6 replies to this topic

[mattswinn]

Hi fellow Mini enthusiasts.

 

Long time reader, first time poster... I'm after a bit of advice regarding my map reading:

 

2 Years ago I had my SPi engine has been fully rebuilt (bored to 1293) and the head reconditioned. I'm running the Swiftune SW05 cam and 1.5 roller rockers, maniflow LCB and twin box system.

 

For the first year after the build i ran the specialist components injection setup and ECU - needless to say i was less than thrilled with this setup so made the decision to change back to the oringial SPi setup over winter.

 

I'm currently now getting the mini ready for it's MOT, and one thing that has caught my eye is my map reading: I seem to be getting 40-45kPa at idle (850rpm), I've read online that it should be in the 30's. I'm a little concerned as i believe this can have quite a big effect on the fuelling of the engine if it's too high?

 

It does smell rich on initial startup, however mems-scan confirms it goes into closed loop after 30 seconds or so and it seems to make the appropriate adjustments to keep it there, albeit the short term fuel trim is making some heavy reductions at times, -19% in some cases. The rich smell does go once it reaches operating temperature. Lambda reading also seems happy (jumping from high to low rapidly).

 

Before the engine came out to be rebuilt i was getting high 30's (37-39kPa) at idle.

 

The vacuum lines and fuel trap are all new (and leak tested in a bowl of water), even the brake servo hose and hoses to the hard line breathing system and charcoal canister have been replaced with new.

 

I also blanked off all the vacuum outlets apart from the one to the ECU and no change to the reading. The ECU was decoded by a specialist and checked over when this was done and passed all the tests, i also have access to another ECU which i have tried and got the same results.

 

The seal around the PTC heater has also been checked and confirmed to have no leaks.

 

The car seems to run fine, although i can't take it out on the road to drive it properly yet to fully confirm this. All the SPi components were tested before assembly and are working correctly.

 

Am i reading too much into this or have i missed something? I would like to try and get the map reading down if its considered to be too high.

 

Thanks in advance.

[Wazzah]

In my opinion your readings are nothing to worry about.

Given that the kPa reading is a vacuum the so called higher readings are actually lower readings.

It is my understanding that fuel is cut by the ECU under high vacuum.

I assume your fuel trap is mounted in the standard position above the manifold and to the rear of the throttle body.

I had trouble once with a rubber hose in the engine bay that connects to the hard pipe fuel tank venting pipe.

I've rebuilt my engine also (1310cc) and am pulling more vacuum as well.

I've also thrown away all silicon vac hoses and gone back to the rover hard pipes.

I had a few unexplained flat spots and the hard pipes cured that.

I also have been down the Delta 400 SC path and switched back to the Rover MEMS.

I had a lot of success with advancing the timing in SX Tune to wake things up.

After my second Delta ECU faulted I gave up but am happy to share my ignition map if you want to try again.

I have no experience with the PTC heater but i'd imagine that a faulty one could cause the rich smell you are experiencing given everything else is brand new as you describe.

[sonscar]

Is not 0Kpa Max vacuum and 100Kpa atmospheric?Larger cams can reduce idle vacuum.Steve..

[Wazzah]

Is not 0Kpa Max vacuum and 100Kpa atmospheric?Larger cams can reduce idle vacuum.Steve..

Yeah your right Steve. Just did some reading on the subject. I was thinking as vacuum as a negative pressure where as it is pressures below atmospheric.

[mattswinn]

Hi all. Thank you for your replies. Just an update on this. Was doing a few checks on the mini this evening and I found that the rockers were waaaay too tight. I reset them to 15thou as they are roller rockers and boom.. map reading now shows 35-38... I’ll take that.. just glad I noticed it before anything bad happened!

[Midas Mk1]

Did you use the sc base map or have it setup? Imo their base maps are only good enough to get you to a dyno.

[mattswinn]

Hi Midas Mk1,

As my post says, I’m no longer using the SC setup. I reverted back to the original SPi setup last winter.

When I was running the SC setup, I was forever going for rolling road sessions, and yes the base maps are pretty hopeless. I think I ended up with 25 different maps in a folder on my computer. Too much faffing about so I sold the system.

When everything’s in order, the rover mems system manages the engine really well.

Matt