Hesitancy after Autodelta Intake upgrade.

[robsco]

Hi all.

The car as some of you know, is a 156 2.5 V6. I fitted the new Autodelta Carbon Intake this afternoon and Autodelta filter. The good news is that the engine is smoother lower down, even the flat spots I asked about on here recently have been ironed out. She also makes a lovely noise, slightly more hard edged and more induction noise when pushing on.

The bad news is that all of a sudden, theres a hesitancy above 4k rpm. Put your foot down in any gear, she pulls like silk up to 4k, and then all of a sudden there's an extremely noticeable hesitancy, maybe 2 or 3 seconds of virtually nothing before she surges forward again. It does it again at about 5.5k as well, I've not revved her any higher than that. Does anyone have any ideas on what it could be?

Ta.

[waynedear]

Have you checked that all the pipework joints are spot on, no misaligned pipes/hoses, is your EM light flashing up when is hesitates ???

[robsco]

Hi mate; checked all pipes etc. The carbon pipe was a VERY snug fit, so there's no problems there. The only other pipe I had to move was the one which leads from the coolant tank and comes round by the airbox unit. That's now back in the clip that holds it in place, no kinks. The EML isn't flashing either. What I don't understand is how it can improve so much at low revs and then not want to know passed 4k?

[14-7]

Sounds more like a MAF issue than something wrong with the filter setup.

Unplug the MAF and take it for a spin to see if the flat spot goes.

[robsco]

14-7 said:

Sounds more like a MAF issue than something wrong with the filter setup.

Unplug the MAF and take it for a spin to see if the flat spot goes.

14-7, do I need to disconnect the battery before I unplug the MAF? I also didn't need to disconnect it when I took the airbox unit out, it just shifted to one side as I replaced the filters, so does it just unplug or are there any screws I need to get at?

ETA - 14-7, I didn't recall, but you told me how to unplug the MAF a couple of weeks ago on another thread! I'll do it tonight.

Edited by robsco on Thursday 9th December 19:14

[waynedear]

On GTV's it just unplugs, not sure about 2.5's

[alfa pint]

Maybe it's the ECU getting used to the new settings? Have you tried a soft reset on the ECU (turn key so that all dash lights on, leave for 60 seconds, turn the engine on WITHOUT turning the key back towards you) and see if that helps matters?

[robsco]

I unplugged the MAF this morning, and hey presto, she's going like the clappers. Maybe its just a coincidence that its shown its colours on the day I fitted the intake. I'll get a MAF on order tonight, how long can I run the car for with the MAF unplugged?

[robsco]

A lex said:

(Ps. should have just stuck in a piece of drainpipe )

You just had to say it, didn't you?

[andy665]

I believe the MAF sensor on your car is the same as fitted to the 3 litre V6. if it is you can buy the same sensor from Vauxhall (for a 1.9TDi), whilst the MAF pipe is the same its simply a case of unscrewing the sensor, withdrawing it and fitting to your existing MAF pipe.

I did this recently on my GTV V6 for a total cost of £65

[robsco]

Hi all.

MAF sensor was fitted yesterday, and my word! I thought she was reasonably quick before, but it's obvious to me now that the MAF hasn't been 100% from the day I picked it up. There were no flat spots or anything for a while after buying, but she's clearly never been producing the power, as the difference is astounding! Any gear, any revs and it just flies, I'm over the moon. The way it pulls like silk from tickover to 7k is truly addictive, 2nd and 3rd gear shoves you back properly into the seat, which I really wasn't expecting.

And from Miss Robsco, the immortal words. "No Rob, please don't, it's making my stomach turn!"
Merry Xmas to all on the Alfa, Fiat & Lancia forum, and thanks Alfisti for the continued help. Here's to a fruitful 2011.

Edited by robsco on Friday 24th December 19:16