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Old 08-04-2010, 01:11 PM   #1
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Default odd starting behaviour

50% of the time my car starts fine. the other 50% of the time (usually when I get the infamous "pop" at startup) it really struggles to start and cranks a little slower than normal. sometimes it starts with a little coaxing and about 10-15 secs of cranking, other times I have to abandon and leave it for a few secs.

Now if I leave the ignition on for 15 seconds or so before I try to start it, it seems to cure it, and when it does do it, if I turn the engine off for 30 seconds it then starts perfectly.

I have a new battery, and new leads and plugs, and I have not touched the startup settings from the DIY basemap. Its a pnp ms.

Could it be the coils are getting a bit knackered, or is it all to do with the infamous startup "pop"???

I dont fancy doing the improved spark mod, as the reason I bought a ms pnp and not a DIY pnp, is because i'm not the most confident with soldering etc...

The rest of the car is running awesome, so this is the only niggle now really.
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Old 08-04-2010, 06:06 PM   #2
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I can mod the mspnp for you mate, tbo all your issues are stemming from that.
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Old 08-06-2010, 03:23 PM   #3
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I can mod the mspnp for you mate, tbo all your issues are stemming from that.
I have heard lots about the "pop" at startup, but nothing about people with this issue...
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Old 08-06-2010, 03:29 PM   #4
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I can mod the mspnp for you mate, tbo all your issues are stemming from that.
I dont think his issues are stemming from that, I dont see how they can be tbh
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Old 08-06-2010, 05:27 PM   #5
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positive battery connection at the starter
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Old 08-06-2010, 05:27 PM   #6
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Originally Posted by oakesy2001uk View Post
Now if I leave the ignition on for 15 seconds or so before I try to start it, it seems to cure it,
What happens if you leave the ignition on for 2-3 seconds before engaging the starter?
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Old 08-06-2010, 05:47 PM   #7
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What happens if you leave the ignition on for 2-3 seconds before engaging the starter?
still does it if I don't leave it for long enough.

It is definitely happening only after this "pop". very odd, its fine when the pop doesn't happen.

Started like a dream on the way to work this morning, wouldn't on the way home, so left it on ignition on position for 10 seconds ish, then it started perfectly....

When it does start without issue, it is literally on the first turn... perfect. When not, it can literally stall the starter its that bad. like the battery is flat, but then you wait 10 seconds, and its fine, starts first turn.
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Old 08-06-2010, 05:59 PM   #8
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sounds like too much fuel when cranking...why not adjust your cranking pw table?
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Old 08-06-2010, 07:11 PM   #9
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thought the diy base map, worked well for people with that sort of setting, or have my RX8 injectors knackered that?

Anyone running similar want to share their settings?
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Old 08-06-2010, 07:17 PM   #10
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did you rescale the cranking table when you fit the new injectors?
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Old 08-06-2010, 07:17 PM   #11
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stall the starter? sounds like igintion is off enough that its iginting fuel when the piston is going up and stoping the piston\engine\starter
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Old 08-06-2010, 08:33 PM   #12
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did you rescale the cranking table when you fit the new injectors?
not touched it from the base map, which will be the issue by the sounds of things. I take it is dosent use the req fuel to scale it?

Any advice on how to scale it?
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Old 08-06-2010, 08:36 PM   #13
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I dont think his issues are stemming from that, I dont see how they can be tbh

But if they only happen after he pop they do stem from that!

The air becomes much hotter localised in the manifold, I had the same 'issues' and Joes circuit fixed it....
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Old 08-06-2010, 08:45 PM   #14
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not touched it from the base map, which will be the issue by the sounds of things. I take it is dosent use the req fuel to scale it?

Any advice on how to scale it?
Dude, RTFM....

It's in the mspnp manual!
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Old 08-07-2010, 01:14 PM   #15
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must have missed that bit in the manual, sorry guys. So with my RX8 injectors (415cc???) and stock 1.8's being 265 the accel enrichments and cranking settings need to be 2/3rds what they are currently......

I'm amazed it starts at all, never mind intermittently. Sorry for the noob error...

Whilst I'm at it, how do I know what injector opening time to use with my RX8's, what are those using them on here running? I'm going to re-scale my fuel table and re-tune anyway, wasting resolution at present. Might as well do it all at once...
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Old 08-07-2010, 01:28 PM   #16
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265/415 = .63

for your cranking table do this:

current value - 1 x .63 +1

EX: 5ms - 1 x .63 + 1 = 3.52ms

for the accel enrichment simply take the value x .63
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Old 08-07-2010, 01:55 PM   #17
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Originally Posted by oakesy2001uk View Post
Whilst I'm at it, how do I know what injector opening time to use with my RX8's, what are those using them on here running?
Guess.


Seriously, the opening time value isn't highly critical. Any error on your part will be compensated for when you fine-tune the VE table.
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Old 08-07-2010, 02:19 PM   #18
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my opening time is set to 1.2, so I have subtracted 1.2 instead of 1. I have also done the after start enrichment's as said above.

I'll go and give it a go.... :-) Thanks guys.

EDIT - well it still starts with the new settings so thats good! They must have been miles out. The pop didn't happen though so will see what happens when it does.

I'm going to have a re-scale of my VE table, as I have 4 unused rows, same with my timing, and do a bit of tuning tomorrow I think.
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Old 08-07-2010, 03:59 PM   #19
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Easy to check the opening time by changing number of squirts from 2 to 4. If AFR's stay the same, opening time is correct.
I found that the opening time for the stock injectors is 0.9 but I forgot to redo it when I installed the RX8 injectors. I'm now running full sequential, so the above procedure no longer works. I'm still using 0.9 with the RX8's but if you could check?
1.2 is a bit too long. Most injectors are < 1ms.
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Old 08-08-2010, 07:50 AM   #20
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1ms seems to work best using the above, so I have changed it to this, don't know why it was 1.2, does seem a little high.

Its lumpy and stalls when I move it to 4 squirts from 2, but when I restart its, lumpy, but closest to the same AFR's when opening time is set to 1ms, So I'll retune to this.

So...

I have tuned my afterstart enrichment, and my cranking pw's, my req fuel is also done. Do I need to change anything else from the DIY base map to match up with my injectors?

What about the figures in the accel wizard page? do I need to do anything with these?

Last edited by oakesy2001uk; 08-08-2010 at 12:01 PM.
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