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Hi guys,

I have an 808 running an ecotec with a big cam (its a race car that has to use a 808 and had to be sealed) no access is allowed to the ecu at all.

My problem is when i start the car it seems happy, super fuely and lumpy as it should be. then if i let it idle it will almost stall then rev up and find its happy spot. i presume this is the ecu finding its idle spot. Although once it finds its idle spot it sounds different.. Hard to describe. when its held at around 3500 rpm when first started you can clearly hear how chunky it is then after its done its idle cycle its "normal".
I use the coolant temp wire to add resistance (fuel).


Main question;
Could my ecu be going into a limp mode once it goes though the idle cycle?

EDIT:
This is more a expression post to get ideas so i can diagnose possible problems.

Thanks

I guess if you can take a log you will get a better insight as to what may be causing it. Sealed ECU is one size fits all and there's probably not much you can do with the tune. Have you got a CEL light and data plug wired to the ECU? I would think you can do that because your not going to change anything with the ECU sealed but be able to diagnose.

It doesnt sound like limp mode just a poor transition from warm up with extra fuel to main run fuel. And the transition is so bad it triggers the stall saver. Sounds like it needs a tune. I bet logs would show you the fuel trims are huge. Sucks how your not able to

This is the stupid speedway officials not knowing enough about it and trying to keep the class all even! oh just run them all on a sealed 808, ecotec's close enough to a early buick .....

the main issue other than the fuelling will be out is that the bigger cam will want a higher idle, and the 808 will be trying to bring the idle back down to stock settings ..... you'll probably need to screw the idle stop in to get it high enough that the IAC can't bring the idle down too low or drill a small hole in the butterfly to add an air bleed that the IAC can't stop.

but the short answer is, it really needs to be tuned 1. for the motor and 2. for the motors mods..... I would be very careful with this thing, if its anything like my experience with an 808 on an ecotec, it needs a lot of timing removed and fuel added! if your flogging the ring out of it for lap after lap I wouldn't be surprised if it burns itself!

I dunno what you have in the car but I would suggest at the very least put a wideband in there and make sure its not going too lean and listen out for knock!

Holden202T wrote:This is the stupid speedway officials not knowing enough about it and trying to keep the class all even! oh just run them all on a sealed 808, ecotec's close enough to a early buick .....

the main issue other than the fuelling will be out is that the bigger cam will want a higher idle, and the 808 will be trying to bring the idle back down to stock settings ..... you'll probably need to screw the idle stop in to get it high enough that the IAC can't bring the idle down too low or drill a small hole in the butterfly to add an air bleed that the IAC can't stop.

but the short answer is, it really needs to be tuned 1. for the motor and 2. for the motors mods..... I would be very careful with this thing, if its anything like my experience with an 808 on an ecotec, it needs a lot of timing removed and fuel added! if your flogging the ring out of it for lap after lap I wouldn't be surprised if it burns itself!

I dunno what you have in the car but I would suggest at the very least put a wideband in there and make sure its not going too lean and listen out for knock!

Thats what i thought it was doing. it will trim back to find a idle. ill get a longer bolt and screw some idle in and see if its different. ive taken timing out of it via the balancer due to doing a head gasket from the standard timing. & had a wideband up it on the dyno last night. air fuel was around 11.5-12. so not to bad, little bit rich but im happier with it that way. with all calculations taken into consideration (compression ratio etc) it should not want any more timing then what i have in it atm.
So in short im trying to diagnose it to get it running better before even thinking about more timing and waisting dyno time like last night

I will spend some time with it today and post back.

if you need to put a longer bolt into the throttle stop then you probably have too much in it, maybe drill a 2-3mm hole in the butterfly then you will be able to close the throttle stop a bit more to have more control over it.