Ok, so here's the deal. I'm going to start looking into supercharging the car within the next year. I want to install some sort of tuning device and a wideband and get used to playing with it before it's boosted. I want to go with an AEM, but might end up going with a APEXI SAFC to start out with.

Ok, so the problem and question. I've been running my car with the MAF unplugged for about 8-9months. It runs pretty decent like this. With the maf plugged in it is very sluggish and will not get out of its own way. First question.... If it runs good with it unplugged is it a bad ECU or just a bad maf? Or both?

Second question..... If I were to use a SAFC or AEM would I need the maf plugged in, or could I overide it and tune it the way I want?

Hopefully this makes sense. I'm just trying to figure out if I need to bother with replacing the maf or if it wont be needed depending on what tuning device I go with. I think the AEM might not need the maf (not sure though)

Oh, and I did search, but couldnt really find an answer. Also, please dont judge me about me driving with the maf unplugged.

 

your gonna need a way to measure air into the engine if you plan on supercharging it. Any DLC codes?

 

I run a megasquirt MS2 on my merkur XR4Ti. It uses a MAP (manifold absolute pressure) sensor. You can set it up for a MAF sensor but the MAP works fine for me from idle to 25# of boost.

I got my MS and everything else from Diyautotune.com

Great guys over there. I also recommend there book on fuel injection.

 

Also...

I'm not sure how the lexus ecu does it but... In my merkur, when it was factory, if I unplugged the "MAF" sensor the computer would go into a limp home mode. Basically it would run a preset fuel map so you could get home.

If the lexus computer works similar then it's possible that your MAF sensor is giving the wrong reading when it's hooked up.


Check out the megasquirt tho. I learned so much about fuel injection after building the ms2, it's pretty amazing how well the factory ecu works. They get it to run at any temperature and still deal with emissions!

 

Hey Mike, Check this thread out https://www.clublexus.com/forums/per...n-92-94-a.html
I found it when I was browsing around on the same theory as to why mine seems to have more power with the MAF unplugged too lol

 

if your ecu is fine.. and want to run a piggy back MAPECU is cheap stand alone megasquirt would be great.

 

Thanks for the input guys! I forgot about megasquirt. That seems like a good way to go also.

As far as the maf being unplugged. I think it does resort to a base map setup for safety. I'm pretty sure the maf is just giving off the wrong reading. I know there is a way to measure what its reading, but I think that might be a little past my skill level. If I were to go with the megasquirt, I wouldn't have to deal with the maf at all.

 

map ecu u can get ride of the MAF as well.. theres 3 different versions.

 

so instead of fixing the AFM (you don't have a MAF, they started in the '95 model year) which you claim is "over your head" so to speak, you want to add another layer of complexity with an aftermarket piggyback fuel controller so you can supercharge your engine?

I think you need to up your skill level, read up, learn, and then fix your car before you begin modifying it for power. Once you do you'll probably come to the conclusion that "hmm, maybe I would want timing control since NA timing curves probably aren't the best for a forced induction engine" and etc...

 

Sorry PD I was a being a little sarcastic. I can fix or replace the afm on the car. I'm just not sure how to go about seeing what the afm is currently reading when plugged in to find out if its working properly. I don't know if its voltage or .... Honestly I havn't looked into it much.

I will want timing control later down the road. I am still searching and learning about the different piggybacks and fuel/timing management systems out there that I could go with. And yes if it is a bad afm or maf, then I'll probably just hold out until I get/install some sort of air/fuel management system instead of buying a new one. There pretty expensive to replace, and it would be pointless if I wouldn't even use it later down the road. I might try and find a good used one for now.