Engine hunting

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paulsv8manta
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Engine hunting

Post by paulsv8manta »

Hi guys,
On to the next problem, the engine is hunting when first started I've been reading up on this and it seems I need a 10000 ohm resistor across the coolant temp sensor. Looking at what is available on the net, they come with varying watts. Anyone know which one to go for 1/4, 1 or 2 watt resistor?
Many thanks
Paul



DaveEFI
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Post by DaveEFI »

Any will be fine as the current flowing through it is tiny.
1/4 watt is probably the most common, and will fit inside the connector easily.
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SimpleSimon
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Post by SimpleSimon »

Surely adding resistance will make the engine run even richer and hence the hunting worse 8) I would never consider an over lean condition (splashy) hunting so am slightly confused here :? generally resistance decays with increasing coolant temp with a CTS
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DaveEFI
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Post by DaveEFI »

The resistor is added in parallel with the sensor reducing the total resistance - making the ECU think the engine is warmer than it is and reducing the fuelling. It was fitted as standard to later flapper installations - my SD1 EFI had it.

However, I'm not sure it will sort the problem.

Hunting is one of those words which seem to have different meanings. I've always though it was caused by a lean mixture for whatever reason. Generally you can get a pretty stable idle with the mixture much richer than needed.
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ChrisJC
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Post by ChrisJC »

Surely you can get the same effect by adjusting the spring tension inside the Air Flow Meter.
Tweaking the timing might help too.

Chris.
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stevieturbo
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Post by stevieturbo »

Why would it be wrong in the first place ?
9.85 @ 144.75mph
202mph standing mile
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paulsv8manta
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Post by paulsv8manta »

Thanks Dave, added the resistor and now its running a lot smoother.

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