My 1985 GTS Coupe is misfiring please help.

Swooki
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My 1985 GTS Coupe is misfiring please help.

Postby Swooki » Fri Aug 16, 2019 2:57 pm

https://streamable.com/a4fu6
https://streamable.com/tj6f4

Here are the two links of my car idling.
I am not sure why it is doing that.
I have changed the spark plugs and still nothing.
The wires look brand new...

My friend said maybe fuel injector? How do i check?


And also, i heard people say to check coil and rotors and cap but I am not sure how. Please help me resolve this.

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jondee86
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Re: My 1985 GTS Coupe is misfiring please help.

Postby jondee86 » Sat Aug 17, 2019 2:18 pm

Doesn't sound like there is much wrong ? Was the engine still warming up
when you made those clips ? Does it actually misfire when under load, as in
while you are driving, accelerating etc ?

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Swooki
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Posts: 115
Joined: Wed Dec 21, 2016 1:48 pm

Re: My 1985 GTS Coupe is misfiring please help.

Postby Swooki » Sat Aug 17, 2019 9:09 pm

jondee86 wrote:Doesn't sound like there is much wrong ? Was the engine still warming up
when you made those clips ? Does it actually misfire when under load, as in
while you are driving, accelerating etc ?

Cheers... jondee86


Everybody I have talked to on Facebook Groups said it is misfiring.
I mean it feels fine but why does it sound like that?
It's definitely idling rough and I can feel it..

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jondee86
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Re: My 1985 GTS Coupe is misfiring please help.

Postby jondee86 » Sun Aug 18, 2019 2:32 am

With the greatest possible respect, facebook groups are not exactly where
I would go looking for informed opinion on mechanical woes. Internet diagnosis
is is a sketchy business at best, but you can sway the odds in your favour by
directing your questions (as you have done) to the intelligent, handsome, well
groomed and mechanically savvy members of forums such as Club4AG ;)

At idle an engine is consuming minimum air and minimum fuel. Intake velocity
is low and fuel atomisation is poor. This leads to unfavourable conditions for
combustion, particularly when the engine is cold. When the engine is cold the
ECU adds extra fuel and a lot of this will condense on the walls of the intake
runners and some will enter the cylinders as liquid rather than as a mist.

All of this causes an unstable fuel mixture to reach the cylinders causing varying
combustion conditions between the cylinders. As the engine warms up conditions
improve with better fuel vaporization and distribution. So you can expect a fully
warmed up engine to idle more smoothly than a cold engine. Looking at your video
clip you have high oil pressure and low temperature, so I guess that your engine
had only been running for a few minutes ? The mixture was most likely rich.

1. Post a clip when the engine is idling after you have been for brisk drive.
2. What did the old plugs look like when you pulled them out ?
3. Have you checked the cam belt tension ?
4. Have you checked the ignition timing ?
5. Have you checked the adjustment of the TPS IDL switch ?

True misfiring is most likely to occur when the engine is under load such as
accelerating hard in 4th up a long uphill grade with your best g/f in the passenger
seat. If it can do that smoothly without missing, then there is nothing wrong
with any of the basics.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

totta crolla
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Re: My 1985 GTS Coupe is misfiring please help.

Postby totta crolla » Sun Aug 18, 2019 2:36 am

I'm with Jondee on this, doesn't sound like there is much wrong. What exhaust and with how many boxes is fitted to the car?