AE82 4AGE Trouble.

YFZR750
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AE82 4AGE Trouble.

Postby YFZR750 » Mon Sep 29, 2014 4:16 am

Hi everyone, new to the forum and I need some help.


I have a Ae82 1985 4AGE Big port T-VIS.

The problem is that the the engine dies momentarily. If I accelerate and reach 5000rpm, it is almost like the spark has been cut. If I keep on the accelerator it will decelerate and then when the revs drop to 4000rpm it would suddenly start going again. And after about 30 mins of driving it would get worse and start dying at 3000rpm. But if I step on the clutch it would rev to the rev limiter.
But somehow when the engine is cool(at operating temp) it doesn't die, but as it becomes warmer the problem comes in.

And when cruising for about on the highway for about 15mins the engine would just die completely. But would start up after it dies.

Things that have been done.

Swapped ECU.
Tank was cleaned completely.
Fuel filter changed.
Fuel pump has been replaced not too long ago.
Bottle of Injector cleaner added.

Could this problem be spark or fuel related?

And also where could I find some instructions of how the diagnostic process is done ?

Many Thanks!

YFZR750
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Re: AE82 4AGE Trouble.

Postby YFZR750 » Mon Sep 29, 2014 4:22 am

Forgot to add, when the engine dies at 5000rpm, and I shift everything is ok untill I reach 5000rpm in the next gear. But the rpm at when it dies lowers as the engine gets hotter.

Eg, when pulling out onto the road it will not die at all.

But when it warms up it would die at 5000rpm.

And when it gets even warmer it would die at 3000rpm.

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jondee86
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Re: AE82 4AGE Trouble.

Postby jondee86 » Tue Sep 30, 2014 10:25 pm

Based on nothing more than numerous similar "dies when hot" posts,
I would suggest you borrow a spare coil and igniter to swap in. Maybe
swap the igniter first (make sure it is well bolted down as it grounds
thru the outer casing). If that has no effect, put your original igniter
back on, and then swap the coil.

Cheers... jondee86
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persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

YFZR750
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Re: AE82 4AGE Trouble.

Postby YFZR750 » Tue Sep 30, 2014 10:43 pm

Hi,

I have tried swapping out the coil and ignitor with no avail.

But it also seems that when the air is cold then it does not do it that much, if not at all...

Regards

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jondee86
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Re: AE82 4AGE Trouble.

Postby jondee86 » Wed Oct 01, 2014 12:14 am

OK... next most popular suggestion is swap out the COR (Circuit Opening Relay).
And while we are talking relays, you could try checking the temperature of all the
relays in the underhood fusebox after the car has been running for a while. Any
relay that gets HOT is suspect. A little bit warm is not a problem, but a hot relay
is not a happy relay.

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.

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Re: AE82 4AGE Trouble.

Postby YFZR750 » Wed Oct 01, 2014 2:13 am

Hi,

I have been to the relays, the one named "EFI MAIN" gets hot. And also the other round one that is closest to it. But the one named "HEAD" is completely cool.

Should I try replacing the two hot ones and see if there's a difference ?

Thanks

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jondee86
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Re: AE82 4AGE Trouble.

Postby jondee86 » Wed Oct 01, 2014 2:43 pm

If it gets hot enough that you don't want to rest your hand on it, then
that's too hot. The EFI relay powers up the ECU, so if that one has an
intermittent fault, it can switch the engine off. Try swapping in another
relay and see if it makes a difference.

The round one is most likely the ENG MAIN relay, which is more to do
with the alternator, and should not kill the engine. And the HEAD relay
is for the headlights.

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.

YFZR750
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Re: AE82 4AGE Trouble.

Postby YFZR750 » Wed Oct 01, 2014 9:42 pm

Hi,

The relays do not get so hot that I can't hold my hand on them.

But what I have done is tried to bridge the wires just to see if it made a difference.

When looking at the side of the relay connectors, ( its on the right hand side of the car when you look from the front)
I bridged A1 and B2, (like on a exel spreadsheet) so I heard a "click" from the blower relay. So I took it out for a drive so it did the same thing, dies at 5500rpm.
So I bridged A1 and B1 and it pulled 100% properly in all the gears. So the next day, weather was warmer than the previous day. After some time of driving it started doing it again.

So I guess this problem is not related to the relay?

Thanks

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jondee86
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Re: AE82 4AGE Trouble.

Postby jondee86 » Thu Oct 02, 2014 1:09 am

Image

Not really a good idea to start bridging stuff at random... but since your
car did not burn to the ground or blow a bunch of fuses, I guess no harm
was done. And if the problem is still there when the relay is not in place,
then obviously that is not where the problem is located.

You could check the COR to see if it is getting hot of making any strange
noises. It's the one with the yellow plug in this pic... high up under the dash
on the passenger side.

Image

When the engine cuts out, does it pop or bang (exhaust backfire) when it
come back to life ? When it cuts out, does it cut sharp and clean like the
key was switched off, or does it kind of fade out like it ran out of fuel ?

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.

YFZR750
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Re: AE82 4AGE Trouble.

Postby YFZR750 » Thu Oct 02, 2014 3:10 am

Hi,

I'll give the COP a check. If I may ask, what does it do ?

Its sharp and clean when it dies, no backfire or missfire when it dies or when it comes back to life.


Thanks

YFZR750
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Re: AE82 4AGE Trouble.

Postby YFZR750 » Thu Oct 02, 2014 3:39 am

At 5500rpm it would die and when I shift, no matter how quick. It will be as if I changed with the engine not dying. Like there is not a "stage" at when it comes to life.

Its almost as if it would die and if I step on the clutch it would just go back down to idle. Smoothly without poping or backfiring.

And also if I accelerate til it dies and I relase the accelerator it would come back to life as the revs drop.

Thanks.

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jondee86
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Re: AE82 4AGE Trouble.

Postby jondee86 » Thu Oct 02, 2014 3:45 pm

Check the diagnostic codes.

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.

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ToeKnee805
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Re: AE82 4AGE Trouble.

Postby ToeKnee805 » Thu Oct 02, 2014 10:49 pm

I second the COR, mine had the same exact symptoms and the COR was culprit. About a year later it did it again, and my EFI relay was getting overly hot, replaced it and good as new. If the COR and EFI relays arent the issue, check your TPS ground, its the one thats grounded on the intake manifold under the injectors. WHen i swapped a new bluetop in, i had forgotten to ground the TPS and it would ALWAYS cut at 5500RPM not just when hot though.
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YFZR750
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Re: AE82 4AGE Trouble.

Postby YFZR750 » Thu Oct 02, 2014 10:59 pm

Hi,

I will first run the diagnostics and if nothing comes up ill try replacing the COR and EFI Main relay and see if it solves the problem.

I would also like to know what is the function of the COR ?

Many thanks

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jondee86
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Re: AE82 4AGE Trouble.

Postby jondee86 » Fri Oct 03, 2014 1:32 am

YFZR750 wrote:I would also like to know what is the function of the COR ?

The Circuit Opening Relay turns the fuel pump on. There are two coils inside.
either of which will close the same set of contacts when energised. Those
contacts supply 12V to the pump. One coil is energised when the engine is
cranking, and only when the engine is cranking. The other coil is energised
when the flapper inside the AFM opens.

So, the pump runs during cranking to get the engine started, and as soon
as it starts, the AFM opens and keeps the pump running when you let go of
the key. If the engine stops (for example, because you hit a pole) the flapper
in the AFM will close and stop the pump even tho the ignition is still on. It is
a safety measure. The idea is to stop the pump feeding gas into any fire
that might start after a crash.

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.

YFZR750
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Joined: Mon Sep 29, 2014 3:49 am

Re: AE82 4AGE Trouble.

Postby YFZR750 » Thu Oct 30, 2014 8:45 am

Hi guys,

Managed to find the problem, inside the fuel tank there is a bucket that the strainer of the fuel pump sits in. And there is one pipe that let's fuel flow into the the bucket when the fuel is lower than half.

Turned out that that pipe that connects the inside of the tank to the bucket was blocked and every time the pump ran out of fuel the engine would die. And at the same time it was killing the pump as it got air then fuel then air again etc. And soon after the pump gave in.

Fix ? Made 3 7mm holes in the bucket for better flow. And replaced fuel pump, and she runs perfectly now.

Hope this helps someone in the future.

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Re: AE82 4AGE Trouble.

Postby oldae82 » Sun Nov 02, 2014 7:06 am

Good detective work. I've been following this thread, had NO ideas to offer, and was really curious to know the answer. My fx cuts out on sweeping left handers when the gauge is at 1/4 or less. I'd made an assumption it was a lack of baffles, but I'll re-examine it in light of what you've found.