Mazda MX-5 Miata banner
1 - 20 of 29 Posts

Registered
Joined
307 Posts
Discussion Starter · #1 ·
Hi, recently ish i had the ms3 mini tuned, and mostly is all good. I didnt leave the car there overnight so he guessed at the cold start tune. (he has a fair bit of mx5 tuning experience so i hoped his settings would be ok)

The cars a 99, ev14 injectors, new bosch battery.
Probably one in 3 starts im getting what i presume is starter kickback as the engine locks as its about to fire.
It takes a bit longer to start every time compared to the stock ecu.

If i could get the car to fire a bit earlier im pretty sure the kickback would be avoided, but i dont know how to do that unfortunately.

The cranking timing is already set to 0 degrees by the tuner, so i cant lower it anymore? I cant use negative figures?
The cranking rpm is set to 300.

Initially it would die after starting sometimes, but i added some fuel to afterstart enrichment and is all good now.

If i prime the fuel pump say 5 times before starting, then the engine fires sooner (same time as stock ecu used to) with no probs at all and no kickback. . - Any ideas why this would happen? Presumably its upping the fuel pressure a bit more from priming multiple times?

Any help appriciated as always 馃檪
 

Banish a little rust a day people
Joined
5,306 Posts
Sub'd as I have the same issue. A proper map improved it a lot but it still ocassionally does it.
 
  • Like
Reactions: UcatchMyDrift?

Happily expanding the To Do list since 1997
Joined
10,688 Posts
Just thinking out loud but I wonder if that might be a symptom of having the crank/run transition happen at too low an rpm setting. I mean, if the ECU decides the engine has started and flips from the 0掳 cranking timing to the more advanced running timing that might actually stop the engine if the rpm is low enough and the ignition timing advanced enough.

Actually, is there a crank-to-run setting where you can blend from one advance setting to the other over a few engine cycles? I don't remember (and should probably have looked it up before I started rattling on).

[Edit to add] the crank-to-run engine speed is the setting "Cranking rpm" in my MS2. Not familiar with MS3 mini but I guess it's all pretty much the same to TunerStudio.
 

Registered
Joined
307 Posts
Discussion Starter · #5 ·
Just thinking out loud but I wonder if that might be a symptom of having the crank/run transition happen at too low an rpm setting. I mean, if the ECU decides the engine has started and flips from the 0掳 cranking timing to the more advanced running timing that might actually stop the engine if the rpm is low enough and the ignition timing advanced enough.

Actually, is there a crank-to-run setting where you can blend from one advance setting to the other over a few engine cycles? I don't remember (and should probably have looked it up before I started rattling on).

[Edit to add] the crank-to-run engine speed is the setting "Cranking rpm" in my MS2. Not familiar with MS3 mini but I guess it's all pretty much the same to TunerStudio.
馃憤馃憤馃憤馃憤. Yes that reminds me of a thread i read a while back. My cranking rpm is set to 300, and im sure i remember reading others setting it to a higher rpm (such as 400-450) so that the the ecu doesnt think that the engine has started when it actually hasnt...,,, which would possibly result in what you say above... Ill give that a try next..
Also, priming the pump multiple times allows the car to start sooner, but contrary to what i said earlier, today it kicked back slightly then too, so i was wrong with my assumption 馃檮.
 

Registered
Joined
307 Posts
Discussion Starter · #6 ·
If you fancy paying for the settings, I had a guy called Tom Chappenden sort my start up settings out for 拢50 over teamviewer. His settings worked first time.

I still have some issues but they are issues with my car, not his tune.

Just out of interest who's map are you on?
I got the car dyno mapped by hybrid tune in suffolk.. I expect they would only charge me around 拢50 at a guess to do the cold start tune if i left the car overnight. Was hoping to get it starting a bit better myself and learn in the process! - ive not given up yet, but i may speak to them at some point thanks...
 

Happily expanding the To Do list since 1997
Joined
10,688 Posts
My cranking rpm is set to 300, and im sure i remember reading others setting it to a higher rpm (such as 400-450) so that the the ecu doesnt think that the engine has started when it actually hasnt
That sounds like it could be the issue then. I think the rule of thumb is to set Cranking rpm a bit higher than the engine can turn on the starter, so you can be confident when it hits Cranking rpm it's because it fired.
 

Banish a little rust a day people
Joined
5,306 Posts
I think in reality is doesnt turn over at much over 100rpm on the starter. Worth a try.
 
  • Like
Reactions: UcatchMyDrift?

Registered
VVT swapped NA & TD04 turbo NB
Joined
420 Posts
I got the car dyno mapped by hybrid tune in suffolk.. I expect they would only charge me around 拢50 at a guess to do the cold start tune if i left the car overnight. Was hoping to get it starting a bit better myself and learn in the process! - ive not given up yet, but i may speak to them at some point thanks...
It's good that you have the patience, I managed to get mine starting better but then it's everything else after and Tom found a bunch of settings that were not only wrong but harmful to my car that I never would have spotted. Good on you for having the patience to learn!
 

Registered
Joined
307 Posts
Discussion Starter · #11 ·
It's good that you have the patience, I managed to get mine starting better but then it's everything else after and Tom found a bunch of settings that were not only wrong but harmful to my car that I never would have spotted. Good on you for having the patience to learn!
Hopefully as the tuner guessed at the settings based on experience, i wouldnt have thought in my case that there would be any damaging settings,, i hope! But thanks,,, im not that patient really! 馃槄
 

Registered
Joined
307 Posts
Discussion Starter · #12 ·
I think in reality is doesnt turn over at much over 100rpm on the starter. Worth a try.
I copied this from miataturbo:

"The point of the Cranking RPM is to give the engine a chance to start and stabilize before going into "run mode". That's why you should set it to slightly above what your car normally cranks at. My car, with a dodgy battery on a cold morning will crank at about 170-180 RPM, but in the summer with a full charge it'll spin at 250-260 RPM. So My Cranking RPM value is set to 400 just to be sure the engine is running good enough to "survive" the "run mode" settings."

So with any luck it will sort it.. Have started the car 3 times and is ok so far.. 馃
 

Registered
Joined
307 Posts
Discussion Starter · #13 ·
Well typically, its still happening. Kicked back pretty bad at lunch today, enough to cause the alarm to buzz for a second droping the battery voltage. Its almost like hydraulic lock,, couldnt be too much fuel?
Ill try and increase cranking rpm to 450-500, but cant see it helping now.
Unless anyones got any other ideas, i better speak to the tuner when i get a week off work in a week or so, see what he says. Just hope my starter survives!
 

Registered
Joined
307 Posts
Discussion Starter · #14 ·
One thing to note is that it doesnt do it on a warm engine.
Plus, it used to happen occasionally on the stock ecu, when for example i released the key before the engine actually started, then turned the key straight away again, it would do it then..
 

Registered
Joined
307 Posts
Discussion Starter · #17 ·
I think in reality is doesnt turn over at much over 100rpm on the starter. Worth a try.
Id be really interested to know if priming the fuel pump 5 times avoids kickback on your car? And enables the engine to start in about half the cranking time? (which is why i think its avoided - as it starts quicker, before it has a chance to kickback)..
 

Registered
Joined
22 Posts
I used to get this a lot on my '97 1.8 with MS2 but haven't had it for over a year now and I haven't changed any parts related to starting or charging. I used to think it was the battery voltage dropping too low (measured down to 8.7V in the logs) but I'm still getting that kind of voltage on cranking. I checked back to my 2020 MSQs and the only relevant difference I can find is that I dropped the cranking dwell from 6ms to 5ms. Doesn't seem like much, but might be worth a try.

FWIW your cranking fuel pulse is a lot higher than mine. At 20C I'm at 200%.

Reading your comment on warm starts being OK - another long shot here - what grade of oil are you using? 0W40 will be thinner and give easier cold cranking than 15W40 for example.

Good luck tracking it down!
 
1 - 20 of 29 Posts
Top