Pennock's Fiero Forum
  Technical Discussion & Questions
  Constant icm failure due to exhaust

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


next newest topic | next oldest topic
Constant icm failure due to exhaust by pontiacfierokid1985
Started on: 07-24-2019 10:57 AM
Replies: 12 (458 views)
Last post by: theogre on 07-25-2019 01:58 AM
pontiacfierokid1985
Member
Posts: 818
From: new bedford ma
Registered: Nov 2009


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-24-2019 10:57 AM Click Here to See the Profile for pontiacfierokid1985Click Here to visit pontiacfierokid1985's HomePageSend a Private Message to pontiacfierokid1985Edit/Delete MessageReply w/QuoteDirect Link to This Post
Question for everyone is there a way to move the icm from out of the distributor. I have custom built headers when i bought my recent 86gt 2.8. Thing is im constantly going through modules since the exhaust cross over pipe literally is right next to the distributor. I heat wrapped that pipe to see if it will help but i dont want to chance when driving a icm failure. I was thinking of cutting a small slit in the cap and running the wires out to the trunk firewall and mounting the icm there so it is away from the exhaust. Has anyone done something think this? I really dont want to buy stock manifolds and cross over just to not blow icm’s
IP: Logged
PFF
System Bot
cvxjet
Member
Posts: 3878
From: ca, usa
Registered: May 2010


Feedback score: (1)
Leave feedback

Rate this member

Report this Post07-24-2019 11:50 AM Click Here to See the Profile for cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
First off, do you have the original heat shields in place that protect the Distributor from the crossover pipe? Second, only buy the AC/Delco ICM....I went thru a few "Masterpro" and "Standard" ICMs before someone told me not to bother and get the good one......

Believe it or not, you are not trying to "Keep the ICM cool"- That thing gets HOT all on it's own....What you are really trying to do is COOL off the ICM by not having too much heat in it's vicinity....Meaning, limit the exhaust heat radiating towards it. (Sounds the same but is actually different)

Some people have moved theirs, but I haven't had one go out since I installed the AC/Delco ICM.....I also carry a spare- it is the last non-AC/D that had not failed- It only has to get me home, and then I would order another AC/D (They are a little bit more expensive ($70-90)....I also carry a spare Coil and of course the tools to change them. I did move my coil to the trunk wall, and then added a heat shield to block the heat radiating from the exhaust towards it (Used a laser temp sensor, driving to work(30 miles) in the morning; In Original location it was 160*, new location was 120* )
IP: Logged
pmbrunelle
Member
Posts: 4587
From: Grand-Mère, Québec
Registered: Sep 2008


Feedback score: N/A
Leave feedback





Total ratings: 63
Rate this member

Report this Post07-24-2019 12:28 PM Click Here to See the Profile for pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I doubt that the original heat shields would fit over the custom exhaust, but why don't you just make some heat shields for your exhaust?

Also, is your trunk blower fan operating and directing cool air to the distributor? If not, make it work... and consider bypassing its relay to be always on with the key in run.
IP: Logged
fierofool
Member
Posts: 12955
From: Auburn, Georgia USA
Registered: Jan 2002


Feedback score:    (13)
Leave feedback





Total ratings: 154
Rate this member

Report this Post07-24-2019 02:59 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Weak plugs, wires or ignition coil can also cause rapid failure of the ICM. Be sure the deflector shield is on the ignition coil that will help direct some air from the cooling tubes, when the AC is operating or whenever the cooling fan comes on.
IP: Logged
Patrick
Member
Posts: 38435
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 465
Rate this member

Report this Post07-24-2019 03:04 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pontiacfierokid1985:

is there a way to move the icm from out of the distributor?


Ignition Module / Ignition Coil remote relocation by larryfiero

IP: Logged
theogre
Member
Posts: 32520
From: USA
Registered: Mar 99


Feedback score: N/A
Leave feedback





Total ratings: 572
Rate this member

Report this Post07-24-2019 03:51 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Several people have remote mount the ICM... Use Search but some are likely better then others. Anything that Generates heat like ICM etc in the trunk can have similar problems w/ lack of air to cool and so on. Most forget the Trunk gets hot from weather, exhaust, etc, w/o putting it other things that dumps heat in there too. That's ignoring other crap, often heavy hard things, take space and gets dropped/thrown in a trunk that can damage it.

Many claim is a weak ICM that fails but several things can kill the ICM like an iffy coil, tach filter, cap and rotor, and even a crappy ICM mounting screw can kill it. Mounting screw Is The Ground for the ignition. Any Problems on high voltage side can kill it w/ spark you often can't see. "Performance"coils including MSD and Accel products won't help either.

Have the engine blower on all the time has problems too like the blower can die soon this way.

Heat shied(s) are a completely passive heat control that works very well but you need to understand how they do their job.
They mostly block IR light from the exhaust or whatever hot hitting on everything behind one.
So when you make one and not sure what to shield then use a small light in several spots and make your shield w/ a shadow to shade what you want to protect.
But watch the size and shape because may block air flow...
IOW You can't just shield the whole distributor because ICM won't get air flow w/ and w/o the engine blower on.

Exhaust wrap is often bad. May keep heat in but the pipes get way hotter then normal and can fail from stress for heat cycling or water gets in and attack the pipe.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)


The Ogre's Fiero Cave

IP: Logged
pmbrunelle
Member
Posts: 4587
From: Grand-Mère, Québec
Registered: Sep 2008


Feedback score: N/A
Leave feedback





Total ratings: 63
Rate this member

Report this Post07-24-2019 06:47 PM Click Here to See the Profile for pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by theogre:
Have the engine blower on all the time has problems too like the blower can die soon this way.


I thought about that, but I feel like blower on all the time is considered a normal operating condition, as it comes on every time the A/C is switched on.
I imagine that for folks in Texas and such, the A/C button is left permanently pushed in. Are their blowers dying often?

Personally I drove my previous Fiero for about 5 years / 50 000 km, blower on all the time, without a blower failure.

I prefer to favour the reliability of the distributor and ignition module by blowing air at them constantly, even if it risks prematurely killing the blower.

The blower fan isn't like fastback taillights; they aren't highly sought after, so replacements are easy to come by. For myself, a 5-year (maybe more, but that hasn't been tested) replacement interval for the blower is reasonable, considering that the blowers are plentiful and easy to replace in the car.
IP: Logged
Patrick
Member
Posts: 38435
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 465
Rate this member

Report this Post07-24-2019 07:05 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

I prefer to favour the reliability of the distributor and ignition module by blowing air at them constantly, even if it risks prematurely killing the blower.


Anyone with an '88 doesn't have that option... without a whole lot of mods.

The heat sink I added appears to be doing the job just fine. My ICM is 12+ years old.

IP: Logged
pmbrunelle
Member
Posts: 4587
From: Grand-Mère, Québec
Registered: Sep 2008


Feedback score: N/A
Leave feedback





Total ratings: 63
Rate this member

Report this Post07-24-2019 07:12 PM Click Here to See the Profile for pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Do the blower-related parts from the early Fieros not bolt into 1988 spaceframes?

Edit: For reference, OP's Fiero is an 86.

[This message has been edited by pmbrunelle (edited 07-24-2019).]

IP: Logged
Patrick
Member
Posts: 38435
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 465
Rate this member

Report this Post07-24-2019 08:01 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

Do the blower-related parts from the early Fieros not bolt into 1988 spaceframes?


I can't swear to it (as it's been awhile since I looked), but I don't believe the 88's even have a hole in the trunk for the blower assembly.
IP: Logged
fierofool
Member
Posts: 12955
From: Auburn, Georgia USA
Registered: Jan 2002


Feedback score:    (13)
Leave feedback





Total ratings: 154
Rate this member

Report this Post07-24-2019 09:47 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Nor do the 88's have the ductwork across the trunk wall or the place to bolt the cooling tubes.
IP: Logged
PFF
System Bot
cvxjet
Member
Posts: 3878
From: ca, usa
Registered: May 2010


Feedback score: (1)
Leave feedback

Rate this member

Report this Post07-25-2019 12:41 AM Click Here to See the Profile for cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
I found that the trunk fan on my car doesn't seem to ever run- (I have no AC); I took it out but saved the blower- made an aluminum piece to finish it's housing, and plan on installing it behind the right IMSA scoop on my 85......I will run a duct across the firewall and then have it aimed from the firewall at the distributor- Hidden and yet functional- I will make sure it turns on- not when the car is running, but when the car has warmed up a bit.

Obviously, someone with an 88 could do this mod- You do need the IMSA scoops or something similar and a blower...I should state that I moved the battery up front also, which cleared the area under the normal battery position for the duct to come up into the engine compartment.

Just a (Crazy) suggestion......
IP: Logged
theogre
Member
Posts: 32520
From: USA
Registered: Mar 99


Feedback score: N/A
Leave feedback





Total ratings: 572
Rate this member

Report this Post07-25-2019 01:58 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:
I thought about that, but I feel like blower on all the time is considered a normal operating condition, as it comes on every time the A/C is switched on.
I imagine that for folks in Texas and such, the A/C button is left permanently pushed in. Are their blowers dying often?

Personally I drove my previous Fiero for about 5 years / 50 000 km, blower on all the time, without a blower failure.

I prefer to favour the reliability of the distributor and ignition module by blowing air at them constantly, even if it risks prematurely killing the blower.

The blower fan isn't like fastback taillights; they aren't highly sought after, so replacements are easy to come by. For myself, a 5-year (maybe more, but that hasn't been tested) replacement interval for the blower is reasonable, considering that the blowers are plentiful and easy to replace in the car.
Some run many years and some do not.

Yes Rad Fan and that blower are used a lot. While Heat Blower is on all the time for most people, isn't at highest speed all that time. I've replace many fan/blower motors and not just GM because these motors are made cheap w/ mostly sleeve bearings that do wear out as oil in them drys, or brushes wear out, etc. Like many fans used in PC and a lot more even tho most are bush less have most of same problems.

And is Not easy to find the engine blower in many places. Most junk yards don't even strip older cars in many areas, just crush to make scrap. Many can't even crush them on site now because cities counties and/or state won't allow this.
You still get new rad fan and heater motor but not this as new part unless you find something similar and mod to fit.

Running a blower may cool but often ICM Heat isn't what kills them but most just believe the hype. Most ICM like many Mil Spec E'parts are made to take higher heat then most others that really Hate Heat. Your CPU tries Throttling before shutdown but most consumer products crash or completely die over 130-180°F inside of the parts. While doing temp test in another tread I left a dash cam on and it crashed well before cabin reach max temp. Cooled down it still works. Storage temp is not the same as running temp for any electric parts.

Patrick and some others added a passive heatsink to the bottom of the dist below ICM. May help or not depending what is killing the ICM for a given owner.
But Passive heatsink shouldn't add to other problems. Unlike most PC Fan(s) sucking/pushing dirt into the heatsinks etc. I've seen Car fans/blowers w/ major dirt in them and/or what the air goes to/thru. Blower is a big reason why many heater boxes are full of crap and catch fire.
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
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock