Author Topic: fd cutting out under load  (Read 662 times)

Offline kylie

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fd cutting out under load
« on: April 08, 2013, 01:17:04 AM »
well i got a small issue with the fd, basically now and then it cuts out when i put my foot down, not at a certain rev range or anything, just when it wants to, dies for a second then cuts back in

oh and since fitting a cat back blitz nurspec im getting lots of black soot on the bumper

anyone know what could be causing this?

Offline tiger18

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fd cutting out under load
« Reply #1 on: April 08, 2013, 05:20:49 AM »
Sounds like you put car in limp mode some how, are you running standard ecu, if so try take battery terminals off and leave for 10 mins then reconnect and try car again. If its still doing same you need to pull ecu codes to see what\'s wrong. Let me know

Offline kylie

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fd cutting out under load
« Reply #2 on: April 08, 2013, 01:29:38 PM »
wouldnt limp mode make the car do this all the time? its only cutting out for like a second when my foots down sometimes, sort of backs off then kicks back in, idles fine and runs fine apart from that

car is running standard ecu but does have hks induction kit and blitz exhaust, issue started shortly after fitting exhaust,  could it be fuelling?

Offline Brett

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fd cutting out under load
« Reply #3 on: April 08, 2013, 01:32:59 PM »
It sounds like you are over boosting, the engine will then cut in order to prevent damage.

You should get a boost controller, and ideally a mappable ECU on there as a priority if this is the case.
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Offline Grant Monkhouse

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fd cutting out under load
« Reply #4 on: April 08, 2013, 01:37:40 PM »
Have you removed the cat? Or only changed the back box?

Offline kylie

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fd cutting out under load
« Reply #5 on: April 08, 2013, 01:56:09 PM »
I\'ve only done and cat back exhaust

At the mo a mappable ecu isn\'t on the cards as too much money has been spent on my other project, but a boost controller is cheap enough :) they as straight forward to fit like on other turbo cars?

Thanks

Offline boosted

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fd cutting out under load
« Reply #6 on: April 08, 2013, 03:51:13 PM »
Short term get a bung for back box bout 15 quid on ebay to slow exit of exhaust gases down.
92 FD rx7 Twins 13.5psi.  EX Track car
EAT SLEEP ROTOR REPEAT.

Offline freddie garcia

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fd cutting out under load
« Reply #7 on: April 08, 2013, 06:41:49 PM »
another cheap option is  to use a fuel cut defender! it should stop u from overboosting with the mods uve got.

Offline Lee Vincent

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fd cutting out under load
« Reply #8 on: April 08, 2013, 06:50:10 PM »
One of those on eBay

Offline boosted

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fd cutting out under load
« Reply #9 on: April 08, 2013, 07:31:12 PM »
Long term get it mapped with an apexi for your mods ...short term stay off the boost....rotary engines are far more susceptible to detonation damage than a piston engine....trust me i blew mine up messing about with it! in all honesty put the original exhaust back on ...get all the bits you want and the apexi fit them and drive off boost to a mapper and voila!
92 FD rx7 Twins 13.5psi.  EX Track car
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Offline samoht

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fd cutting out under load
« Reply #10 on: April 08, 2013, 07:49:41 PM »
Quote from: freddie garcia;855321
another cheap option is  to use a fuel cut defender! it should stop u from overboosting with the mods uve got.

A fuel cut defender will simply let the engine keep boosting (because the fuel won\'t be cut).  You will then be making boost above what is safe with the stock map, so will not have enough fuel in the engine to balance the amount of air.  This causes lean combustion, which raises the temperature, leading to detonation and a near-instantly wrecked engine.  I can\'t emphasise enough, if you hit fuel cut you cannot simply bypass the fuel cut, you need to first ensure you have enough fuel to handle the extra boost.

Don\'t just take my word for it, here is a fuel cut defender:
http://www.sumopower.com/product/hks-fuel-cut-defender-4501-ra002

Warning ; Due to the characteristics of this product , higher than recommended or unsafe boost levels may be attained by
the installation and use of the FCD . This may result in severe damage to the vehicles engine or other mechanical parts.
« Last Edit: April 08, 2013, 08:03:40 PM by samoht »

Offline samoht

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fd cutting out under load
« Reply #11 on: April 08, 2013, 08:03:07 PM »
Quote from: boosted;855323
in all honesty put the original exhaust back on ...get all the bits you want and the apexi fit them and drive off boost to a mapper and voila!

This is the best advice on this thread.


Buying a boost controller will actually run ok if set right, however it\'s fairly pointless on its own.  

You\'ve upgraded the exhaust, which is now giving you higher boost because it has less backpressure (gases exit more easily), so the pressure difference across the turbo (hot side) is greater.

More boost = more air in the engine.  To make more power, you just need to add more fuel to match the extra air, and all will be well.
However, the stock map doesn\'t have fuel settings to match this much extra air.  Therefore, the fuel cut is kicking in as a safety mechanism to save your engine - because having too little fuel for your air is known as running lean, and causes deadly detonation.

Now, you could fit a boost controller to reduce the boost back down to a safe level.  However, you\'ve now gone back to approximately the same (safe) boost level that you had before you changed the exhaust, so power output will also be approximately the same.  Hence rather than buying another part, you could save money by just refitting the standard exhaust and achieving about the same result.


Thinking of it another way:
* The power you can make is limited by how much fuel you can inject
* The stock map only supports injecting up to a certain amount of fuel
* Therefore, to make more power you need to change the stock map with e.g. an Apexi PFC.  Trying to make more power without changing the stock map will not work, but it may destroy your engine.

Technically, there are other, cheaper and less reliable ways of injecting more fuel, but you\'re really into guesswork land there, and the rotary is especially unforgiving of wrong guesses when it comes to fuelling.
« Last Edit: April 08, 2013, 08:15:32 PM by samoht »

Offline kylie

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fd cutting out under load
« Reply #12 on: April 08, 2013, 08:41:18 PM »
thanks everyone for the good advice, my first rotary so bit of a learning curve for me as im used to classic mini\'s, bit of a difference :2eek

i fitted the exhaust as the standard one was rotten and a friend had a nurspec to hand, lesson learned though, i\'ll hunt down a standard exhaust to sort it out for the mo, i\'ll put the nurspec to one side until funds allow me to buy an apexi, either that or sell my mini project..............dont think i\'ll do that lol

thanks again

Offline kylie

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fd cutting out under load
« Reply #13 on: April 08, 2013, 08:44:58 PM »
unless......anyone wants to buy a greddy manifold and external wastegate? or swap for an apexi? :D

Offline samoht

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fd cutting out under load
« Reply #14 on: April 08, 2013, 10:24:37 PM »
Ah, didn\'t realise your original exhaust was dead.  In that case you\'ll need to buy something anyway, so could get a boost controller I guess.