supra head gasket questions+ rebuild

[ddmcse]

holy crap it actually says # 6 in the manual
thanks for the green arrow . i looked at those pages a few times on friday night and didn't see that line once

well it was friday night

[Bill UK]

Originally Posted by supramacist

Those coil packs don't look fun to me.
They look more pricey than the standard dist cap and rotor.
Plugs and wires cost the same.

What's the life expectantsy of a new oem set of those and what do they run, american if you please.?

I haven’t heard of anyone needing to replace theirs, so I assume they are fairly reliable. Toyota lists them as three separate part #`s, but you may need to order all three together. At a guess I would think they must be about $250 plus for all three. The best option is to buy them from ebay. Ebay 1 and Ebay 2 if any of the coils where faulty you could always swap them for one of your existing coils, that’s providing all three didn’t go down.

[Bill UK]

Originally Posted by ddmcse

holy crap it actually says # 6 in the manual
thanks for the green arrow . i looked at those pages a few times on friday night and didn't see that line once

well it was friday night

Hi ddmcse I have edited the original picture so you don’t miss it next time; you will need to refresh your cache (delete your cookies) some computers will hang on to the last image in the cache even though it doesn’t exist on the website, you may still see the old image with the yellow arrow.

[ddmcse]

i toss my cookies often
j/k
i have always timed with #1
after more investigation i find that my EM -17 isn't the same as yours
mine is compression

IG section looks like this
MK3 TSRM On-Line

[Andy C]

i must admit the whole thing was driving me nuts, it all makessense now though hey.

im going to be running my car about 11 psi just waiting for the exhaust, running 7psi at the moment with shimmed waste gate, does anyone now if running at 11psi will make the car run lean?

i have stock gasket and arp head studs torqued to 82 is thissafe to run 11psi?

cheers guys.

[ddmcse]

Andy here's a new term for you: FCO . wait till you find out what this is !

[Andy C]

HEY DDMCSE checked it out and found this, so im assuming the car cant run lean then just cuts the fuel.

what about the stock head gasket i fitted and arps will the head take it. cheers.

oh one last thing mate i have gurgling behind dash. wouldnt of thought head gasket. temperture fine water levels fine no smoke no water in the oil etc. plus only just finished head gasket replacement and gurgling was there straight away. suppose it could be air in the system




The boost pressure of the Toyota Supra can be raised to a certain limit. If the boost goes beyond this limit, the computer will cut of the fuel delivery for a certain period of time (about two or three seconds) because it assumes 'something is wrong'.
This boost cut or FCO (Fuel Cut-Off) is a nice thing to have, nobody wants their Supra to blow up of course. But there is one bad thing about it; it's way too early. The fuel gets cut off at about .70 kg/cm2 (that's about 10 PSI).
This really depends on the weather etc. In my situation this was (I live in Holland where it rains a lot), on other situations the boost cut can be a little bit higher, but after all, it's way too early.
Before I started to search for a solution to get rid of the annoying FCO, I first researched how the FCO gets activated and why exactly.
The computer of the car, monitors the amount of air sucked in via the Air Flow Meter (AFM) of which you see here a picture:

As you might be able to imagine, all air filtered by the intake gets through the AFM before it hits the wheels of the turbo. This AFM measures the amount of incoming air. Only a certain amount if air can be measured, e.g. the AFM has a physical limit. The exact limit I don't know.
The more air is sucked in by the turbo, the more fuel needs to be injected into the engine. This is achieved by giving the fuel injectors a 'longer' pulse. How long the pulse is, is normally counted in percentage 'duty cycle'. A duty cycle of 0% means no fuel at all and 100% means completely open. 100% is in practice impossible; the highest duty cycle in fuel injectors is something about 80%.
Now what is the physical limit causing the boost cut? This is a combination of the limits for both the AFM and the fuel injectors. At the boost cut level, the AFM cannot measure any much more air, and the fuel injectors are at their highest duty cycle. If people can confirm this (and the levels) please email me!
So the solution to this FCO problem, is somehow telling the computer the amount of air going thru the AFM is less than the actual intake air mass. This can be achieved by tampering with the Air Flow signal. A device taking care of this tampering is the HKS Fuel Cut Defenser (FCD).
The HKS fuel cut defenser
The fuel cut defenser from HKS tampers in such a way with the air flow signal, that the computer is told there is about 80% of the air sucked in, instead of the actual 100%. So the FCO is just a device to get rid of the fuel cut temporarily.
Although this can solve most of your problems, an FCD can be a highly dangerous device. As the computer is told there is about 80% of the original air flown in, the injectors are controlled to flow this amount of fuel as well, so in fact the engine will run more LEAN than originally planned. And this is NOT GOOD.
Lean conditions on engines can be really harmful. Pistons and valves can get too hot and your engine can be gone within minutes! So be warned, know what you do when you put in a FCD. When HKS designed this unit, they assumed your car was running way too rich, which is a fact. But running cars too rich is done to prevent lean conditions. So don't screw the air flow signal too much when you're not absolutely sure, ok?
Conclusion: The HKS FCD is a nice device for just a little tuning whatsoever, but when you start 'serious' stuff, keep your hands off the FCD.
So when we're not really 'allowed' to tamper with the airflow signal, how do we get rid of the boost cut then? Answer: Just REPLACE the airflow meter.
Replacing the AFM is a very common 'upgrade stage' in tuning cars. HKS has their own unit for replacing the airflow meter called the 'Vein Pressure Converter' VPC. This unit is quite expensive and totally not needed, as I found out after doing the Lexus Riemer upgrade.
The Lexus Riemer upgrade, is called as the two words stand for the most important ingredients: Lexus for the Lexus Air flow meter and Riemer for Reg Riemer, a Supra enthusiast from the states.
With this upgrade we replace the air flow meter of the Toyota Supra with one from a Lexus LS-400. This air flow meter is completely interchangeable with the Supra one; the electronics on the airflow meter even has the same serial number!
The only difference the Lexus AFM has with the one from the Supra is the size. The Lexus AFM is approximately 25% bigger, so the amount of air measured is about 25% less than the 'real' airflow.
Now when the computer gets this tampered signal, it will control the fuel injectors as if 25% less air was taken in; the duty cycle will drop with approximately 25% as well. Your car will run way too lean. To compensate this lean condition, the Lexus Riemer modification will tell you to replace your stock fuel injectors with 550cc fuel injectors.

[supramacist]

The gurgling behind the dash is what I call the ''waterfall''.
It means you have an air bubble in your coolant system.

Fill the catch can with a 50/50 mix.
Jack the nose up. And remove the radiator cap. While the engine is cool.

Inspect the cap. Particularly the rubber stopper.
If it's cracked and hard and worn or fatigued. You could be sucking pirate air into the system. Caps are like 15$ from the dealership.

If it looks good and you aren't getting buubles.
Go back to filling the catch can with 50/50 and drive normal.
Watching your instrument clusters and if all's well after your build.

The engine will work the bubble out on it's own.

If you actually have to ''burp'' at this point. That could be a sign that something is wrong. And you should inspect more deeply.

These ofcourse are opinions and there is a reason they are free.

[Andy C]

ok mate ill do that first thing tommorow morning getting a bit late now to do it and the engines rather warm too. lol.

burping?

hope your cars alright mate, and got whatever problem you had sorted.

[Spudboy]

Originally Posted by Andy C

as I found out after doing the Lexus Riemer upgrade.
The Lexus Riemer upgrade, is called as the two words stand for the most important ingredients: Lexus for the Lexus Air flow meter and Riemer for Reg Riemer, a Supra enthusiast from the states.
With this upgrade we replace the air flow meter of the Toyota Supra with one from a Lexus LS-400. This air flow meter is completely interchangeable with the Supra one; the electronics on the airflow meter even has the same serial number!
The only difference the Lexus AFM has with the one from the Supra is the size. The Lexus AFM is approximately 25% bigger, so the amount of air measured is about 25% less than the 'real' airflow.
Now when the computer gets this tampered signal, it will control the fuel injectors as if 25% less air was taken in; the duty cycle will drop with approximately 25% as well. Your car will run way too lean. To compensate this lean condition, the Lexus Riemer modification will tell you to replace your stock fuel injectors with 550cc fuel injectors.

With this Lexus AFM, do I use the stock AFM sensor (black electrical box)??

I'm thinking about getiing a AEM EMS (stand alone engine management).
I wonder if I can effectively map my air/fuel mixtures with this EMS without buying a Lexus AFM. What do you think.

I already have 550cc injectors, running lean with slight mis-fire especially noticeable at idle. Can you suggest a good place to buy this Lexus AFM and if I need a Lexus sensor? Maybe I make that change and everthing is great and I skip the EMS purchase. (save tons of money)