Hello all, I am hopeing someone can help me. I put a Supercharger on my 99 7.4 MPI last year which has turned out to be a year long problem. After installing it, I found that the factory ECU had a very low rev limit (4500), so I asked Supercharger about getting that changed. They recomended Arazona Speed and Marine. I sent it off to have them bump up the rev limiter. They called me recomending making many other changes to which I agreed since they said it would just make things better for me.

I got it back and the boat would not keep runnning. I sent it back, they noticed that they had not changed the ECU from a 4 bar to a 2 bar sensor, but they had sold me a new 2 bar to go with it. I spend another $45 in shipping to have them re-program again. Once I got it back that time, the boat ran, but I found that something else was wrong. No matter what the RPM, if I push my throttle past the 3/4 mark (either out of the hole or gradually), once I get past the 3/4 mark, the engine startes to stall and I get an engine alarm. Once I back it off below the 3/4 mark, after about 30 sec, the alarm goes away.

I spend $45 in shipping again and had them re-program to fix the problem, but after re-programming again (or so I was told), it is still doing the excact same thing. I asked them to just put it back to factory (which was an FE28) and they said they don't have the program to do that.

So I feel I am faced with no option but to purchase a new ECU as an FE28 in order to get my boat running correctly again and just forget about moving up the Rev Limiter. But I cannot seem to find anyone on-line who can sell me a new one.

Does anybody have an suggestions on how to either fix my problem or get a new ECU?

Thanks
Dave

just out of curiosity did you call precision marine and ask them, they are ecu experts.

http://www.offshoreonly.com/links/sh...&searchid=1590

Ditto.

Precision did the ECU work on my new motors....I had a few problems (mainly my fault) and Mark went above and beyond to get things right for me.

could it be that your fuel system is not keeping up?

No, not fuel, like I said, it does not matter what the RPM level is, it is based on postion.

I don't get why people are not doing custom tunes on these boats. You are playing with fire doing mail order tunes with forced induction. Its amazing that the boating industry is 15 years behind what we are doing with hot rods right now. I would be using GM computers and have a professional tuner on my boat with me. Then have it run right, the way I want it. We are doing this with all the new GM cars right now.

We have made 700rwhp on stock ls2's in the cars. Thats right only 6.0l's of motor. Then having them last 20k plus miles.

Just my thoughts take them for what they are worth.

Welcome to the world of speed-density fuel metering. You CANNOT tune the ECU without having the engine present with a wide band oxygen sensor installed. Shame on ASM for taking your money. They are ripping people off.

Michael

ANY ECM tuning outside of a dyno with a wideband O2 or in the boat with a wideband O2 is a complete shot in the dark. If you even get close, you are lucky. I am amazed how much my AFR changes just with different props!