NoPistons -Mazda Rx7 & Rx8 Rotary Forum

NoPistons -Mazda Rx7 & Rx8 Rotary Forum (https://www.nopistons.com/)
-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   startup problems when hot! (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/startup-problems-when-hot-69407/)

-stig- 03-29-2008 02:56 PM

hello!



i have a newbuild full bridge engine, and i have big problems getting it to start when its hot. no problem when its cold... starts fine up to 50-60degree celsius. over that and the engine wount start, but runs really fine when its running..



got a power fc, 850/1600 and 2xwalboros. have tryed to lean it out and richen it up, but no reaction. it started fine on this map when hot last year, only difference is the bridgeport..



any ideas? have tried the cranking ms, but no responce...



regards,stig

hsmidy 03-29-2008 05:01 PM

well efi n/a engines isnt an area ive had alot to deal with but, ive had this problem with a carb n/a bridgy, it was flooding the engine when hot,



also how old are your injectors? they arent leaking are they?

Lynn E. Hanover 03-29-2008 09:10 PM


Originally Posted by -stig-' post='897428' date='Mar 29 2008, 12:56 PM
hello!



i have a newbuild full bridge engine, and i have big problems getting it to start when its hot. no problem when its cold... starts fine up to 50-60degree celsius. over that and the engine wount start, but runs really fine when its running..



got a power fc, 850/1600 and 2xwalboros. have tryed to lean it out and richen it up, but no reaction. it started fine on this map when hot last year, only difference is the bridgeport..



any ideas? have tried the cranking ms, but no responce...



regards,stig



What is a cranking ms?



If the closing point was moved much during the port job, (and if not whats the point?). you will find the compression down from preporting days. This means lower cranking compression, less fuel vaporizing and hard starting. A good hot battery and if all else fails, an MSD at least on the leading plugs. If everything is still the same, and it won't star on the starter, but starts easy when you bump start it. It it as I said, and a more energetic starter is required. Squirt in some motor oil and fuel mixture with an oil squirt can and try it. If it starts that way I was right. Always park on a hill.



Lynn E. Hanover

Lynn E. Hanover 03-29-2008 09:10 PM


Originally Posted by -stig-' post='897428' date='Mar 29 2008, 12:56 PM
hello!



i have a newbuild full bridge engine, and i have big problems getting it to start when its hot. no problem when its cold... starts fine up to 50-60degree celsius. over that and the engine wount start, but runs really fine when its running..



got a power fc, 850/1600 and 2xwalboros. have tryed to lean it out and richen it up, but no reaction. it started fine on this map when hot last year, only difference is the bridgeport..



any ideas? have tried the cranking ms, but no responce...



regards,stig



What is a cranking ms?



If the closing point was moved much during the port job, (and if not whats the point?). you will find the compression down from preporting days. This means lower cranking compression, less fuel vaporizing and hard starting. A good hot battery and if all else fails, an MSD at least on the leading plugs. If everything is still the same, and it won't star on the starter, but starts easy when you bump start it. It it as I said, and a more energetic starter is required. Squirt in some motor oil and fuel mixture with an oil squirt can and try it. If it starts that way I was right. Always park on a hill.



Lynn E. Hanover

Lynn E. Hanover 03-29-2008 09:10 PM


Originally Posted by -stig-' post='897428' date='Mar 29 2008, 12:56 PM
hello!



i have a newbuild full bridge engine, and i have big problems getting it to start when its hot. no problem when its cold... starts fine up to 50-60degree celsius. over that and the engine wount start, but runs really fine when its running..



got a power fc, 850/1600 and 2xwalboros. have tryed to lean it out and richen it up, but no reaction. it started fine on this map when hot last year, only difference is the bridgeport..



any ideas? have tried the cranking ms, but no responce...



regards,stig



What is a cranking ms?



If the closing point was moved much during the port job, (and if not whats the point?). you will find the compression down from preporting days. This means lower cranking compression, less fuel vaporizing and hard starting. A good hot battery and if all else fails, an MSD at least on the leading plugs. If everything is still the same, and it won't star on the starter, but starts easy when you bump start it. It it as I said, and a more energetic starter is required. Squirt in some motor oil and fuel mixture with an oil squirt can and try it. If it starts that way I was right. Always park on a hill.



Lynn E. Hanover

RX7 13B 4 UR AZZ 03-29-2008 10:06 PM

triple post madness

dudemaaanownsanrx7 03-29-2008 11:47 PM

When hot the engine wont need as much fuel, which is why mazda had a hot start system to lower the rail pressure. I've just begain learning to tune with the power FC... all i can suggest is playing with the fuel maps and checking your timing. The bridgeport as was mentioned wont allow as much compression. You can try flooring the gas pedal so the injectors dont fire and then when it begins to start let off.. im guessing the car starts just fine once you let it cool down? what plugs are you running? are they fresh?

-stig- 03-30-2008 05:51 AM

the engine is a rew with a t78 turbo.



I'll check my compression today, just too be sure...



cranking ms is how much fuel in the startup.



starts like a dream when cold!



injectors are 1year old, i could get them checked tho...



plugs are ngk 10'r, brand new...



i have tried pretty much with the throttle and fuelmaps, just need to try som more!

dudemaaanownsanrx7 03-30-2008 12:10 PM

there is some water temp adjustment tables for the fuel and timing. Did you try playing with them? the base "IGN vs Water Temp Cool" retards the timing 15 at 60c. Also if you're using the power FC to control idle, it uses a hidden map to adjust the timing, this map is apparently retarded significantly and can't be adjusted. I don't know if this map is used during cranking or just under idle though, i'm still new to tuning with the PFC myself. Do you have o2 feedback off?



Those plugs are a little on the cold side which could be adding to your hot start issues.. Do you run an ignition amp?

How much power are you looking to run?

-stig- 03-31-2008 02:54 AM

i hae played a bit with those maps, but with no luck, and the IGN va water temp cool is set to "0"...



i use the FC to control the idle, but it cant hold the idle now, have to adjust on the throttlebody to make it stay alive.



can i turn the idle control of?



o2 feedback is of yea, have no o2 sensor for the FC on it!



hmm... used the same plugs last year, worked fine... but could they be too cold? and would that affect the hot-start?



I've got the hks twin power. was hoping for some good power, up against 500rwhp.



stig


All times are GMT -5. The time now is 11:20 PM.


© 2024 MH Sub I, LLC dba Internet Brands