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High RPMs by FireGirl
Started on: 03-13-2016 05:25 PM
Replies: 14 (453 views)
Last post by: FireGirl on 03-31-2016 10:12 PM
FireGirl
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Report this Post03-13-2016 05:25 PM Click Here to See the Profile for FireGirlSend a Private Message to FireGirlEdit/Delete MessageReply w/QuoteDirect Link to This Post
Lots of options under search for this as I don't know what's causing it. Hose leaks, EGR issues, I don't know...

RPMs sit at 3000 when cold and 1900 when idling warmed up, it felt like the RPMs went up really high when driving, and my suspicion was proven when going 70mph and at 4500RPM, when the yellow zone is at 5500RPM....

It seems to drive fine other than that though, it's been a while since I worked on my fiero but I just did a full service on it within the last couple of years, replaced spark plugs and wires, put in a new distributor and I feel like I put in a new EGR. I haven't touched any hoses yet.

Basically I don't know what I should specifically search for to help get my RPMs down...suggestions? Pictures really help with me...


Edit on the RPMs.
And it is a manual 86GT
4 speed

[This message has been edited by FireGirl (edited 03-21-2016).]

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fieroguru
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Report this Post03-13-2016 06:46 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would start by verifying RPM on the tach to actual RPMs via the ecm (use scanner or data logger).

As the tachs age and get close to failure they read higher.
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FireGirl
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Report this Post03-14-2016 03:50 AM Click Here to See the Profile for FireGirlSend a Private Message to FireGirlEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroguru:

I would start by verifying RPM on the tach to actual RPMs via the ecm (use scanner or data logger).

As the tachs age and get close to failure they read higher.


I will try that but it took a quarter of a tank driving for 45 minutes! I don't feel like that is normal?
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olejoedad
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Report this Post03-14-2016 09:46 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
45 minutes X 60 MPH = 45 miles.
At 25 MPG that's almost two gallons, pretty close to 1/4 tank in a Fiero......
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css9450
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Report this Post03-14-2016 09:58 AM Click Here to See the Profile for css9450Click Here to Email css9450Send a Private Message to css9450Edit/Delete MessageReply w/QuoteDirect Link to This Post
Yeah the gas gauge and the tach aren't really noted for their accuracy on the Fiero.... Need to get a scan tool on it to know for sure.

Someone mentioned the fancier timing lights show RPMs too. Mine doesn't, but I have only the simplest model.
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Blacktree
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Report this Post03-14-2016 11:50 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Does your Fiero have an automatic transmission? If so, then the torque converter should lock at around 35mph (if you're not accelerating hard). When the torque converter locks, it will feel almost like a gear shift... the engine RPM will drop a little bit and you'll feel a slight nudge.

If your torque converter isn't locking, the engine will have higher RPM at highway speed, and fuel economy will suffer. There's a square electrical plug on the transmission for the torque converter lock-up control. If that connector comes loose, the torque converter won't be able to lock. That connector is on the front (i.e. firewall side) of the transmission, basically behind the driver's seat. It's a square plug that can hold 4 wires, but only has 2 wires in it.

Hope that helps.
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Fiero84Freak
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Report this Post03-15-2016 04:39 PM Click Here to See the Profile for Fiero84FreakClick Here to Email Fiero84FreakSend a Private Message to Fiero84FreakEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FireGirl:
RPMs sit between 1000-2000 when idling if I recall correctly, it felt like the RPMs went up really high when driving, and my suspicion was proven when going 70mph and at 3500RPM, when the yellow zone is at 4500RPM....


To go a bit further off what Blacktree said above, if the car is an automatic remember than the three speed TH125 is ultimately geared for a 55 MPH cruising speed when the US national highway speed limits were 55. Obviously driving 55 MPH on an interstate nowadays will get you ran over, and if your torque converter isn't locking up then it'll likely sound like the car is trying to kill itself at speed with high noise. The manual transmission cars tend to not pull such high RPMs even with increased cruising speed due to their gear range. If you're driving 65-70 MPH you're going to naturally be turning higher RPMs than intended. Honestly what you stated is a bit high, but you will typically see higher RPMs cruising simply due to elevated traveling speed than intended.

Confirming proper gauge operation is key also. In all four Fieros I've owned every one of them had some sort of gauge or gauges that didn't read correctly.

Also Note: Please state what year, model, engine, trans, Fiero you have to make fielding technical questions easier. Your problem could be trim level dependent.
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Patrick
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Report this Post03-15-2016 05:16 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 Fiero84Freak:

Please state what year, model, engine, trans, Fiero you have to make fielding technical questions easier.


Yeah, asking questions regarding highway gas mileage while supplying absolutely NO information regarding engine or transmission type is a little silly to say the least.

[This message has been edited by Patrick (edited 03-15-2016).]

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dratts
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Report this Post03-15-2016 05:48 PM Click Here to See the Profile for drattsClick Here to Email drattsSend a Private Message to drattsEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Yeah, asking questions regarding highway gas mileage while supplying absolutely NO information regarding engine or transmission type is a little silly to say the least.



Easy there big guy! Some of us are not wrench twisters.
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Patrick
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Report this Post03-15-2016 06:13 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 dratts:

Easy there big guy! Some of us are not wrench twisters.


I'm not a doctor, but I suspect blood type is basic background info prior to a transfusion.
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dratts
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Report this Post03-15-2016 06:37 PM Click Here to See the Profile for drattsClick Here to Email drattsSend a Private Message to drattsEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by Patrick:

I'm not a doctor, but I suspect blood type is basic background info prior to a transfusion.


Didn't mean to come down hard. You still are rated + by me. I don't think she's a hard core Fiero owner
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Patrick
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Report this Post03-15-2016 07:27 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 dratts:

Didn't mean to come down hard. You still are rated + by me. I don't think she's a hard core Fiero owner.


Dratts... relax, this isn't O/T. I was just teasing the OP, and I didn't feel you were coming "down hard" on me at all. Let's all lighten up.
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FireGirl
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Report this Post03-21-2016 11:21 PM Click Here to See the Profile for FireGirlSend a Private Message to FireGirlEdit/Delete MessageReply w/QuoteDirect Link to This Post
lol sorry guys! It has been awhile since I've worked or even touched the fiero. Now getting back into it by myself, I apologize in advance in my lack of lingo. I did update my original post of what we're dealing with.

Sorry to leave out basic info
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Australian
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Report this Post03-22-2016 03:53 AM Click Here to See the Profile for AustralianClick Here to visit Australian's HomePageClick Here to Email AustralianSend a Private Message to AustralianEdit/Delete MessageReply w/QuoteDirect Link to This Post
Could even be a freyed inner throttle cable.
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FireGirl
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Report this Post03-31-2016 10:12 PM Click Here to See the Profile for FireGirlSend a Private Message to FireGirlEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Australian:

Could even be a freyed inner throttle cable.


Hehe I just got back from a year Australia, only spent 2 days in Sydney! Was beautiful (Sorry off topic I know).
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