Ignition Failure Sensor / IFS harmful when bypassed?

First of, there must be a ton of topics about it, but the search function doesn't show them. (not enough characters maybe?)

So, what exactly does the IFS do?
They tend to fail a lot for a failure sensor. What will happen if the ignition fails and the IFS is bypassed?
In other words, can it do harm to always have it bypassed?

Quote:

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Originally Posted by metaripley

First of, there must be a ton of topics about it, but the search function doesn't show them. (not enough characters maybe?)

So, what exactly does the IFS do?
They tend to fail a lot for a failure sensor. What will happen if the ignition fails and the IFS is bypassed?
In other words, can it do harm to always have it bypassed?

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Hi,
I think you need to be a member to search correctly I believe :)
Well worth the price for all the information available :)

It detects the ignition pulses that actually occur, and sends the successful ignition event back to the ECU, and also to the dash for the tacho. The ECU can then tell whether the ignition event it just requested was successful.

Because of its location, right at the top of the engine, under the plastic cover, it gets very hot, and hence fails. Thankfully, it's rather cheap part (at time of writing, just £33 at Viamoto, and very simple to replace - 5 bolts to remove engine cover, 2 bIf olts and an electical connector to replace the IFS itself.


If it's bypassed, then the ECU loses the ability to detect misfires.

Quote:

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Originally Posted by Confused

It detects the ignition pulses that actually occur, and sends the successful ignition event back to the ECU, and also to the dash for the tacho. The ECU can then tell whether the ignition event it just requested was successful.

Because of its location, right at the top of the engine, under the plastic cover, it gets very hot, and hence fails. Thankfully, it's rather cheap part (at time of writing, just £33 at Viamoto, and very simple to replace - 5 bolts to remove engine cover, 2 bIf olts and an electical connector to replace the IFS itself.


If it's bypassed, then the ECU loses the ability to detect misfires.

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You can bypass the IFS by connect the tach signal directly to the ECU but as Garry says you lose the reason why it is there in the first place.
But you have to remember the following. If the IFS fails the car will not start. So if you are worried about failures make the connection required to bypass the IFS and don't connect them then if the the IFS fails you can just lift the bonnet and bypass the IFS immediately.
i would not recommend bypassing the IFS all the time but there is no reason why you would want bypass it for no reason.

Sent from my MI 5s using Tapatalk

Thanks. That is clear for me now.

One more thing, if its heat that is killing the thing, why not relocate it to a cooler place?
Its not location bound is it?

It's positioned close to the ignition coils. You could move it, but you'll have to do wiring changes, which introduce their own potential for failing.

It's a £35 item which might last another 20 years... I'd just replace it and consider it a consumable item, like spark plugs.

The IFS I buy in 50's as they do fail quite often - That said the one on my FTO has only been changed once in 20 years.
50 lasts me about 6-8 months
They are used on a loads of Mitsubishi models from Colts, Galants, FTO's and a few other Manufacturers such as Kia and Hyundai
and of the several 100 I've sold since starting Viamoto I've had ONE warranty that failed within 12 months - it's going to happen with electrical components
I just sent another and job fixed.
So yes you could say they are a long term consumable!
Mike
Viamoto

Thanks Mike!

I'll add one as a backup on my next order. Would be faster then make the actual bypass.