Is it bad to hit fuel cut / Dodgy indicators?

Discussion and technical advice the SW20 MR2. 3S-GTE, 3S-GE, 3S-FE etc
Anything and everything to do with maintenance, modifications and electrical is in here for the Mk2.

Moderators: IMOC Moderators, IMOC Committee Members

Post Reply
Ginjaninja92
Posts: 185
Joined: Wed Jul 27, 2011 2:58 pm
Location: Glasgow

Is it bad to hit fuel cut / Dodgy indicators?

Post by Ginjaninja92 »

Hey ya'll,

Two completely different questions.

Firstly, is it bad to hit fuel cut? I'm in a rev 3 turbo with exhaust, intake, SMIC, Apexi Bov and EBC.
With the EBC set to 1.1 bar it will creep to 1.35 and hit fuel cut, only started creeping after I upgraded the SMIC. I guess coz it flows too well now?

Secondly, my left indicator has went funny. Front and side indicators dont work and back flashes super quick? Is it maybe a bad earth or relay?

Any help appreciated :thumleft:

Dan
androo007
Posts: 2363
Joined: Mon Mar 03, 2014 1:43 pm

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by androo007 »

Yes very bad make sure you don't do it again. Your ebc is not set up correctly - prob too much gain set.

Hitting fuel cut is going off the grid....it's the last piece of self defence the ecu has.
Dame
Posts: 307
Joined: Thu Jun 16, 2005 7:59 am
Location: Cheltenham
Contact:

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by Dame »

Indicators, sounds like a bad connection to the bulbs at the front of the car, could be earth though I think they share it with the side lights. Are those working?

Definitely not the indicator relay, nothing would be flashing otherwise. The reason why the rears are flashing quicker now is to indicate that one or more bulbs are not working.
Ginjaninja92
Posts: 185
Joined: Wed Jul 27, 2011 2:58 pm
Location: Glasgow

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by Ginjaninja92 »

I know in basic terms what fuel cut is and why its there, I know it's obviously not good but I'd like to know what is actually happening when the ECU cuts fuel.
I'm I likely to be doing damage any time I boost to 1.3 bar and hit fuel cut?

Thanks for the info Dame, my dad suggested it could be a bad earth so I'll check that out. Am I right in saying it'll just be earthed in behind the sidelight unit?
archangel
Posts: 264
Joined: Sun Jun 26, 2011 1:31 pm
Location: London

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by archangel »

Yeah not good to be driving to fuel cut level. It may start leaning out just before and you are risk of det. Which EBC do you have? They normally have settings to control boost creep so that you can control the wastegate behaviour even when you have hit your target boost.
androo007
Posts: 2363
Joined: Mon Mar 03, 2014 1:43 pm

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by androo007 »

Fuel cut is exactly that - the ecu reads a boost level that is unsafe for the engine so stops you pushing anymore as certain death will follow.

Is it bad? Yes. If you want to keep pushing the car to the extreme edges of what it can handle it won't last long. It's not even efficient at 1.3 bar just blowing hot hot air.
kurkjones
Posts: 152
Joined: Mon Nov 09, 2015 6:40 pm

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by kurkjones »

Jumping into this thread, I have similar issue hitting fuel cut with my rev1 turbo. I was told the CT26 and stock internals can hold 1.0 bar comfortably on the Rev1s as they are stock set to something like 0.87 bar. I put a blitz exhaust on and now hit fuel cut, although I did fit a MBC (grainger valve) and that stops me hitting fuel cut for now. But I want to fit a HKS FCD and raise it to 1.0 bar. Will the rest of the setup not cope OK at this pressure?
Toyota MR2 - 3S-GTE - 1991 Turbo - Yellow
Al-sw20
Posts: 1623
Joined: Sun Jan 23, 2005 6:01 am
Location: Christchurch, New Zealand
Contact:

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by Al-sw20 »

The HKS FCD will only let you raise the cut to 17psi, or eliminate the cut all together.

Car will be fine at 1 bar as long as it's in good shape. New ignition, fuel filter, 98+ RON fuel used, coolant system in good shape.
kurkjones
Posts: 152
Joined: Mon Nov 09, 2015 6:40 pm

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by kurkjones »

Al-sw20 wrote:The HKS FCD will only let you raise the cut to 17psi, or eliminate the cut all together.

Car will be fine at 1 bar as long as it's in good shape. New ignition, fuel filter, 98+ RON fuel used, coolant system in good shape.


Have you fitted one? Just had a look at ECU and can see there are three brown cables, any one of them could be earth... So annoying when nothing is clear in the instructions!
I heard you can also disable the stock turbo pressure sensor(near diagnostics box) by taking out vacuum hose from it and where it goes, then can just vacuum my aftermarket gauge into that place and it does away with the stock gauge sending info to the stock FCD, anyone heard of this?
Toyota MR2 - 3S-GTE - 1991 Turbo - Yellow
Al-sw20
Posts: 1623
Joined: Sun Jan 23, 2005 6:01 am
Location: Christchurch, New Zealand
Contact:

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by Al-sw20 »

Yep pulling the hose from the base of the boost pressure sensor and then using that port on the manifold for my aftermarket boost gauge is how I deleted the fuel cut.

It does delete the boost cut entirely. You only have the stock knock sensor as back up protection. If you are comfortable with this, go for it.
Ginjaninja92
Posts: 185
Joined: Wed Jul 27, 2011 2:58 pm
Location: Glasgow

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by Ginjaninja92 »

Bringing this back up,

I've been out changing the settings on the Profec B Spec II this afternoon to see what's going on. The settings were as follows:

(lo) -
Set 55%
Gain 0%
Start Boost 0 bar
Warning 0.95 bar
Limiter 0%

(hi)
Set 75%
Gain 0%
Start Boost 0 bar
Warning 1.15 bar
Limiter 0%

In this state, when set to (hi), I would often over boost to 1.25 bar and occasionally hit fuel cut at 1.35 bar. Not good!

So in (hi) I upped the Gain and Start Boost in increments of 10 (% & bar), which felt like it increased response (as expected), until they were at 80% Gain and 1.00 bar Start Boost, but with this I would peak at 0.82 bar. So I upped the Set in increments of 5%, which steadily increased the peak until I had it at 100%, where boost peaked at around 1.1 bar. Good!

So...

For those with experience, do these sound like normal safe settings to run? Anyone know their settings for comparison?

P.S trying to find the indicator problem as we speak.


Thanks wise and powerful MR2 owners.
2barGee
Posts: 2409
Joined: Sat Dec 18, 2004 6:13 pm
Location: Pontefract

Re: Is it bad to hit fuel cut / Dodgy indicators?

Post by 2barGee »

You want to set a % to the limiter because at 0% it wont do anything!

I set mine to 20% so if it does every overboost it will bring it back down :thumleft:
Post Reply

Return to “MR2 MK2 1990 - 1999 NA & Turbo”