-5k and accelerate.

So that's inconclusive yet. I thought that would be resolved when I swapped, since the idle stop was
Compromised on my old TB.

Anyone have a clue?
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-06-2013 09:27 AM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did notice at:

3K rpm spun 60mph before swap.

3k rpm spins 55mph now after swap.

500rpm would account for the 1500rpm idle.
IP: Logged
Blacktree
Member
Posts: 20298
From: Central Florida
Registered: Dec 2001


Feedback score:    (11)
Leave feedback





Total ratings: 349
Rate this member

Report this Post10-06-2013 09:45 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your previous throttle body probably had the idle stop set differently from your current one. So now, your ECM has to re-learn how to idle the engine. Try this:

1) Disconnect the negative battery cable to reset the ECM.
2) After you re-connect the battery cable, jumper the test terminals in the ALDL connector, and turn the key to the Run position. This will reset the IACV.
3) Remove the jumper from the ALDL connector, and drive the car. Make sure to drive at least 35 MPH. This should complete the idle re-learn procedure.

If the engine still acts odd after this, then it's time to start troubleshooting.
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-06-2013 10:09 AM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is this the actual procedure?
IP: Logged
PFF
System Bot
Gall757
Member
Posts: 10633
From: Holland, MI
Registered: Jun 2010


Feedback score: N/A
Leave feedback





Total ratings: 88
Rate this member

Report this Post10-06-2013 10:18 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
That's pretty much it....There is an ECM disconnect next to the battery if you would rather not disconnect the battery.

[This message has been edited by Gall757 (edited 10-06-2013).]

IP: Logged
PatrickTRoof
Member
Posts: 547
From: Baltimore, MD, USA
Registered: May 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-07-2013 02:20 PM Click Here to See the Profile for PatrickTRoofClick Here to Email PatrickTRoofSend a Private Message to PatrickTRoofEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Blacktree:

Your previous throttle body probably had the idle stop set differently from your current one. So now, your ECM has to re-learn how to idle the engine. Try this:

1) Disconnect the negative battery cable to reset the ECM.
2) After you re-connect the battery cable, jumper the test terminals in the ALDL connector, and turn the key to the Run position. This will reset the IACV.
3) Remove the jumper from the ALDL connector, and drive the car. Make sure to drive at least 35 MPH. This should complete the idle re-learn procedure.

If the engine still acts odd after this, then it's time to start troubleshooting.


This worked for me. Thank you so much! I was tearing my hair out looking for a vacuum leak.

[This message has been edited by PatrickTRoof (edited 10-07-2013).]

IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-07-2013 03:08 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
Worked here too. I did have a broken line to cruise, invisible until you moved it.

Idling in drive @ 1100
Idling in neutral 1300-1100.

Blocked off EGR for extra caution.
Double checked all lines for leaks (none)

Anything else could cause my +200 rpm?

Timing related perhaps?
IP: Logged
fierofool
Member
Posts: 11752
From: Auburn, Georgia USA
Registered: Jan 2002


Feedback score:    (13)
Leave feedback





Total ratings: 150
Rate this member

Report this Post10-07-2013 03:39 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
The different speeds you noted with corresponding RPM wouldn't be correct. If the car is running a given MPH, the rpm will be the same in the same gear. Modifications in the area of the throttle body wouln't change this. Only thing that would is that it's in a different gear.

Yes, timing could account for the higher idle. The ECM kicks up the idle to compensate for the drag of the engine when you put an automatic into gear. Keeps the engine from stalling. Retard the timing a bit.
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-07-2013 04:19 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
Button on my TV cable is jammed. Can't push it in so I'm ordering a new one.
It shifts pretty hard.

I've even noticed a bog at 2k, give it some gas and it'll shoot up 2k+ rpm from 2k rpm and accelerate.
Spinning 60mph at 3000rpm has always been normal for me.

50-2500
60-3000
70-3500
80-4000
IP: Logged
87FieroSport
Member
Posts: 886
From:
Registered: Jul 2012


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-08-2013 01:46 PM Click Here to See the Profile for 87FieroSportSend a Private Message to 87FieroSportEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'll try to retard the timing tonight and see if it helps.
Sits flat at the 1100 mark now, little bumps to 1150 at times.

Was at 1300 before, close to 1400 so my idle screw was definitely an issue.
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock