Sweet!

 

Excellent. I will keep this thread in mind when setting up my cranking pulse injection.

 

lol, cool. i lol cause i've been there!

 

lol.

 

Well, i spoke too soon. still is giving me trouble. it started to get cold again here in atlanta and now she still wont hot start. hm....

Like i said, it started a couple of times, but when it wasnt soo cold outside

 

if the weather changes, it'll be in a different part of the map, you really need to tune it in the summer and in the winter to get it 100%

if it makes you feel better the Rx8's do it too, if you have a cold morning, and a hot afternoon, the car doesn't like it

 

Ok. im gonna go ahead and fiddle with it some more. wish me luck.

 

Well, its official. I have no idea why my car wont start hot. None. zero.
I upped the idle rpms - nothing
I lowered the idle rpms - nothing
Made sure i had high Impedance injectors. yup.
reduce my prime pulse timing - nothing
reduced it some more - nothing
Reduced the amount of fuel in that area of the map. like -1,-2, and 0 psi of the map between 0 and 750 rpms. nothing.

literally nothing i have done has helped at all.

 

what i do, and seems to work is the following. its based on info in the FSM's and training books, as i'd ideally like to start with the stock map and corrections and tweak that, because it works.

it helps to be methodical, there are thousands of data points, ((32x32)x2)+all the correction maps, in the ecu, so it helps a lot to have some logic to figuring all of these out

cranking RPM in the main setup is either 380rpm or 499rpm, in the various training manuals they mention what the stock ECU uses as cranking, and i think the Rx8 is like 380 and the FC is 499, but either should work and it just needs to be lower than you idle speed.

second the FSM, and training manuals all say the cranking timing is 5 BTDC, so i start there. you'll find on a really cold engine this can be too much, and on a hot engine you can run a little more, but i just start @5 BTDC

third, i get it idling right. i like to find a good pulsewidth, and make the cells around idle, all really close, so if it varies a little nothing changes, the ECU does interpolate between cells so any big jumps will make things unstable. idle timing is anywhere from -5 and 20, like stock to +5 and um i keep the 15 degree split. you can run more timing at idle, but it seems to get rougher. verify with timing light is a good idea.

fourth, the coolant correction should be off by 65C, another value from the FSM's, basically @65c, the stock ecu goes into closed loop, so all the coolant and air temp corrections are zero from 65C up. if you wanted to set some overheat protections, its fine, but make the area from 65c to 90c flat.

fifth, then you should work on the primer map. the primer map needs to be pretty much manually done from the coldest temp you ever see to the hottest. i find the best starting is right on the verge of flooding, i start lean and add fuel. its usually easiest to do hot starts as you can just do it one after another. cold starts take forever as you need to let the car cool in between.

 

what stock map?

 

Post your map and do a hot compression check.

 

Ok i will. i dont have a way to check compression though. So i will do the choo choo train of hope (unplugging the power from the haltech and taking a spark plug out.)

 

the stock ecu.

 

So the FSM and training manuals have spark and fuel table information?

 

here and there. the JC cosmo training manual has the timing map, but the load units are unlabeled, so its a bit useless. its also kind of teeny

also if you do some searching, Henrik has posted the stock ECU correction maps, and the S4 timing maps, the stock maps are load vs rpm, and psi and load are different enough, that you can't just plug it in. however you can get an idea of what the factory ran for timing.

 

here is my maps. FML2 is the map thats currently on the car. you can see what i was trying to go for.

 

what's your idle speed and vacuum, approximate is fine

 

-8psi and 1000 rpm

 

ok so i took the FML2 map and did the following: most of which can be found in the training manual, http://foxed.ca/index.php?page=rx7manual#secondgen

try it, i think i changed too much stuff for it to work, but make sure the ignition settings didn't get borked, and try it, it'll either work or it won't!

the cranking Rpm got raised from 380 to 470, per the training manual

fuel map; the ecu is interpolating between cells, i like to have the cells around idle be the same or really close, it was 2.1 @-8.7 and 2.7@-7.2, i averaged it out (literally, 2.17+2.7/2), to 2.54 in the cells around idle. 2.54 seems like it should be rich, but it depends. idle P/w should be really stable now.

injector firing angle; i changed it to the values in the training book. i've never really noticed a difference, but we have the default values, so might as well use em

coolant temp correction; i linearized it.

post start enrich, Mazda raises fuel pressure over 65C coolant temp, Haltech uses more pulsewidth. i added the Mazda break point, but i actually left the value that you had.

prime pulse time; changed to the values in the training manual, bring your life jacket! this will need to be tweaked, i probably should have left this alone...

ignition: i smoothed out the idle rpm timing a little, like the fuel, i want the timing to be stable @idle

split map: i gave you the 15 degree split at idle, just to be more stock

crank timing; i changed it to Mazda's 5 Btdc.

ignition air temp; Henrik posted the actual map from the stock ECU, so i put it in.

ignition coolant temp; Henrik posted this too.

and thats it! good luck

 

Ok cool, i will check this out and post results.

 

FWIW I upped my ignition cranking as the engine gets hotter. My engine is (street) ported though and has 8.5 rotors. I believe my ignition cranking at 185F is 18 degrees. If not 18, it's close to that number. Primer pulse is around 12 IIRC. The engine starts very well after heat soaking.

 

hm.......

 

yeah, but i dont have any BAC valve. i need one.

 

- Are you using the FFE trigger kit? Trigger angle with those is supposed to be 90*.
- Did you wire the trigger loom with the green wires for ground? If so, and you should have, the check boxes for -ve at the bottom of the page should be unchecked.
- No way you should need that much trigger filter. Are you even getting an RPM signal when you're cranking it and it won't start?
- Why is the filter level of the TPS set to 20?

I don't see anything in the mapping that would keep it from starting. I'd change some stuff, but it should fire. The trigger settings are all wrong and if the trigger angle is wrong, you're timing is 10* retarded.

 

Hello, I have the same problem.
When the CTS is below 122-158F it`s no problem with starting but when the CTS above 185F don`t start.

Ported, fresh rebulid engine with good hot compresion.
Cranking speed when it`s cold or hot the same.
I don`t have stepermotor, idle control only by screw in throttlebody and it`s set at 1500rpm with -54kPa when idling. Fuel pressure in vacum are 37PSI.
Injcetors no leaks.
Spark plugs and wires are new.
It`s race car so no AC no stereo etc.

I tried with Inj Dead Time but when it`s hot or cold battery voltage at cranking are the same.
I tried with Prime Pulse Time in range of 5-30ms
I also tried Crank Timing 5-15 (when engine is cold it`s starting at 10deg with no problem).
It`s very hard to tune when engine turn of and don`t start when it`s hot.

Any idea what`s wrong ? It is related with 113F air intake temp. or fuel map in 0-500rpm ?

Sorry for my english.