Pennock's Fiero Forum
  Technical Discussion & Questions
  85 fiero2.8

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


next newest topic | next oldest topic
85 fiero2.8 by Jecklen16
Started on: 12-21-2013 08:20 AM
Replies: 22 (357 views)
Last post by: 84fiero123 on 12-24-2013 10:30 AM
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-21-2013 08:20 AM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
So most things on my fiero are starting to come together thanks to your guys help. One thing that keeps bothering me though, is that when I accelerate hard, it feels like the engine pulses with power revving up to halfway to redline stopping for a sec sounding like its winding down then going past. Like its bogged down by something. Especially if I floor it in any gear but 4th and even that feels like power is being sapped. Any idea what to check?
IP: Logged
PFF
System Bot
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-21-2013 09:13 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

So most things on my fiero are starting to come together thanks to your guys help. One thing that keeps bothering me though, is that when I accelerate hard, it feels like the engine pulses with power revving up to halfway to redline stopping for a sec sounding like its winding down then going past. Like its bogged down by something. Especially if I floor it in any gear but 4th and even that feels like power is being sapped. Any idea what to check?


Is the check engine light on? What kind of condition are the ignition components in?

Usually a "flat-spot" in acceleration can be caused by bad sensor information to the ECM...

Unless the Fiero has really low miles, all the sensors are probably really old at this point, I would maybe also suspect an improperly adjusted TPS.
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-21-2013 09:33 AM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
No check engine light is on. I just replaced the temperature sensor for the ecu which others should I replace? What's the TPS and how do I adjust it?
IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-21-2013 10:08 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

No check engine light is on. I just replaced the temperature sensor for the ecu which others should I replace? What's the TPS and how do I adjust it?


Well, when I was planning for the complete restoration of my Fiero, I replaced all the sensors which included the MAP, the TPS, the IAC, the vacuum sensor, the IAT (intake air temperature sensor), the O2 sensor, etc.


There are others that are much smarter than me on here, but I think the IAC does nothing for driveability, just at idle and when stopped, and the O2 sensor does nothing when you're at wide open throttle.

The IAT is one that always goes bad but never properly indicates through a check engine light. This is the one located on the air filter canister. It's not ideally located either... but I keep it there because I want it to look stock.

The MAP and vacuum sensor probably has a lot to do with your drivability issues. But the TPS could be the culprit. I know HOW to adjust it, but I don't know how to "properly" adjust it. Basically, you need to slightly adjust the TPS arm on the throttle body so that it correctly represents to the ECM the actual position of the throttle. I THINK this could be your issue.

I would also check to make sure that your ignition system is up to par... assuming your plugs, cap & rotor, and the ignition control module (located under the cap in the distributor) are all new or in good order.

IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-21-2013 10:23 AM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
So I need to find a way to properly adjust the TPS and the ignition module in the distributor? How can I test the ignition control module? Is there any tutorial on adjusting the TPS? other than that the rest of the ignition system has been replaced.
IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-21-2013 05:21 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

So I need to find a way to properly adjust the TPS and the ignition module in the distributor? How can I test the ignition control module? Is there any tutorial on adjusting the TPS? other than that the rest of the ignition system has been replaced.



Well, the ignition control module is either good, or bad... most parts stores should be able to test it for you, but I suspect it might be ok.

The TPS just needs to have the little arm bent.

I gues what I would check is... open the throttle 100% and see if there's any more play in the TPS. The throttle has a little arm that rides on top of the TPS "lever." Ideally, the throttle body should correctly put the TPS arm through it's entire throw (if that makes sense). If the throttle body is fully opened, but the TPS arm can still be moved further in that direction, then it would indicate that it's not properly giving the signals it should.

A hesitation basically means the air/fuel/timing isn't being set right. Air is simple... nothing is clogged, and when you open the throttle body 100%, you're getting maximum flow... so you need to make sure that you're getting the appropriate level of fuel to match that amount of air, and the spark needs to be able to support that.

A cheap test/fix would be to run a can of seafoam in your gastank (white cylindrical can that says Seafoam in red cursive). Pour the entire contents in at the gas station before you fill up. Then drive the car and beat the piss out of it. If you've NEVER done this before, you may see an enormous cloud of white smoke that will scare you to s**t because you'll think your car is on fire. What's really happening is that all of the carbon deposits on the valves and the piston tops are burning off in the combustion chamber. So I would definitely do that first. This will also clean your injectors to ensure you're getting good fuel flow.

Now assuming that everything in the distributor... IE: cap, rotor... and the plugs are properly gapped and the wires are good... and your timing is set right, then everything should be good.


Hope some of that helps...
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-21-2013 05:39 PM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thank you very much for your help. I've been putting mystery oil or whatever its called in my tank the last 2 fillips but haven't noticed any smoke. I'll grab a can of seafoam. Do spark plugs come pre gapped? If not I'm about to hate life. I'll change the fuel filter just in case as well because my fuel pump seems to be really loud.
IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-21-2013 06:27 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

Thank you very much for your help. I've been putting mystery oil or whatever its called in my tank the last 2 fillips but haven't noticed any smoke. I'll grab a can of seafoam. Do spark plugs come pre gapped? If not I'm about to hate life. I'll change the fuel filter just in case as well because my fuel pump seems to be really loud.



Yeah, things like the fuel filter and other maintenance items should be taken care of too if you haven't already done them in a few years.
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-21-2013 06:38 PM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
This car is a new purchase and in pretty bad shape so I doubt much upkeep has been done.
IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-21-2013 08:26 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

This car is a new purchase and in pretty bad shape so I doubt much upkeep has been done.



Ahh... ok. Good point of reference is to just do the maintenance on everything so you know at what point you're starting.

I also just realized I didn't answer your question. Spark plugs USUALLY come pre-gapped... but a spark plug can be used in a number of different engine configurations so it's not always correct... and truthfully, the gapping is usually messed up in shipping because the plugs are banging around (unless they came with the protector cap on them that some decent ones do).
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-21-2013 08:51 PM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
I looked them up they are pre-gapped and they had protectors on them. Just for peace of mind I'm still going to pull them ha. Alright looks like I'm going to replace all the sensors. Also looks like the previous owner put a performance coil on it and did a crappy job hooking it up. Just hooked up the new tach filter as well to replace the one the PO removed... Tach still doesn't work though. Lots of work ahead!
IP: Logged
PFF
System Bot
Dodgerunner
Member
Posts: 9682
From: Lincoln, Nebraska
Registered: Sep 2004


Feedback score:    (61)
Leave feedback





Total ratings: 323
Rate this member

Report this Post12-21-2013 11:44 PM Click Here to See the Profile for DodgerunnerClick Here to visit Dodgerunner's HomePageClick Here to Email DodgerunnerSend a Private Message to DodgerunnerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 82-T/A [At Work]:

Well, the ignition control module is either good, or bad... most parts stores should be able to test it for you, but I suspect it might be ok.

...


Humm I can say this is not true. I had one that would run just fine up to around 69-70 mph and then start cutting out. Stay below that and it ran just fine. Drove all the way from Lincoln NE to Gunnison CO and back with it. Just when I'd hit 70 it would say "Hey cut that out"

You might also check fuel pressure to see what it is doing at high loads and speed.
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-22-2013 08:13 AM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
What should my fuel pressure be at idle and what under load?
IP: Logged
fierofool
Member
Posts: 11834
From: Auburn, Georgia USA
Registered: Jan 2002


Feedback score:    (13)
Leave feedback





Total ratings: 151
Rate this member

Report this Post12-22-2013 09:23 AM 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
As 82 said, every spark plug comes pre-gapped. But to what specification? It's always best to check gap on any new plug and be sure it's set to your vehicle's requirement.

Fuel pressure should be about 42-45 psi without the engine running. It shouldn't drop below 38-40 with the engine running at idle speed.

Agreed that ignition modules can be kinda-good or kinda-bad. I've had units fail, replace them with another, and later reinstall the failed unit and it would work. My Brother's car had a surging and miss at road speeds and it turned out to be the ICM.

The ICM can also allow the fuel system to prime, but won't allow the fuel pump to run at startup. Check the pins in the ICM harness to be sure they're inserted fully into the harness plug. You should be able to see the metal if you look at the end of the harnesses.
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-22-2013 02:40 PM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
Just cleaned all connections to ICM, TPS and all electrical connections and put dielectric grease on everything and now she runs PERFECT! Thank you for all of your help everyone! On to my tachometer issue!
IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-23-2013 11:10 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

Just cleaned all connections to ICM, TPS and all electrical connections and put dielectric grease on everything and now she runs PERFECT! Thank you for all of your help everyone! On to my tachometer issue!



Awesome... definitely run a can of Seafoam though (and change the fuel filter) you will be even more pleased... I guarantee it!
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-23-2013 01:54 PM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
Okay so belay my last. She now runs the same as she did previously. Obviously my first thought was one of the electrical connections (all of their clasps were broken off so they are pretty much just staying connected with hope) became disconnected or loose. I tested all of them and I found one to have a strange response. When I press on this connection the engine revs higher for a second then back to normal. If I stop pressing on it it revs higher for a second then evens out. It looks like the connection is half melted though the pin is in good condition. I included a picture down below with the connection I am pressing on circled in red. I guess my questions are, 1. What is this 2. Best course of action to fix it. 3. What should I do to all of my connections to make sure this doesn't happen?

This images is larger than 153600 bytes. Click to view.
IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-23-2013 02:59 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Jecklen16:

Okay so belay my last. She now runs the same as she did previously. Obviously my first thought was one of the electrical connections (all of their clasps were broken off so they are pretty much just staying connected with hope) became disconnected or loose. I tested all of them and I found one to have a strange response. When I press on this connection the engine revs higher for a second then back to normal. If I stop pressing on it it revs higher for a second then evens out. It looks like the connection is half melted though the pin is in good condition. I included a picture down below with the connection I am pressing on circled in red. I guess my questions are, 1. What is this 2. Best course of action to fix it. 3. What should I do to all of my connections to make sure this doesn't happen?



So, the top one is your Throttle Position Sensor (TPS) and your second one (below) is your Idle Air Control (IAC) valve.

Both of them are pretty badly melted. I can only guess as to what caused it, but I suspect it could have been as a result of any number of things, maybe as a result of a cracked EGR tube blowing hot exhaust directly onto the wires (the EGR tube is that heat shield wrapped tube directly below those wires). Or, there might have even been a fire in there at some point... mabe something fell on the exhaust Y-pipe and burned?

Either way, I would definitely try to fix those wires ASAP... they're certainly not doing you any good there and probably aren't providing proper connection.

TPS Connector: http://www.fierostore.com/P.../Detail.aspx?s=65508
IAC Valve Connector: http://www.fierostore.com/P.../Detail.aspx?s=65506

If the wiring isn't completely shot... then you could probably try to disconnect or break the existing connector and keep the pins intact on the existing wire, and then just insert them correctly into the new block. Do this one by one so you don't mess up the orientation of the wires in the plug connector (otherwise your problems will get much more complicated).

If you do decide to cut / splice the wires, make sure you soldier them, and not just use crimp connectors.
IP: Logged
Jecklen16
Member
Posts: 71
From: norfolk va usa
Registered: Oct 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post12-23-2013 03:21 PM Click Here to See the Profile for Jecklen16Click Here to Email Jecklen16Send a Private Message to Jecklen16Edit/Delete MessageReply w/QuoteDirect Link to This Post
Wow those are expensive connectors. They should be here in a few days I'll let you know how it goes. Thank you very much for all of your help!
IP: Logged
fierofool
Member
Posts: 11834
From: Auburn, Georgia USA
Registered: Jan 2002


Feedback score:    (13)
Leave feedback





Total ratings: 151
Rate this member

Report this Post12-23-2013 06:10 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
This site has lots of terminals used on the Fiero. Cheaper than most other places, too. http://www.clipsandfasteners.com/

Rock Auto also has a good selection.

Edit" Clips and Fasteners was the wrong link, but it might be of use for other things.

[This message has been edited by fierofool (edited 12-23-2013).]

IP: Logged
82-T/A [At Work]
Member
Posts: 18328
From: Florida USA
Registered: Aug 2002


Feedback score: (1)
Leave feedback





Total ratings: 185
Rate this member

Report this Post12-23-2013 06:16 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fierofool:

This site has lots of terminals used on the Fiero. Cheaper than most other places, too. http://www.clipsandfasteners.com/

Rock Auto also has a good selection.



OMG... where has this link been all of my life (or at least the part of my life after the internet became popular).

I can't believe how much stuff is on there... amazing.


Thanks for posting that!
IP: Logged
PFF
System Bot
fierofool
Member
Posts: 11834
From: Auburn, Georgia USA
Registered: Jan 2002


Feedback score:    (13)
Leave feedback





Total ratings: 151
Rate this member

Report this Post12-23-2013 08:41 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
Add this one to your bookmarks. http://www.perfectfit.com/1.../AUVECO-Catalog.html

Using the P22 Fiero Parts List, you can cross reference OEM numbers, too.
IP: Logged
84fiero123
Member
Posts: 29950
From: farmington, maine usa
Registered: Oct 2004


Feedback score: N/A
Leave feedback





Total ratings: 325
Rate this member

Report this Post12-24-2013 10:30 AM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
When that connector went on mine I went to NAPA and they had them right on the shelf, price wasn't bad ether, never shy away from checking your local parts stores and even dealer when buying parts. you would be surprise just how many parts are still available as many fit many years and vehicles. You don't have to wait, usually and you don't have to pay for shipping and if they don't have it in stock they can usually get it in a day or 2 if its the weekend.

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 12-24-2013).]

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