I have an UK MY02 with Ecutek remap, decat up pipe, decat down pipe, sports cat and PE back box.

Yesterday I did around 220 miles, I drove about 100 without stopping, the car ran perfectly (ambient 16 deg C). I stopped in Pickering for about 50 minutes and then I got hesitation around 3000 revs and general lack of smoothness. I parked in Scarborough for about three hours and all the way back home (about 100 miles) the car seemed to be hesitating and not pulling smoothly.

The hesitation isn’t bad but noticeable, I think that I may have heard the engine knock once at fairly high revs (knocklink on order), coming home the ambient was around 9 deg. C so I would expect the car to run better not worse.

I have done numerous logs with Deltadash, nothing appears out of the ordinary.

Can anyone suggest any sensors or parts that may become defective after a period of heat soak?
Would changing the plugs help?

This fault is starting to drive me nuts!

Any help or suggestions welcome.

Cheers

Edward.

[Edited by Edward - 5/19/2003 11:23:52 PM]

Tried a different fuel ?

Murray, I havn't tried any different fuel as I think it's something to do with heatsoak.

Cheers

Edward.

I am not sure that the problem is heatsoak, unless you were hammering the crap out of the car, and you should have been experencing it before you shut the car down and left it for a while. Plus you outside temps are pretty low. I would question the fuel first, may have been dirty old or what ever.

I agree with Submann. We have ambient temperatures up to 305 degrees C here and heat soak only seems to really come into play at 20 degrees or so. Also - once you car starts moving for 10-15 seconds, heat soak is eliminated.

Make that 35 degrees and not 305

I've just had my car Ecutek'd (full decat) and I'm having similar problems. When accelerating, mainly in 3rd and 4th around 2500>3000 revs, the car lurches before clearing it's throat and then pulling smoothly. Accel with WOT seems to help a bit.

I'm just coming up for 200 mls since the Ecutek was fitted so I'm hoping it's still 'running in'.

Thanks for the replies everyone.

I went out again last night, ambient around 10 deg C, I refilled the tank.

Full throttle seems fine, I tried a few runs up a long straight in third from 2000 - 4000 rpm with constant throttle, with anything less than full throttle the car is lumpy and hesitates (I drove a couple of miles in between each run).

I tried reseting the ECU - this made no noticeable difference (approx. 1000 miles since last reset).

I have a feeling the car has always been like this, but in normal everyday driving it's not often you keep constant throttle also before the new exhaust and remap I would always tend to be in one gear lower for the same speed.

Any other suggestions ?

Cheers

Edward.

[Edited by Edward - 5/22/2003 12:50:37 PM]

Not sure but could it possibly be due to overboost spike or spool up of the turbo that it appears to hesitate?

Murray, when I log it with Deltadash I don't see any signs of a boost spike.

Taylor do you have Deltadash ?

E.

[Edited by Edward - 5/22/2003 5:29:23 PM]

No boost spike, and I assume no engine retard?
I dont know what to suggest except:
Dirty lambda?
Failing air flow sensor?
Under fuelling ?
Over fuelling ?

Check your spark plug gaps. If they're gapped a little too large, then as boost comes in, it will struggle to spark and ignite properly. Ecutek will make this much worse as the boost is higher than OEM.

Do a search on here, but most people reckon on 0.7 to 0.75mm plug gap for a modified engine. If you're running heavy mods, potentially worth upgrading the plugs too.

Could it be the aircon kicking in? This wouldn't happen on WOT.

Hades - thanks for the suggestion, I've just taken out the two plugs at the air filter side, both are gapped to 0.7mm, one strange thing is that the manual says PFR6B, but the plugs are PFR6G. The car has only done 12k miles so I presume these were fitted at the factory.

Speedking - I have tried the car with and without the aircon switched on - it didn't make any difference.

The hesitation seems to be quite a common problem in America where a lot more new age models have been tuned, in interesting link:
NASIOC

also worth looking at:
Vishnu

E.