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1985 Fiero stall Issue. by florabridie1010
Started on: 07-20-2015 05:26 AM
Replies: 9 (263 views)
Last post by: florabridie1010 on 07-21-2015 08:09 AM
florabridie1010
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Report this Post07-20-2015 05:26 AM Click Here to See the Profile for florabridie1010Click Here to Email florabridie1010Send a Private Message to florabridie1010Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hi everyone,
I'm new to the forum and looking for some help with my
85 Fiero 4 cylinder Automatic.
Last summer the car stalled when either D or R was selected.
Local garage renewed distributor cap rotor plugs and leads.
Still stalled garage gave up.
Also changed auto box oil and filter.
So after this here Is the long list of parts renewed.
TPS, IAC, Coil, Thermo switch, Oxygen sensor, pick up coil
in distributor, thermostat and caps.
Charge rate ok. All vacuum pipes good. No chaffed or loose
connections. All engine earths good.
PCV valve cleaned and rattles.
EGR valve stalls warmed up engine when pressed.
Magnet in distributor ok.
Code scanner gives me no bad fault codes and reads 12 engine
static but warmed up and engine running check engine light flashes
1 second on 1 second off with scanner plugged In.
OK so here's the problem...
Start up perfect runs slightly lumpy at 1700 RPM after 4-5 minutes
sounds right all 4 cylinders sweet.
Car brings down revs after warm up to 900.
So far so good. At just over 100f on the gauge if I select either D or R
revs drop to 500 and engine nearly stalls or does stall.
Allowing the engine to reach full warm up no problem with stalling
when shifting gears.
Let It stand for 15 minutes jump In start up select either D or R and
back to near stall or full stall.
Seems this problem Is worse at about quarter engine temp
range. On the road runs well as It should.
The other problem Is a hesitation when at normal run temp
just as you start to press the gas pedal revs drop by about
100 RPM and can stall the engine.
Done this a few times pulled up put In reverse foot
down hesitates then stalls.
Any Ideas on this one?
If the engine run system says everything Is ok where do I
look next? Mileage Is 76,000 car only used In Summer.
Help!!

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Gall757
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Report this Post07-20-2015 11:46 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Welcome to the forum!

If you have not done so, do a search on the TCC. Yours may be making the problem, and the test is easy.

http://www.kichline.com/chuck/fiero/TCC.htm

[This message has been edited by Gall757 (edited 07-20-2015).]

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florabridie1010
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Report this Post07-20-2015 03:06 PM Click Here to See the Profile for florabridie1010Click Here to Email florabridie1010Send a Private Message to florabridie1010Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hi again,
And thank you for the quick response.
Checked the TCC and It's been disconnected
has been for a long time judging by the dirt around
the plug In point.
I guess this rules out the TCC as being the guilty
party?
Checked out your web link on this problem Interesting
reading. I was told that this was a major problem
when the Fiero came out and that GM did not come
up with a cure, hence this car has been unplugged?
Thank's again for your help.

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cebix
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Report this Post07-20-2015 03:16 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is fuel pressure good? I had similar problems and turned out fuel pump hose inside the tank went loose and instead of delivering full fuel to the TBI it sprayed some back inside the tank, sometimes less, sometimes more...

[This message has been edited by cebix (edited 07-20-2015).]

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florabridie1010
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Report this Post07-20-2015 03:27 PM Click Here to See the Profile for florabridie1010Click Here to Email florabridie1010Send a Private Message to florabridie1010Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hi again,
I've watched the fuel spray at the TBI and when the
engine stalls delivery Is there at point of stall.
On the road when hot car runs well, everything good
Performance Is there, I will check fuel pressure though!
Thanks.

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cebix
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Report this Post07-20-2015 05:03 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yeah I saw fuel out of the injector too. Was driving pretty good too but sometimes not. Was throwing a 44 code though which your seems not to (lean mixture).

EDIT: Do you have AC? Also this may be a long shot but does the ECM know you're in gear? Check the voltage at pin 5 of C2 connector at the ECM (orange/black wire). It gets grounded through the gear selector switch when in P or N. When in R, D, 2, 1 it should NOT be grounded.

EDIT2: Regardless of this problem I think you should fix the TCC anyway. I was driving with it disconnected for a few days and it was a nightmare - driving 45mph was as noisy as 65 with the TCC working. Also no engine braking and that slippy feel stays with you. Not good for MPG either.

[This message has been edited by cebix (edited 07-20-2015).]

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Jason88Notchie
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Report this Post07-20-2015 05:47 PM Click Here to See the Profile for Jason88NotchieClick Here to Email Jason88NotchieSend a Private Message to Jason88NotchieEdit/Delete MessageReply w/QuoteDirect Link to This Post
Still sounds like the IAC. I see it was replaced, but check the electrical connections to make sure it is getting a proper signal. May be just a bad connection.
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florabridie1010
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Report this Post07-21-2015 06:43 AM Click Here to See the Profile for florabridie1010Click Here to Email florabridie1010Send a Private Message to florabridie1010Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for your help, ok the car has AC, and I put
a digital voltmeter on the orange and black lead from
the gear switch with plug In connector In place
getting good earth when In P and N and In R and D
I get half a volt maybe some small feedback from
the ECM?
Ran the car through to hot still has that dip In revs
when slowly pressing the gas pedal as much as 200
RPM. Let the engine cool down one hour later starts
readily then stumbles and dies. Start up again same
thing, run 5 minutes and Then runs ok.
It's almost like the IAC Is not doing anything to prevent
the stall. Put the old IAC back In and no different.
Connector and wiring on the IAC plug look sound.
Really appreciate these suggestions keep them coming!
Thanks.

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Gandalf
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Report this Post07-21-2015 08:04 AM Click Here to See the Profile for GandalfSend a Private Message to GandalfEdit/Delete MessageReply w/QuoteDirect Link to This Post
Where in the UK are you?
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florabridie1010
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Report this Post07-21-2015 08:09 AM Click Here to See the Profile for florabridie1010Click Here to Email florabridie1010Send a Private Message to florabridie1010Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hi, I'm In North Yorkshire not far from York.

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