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Discussion Starter #1
Hi all,

Before I go digging for a fault which might not actually be there, I thought I’d ask...

Do R53s all hesitate a little for the first 1-200m after cold start? Not a misfire per-se, more a different feeling throttle map.

It feels the same as on a Clio 182, where it was an emissions regulations trick to run lean (or rich, one of the two) so that the cat lit up faster.

lasts for the time taken to get in, start up, belt on, then drive 200m or so off my estate/round the factory at work
 

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I have one that does it and have had a couple that didn't.

In this particular car that does, i had changed the ecu to one from another r53 and it solved the problem. So I'm pretty confident it's something within the ecu (mapping or cold start settings).

I've also found with mine if i let it run for a minute before setting off, most of the time it won't stumble.

What year is your R53?
 

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Discussion Starter #5
I have one that does it and have had a couple that didn't.

In this particular car that does, i had changed the ecu to one from another r53 and it solved the problem. So I'm pretty confident it's something within the ecu (mapping or cold start settings).

I've also found with mine if i let it run for a minute before setting off, most of the time it won't stumble.

What year is your R53?
Mine is a 2005 car, and it’s done it whilst standard, and now still with a reduced pulley. Like yours, if left to idle, it’ll be fine.

Having thought about it driving to work, I wonder if maybe, just maybe, there’s a slight exhaust chuff/blow. Conceivably, if there’s one pre-cat, it’ll be confusing the lambda sensor, so might look to rule that out over the weekend.
 

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Mine is a 2005 car, and it’s done it whilst standard, and now still with a reduced pulley. Like yours, if left to idle, it’ll be fine.

Having thought about it driving to work, I wonder if maybe, just maybe, there’s a slight exhaust chuff/blow. Conceivably, if there’s one pre-cat, it’ll be confusing the lambda sensor, so might look to rule that out over the weekend.
Mine is a late 04 fl model. I've noticed most threads I've come across of people with the same issue seem to have early face lift models.

It's not much of a big deal really and I've decided just living with it is the best (easiest) course of action.
 

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It feels the same as on a Clio 182, where it was an emissions regulations trick to run lean (or rich, one of the two) so that the cat lit up faster.
Yup, there's a cat warm-up type of thing in the ECU. It runs slightly lean for a short period (or periods) of time, after the O2 sensor has been warmed up and the ECU goes to closed loop. At least it's there in the newer (facelift?) ECU. Especially annoying when running on E85, as it would need a much longer cold start enrichment than gasoline. There seems to be no way around it, except to disconnect the O2 sensor, lol.

Don't recall noticing it before I switched over to ethanol... it's been 8 years though, so might have forgotten.
 

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Bit of an update. My car has now stopped doing this. The only thing that has changed is that i filled up with lower quality fuel.

I usually use 98 octane premium unleaded which is the highest grade available in Australia. Recently the petrol companies decided to raise the price of fuel by 30% overnight before a public holiday.

The only petrol station that was still cheap only had 95 octane fuel (middle grade) with 10% ethanol content. I reluctantly filled up. The next morning the car fired up beautifully and hasn't had a stumble or chug since.

Unbelievable really that lower quality fuel has solved the problem. It's usually the other way round. It's also solved an intermittent issue of not starting on the first attempt. Car has started on first attempt for over a week now.

Overall, I'm probably losing a few hp due to the lower octane but I can live with that and going forward im going to interchange between 98 and 95 and see how that goes.

@FEDesignLtd what grade of fuel are you using? Maybe try something different and see if you get similar results.
 

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Discussion Starter #10
Bit of an update. My car has now stopped doing this. The only thing that has changed is that i filled up with lower quality fuel.

I usually use 98 octane premium unleaded which is the highest grade available in Australia. Recently the petrol companies decided to raise the price of fuel by 30% overnight before a public holiday.

The only petrol station that was still cheap only had 95 octane fuel (middle grade) with 10% ethanol content. I reluctantly filled up. The next morning the car fired up beautifully and hasn't had a stumble or chug since.

Unbelievable really that lower quality fuel has solved the problem. It's usually the other way round. It's also solved an intermittent issue of not starting on the first attempt. Car has started on first attempt for over a week now.

Overall, I'm probably losing a few hp due to the lower octane but I can live with that and going forward im going to interchange between 98 and 95 and see how that goes.

@FEDesignLtd what grade of fuel are you using? Maybe try something different and see if you get similar results.
Ahhh, that’s worth a try! I habitually use 98 Ron, so no harm in trying 95 for aback-to-back test
 
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