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2.8 Erratic/high-idle Issue by ITALGT
Started on: 01-07-2015 08:42 PM
Replies: 95 (7655 views)
Last post by: 0z on 09-21-2019 11:07 PM
ITALGT
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Report this Post02-19-2015 08:34 PM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Progress.

That word hasn't been used much in this thread lately.

Tonight I decided to take a closer look at the distributor, coil, ICM and associated connections for problems. I started first by removing the coil and cleaning all bracket contact points to ensure it had a good ground. While the coil was removed, I took off the distributor cap to install a new ICM that I picked up today. Just as I was about to install it, I noticed something I hadn't seen before; the magnets for the pickup coil were... well... disintegrating.

Chunks are missing from some of the magnets; this might explain the bucking/jerking that's been slowly getting worse and worse. And the last time I pulled plugs, only one looked good... the rest were getting coated with black soot. Maybe there's one good magnet and therefore one good spark plug? I think I might actually see what's happening here. Weak spark on 5 cylinders and timing fluctuations caused by the play in the shaft could very well cause a rich condition and constant open loop.

I know the PO replaced the distributor, but I have no idea what brand it is. I do know that there is excessive vertical play in the shaft and the magnets are falling apart.

I have a new Cardone Select distributor ordered from Rockauto.com.

Progress.

[This message has been edited by ITALGT (edited 02-20-2015).]

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LornesGT
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Report this Post02-19-2015 08:44 PM Click Here to See the Profile for LornesGTSend a Private Message to LornesGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
I am surprised it ran at all.
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ITALGT
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Report this Post02-19-2015 08:52 PM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by LornesGT:

I am surprised it ran at all.


That makes two of us.

Just goes to show that just because a part is "new" doesn't always mean it's "good."


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Patrick
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Report this Post02-19-2015 09:01 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ITALGT:

I noticed something I hadn't seen before; the magnets for the pickup coil were... well... disintegrating.


Well, come on... let's see some pictures!
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ITALGT
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Report this Post02-19-2015 09:20 PM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'll try to post pictures if I get the chance... probably when I pull the distributor out to put in the new unit.

I've gotten excited many times in this process only to be crushed by disappointment, so I'm going to try containing my enthusiasm on this one.

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LornesGT
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Report this Post02-20-2015 03:56 PM Click Here to See the Profile for LornesGTSend a Private Message to LornesGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
The coil in my distributor disintegrated in my hand as I pulledl it out, I am suprized it ran at all. I still had a bad idle unfortunately. I don't think it is all that great now but just to doggone cold to do anything about it, I had it better for a short time.

[This message has been edited by LornesGT (edited 02-20-2015).]

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ITALGT
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Report this Post02-20-2015 04:24 PM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by LornesGT:

The coil in my distributor disintegrated in my hand as I pulledl it out, I am suprized it ran at all. I still had a bad idle unfortunately. I don't think it is all that great now but just to doggone cold to do anything about it, I had it better for a short time.



How old is your distributor out of curiousity?

The reason I ask is that this one is a fairly new distributor (with star-type pickup) that the previous owner installed. I am just surprised that the magnets are falling apart and there is so much play in the shaft, being that it's almost new. I wish I knew what brand it was.

Something I forgot to mention... on top of the pickup coil, there are supposed to be four tiny screws that secure the star; on mine, one of them is missing.

I elected to replace the entire distributor considering all of these issues. I also ordered new coil and ICM pigtails and will install them at the same time.

[This message has been edited by ITALGT (edited 02-20-2015).]

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LornesGT
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Report this Post02-20-2015 05:18 PM Click Here to See the Profile for LornesGTSend a Private Message to LornesGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Could be original I don't know, I have only had the car 2 years, I just disassembled and cleaned it up.
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88cryan
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Report this Post02-21-2015 11:00 PM Click Here to See the Profile for 88cryanClick Here to Email 88cryanSend a Private Message to 88cryanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Does the idle "sound right" to you when its idling or does it sound like it is high? I skimmed the pages and didn't see anyone mention the tachometers being inaccurate and off sometimes. My 88 GT reads 400 rpm high. It displays 1200 rpm on the gauge when hot but I confirmed with WINALDL that i'm idling right. Just my .02, but if not I hope the distributor helps!!!

[This message has been edited by 88cryan (edited 02-21-2015).]

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ITALGT
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Report this Post02-22-2015 10:56 AM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 88cryan:

Does the idle "sound right" to you when its idling or does it sound like it is high? I skimmed the pages and didn't see anyone mention the tachometers being inaccurate and off sometimes. My 88 GT reads 400 rpm high. It displays 1200 rpm on the gauge when hot but I confirmed with WINALDL that i'm idling right. Just my .02, but if not I hope the distributor helps!!!



I thought of that... but the way it is acting, I doubt that's the case. What it does now is fluctuate about 1400-1600 RPMs, with an occasional big drop under 1000 as if it's trying to establish the regular idle but can't and about dies... so it jumps right back up to around an erratic 1500 in open loop. Still idles way high when cold too. Sounds like it would be caused by a vacuum leak, but I've been through the system a hundred times now and can find no leaks. I can also kill the engine by putting my finger over the IAC port, which should also indicate that there are no vacuum leaks.

I also have performed the IAC reset and checked the minimum idle air circuit, but no change.

I hope it's been the distributor the whole time... I'll find out by next weekend.

On a side note... one benefit of going through things like I have is that I've caught a few issues before they became big ones. The fuel pump was a prime example, as it was surely going to fail any time. Last weekend when checking the ECM grounds, I noticed that the clutch slave cylinder mounting bracket was busted on one side and was only being held on by one bolt! I have no idea how long it had been this way. I drove it for several days with a vise grip holding the broken section together, until yesterday when I received a new steel bracket from RD and replaced it. It sure is nice catching these issues before they leave me stranded on the side of the road!

[This message has been edited by ITALGT (edited 02-22-2015).]

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ITALGT
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Report this Post03-01-2015 07:48 PM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
'Nother update...

The new Cardone Select distributor is installed, and the engine is running much better. Idle is still high at about 1400-1600 even after an IAC reset, but exhaust fumes are now next to nothing and the engine finally wants to rev again. That "new" distributor from the PO I took out definitely had some issues. All that said... something is STILL not right with this engine, although it's not nearly as bad as when this process started.

I didn't have time this weekend to solder in the new ICM and coil pigtails, so I'll try knocking those out tomorrow night. In the meantime, I'm not totally convinced the new EGR valve installed by the previous owner is functioning right, so I am going to replace it next. It could have be the problem all along and is worth checking; the EGR solenoid is operating and providing vacuum, so the valve might be stuck open causing the idle issue. It's either that or I have a lower intake vacuum leak that's been evading me... I'm running out of possibilities here.

Stay "tuned."

[This message has been edited by ITALGT (edited 03-13-2015).]

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ITALGT
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Report this Post03-13-2015 07:38 PM Click Here to See the Profile for ITALGTSend a Private Message to ITALGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
This daily driver Fiero is running good with the new distributor, no engine codes to speak of now. Rich condition is gone, but the idle problem persists; it remains erratic at 1400-1600 RPM's when warmed up.

EGR valve was replaced last weekend with no change. I also changed the oil due to the previous rich condition.

155,000 mile 2.8... possibly a stretched timing chain? I'm not honestly sure at this point. But when downshifting, rev's become unstable as the engine herk's and jerk's down the RPM range. Power seems decent but I can tell it's not where it should be.

Any ideas or suggestions out there?

[This message has been edited by ITALGT (edited 03-13-2015).]

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Brent7088
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Report this Post11-28-2015 10:28 PM Click Here to See the Profile for Brent7088Click Here to Email Brent7088Send a Private Message to Brent7088Edit/Delete MessageReply w/QuoteDirect Link to This Post
ITALGT - Did you ever find a permanent solution for your idle problem? I've had virtually the same issue for several years on my 86 2.8 GT auto.

Mine idles high at startup, goes up and down for several minutes and when finally warmed up, still idles too high. It's not the EGR tube, as I replaced it with an aftermarket a few years ago.
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Patrick
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Report this Post11-28-2015 10:35 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Brent7088:

Mine idles high at startup, goes up and down for several minutes and when finally warmed up, still idles too high. It's not the EGR tube, as I replaced it with an aftermarket a few years ago.




 
quote
Originally posted by Patrick:



In the image above you can see the IAC port. Cover that hole with your thumb when the engine is idling high. If the RPMs drop a lot, then it would appear that perhaps the IAC valve is sticking open. If the RPMs don't drop, I'd suspect a vacuum leak.

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mrstan
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Report this Post12-13-2015 01:37 AM Click Here to See the Profile for mrstanClick Here to Email mrstanSend a Private Message to mrstanEdit/Delete MessageReply w/QuoteDirect Link to This Post
did you replace the egr solenoid? I did not understand if you did or not.
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0z
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Report this Post09-21-2019 11:07 PM Click Here to See the Profile for 0zSend a Private Message to 0zEdit/Delete MessageReply w/QuoteDirect Link to This Post
I wonder how this all ended......
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