ECM flash

[mudchucker]

Originally Posted by tmoss

your cam may not be providing enough idle vacuum to idle right - bet that is where yoiur problem is - right? Does it run fine at WOT? Definately only run 19# injectors with the SD EEC. An AFPR can help with tune if your car needs more than 39# of fuel.

Unfortunately that is not where my problem is. What is happening is at WOT it runs great until about 3000-3500 rpm then it start bucking and kicking, sometimes even backfiring. I would have thought it was a timing issue, but i have tried every timing mark from 0-full advance trying to get this thing to run right. Spout in, spout pulled, nothing helps. it seems like it is running rich as hell at idle and leans way out as the rpms go up. I have installed a larger fuel pump and just put on an adjustable regulator, didn't change a thing. My only other thought is maybe the MAP isn't getting enough vacuum to do what it is supposed, but not sure. So i figured i was beyond spec for the stock ECM and changing to MAF is the next option, or getting a custom tune. However, i can't seem to get anyone to give me an idea of cost for an ECM tune. I know how much it will cost to go to MAF, but i am trying to way my options.

Thanks,
Aaron

[tmoss]

If you could find someone with an SD car that runs well, a swap of the MAP for a short period could rule it out. If you have a spare SD computer you might try that too. I have one at all times waiting in the wings. Almost sounds like it is computer related because once the MAP sees low vacuum and the Fuel regulator goes wide open, it is the injector controlling fuel then. You did pull the vacuum hose off the fuel regulator and checked for fuel in the vacuum hose right?

[mudchucker]

Originally Posted by tmoss

If you could find someone with an SD car that runs well, a swap of the MAP for a short period could rule it out. If you have a spare SD computer you might try that too. I have one at all times waiting in the wings. Almost sounds like it is computer related because once the MAP sees low vacuum and the Fuel regulator goes wide open, it is the injector controlling fuel then. You did pull the vacuum hose off the fuel regulator and checked for fuel in the vacuum hose right?

I do have another ECM that i will try tomorrow. Didn't think about that. Why would there be fuel in the vacuum line? Also, with SD don't i have to have the ECM flashed or retuned with any major upgrades? I do have a large comp cam, wndsor Jr. heads Covra upper and lower, 65mm throttle body.

[tmoss]

If the diaphragm in the fuel pressure regulator fails, it won't control fuel pressure correctly and the leaking fuel gets sucked into the upper intake by the vaccum line = WAY too rich.

Look ast my sig, 277rwhp on 19# injectors and I have nothing more than an adjustable fuel pressure regulator and the base timing as tuning tools. A "large comp cam" and definately the 24# injectors are playing havoc with the computer VE tables. Do you have the 19# injectors you could put back in? If a MAP check, computer change and trying the 19#ers result in no change, I'd definately go to MAF and forget fooling around with a chip for the SD system - it will be cheaper and work better.

[mudchucker]

Originally Posted by tmoss

If the diaphragm in the fuel pressure regulator fails, it won't control fuel pressure correctly and the leaking fuel gets sucked into the upper intake by the vaccum line = WAY too rich.

Look ast my sig, 277rwhp on 19# injectors and I have nothing more than an adjustable fuel pressure regulator and the base timing as tuning tools. A "large comp cam" and definately the 24# injectors are playing havoc with the computer VE tables. Do you have the 19# injectors you could put back in? If a MAP check, computer change and trying the 19#ers result in no change, I'd definately go to MAF and forget fooling around with a chip for the SD system - it will be cheaper and work better.

I had the 19#injectors in for the past several months and was told to try the 24's in hopes to helps, but it didn't change a thing. I will check the MAP today and see what is going on there.

thanks for the help.

[USMC302]

I' don't think this will help you but here is how to reset the ECM...

Disconnect the negative battery cable.
Turn the headlight switch on.
Wait 10 minutes.
Turn the headlight switch off.
Reconnect the battery cable.

Your ECM is now reset.

After resetting the ECM,

1) Start the engine, and allow it to idle for 1 minute.
2) Shut it off, and wait 10 seconds.
3) Start the engine, and turn on the headlights on high, and your a/c, with the fan on high, and let it idle for 1 minute.
4) Turn all the accessories off, and turn the engine off, and wait 10 seconds.
5) Start the engine, and make it idle @ 2000 rpm for 1 minute.
6) Shut it off, and wait 10 seconds.
7) Start the engine, and turn on the headlights on high, and your a/c, with the fan on high, and make it idle @ 2000 rpm for 1 minute.
8) Turn all the accessories off, and turn the engine off, and wait 10 seconds.

This is the best way to relearn the ECM, but you should take a 10 minute test drive afterwards to make sure all is well.