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Techspy

Low power at low rpms at takeoff

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Well, I am slowly getting things sorted after buying my S4 back...Thanks for all the help guys..

 

Now, I have noticed this issue since I got her back but was more focused on other issues (idle issue resolved with an IACV and TPS replacement). So, its seems that she just doesn't want to get moving from a stop very well. I am not talking about a hi-rev fast start, I am talking about a normal start from a red light etc. If I just try to take off normally it seems that the car has no torque. I don't want to rev high and ride the clutch every take off so i just give it some revs and let the clutch out but it gives that "almost ready to stall" feeling but not because it is missing or anything. The car drives great otherwise and have plenty of power. It has a high torque chip, no cat, lightened flywheel, no EBPV, WCE turbo, blow off valve, new primary injectors, etc. All freescan logs look good (thanks Travis), and no exhaust leaks but it has a really rich smell at idle. I have contributed that to not having a cat and am considering putting one back on it because of the smell but am wondering if there is something else amiss.

 

My GF asked one day, "Why does it seem to struggle to get moving?" That is the best way to describe it really and I have tried searching for different terms on here to see if anyone else has had a similar issue with no luck.

 

So, anyone have any ideas on the falling on its face with normal takeoffs? How about the rich smell? Could they possibly be related?

 

Thanks guys...really want to get this sorted.

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Do you have an A:F gauge?  I see that mine often goes, lean->rich right when I take off from a stop, which is what causes that stumble where it almost wants to stall.  It is much better in the morning with the fast idle.

 

It is somewhat normal for the Esprit to kinda fall on it's face when taking off from a stop.  It should be much better without the cat and restrictive exhaust. 

 

I think it is several issues.

1)low compression engine has no power without boost.

2)restrictive exhaust with turbo at low rpms.

3)poor control of primary injectors at low duty cycles.

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Thanks Travis. Compression is good on all 4 cylinders (checked a few months ago), and the other 2 issues you mentioned are ok. Oh I see what you mean...thats just the way they are. I was hoping that it is somehow related to the rich idle I have. Oh well, I guess I will just try a hi-flow cat and live with it. I wish there was someone with an s4 around here so I could have something to compare to.

 

I am considering replacing my o2 and MAP just to see if it is any better. Do you think there is any chance that would help?

 

By the way, are you still having good performance with this O2 sensor you fitted? http://www.amazon.com/Bosch-13030-Oxygen-Sensor-Fitment/dp/B000BZG5QM

Edited by Techspy

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The 3 items I listed were normal for every Esprit turbo really.

 

The O2 sensor is worth replacing, they don't last forever.  That is the one that I am using, seems to work just fine.  The Engine is able to hold a perfect 14.6 A:F while cruising and idling, and the A:F numbers for boost appear to match the desired numbers with each gear.

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Yeah I re-read it and understand what you are saying..

 

I just ordered the o2. Like you said, it cant hurt. Thanks again.

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Well I replaced the o2 sensor and it is working great. Didn't see any real change in the way the engine runs but it is darn near perfect anyway. Still have the rich smelling idle. I guess I will go ahead and try a hi-flow cat.

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Cats are an absulute con

What it does is turn carbon monoxide in to carbon dioxide by re burning the exhaust gases and it uses more fuel to do this, also leaded fuel cannot be used, but you can take the lead out anyway, so this was an oil company environmental scam in my view silencing the environmentalists by turning some gases into carbon dioxide ( green house gas ) actually using more fuel with less power and more global warming, not to mention setting back engine design about 10 years - on the plus side its really quite difficult to kill your self with exhaust fumes if you have a cat fitted ( dont try this )

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I am with you but am getting pretty strong exhaust smell (like running rich) at idle. I have tried everything else and don't have any other solution.

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   John, would you read your personal e-mail box, please?

 

          Thanks, Feijucho.

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Cats are an absulute con

What it does is turn carbon monoxide in to carbon dioxide by re burning the exhaust gases and it uses more fuel to do this, also leaded fuel cannot be used, but you can take the lead out anyway, so this was an oil company environmental scam in my view silencing the environmentalists by turning some gases into carbon dioxide ( green house gas ) actually using more fuel with less power and more global warming, not to mention setting back engine design about 10 years - on the plus side its really quite difficult to kill your self with exhaust fumes if you have a cat fitted ( dont try this )

Errrr....  sorry but that's nonsense.  What the cat does is convert CO, unburned hydrogen and NOx to CO2 and water, and nitrogen, of which CO2 is obviously something we would prefer not to have, but is far less harmful to all concerned than CO unburned HC and NOx.  No extra fuel is provided to the Cat to do this, but in order for both the oxidation and reduction reactions to take place it is necessary to run at the stoichiometric point, with a chemically balanced air:fuel ratio.  Before Cats were used, some cars were run lean at light loads, so there is a small loss there.

 

It is also possible to run lean with a Cat, and the Cat will still convert the CO and HC in this way, but not the NOx.  NOx is generated when running lean, but not at light loads, so more sophisticated systems can also run lean at that point.  The Esprit does not have this lean running mode.

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Hi,

 

I own a 1998 GT3 Esprit.  When I read your problem it sounded like a problem I am having now.

 

The way I would describe it is that I am getting hesitation with the engine after driving for 30mins or more.  It feels as if the car is going to cut out, but it doesn't.  Also, I am getting uneven acceleration and have to over gas the throttle to prevent what feels like a possible stall.  I had the engine frees scanned and everything was working ok 4 months then the fault developed 2 months ago after a really enthusiastic drive.

 

Do you think I should change the O2 sensor first, or is there something else it could be?

 

Thanks,

 

Mark

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Mine was never different from cold to warm. I pretty much accepted it as just the way a high revving turbo engine is. I did however install green dot cam gears during my recent rebuild and that is supposed to help a lot for off-boost drive-abilty and should help with what I was experiencing. I have yet to drive it after the rebuild so I can't give a report yet.

 

Being that yours get worse as it warms up, I doubt it is the same thing I was experiencing.

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Botox,

 

your problem sounds like fuel pressure to me, you should check it.

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