Sam280Z

Tim, I knew that you knew that Metro, hurry up and try something. I want to see this thing run. Sam

The "Minimum injector on time" equivalent in MS is the injector deadtime. You can bump that up but it will limit the control precision because all adjustments to the PW are performed before the dead time is added. Only do it as a test. This can let you know if it will run evenly and steadily with a richer mixture.

To get your PW up, you can drop the fuel pressure a bit and recalculate your reqfuel as well. There are conversion calculators on the web. I did this on mine when I had only the large injectors. If that helps and you need to keep it that way, I recommend getting actual flow values and dead times via test mode testing.

I agree. I'm not suggesting that he tune around it. My suggestions are to see if he can eliminate the behavior s so we can see what is causing it. How flexible are the connectors? Have you tried grabbing the throttle bodies and giving them a good shake? Could it be possible that the vibration is causing the throttles to open and close slightly?

In my experience, vacuum leaks just raise the engine speed when the ecu can compensate for the mixture. I had a pinhole leak in the weld when I modified my manifold. It just hissed. You could actually hear it over the engine running. Not saying you don't have one, but a can of carb cleaner should be able to tell you pretty quickly if you do. Tony's spray paint idea will work too. Your deadtime is .8ms. That is over half of the PW. Sub 2ms PW is problematic. MS3 has a whole section on tuning this area. I don't have any experience with low impedance injectors, so I can't offer anything on the PWM settings. Can you get it to idle at say 1200 - 2000 RPM? Does it do the same thing? Try dropping your spark advance to 10 deg or even less. You will have to open the idle up letting in more air. This will require more fuel and will drop manifold vacuum. Mine runs at more like 65kPa at idle. The same behavior with the small injectors could have been from the AFR table and spark advance affecting your fueling. Need a log to tell.

Your PW is sub 2ms. That is in the non-linear range of the injectors. You have no precise control over how much fuel is being injected. Try changing "number of squirts" to 1. (I'm running sequential and can't remember if this doubles the pulse width - I think it does.) You may want to turn on "sequenced batch fire" so you can have consistent injector timing every time you start. Just to be clear, your target AFR table has a different load range than the VE table. You should make them the same and adjust the values accordingly. I only suggest turning off "include AFR" for testing purposes. Your current settings bounce between 12.5 and 13.8 target AFR. This is included in the fueling calculations when "include AFR" is on. (Once you figure out the fluctuation problem, turn it back on.) I think this combined with the small pulse widths (due to large injectors) causing you to lose control of fueling is causing the fluctuations. To get the PW down, you can try any combination of the following: bump the idle up, pull some timing at idle (try 10 deg), switch to 1 squirt per cycle, bump up your AFR target. With large injectors far back in the manifold it will be more difficult to tune idle, cruise, and transient conditions. See my MS3 build thread: http://forums.hybridz.org/topic/102280-ms3-w-ms3x-install-l6-turbo-sequential-injection-boost-control/

Just had time for a quick look. Your AFR target table needs some work. Try turning off "include AFR" and setting your timing to "fixed". See what that does.

Post your msq and a data log of the behavior.

Were those 2 loose studs loose because they stretched when the wheel bent or did they never have the opportunity to clamp the wheel to the hub because the wheel was already bent or not installed evenly? Studs are really hard and I would expect them to break before stretching any appreciable amount beyond yield. If the two parts had clearance between them (even a miniscule amount) after the fasteners were tightened, they will be loose when the 0 arts separate.

I'm just speaking from my experience (and only about cruise economy - sorry, I wasn't very clear). The tau layer is an issue with economy as well. Liquid and unatomized fuel doesn't burn efficiently. However, you will be able to get higher maximum power fuel economy with the injector placed further away from the valve. There is not much of a tau layer with high airflows and with the injector placed further away, there is more time for mixing and evaporation with the associated charge cooling.

The piston and bridge are there to create a restriction. That's what creates the pressure drop that allows the atmospheric pressure in the float bowl to push the fuel out of the jet. I doubt that removing the restriction would make it too sensitive. I run triple throttle bodies with no problems. I like the idea of replacing the suction dome with injector holders. There is a reason that factory throttle body injection puts the injectors upstream of the throttle. The acceleration of the fuel and air through the throttle air gap at idle and cruise helps atomize the fuel.

Not just emissions, but drivability and fuel economy as well. It also makes it easier to tune.

Good call Tony.

> A lot of blowby is inconsistent with your compression readings. Can you do a leakdown test?

Yea,my cars are all 77-78 280Zs. I'm not familiar with the 240z tachs.

I've found that the stock tach is dead on accurate, at least on the 77 and 78s. I tested with the Crane Hi6 tach test.

I'm using a msd tach adapter. If you search msextra.com, there are some posts that describe how to build one using a relay coil to provide the flyback voltage spike needed to drive the tach. I've never done this, but others have had success.

"I guess my cam input was set to MAP sensor, which is incorrect" That's what I was getting at when I said: "MS3 can detect engine phase based on MAP signal. I'm not familiar with where the settings are but you should not be using this." You should set the cranking speed to just under the slowest running speed you expect to see. 600 RPM is probably better. If the engine is running slower than this crank settings engage. 200 RPM is slower than your engine will crank so if you use that your crank settings will never come in to play.

Post your msq. In the meantime here are some guesses: It sounds like you are trying to use inappropraite MAP sample settings. You should set it to "use event average". MS3 can detect engine phase based on MAP signal. I'm not familiar with where the settings are but you should not be using this.

CAS plug wiring. Since I've gotten multiple requests for this info I thought I'd post it here: If you turn the distributor over and look at the plug receptacle from the bottom with the receptacle on top of the dist shaft, the top right is 12V positive (B/W), bottom right is ground (Black), the other two are the two optical sensors - top left is outside ring of slots ((G/Y) and bottom left is inside ring (G/B).

"MLS head gaskets need to be run with no coolant in the water first. Then coolant added later." I've never heard of this. Do you have a source for his info? Sam

Have you consulted with a notary who knows their stuff? The reason I ask is that I have a friend who is a notary (not an expert on automobile titles etc however). He said that the bonded title is not a title per say, but a document that allows you to do some things that require proof of ownership such as buy insurance etc... I would not take the word of a DMV employee on exactly what can and cannot be done. BTW, I used to see your car parked downtown Baton Rouge. Was that you or the PO? Sam

As far as I can tell, the grounding methods as drawn in both the DIY and MSExtra website documentation are electrically the same. All sensors grounds are run to pin 7 on the DB37 connector and the DB37 connector grounds all run to the same place and grounded to the same place the battery is grounded, i.e. the engine block.

Theoretically, you are probably right. However, that has not been my personal experience - particularly with the wideband.

Read this: http://msextra.com/doc/general/grounding.html