I recently put a s5 TII block into my s4 n/a, and Im using a zeal plug n play megasquirt to run it.

First problem is the rpm signal, during cranking it reads 0 rpms at first, then it jumps up to 50-200. The entire time it reads "cranking" on the bottom so I would think it is getting a signal, but for some reason its just not displaying?

Second problem is that it is not holding the settings for some reason.. It just resets it self to 350 cubic inches, and wipes out the primary fuel map, but the secondary seems unchanged. Im thinking this is a problem caused by the laptop we are using. It has an older version of megatune on there as well, and when you start megatune it pops up with a few errors.

We are going to try using a different laptop to see if that changes anything. Also I think I will try to clean up a few grounds, mabey add a few.

Anything I may have overlooked?

Edit: ok, Im almost positive the rpms problem is a ground... I had cleaned a few grounds and the rpm signal was good but now its not. weird

Thanks

 

Sounds like you've about answered your own question about the RPM issue. Good grounds are very important, especially with the megasquirt. Just about every time anyone has complained of an RPM issue, cleaning up the grounds fixes it.

As far as the settings go, you shouldn't be using a primary fuel map and a secondary one, there should be the primary fuel map, and staged injection should be configured.

The settings we sent already preloaded should've been enough to get your engine started. If you need a T2 map, PM tofuball, and he'll send you our base T2 settings.

the "350 cubic inches" setting is not stored on the MS, only "req_fuel" is stored there. The 350 cubic inches is just one of the things you set in the wizard to figure out a good req_fuel.

I believe we also sent a version of megatune on the CD we sent with the MS, so you could just load that on your laptop.

Ken

 

Definitely, the MegaSquirt is a VERY sensitive device. If you've got noise or bad grounds, it will pick that up.

 

Ken it's setup that way because I set it up that way. I have it running with staged injection and dual fuel maps. I run the second map starting at a higher load and rpm which primarily kicks in on at the first signs of boost. The main fuel map really only runs up a short way into boost but also up the rpm range so that I know he will always have fuel no matter what load the car runs at. After a certain load point shortly into boost, the primaries do not add any more fuel. I use the secondaries to add all of the fuel above about 2 psi or so. I want the amount of total fuel injected to increase farther up the intake manifold as rpms and boost rise and I really want to taper fuel AWAY from the primaries. I do this for atomization. I hope I'm describing this properly. It's a bit unconventional but it works. It also gives me additional load points for tuning in boost that I didn't have before. You need to rethink your injector size a little bit when doing this as your primaries don't contribute as much as they normally would but he's only going to run about 8 lbs of boost or so on a stock TII turbo so what he has in there right now is fine.

The biggest issue has been with the fact that I can't get the car started. He doesn't have a tps and I've always had issues when trying to tune in vacuum mode (or whatever it's called).

 

Well, my suggestion is to start up the car on the settings we sent. Then I can tell what the issue is being caused by. We tested each MS and adapter in our test car before sending it, so if you start out with what we sent, and see if the car will start that way, it'll be easier for us to pick up and help you debug.

Your explanation of your settings makes sense, but I want to start with as many things in a state I know and am familiar with before moving on.

Did you guys get the RPM signal fixed up? Does it display good RPMS all the time now?

The "vacuum" mode you're talking about is "Speed Density"

Ken

 

That's actually the main problem. It doesn't want to read an ignition signal while cranking. We can pull start the car every time though and I can keep it idling after it does start. Brad's checked his grounds over and over again and has even added grounds between the block and the battery. I'm working on a brand new harness so we don't have to use the stock one anymore. I haven't really had any time lately to work on it.

 

ahh, ok, have you tried adjusting the hysteresis pot?

 

Hysteresis pot? That's a new one on me. What's it do?

 

It's a potentiometer on the v3 conditioner that adjusts how low the input signal must drop before the circuit output drops to ground. It is used for trying to get rid of noise on the input signal (depends on the noise though).

Here's a link that describes what the potentiometers do:

http://www.megamanual.com/ms2/vradjust.htm

EDIT: Rotarygod, PM me your phone number, or I can give you mine... I've had an idea and I want to walk you through doing it. If it works, I'll post details here.

Ken