It is currently Sun Jun 16, 2019 3:57 pm



Post new topic Reply to topic  [ 12 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Map Sensor or Not
PostPosted: Mon Jul 23, 2018 12:14 pm 
Offline

Joined: Thu Jul 12, 2018 11:34 am
Posts: 7
ECU Model: S60 Pro
I have a standard Peugeot 1.6 16v TU5JP4 engine running the original plastic inlet and a cable operated throttle body.

I have used all the original sensors and have the engine running on a TPS v RPM map with MAP compensation.

The problem is that with this induction set up the MAP sensor is seeing about 40 kpa at tickover this means a fueling compensation of about -60% even at higher revs the MAP reading never gets above 60 kpa
This may change when the engine is under load (but i don't know if it will)

This means i am adding fuel to the main map for the MAP compensation to take it away.

The question is with this set up is there any point in running a Map Sensor?

Thanks


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Mon Jul 23, 2018 12:47 pm 
Offline

Joined: Thu Jul 28, 2011 4:10 am
Posts: 919
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)
Your choice really, but you need to decide. Some say that TPS v rpm is sharper, but TPS v RPM with map compensation is sort of automatic and provides a very flat fuel map.

Have a look at the 2 sample fuel maps for the Zetec engine as an example.

Think, do you ever plan on driving up mountains ? If so you would benefit from the map sensor, I run one for altitude correction but honestly it's just another thing to go wrong.

Once you get to full throttle you should be close to 100kpa, depending how restrictive the air filter etc is.


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Mon Jul 23, 2018 2:26 pm 
Offline

Joined: Fri Feb 28, 2014 1:03 pm
Posts: 1226
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79
The other reason to run a MAP sensor is when using an air idle control valve, or DBW, to control the idle.
If the valve is adding or removing air, the manifold pressure will change, and so will the fuelling requirement.

If you don't plan on running up mountains, or using an idle air valve, then you probably don't need it.


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Tue Jul 24, 2018 7:41 am 
Offline

Joined: Thu Jul 12, 2018 11:34 am
Posts: 7
ECU Model: S60 Pro
Thanks Guys

That is pretty much along the lines that i was thinking, the standard idle control on the throttle body i have is a marelli stepper motor system and unfortunately my ECU is not compatible.

So it has been replaced by a machined bolt to provide manual adjustment.

As for dealing with changes in atmospheric pressure i had considered putting a MAP sensor in the airbox before the filter, but this may just cause me problems.

Thanks


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Tue Jul 24, 2018 1:16 pm 
Offline

Joined: Tue Jan 16, 2018 9:38 am
Posts: 62
Location: Aberdeen
ECU Model: S100 Pro
Distributor: DTA
I fitted MAP sensors to 3 N/A cars over the winter (as part of a full rewire and S100 installation), One seeing atmospheric/engine bay and the other two piped into the airboxes.
And from looking at the logging, they barely change; typically from 99 to 101kpa at all times.
So, I probably wouldn't bother for the majority of installations (apart from the examples given in previous posts).

Steve


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Fri Aug 03, 2018 9:52 pm 
Offline
User avatar

Joined: Wed Jul 27, 2011 5:30 am
Posts: 573
Location: New Zealand
ECU Model: S80 Pro
SMR, often you'll plumb them to the manifold though, so you see the pressure the engine/manifold sees. For turbo you must do that anyway.

_________________
| '94 GSR Lancer | '96 Toyota Carib 20V | '83 Toyota Starlet | www.ignitionautosport.co.nz |


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Sun Mar 03, 2019 2:25 am 
Offline

Joined: Wed Jan 28, 2015 5:42 am
Posts: 60
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75
Alex DTA wrote:
The other reason to run a MAP sensor is when using an air idle control valve, or DBW, to control the idle.
If the valve is adding or removing air, the manifold pressure will change, and so will the fuelling requirement.

If you don't plan on running up mountains, or using an idle air valve, then you probably don't need it.

Thanks Alex - using MAP with an idle valve sounds like it is just what I need to control idle on my (not a track day!) automatic to correctly adjust idle when Drive is engaged. Currently 'free' idle (with idle control turned off) is around 1200rpm and ignition is retarded by the idle control loop to bring this down to circa 900 rpm. However this is inefficient and I hate inefficiency!

Similarly, I guess the addition of a MAP sensor would allow one to configure slightly leaner running at steady speed and on overrun, where currently I have to guess where these transitions (from power to overrun) lie on the fuelling map. More efficiency gains!

Thanks, Richard


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Sun Mar 03, 2019 4:35 am 
Offline

Joined: Thu Jul 28, 2011 4:10 am
Posts: 919
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)
Richard, correct me if I'm wrong but I'm not sure if you have a wide band fitted even?
So you are only guessing really. Get one and you can target rich and lean conditions to achieve what you are looking for, I use this on my cars and target 0.85 at full power and about 1.05 at motorway speeds.
But to get a strong idle try one of the 2 wire valves, add map compensation and a wideband. If you are really keen move to sequential and save a little more fuel, I did and the motor is sweeter.

Having a map sensor won't help you target leaner as you can just do that anyway via the main fuel map.


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Sun Mar 03, 2019 6:23 am 
Offline

Joined: Wed Jan 28, 2015 5:42 am
Posts: 60
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75
Thanks Rob, I learn something new from each of your excellent posts!

You're right, I don't yet have closed loop/wideband fitted which I should!

My thought on the use of MAP for steady speed/overrun conditions is that it enables fuel compensation to be applied based on engine load - rather like on a carburettor car which I remember fondly from my youth! I agree that if I had closed loop configured, the lambda correction map can adjust the fuelling but, without using a rolling road, one has to guess where steady speed/overrun transition states occur in setting up the map; MAP would surely identify this accurately for the purposes of applying fuel compensation? Even with a rolling road, factors such as transmission efficiency, rolling resistance and aerodynamic profile would all affect at what loads steady speed running is assumed to occur?

Your comments on sequential injection are interesting. I hadn't really looked at this before but think I will. I wonder why engines capable of supporting sequential injection (like mine) aren't set up to use it? Does it complicate the tuning process?

Thanks again, Richard


Top
 Profile  
 
 Post subject: Re: Map Sensor or Not
PostPosted: Wed Mar 06, 2019 11:38 pm 
Offline

Joined: Mon Jan 16, 2012 1:39 pm
Posts: 113
ECU Model: S40 Pro
Firmware Version: 58
i am thinking the last days to use tps as main load and map 20x14 corrections, instead of map as main load, yeah i know i am a map sensor guy i prefer it than tps...

so anyone has try it ? any benefits ? something to mention as a feedback ?


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ]  Go to page 1, 2  Next

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Theme designed by stylerbb.net © 2008
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
All times are UTC - 5 hours