Starting at 88 kpa on map

[boostin]

Hey guys

Have been out if the ms loop for a bit since its in the car I drive for winter, trying to diagnose some hard starting, then I noticed it likes to start at 88 kpa in the fuel map, why is this and can I change it?

[slow_hemi6]

What is the atmospheric pressure where you are? There is no vacuum in the intake manifold when you start to crank and depending on plenum size it can take a little while to pull down.

[boostin]

What is the atmospheric pressure where you are? There is no vacuum in the intake manifold when you start to crank and depending on plenum size it can take a little while to pull down.

Looks like approx 102kpa, never thought of this hmm, interesting.


See the problem is it's such a rich start cause of it being so high in the fuel map, but should it not listen to my priming pulse that I chose?

Maybe it's happening so quick but it's the after start enrichment that's following

[whittlebeast]

My 250 PSI cold cranking 4 cylinder comes to life in the 95 KPA range. I normally comes to life in about .3 sec of cranking at about 150 RPM. 80 KPA intake cranking MAP is not your issue. Start up setting is the battle. My motor switches to the VE table at 300 rpm.

Andy

[Matt Cramer]

MS1 does have a "fixed MAP after start" option that is sometimes used to compensate for an uneven MAP signal immediately after startup.

[boostin]

MS1 does have a "fixed MAP after start" option that is sometimes used to compensate for an uneven MAP signal immediately after startup.

I have switched to this, but still having a hell if a time starting it some days.

Think my problem is compounded by it being a tbi set up, spraying gas at a closed throttle plate

[whittlebeast]

Andy

[boostin]

Andy

Ha ha ok I can when I get some skate time

[whittlebeast]

This is the sort of thing I am looking for when chasing down starting.

Here is what my motor looks like in the first second of coming to life. You can see from the MAP, when the motor starts to to crank. You can see from the Engine code when the squirt detects the motor is cranking as an Engine code 3. As soon as the motor exceeds 300 RPM you can see the engine code switch and you will also see the VE come on line. At the bottom, you see that the MAT and CLT are stable indicating that the grounding of the sensors is totally isolated on a dedicated ground plane.

You can't see it in this screen shot but my AFR comes on line 17 sec later. I power my wideband fron the same relay that powers my fuel pump.

Sorry, Forgot this screen shot.

http://www.nbs-stl.com/CrxTypeR/B18C%20Startup.PNG

Hope this helps

Andy