Technical Hesitant Sei

[Invisible Man]

Hi,
Slowly getting bits fixed on my Sei. Brakes and rocker gasket are done.

I've noticed when revving the car from idle there is a second of hesitation before the revs pick up. It doesn't cause the car to stall but is slightly annoying!

The car also rough idles. It'll idle fine then for a split second the revs drip ever so slightly before coming back up.

Ive read it could be a pipe to the MAP (But i dont know what the MAP is or where it is lol). Ive also read it could be the Lambda sensor (which i assume is on the exhaust).

No engine management lights come on.

Any ideas?

Cheers,
Shaun.

 

[Dermist]

This is exactly what I have just lived through on my sporting MPI.


It started with failed HT leads (blue arcing in the dark), at the same time the coil pack A failed. This took out the ECU.


Whilst all this was happening, I replaced the Lambda sensor as several posts mentioned this a possibility.


Eventually it turned out to be a duff injector (no.4). This is really easy to check it turns out.


Disconnect all the plug caps from the injectors
Set the Multi-meter to the lowest Ohms setting you have.
Place the two probes on the pins coming out of the injector body.
You are looking for approx. 14ohms, and all 4 should be all the almost the same value.
The one I had was reading 76ohms, the other 3 all 14.6Ohms.


I replaced all four injectors (ebay £30) as they came complete with the fuel rail and you have to remove all 4 to replace 1, so I have 3 spare!


Check these using the above test before you install them!


The Engine Management light kept referring to a mis-fire which lead me down the ignition route, and when I pulled the plugs off the coil to check to see if the engine bogged down, it didn't do it on cylinder 4! So that's when we checked the injectors as there was little else.


As to the bogging down, mine did this and still does, though not as much.


Hope this helps either you or someone in the future!


Dermist

 

[Invisible Man]

Hi,
Thank you for the very comprehensive reply. It was much appreciated

I went out to look at the car today armed with your advice. When i took the airbox off i noticed the gasket that seals the air box to the throttle body had gone hard and one side had been trapped underneath curling its edge over; it had hardened in this position. I seated the airbox as tightly as possible and hey presto the lumpiness had gone. So it looks like it was an air leak

I'm assuming Fiat still sell spares for the Sei? I plan on nipping into the dealers on monday and hopefully getting a new part.

Thanks again. Your advise is much appreciated,
IM.