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Car issues again by Monkeybean007
Started on: 03-23-2020 12:02 AM
Replies: 30 (324 views)
Last post by: Monkeybean007 on 03-26-2020 03:41 PM
Monkeybean007
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Report this Post03-23-2020 12:02 AM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
85 gt v6 2.8l -- My car runs amazing when I first start it up and start driving but when the car warms up it starts to random misfire, and I get low acceleration and power under load . I've replaced some stuff so far

-o2 sensor
-tps
-alternator
-new spark plugs
-new spark plug wires
- fuel filter
-fuel pump

I think thats everything I can think of off the top of my head, I also took apart egr and cleaned it out and gave it a good scrubbing. Any help would be appreciated I love this car and just want her to run well.

Gonna try cleaning and testing IAC tomorrow as that seems to be a common issue from all of the readings I've done on the forums here.

[This message has been edited by Monkeybean007 (edited 03-23-2020).]

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TM_Fiero
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Report this Post03-23-2020 06:55 AM Click Here to See the Profile for TM_FieroSend a Private Message to TM_FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
Maybe the ICM. They routinely go bad in Fieros. Members more knowledgeable about this will chime in. Any check engine lights?
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wftb
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Report this Post03-23-2020 08:49 AM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
The ceramic material inside the cat convertor tends to crumble with age and sometimes will almost completely block the exhaust flow. It is pretty random, sometimes the chunks will settle out and you dont notice it as much. Usually a good full throttle rip through first and second gears will have the engine choaked pretty well.

The ICM sometimes gets corroded and needs to be cleaned and a new layer of heat transfer paste put on. That would be consistent with it running rough after it warms up.

------------------
86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

[This message has been edited by wftb (edited 03-23-2020).]

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Gall757
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Report this Post03-23-2020 11:06 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Another Idea:

Engines running cold use default computer values, while a hot engine uses sensor inputs. IF one of the sensors is bad, it will only bother the engine when it is hot. The coolant temperature sensor, (CTS), is a candidate. ICMs will do this also because they expand when they get hot, and sometimes break solder joints on the internal board.

[This message has been edited by Gall757 (edited 03-23-2020).]

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Monkeybean007
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Report this Post03-23-2020 11:17 AM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
I've already replaced coolant sensor and no codes are being thrown unfortunately, replacing/removing cat is also on my list of things to do, I was thinking sensors as well, so icm seems to be the next thing I should check out?
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Report this Post03-23-2020 02:55 PM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
Any back-firing when its warm & stumbling?

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theogre
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Report this Post03-23-2020 04:35 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
What new plugs and plug wires?
New either could still have problems and more so w/ "gimmick" or "Performance" ignition parts

discon the tach filter and See my Cave, HE Ignition

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Monkeybean007
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Report this Post03-23-2020 05:05 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
It stumbles and dosent like to accelerate past half Throttle
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Monkeybean007
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Report this Post03-23-2020 07:08 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
Just replaced IAC valve as the other one was stuck out , didn't fix the issue , slowly loosing my mind.
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Patrick
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Report this Post03-23-2020 07:46 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 Monkeybean007:

85 gt v6 2.8l -- My car runs amazing when I first start it up and start driving but when the car warms up it starts to random misfire, and I get low acceleration and power under load.


Not sure why you'd think the Idle Air Control valve would have any effect on a random misfire and beyond half-throttle issue.

I agree with what Gall posted. Get a scanner (or WinALDL) on there to see what's going on with the sensors.

 
quote
Originally posted by Gall757:

Engines running cold use default computer values, while a hot engine uses sensor inputs. IF one of the sensors is bad, it will only bother the engine when it is hot.

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Monkeybean007
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Report this Post03-23-2020 07:49 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
Because it had a super rough idle, tested the IAC valve and no resistance or anything pulled it out and the mechanism was stuck open wouldnt adjust, hence the replacement.\
And I'm going tyhrough parts that change when the engine heats up, the IAC is one of those.
I also don't know where to get a scanner other than the one I have seen on the fiero store, and the car dosen't have a check engine light up, I know I'll still be able to check stuff without it but just thought that might be an important piece of info, Is there a scanner I can get off of amazon ?

[This message has been edited by Monkeybean007 (edited 03-23-2020).]

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Patrick
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Report this Post03-23-2020 09:11 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 Monkeybean007:

Is there a scanner I can get off of amazon ?


I use WinALDL with an appropriate cable and ancient laptop. Works great.

Have a look at This post. Click on the link there to his website.

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Monkeybean007
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Report this Post03-23-2020 10:16 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
whats the cable called for my fiero its not an obd1 as I tired that at the local parts store and it didnt fit, the oine they used was an alldata one but when I look those are super expensive kits lol.
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Gall757
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Report this Post03-24-2020 08:44 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
As Patrick instructed.....there is a link to the phonedawgz web page.

http://www.reddevilriver.co...DL_Serial_Cable.html

edit: listing the parts you have changed sounds great, but new parts are not as reliable as they used to be....

[This message has been edited by Gall757 (edited 03-24-2020).]

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wftb
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Report this Post03-24-2020 09:03 AM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
Buy a sawzall and cut the cat out and put a straight pipe in for now. You can buy
exhaust pipe and adapter pieces at any prts store. Your cat is a year older than mine and mine was plugged 14 years ago. Get a new high flow cat if it isnt plugged. They are not much money and better than the original.

------------------
86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

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Monkeybean007
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Report this Post03-24-2020 11:19 AM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by wftb:

Buy a sawzall and cut the cat out and put a straight pipe in for now. You can buy
exhaust pipe and adapter pieces at any prts store. Your cat is a year older than mine and mine was plugged 14 years ago. Get a new high flow cat if it isnt plugged. They are not much money and better than the original.



Thanks I'll definitely give that a try and I'll pick up a cable as that seems like the easiest solution because from what I'm hearing it'll essentially tell me what's wrong even though it's not throwing codes correct?
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Report this Post03-24-2020 11:33 AM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
That I don't know but if other people that have that equipment say it will work I would believe them. I just think you should do one thing at a time and not waste a bunch of money buying stuff you dont need. That being said, working diagnostic tools always come in handy sooner or later.

------------------
86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

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Monkeybean007
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Report this Post03-24-2020 11:35 AM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
That's what I've been doing just one thing at a time and seeing if it fixes the issue, if it doesn't the part needed to be replaced anyways as most sensors are old, just trying to narrow it down so I can have it running well while I replace everything else 😂
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Monkeybean007
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Report this Post03-24-2020 07:28 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
So alot of things im seeing for bad icm is that the car struggles to turn on , my car starts totally fine?
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Gall757
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Report this Post03-24-2020 08:42 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Monkeybean007:

So alot of things im seeing for bad icm is that the car struggles to turn on , my car starts totally fine?


ICMs fail in different ways. Some auto parts stores can stress test them. Autozone near me had a tester.
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Monkeybean007
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Report this Post03-24-2020 08:59 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
Where would the icm be for my car on the distributor,inside is it its own separate unit?
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Report this Post03-24-2020 09:03 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
The piece of plastic in the distributor where the two different cables plug in is the ICM. While you have the cap off look at the pick up coil. If it is falling apart it needs to be replaced. It requires the removal of the distributor to get it out. When removing the distributor always replace the O-ring or you will have an oil leak.

This is what a good pick up coil looks like.

[This message has been edited by phonedawgz (edited 03-24-2020).]

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Monkeybean007
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Report this Post03-25-2020 12:40 AM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
So icm has already been replaced and I tested it on my own and then took it to O'reillys and it passed their too so not the icm.
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Gall757
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Report this Post03-25-2020 08:41 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Monkeybean007:

It stumbles and dosent like to accelerate past half Throttle


That would suggest starving for fuel or a clogged CAT, but it should happen with the engine hot or cold.
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Monkeybean007
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Report this Post03-25-2020 10:55 AM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:


That would suggest starving for fuel or a clogged CAT, but it should happen with the engine hot or cold.


It's running super rich though and is burning through gas like crazy, so I don't believe it's getting starved of fuel 🤔
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Gall757
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Report this Post03-25-2020 12:12 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Monkeybean007:


It's running super rich though and is burning through gas like crazy, so I don't believe it's getting starved of fuel 🤔


With that bit of information, I would say the Coolant Temp Sensor is not working.
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Monkeybean007
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Report this Post03-25-2020 12:16 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:


With that bit of information, I would say the Coolant Temp Sensor is not working.


Already replaced it and verified that it's working.
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Gall757
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Report this Post03-25-2020 12:37 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
A sensor is sending bad information to the computer. Are there any leaks in the exhaust system? The O2 sensor may be working, but picking up bad information.
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Monkeybean007
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Report this Post03-25-2020 12:40 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
No leaks from what I can tell, and I mean it could be faulty o2 sensor I replaced it and it had right readings?
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Report this Post03-25-2020 10:09 PM Click Here to See the Profile for SpoonSend a Private Message to SpoonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Monkeybean007:

No leaks from what I can tell, and I mean it could be faulty o2 sensor I replaced it and it had right readings?


The 2.8 O2 sensor is the single wire type. So it's ground in the exhaust piping its screwed into. The exhaust is bolted to engine. Engine has several ground straps to body and chassis and they like to break over time. Pick up some 1" braided ground straps long enough to connect from engine block to car body and chassis.

Plan "B". Use a cheap $8 multimeter from Harbor Freight and check for resistance Ohms between body of O2 to engine and then to car body. The lower the reading the better.

https://www.amazon.com/Stan...d=1585192100&sr=8-18

It worked for me.

Spoon

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Monkeybean007
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Report this Post03-26-2020 03:41 PM Click Here to See the Profile for Monkeybean007Send a Private Message to Monkeybean007Edit/Delete MessageReply w/QuoteDirect Link to This Post
Tomorrow imma cut the cat out and temp replace it with a straight pipe, will probs get a high flow one in the near future and see if that fixes the issue and then I'll add more grounds I already went through and redid some and cleaned some others

[This message has been edited by Monkeybean007 (edited 03-26-2020).]

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