Need Help with my 97 330hp 454 mpi..
Long story short my ECM thinks my Coolant temp goes from -40 to 180 at random thus flooding the engine. usually when i floor it out of the hole... Been fighting it for years.
my kids are old enough to want to ski and tube so i have to do something...
my options are:
1. find an old ECM and hope its in good condition. I'm also having VST issues now...so that's more money on old stuff
2. convert to Holley HP EFI or something similar, and still have to do something about the VST
3. Convert to a Carb... whats all involved besides intake and the carb,and flame arrestor? Ive had mixed answers on this

any and all help is needed and appreciated here. i'm definitely savvy on wrenching on cars... I'm also familiar with Holley HP EFI since i run it on one of my cars (its pricey though)

If it's a mefi 1it wont be locked (should be since it's a 97) it could simply be programmed to add 0 fuel at -40, when I tune any mefi I always put zero extra fuel in the -40 box anyways as that is ALSO the default it will revert to if connection is lost to ect. I would be inclined to believe you have a loose ect connection or damaged wire in harness as a open ect circuit will plunge the tune into-40. On a mefi 3 it adds 40+% fuel for -40, not many of us get much -40 boating in

its not the ecu,,its in the ect wiring.

any one have a pinout they can send me?

i have converted a few to carb using the eldebrock 1410 was easy and runs better than the fuel injection where the computer failed

Better how? I can see maybe a little more power but what about fuel economy? i was thinking economy will go down 20-30%

No - the EFI from Merc runs on the very rich side of things. You'll probably make gains on the economy side.

This is a simple wiring from the sensor issue or a sensor issue itself. For the love of God don't swap a new ECU. That is not the problem.

well i installed all new sensors and have had them checked so yeah maybe a wiring issue but without a pin out im looking for a needle in a hay stack

no your not,,your looking at 2 wires,,black(ground from ecu) and yellow,also from the ecu.easy to find on the computer plugs.ohm them out and find the problem.
or,pull the 4 wire plug on the distributor and slap an intake and carb on it.your choose