Home Register Manuals 164 Forum Interactive Library
Login

 
 

164Q4 ecu question

For the technical things.

164Q4 ecu question

Postby Mitsos » Mon May 01, 2017 10:29 am

Hello everyone! I am using a modified Q4 engine in my 75 and I was wondering if anyone has experience/knowledge about the fuel cut-off rpm. In most other ecu's (any brand), during deceleration in gear, fuel delivery is restored at ~1400-1600rpm. In the 164Q4 ecu, fuel is restored at 3000rpm, which I believe is connected to the 4wd feature. Does anyone know if this is a matter of mapping or something that can be easily adjusted by changing some resistors (for example) on the ecu board? Thanks in advance for any answers.

Jim K.
Mitsos
 
Posts: 5
Joined: Tue Dec 27, 2016 6:25 pm

Re: 164Q4 ecu question

Postby Alfan » Wed May 03, 2017 7:33 pm

Well, my answer won't help you... But I would like to know where you found this information, as I find it very interesting?

My guess it that it would be difficult to modify using components, as I think you risk modifying other things as well, since RPM is a very critical part being monitored for many things.
1994 Alfa Romeo 164 Q4 Proteo Rosso 535.000km
1989 Lancia Thema 8.32 Verde Indy 260.000km
2015 Alfa Romeo 4C Rosso Competizione 75.000km
User avatar
Alfan
Q4 owner
 
Posts: 1023
Joined: Thu Oct 22, 2009 8:20 pm
Location: Denmark
Country: Denmark (dk)

Re: 164Q4 ecu question

Postby Mitsos » Thu May 04, 2017 3:03 am

In my 75 3.2liter, I have installed an afr gauge. With this and a precision tachometer (Stack), it is very simple to see when fuel is cut off and restored on deceleration. 3000rpm is the magic number for the 164Q4 ecu. In contrast, in the Lancia Kappa 3liter 24v engine (fwd car) deceleration fuel is restored at ~1700rpm (from the factory manual). I believe the rpm difference from the 164Q4 engine has to do with the 4wd feature. Other differences between the two ecu's like the two lamda sensors of the Q4 vs one in the Lancia do not play a part in this cut-off feature.

Jim K.
Mitsos
 
Posts: 5
Joined: Tue Dec 27, 2016 6:25 pm

Re: 164Q4 ecu question

Postby AlfaWhiz » Thu May 04, 2017 5:14 am

I don't have an answer for you, but it's interesting to me: why do you want to modify it? Does it cause any unwanted behavior?
User avatar
AlfaWhiz
 
Posts: 352
Joined: Thu Feb 06, 2014 1:15 pm
Country: Poland (pl)

Re: 164Q4 ecu question

Postby Mitsos » Thu May 04, 2017 6:04 am

The feel of the car when driving normally is different than what you would call 'normal'. Deceleration in gear is not as good as it could be (engine braking is less at 3krpm) and there is also the matter of higher fuel consumption... Don't laugh, 98RON gasoline costs ~1.80€ now here in Athens -the reason for 98RON is 11.5:1 compression ratio and many other engine mods.
I have a Lancia Kappa ecu (0261203482). When we figure out how to disable the immobilizer feature, I will try it on the Alfa and see what happens.

Jim K.
Mitsos
 
Posts: 5
Joined: Tue Dec 27, 2016 6:25 pm


Return to Technical

Who is online

Users browsing this forum: No registered users and 1 guest