Ha... No, I didn't cut the sensor cable. I had to unwrap my Megasquirt wiring harness, cut the 02 input wire and re-route it into the passenger compartment.

As for the ground - the LC1 had two grounds, one for the sensor and one for the heater. The LC2 has a single ground wire for everything. I didn't want to run the heater ground through the megasquirt, so instead I grounded the lc2 to the engine at the same point I grounded the Megasquirt (left cam cover).

Minor update -

I ran the engine a bit more over the weekend, and found that the a/f ratio is actually in the 12-13:1 range. Apparently the LC2 takes a little bit to initialize, then it reads fine.

I was also able to make some adjustments to the idle air valve (in other words, figure out how it works). The car is now idling around 1200 rpm, which is better than the 2500 I had before. I'm not sure how I'm going to get the idle the rest of the way down, but I think I'm on my way.

On the idle issue: is the Throttle Blade all the way closed? The TB should have a stop screw for adjusting the blade at the idle stop. If the Idle is high try closing the blade more if you can.

Yes, the throttle blade is closing completely. It was slightly open when I started, but it is closed now.

I'm thinking that I may have a vacuum leak somewhere, but honestly, I doubt I'll figure out much until I can get the car outside (or at least keep the garage door open a few minutes without freezing to death).

Here are my thoughts on the air leak...

Have you turned the idle air bypass screw all the way in?

I found that the 3.2 intake runners can catch on the air shroud in spots. Minor file of corners of shroud makes them sit level.

Also, the MS has an idle valve test mode that you can use to fully close the idle bypass valve. Make sure it is all the way closed using a flashlight through the valve.

the 3.2 manifold also wants an 0-ring on the throttle body. I am not sure if you installed that when you switched it out.

There are usually several air ports on the Bosch (Porsche) throttle bodies. Make sure they are all capped off if you are not using them for the MAP sensor connection.

You can pressurize the manifold through the MAP line using an air compressor and about 10psi. if you seal the top of the throttle with some tape you should be able to find the leak pretty easily.

Hmm... idle air bypass screw?

I'm guessing that is the screw on the throttle body that I haven't touched. That may be the issue. I'll check that out next.

No idea why I hadn't thought to check that.

I did use the MS idle valve test mode. Surprisingly enough, my idle valve is open below 35% and above 55%. I'm going to mess around with those settings a bit more and see what I find out.

O-ring (a new one) is in place on the throttle body, and all of the vacuum connections are capped off (or at least, they should be - I'll double check).

I'll probably use the low pressure test you mentioned. That seems like the easiest and fastest way to find the problem.

Thanks!!!

Yes. The TB should have a set stop for the butterfly valve to ensure it does not contact the side walls and gouge or get stuck. This is usually set at the factory and does not need adjustment.

Then there is a bypass valve with a needle valve. on the 3.2 throttle body it is on the front center bottom right above the idle valve. It is a very fine thread so it will take a lot of turns to see a big difference.

Hope that solves it.

I'm running a 944 throttle body (because it was cheap), and unfortunately, the stop for the butterfly was missing. I replaced it with a socket head bolt and nut.

I haven't messed with the idle air bypass screw screw (yet).

Is this correct, or did you say it backwards? My 3.2 ICV is CLOSED <25 and WIDE OPEN at 60.

Jamie mentioned testing by looking at the moving valve inside the air path. I did it by sucking/blowing on the hose while using the MS3 test routine to vary the valve position.

Latest update -

The car is idling nicely now. I turned in the idle bypass screw on the throttle and figured out how the idle valve was supposed to be set.

I did write the idle valve settings backwards. It's fully closed around 30% and fully open around 65% or so.

I also got the LC2 mounted, properly ran the vacuum hose, and basically got a lot of things tidied up.

No updates for a while, but quite a bit of progress has been made.

I've started to tune the car, or more accurately, I've started to try and figure out how to tune the car. It's running pretty well, but really rich.

Here's a question for the forum - at idle, the car is making an odd noise. It's hard to describe, it almost sounds like a bearing, but not exactly. It's a high-pitched noise, and it seems to be coming from the intake. It is louder at the cone filter. It could actually be a whistling noise. It did not make this noise before, but I recently cleaned out the throttle bypass valve on the throttle body. Is it possible I'm hearing the air whistling through the bypass? I'm using a 944 throttle body, if that makes any difference.

The whistle noise could simply be air flowing via the idle by-pass screw on the TB and/or the IdleControlValve. While at idle try turning the idle screw clockwise to close off the by-pass, if the noise goes away it's the idle bypass and nothing to worry about. But also in that bypass it has a o-ring to seal off air. Remove the screw (counter-clockwise) and inspect it.

Sal,

Thanks for the reply. I was suspecting the idle bypass screw. I had the throttle body off to make some changes to my throttle linkage, and while I was doing that, I removed the screw and cleaned everything out. It was pretty heavily gunked up, so I don't think it was flowing much air previously. In fact, I couldn't get the car to idle evenly if I closed the throttle completely.

On an unrelated note, I just finished spraying most of my interior. I had my car resprayed silver (from Copper Brown Metallic) a while back, and I never got around to changing the cork interior to black. I finally got that taken care of. I used colorplus 917 black. So far it looks pretty good.

I recovered the seats earlier in the year. I had redyed the original seats with Leatherique and the results were not impressive. During one particular hot summer day, I left the seats tilted forward. When I tilted them back, I found that they had stuck together and the leatherique ripped right off. This was probably two years after dying them.

http://forums.pelicanparts.com/uploa...1434408622.jpg

Okay, I've driven the car a few times and I've taken a few logs. However, I'm quickly realizing that I have no idea how I'm supposed to go about tuning the car.

Can anyone point me to a good tutorial on how to tune? There's a million settings and although I feel like I have a general idea of what does what, I'm not clear on what I am supposed to actually do!

Most of the info on the web seems to be about setting things up and getting the car started. After that, there's not much info (at least that I can find). I asked for some advice on the ms extra boards, but didn't get any responses (I did get some info on getting the tach working, but that was it). I even posted my log and current tune.

The issues with the car are the following:

- bogs down when given throttle
- idle is inconsistent
- hard to start when warm (will start immediately if I give it some throttle while cranking)
- on the last trip, once the car warmed up, it started missing and the AFR went really lean

I can post a link to a log and my tune if anyone is interested. I feel like there are probably obvious mistakes in my tune that I'm not aware of.

Here's a pic of the car (for something to look at):


http://forums.pelicanparts.com/uploa...1435192186.jpg

Are you using Tunerstudio or the default MS tuner?
Tunerstudio is worth every penny of the $60 some odd dollars they want for it .
Made all the difference when tuning my car.

Yep, I'm using tunerstudio. Even sprung for the full version.

I went for another run and the car ran terrible. I'm suspecting that I may be low on fuel, or perhaps I'm having some other fuel-related issue. I'm going to have to get some more gas and then do a little troubleshooting.

Here's a clip from MegaLogViewer. Those spikes and drops in RPM are what I'm talking about. The graph looks pretty bad.

https://dl.dropboxusercontent.com/u/...2023.37.22.jpg

You need to tune the car. Its WAY TOO LEAN.

Start with the free-rev, no load sites. Add fuel until the AFR is about 13.5:1 across the arc on your map that will go from your idle VE value to the 4500 free rev value. Then blend the map in the areas where you did not hit on the table to match.

Then set your target AFR to 13.5:1 and use VEAL to rough the map in so that the car is drivable. Drive slow and hold RPM points at different MAP values so that the computer has time to adjust the fuel trim. This will get the car drivable so you can properly tune safely.

Be careful. I see AFRs in excess of 20:1 and that will blow up a motor quickly due to potential detonation.

You also have an RPM noise spike. I doubt you have hit 11k+ rpm as shown in your max rpm value. fix this.

I don't know what is going on with those AFRs. I think I may just be low on fuel or something else is causing the fuel to cut out. I'm going to pick up some fresh fuel today and see if that makes any difference.

By setting the target AFR, do you mean that I should fill in the AFR table with 13.5 in every block?

Thank you for the advice, I really appreciate it.

Yes, Since you are going to tune the car by driving it, first, must be safe to drive. You should never try to drive the car until you can free-rev the car (in neutral) cleanly off idle through about 4500 rpm. cleanly means with good AFR.


The AFR target is where the car will run very well but not optimized for peak power under WOT or for fuel mileage under low throttle conditions.

If you were on the dyno you would just tune around each cell on the engine.

Ok, tuning the car is coming along pretty well. I haven't had a lot of time to mess with it, but here and here I've taken it out and made some changes.

One problem I'm having is stalling at stop signs and red lights. When coming to a stop, the RPMs drop drastically and usually the car will stall. Sometimes it will nearly stall and then then even out and idle.

Otherwise, the car idles fine. I can rev it without any problems stalling. The problem only shows up at stop signs and red lights. I don't get it.

Just thinking out loud - could it have something to do with the load on the engine? Idling in neutral vs idling with the clutch in? What should I be adjusting to take care of this?

On a separate note - I bought a DC adapter for my laptop, which makes tuning much easier. My old thinkpad never had much battery life.