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baggedgoods

Won't stay running

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Hey guys, I'm having idle issues where I can't keep the car running and it never seems to want to catch. Either it runs too rich and dies or runs too lean and runs very badly. I have to keep steady pressure on the throttle to keep it from dying. Clearly that means that I need more air, so I would lower my VE values and it wouldn't seem to help any. The car ran better and would actually idle around 600rpm with all the idle valves on the plenum, but none of them were wired up. I've since took them all out, as well as the egr valve, and blocked all the holes off. I have my tune and a few datalogs.

The datalog labeled IDLE(not idle1 or idle2) is when the car had the idle valves on the car but not wired up to anything. The others are without the idle valves.

 

 My injector PW seems very jumpy as well as the dead time. I have them grounded directly to the MS. They are low z injectors so I chose to limit the current in TunerStudios instead of using drop resistors. I made sure no ground wire or sensor wire was in contact with any noise issues(dizzy, spark plug wires, coil). I messed with the ASE and WUE to try and stabalize my afr's and keep the damn thing running, but I've had no luck with it so far.

 

I have an MS2/Extra v3.57 Firmware 3.3.0 straight from DIY.

CurrentTune1.zip

idle.zip

idle1.zip

idle3.zip

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This is a Turbo car correct? Injectors are Turbo ZX 260cc. What Boost are you now running? 

 

First thing I saw was that your VE Table was scaled and calibrated calibrated for a normally aspirated engine. AFR and Ignition tables are also calibrated for a normally aspirated engine. Dead time may be a bit low on those injectors. 1.0 to 1.2ms is more probable 

 

I actually have a tune that I've worked on for another member. He's been fighting an overly rich mixture at idle as well. He downloaded someone elses tune. Problem with that is the VE Table does not Automatically recalculate.  You can change the Fuel injector size, AFR Tables and Ignition Tables and save them But the VE Table does not change until you manually force a new Table generate. 

 

This tune I've worked on is fairly conservative. Will run up to 15 psi boost, but I've got it Boost locked at 10psi for the other fellow. 

 

Tell me more about your engine mods and fueling system. If it meets the criteria, PM me and I'll send you the Tune. Going to bed right now. 

Edited by Chickenman

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It's an 85 300zx turbo. I have a stock fuel system, stock ignition system (except for drop in DiY wheel), bigger turbo, intercooler, 38mm wastegate, AEM wideband. I want to run 15psi until it runs really well, then I'll switch to e85 with an upgraded fuel system and throw a bit more boost at it. The reason for the main table being only for an NA is because I plan to use dual table for both fuel and ignition. I'm just trying to get the car to run before I mess with any boost.

 

I've deleted the maf, air regulator, stock ecu, power transistor, idle valve and egr valve.

 

TunerStudios says that low z injectors normally have .7 ms dead time. But a longer dead time would be less fuel correct? Also, my pulse width numbers seem to be very erratic, and jump around alot. I'm not sure if that is normal or not as well as my duty cycle. The car hardly wants to start. When I blip the throttle it will fire right up and stay running as long as I have my throttle somewhat open. I would then adjust for less fuel and then it would start to run stupid lean and hunt around. I have to do this with the throttle open about 10% or else it will die. It almost seems that the intake just isn't getting enough air. I've heard of people deleting their idle valve with the stock ecu and the car fires right up like nothing is different. Also, the first datalog labeled "idle" is with all the idle valves on the car but not wired in as well as the egr (without a vacuum line to activate it, so basically it's just there). This just furthers my hunch on the intake not getting enough air to hold an idle.

 

As for the firmware, I'm not really familiar with updating the firmware but I've read that it isn't all that necessary, especially if you've got the car running really well. (Which in my case, I dont)

Edited by baggedgoods

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For the idle air, you capped off the hose connection on the Throttle Body?  No vent hoses attached at all?  Can you post up a Picture of the TB. Make it a wide shot so I can see any hose routing. 

 

There is no IAC valve on these cars. Those are PWM solenoid valves. The Z31 ( and 280Z and ZX ) use an Auxiliary Air Regulator. It is a simple heated Bi-Metallic spring that moves a slotted slider. There is no need for any Idle Control programming. It use 12v and the facory Thermistor, which is another Bi-Metallic resistor. All analog control. 

 

The injectors back in those days had a lot of latency. They were slower to react than later versions. Erratic PWM is a sign of too low injector times. When you change injector dead times you have to generate a new VE table to compensate. Has no affect on actual fueling, just makes sure the injector is fully open. Low-z injectors  are Peak and Hold. They initially ( this is all in milliseconds ) pull a high current till they open all the way. Once they are fully open the current is reduced, this is the Hold pattern. 

 

Injector dead time is the time it takes for the injector to open all the way, or Peak. If it is not long enough, the reduced current at the Hold period is not enough and the injector starts to close prematurely. Erratic Pule Width is a symptom of not enough dead time. Try 1.0 to 1.2ms. 

 

Update your firmware. The developers don't spend hundred of hours developing new firmware  just for fun. They have bug fixes and additional features. 3.4.2 is a Mature build. It is stable  and a final release. It's evolved through 3.4.0 and 3.4.1.

 

Tune i made was built on 3.4.2.  I don't want to release it on an earlier build as there can sometimes be mismatches in coding. I'll be more than happy to send it to you to evaluate, but only if firmware is upgraded. I think you will be pleased with it. Ready to test on another car that has similar issues as your car. VE Table was wildly in accurate initially on his car .... as is your's .

That usually happens when you copy a tune from someone else. I develop my tunes from the MS default base Map. So I'm starting with a clean slate. 

 

Do you have the Registered ( $59.95 ) version of TS. It's well worth the price. Unlocks a number of features. And you can always upgrade to the Ultra edition at a later time... for a discounted price. 

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BTW, those recommendations in the drop down menu's are " Condensed " versions. They are only " Tips " and should not be taken as Gospel. If you read the actual MSEXTRA manuals, in the TS tuner settings manual they mention that Low-z injectors are commonly .7ms to 1.0ms ( if memory serves me correct.... I've had a lot of late nights and doing a lot of remote tuning lately ) .

 

And some injectors are more laggy than others. Age plays a factor too. 

 

I've also found that a lot of those " drop down tips " are not always updated. I've found some that refer to settings on much older board versions.  Always have a look at the MSExtra Manuals for the latest updates.

 

The best thing about MS is that they have a lot of information. The worst thing about MS is that they have a lot of information.

 

I've found that there Navigation of information can be quite scattered. It's all over the place with a lot of references to older versions of hardware and software that can be conflicting. You also have to be careful with links from Google. I've found that these often refer to archived information for older board builds and software. Most have a warning about being archived information... but it is not consistent. 

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Alrighty. I had custom made my intake pipe to have two bungs on it (1 for AAC, the other for the air regulator) I've capped both, the hard line vacuum lines and coolant lines have been removed as well. I'm not at my car right now and have no pictures of the throttle body. The only line to the throttle body and intake pipe is the coolant line for the TB.

 

After work tonight, I'll upload the new firmware. But for where the car is sitting now, I don't have internet access, would that be an issue? Or is the firmware a software that can be downloaded and uploaded without internet? And do you have a quick guide as to how that's done? (Sometimes the MS manual goes over my head) JUST KIDDING, I FOUND THE DIY EXPLANATION, WE'RE GOOD HERE

 

I'm just puzzled because prior to removing all the intake shit, the car idled fairly well without me having to adjust anything. I did remove a few unused vacuum lines that went to the vacuum pump?(above the carbon canister) and plugged them. They weren't plugged to anything since ive started this megasquirt project, but I only plugged the lines and hadn't gotten around to removing them yet.

Edited by baggedgoods

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Maybe the stuff you removed wasn't "shit".

 

https://www.diyautotune.com/support/tech/other/idle-tuning-megasquirt/

Haha you've got a point. I think that the air valves not being wired up might have been wide open to allow more air into the intake. Plus the aac valve had the idle screw on it. But like i said, I've heard of people removing all the idle "shit" (with the stock ecu) and it running just fine.

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Plus the aac valve had the idle screw on it. But like i said, I've heard of people removing all the idle "shit" (with the stock ecu) and it running just fine.

 

You could build a fake foot to set on the throttle pedal.  OR use a broom handle.  Or put the screw valve back on.  Or use an electrical valve controlled by the MS you spent all that money on.  Many ways. 

post-8864-0-53516800-1493318968_thumb.png

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Alrighty. I had custom made my intake pipe to have two bungs on it (1 for AAC, the other for the air regulator) I've capped both, the hard line vacuum lines and coolant lines have been removed as well. I'm not at my car right now and have no pictures of the throttle body. The only line to the throttle body and intake pipe is the coolant line for the TB.

 

After work tonight, I'll upload the new firmware. But for where the car is sitting now, I don't have internet access, would that be an issue? Or is the firmware a software that can be downloaded and uploaded without internet? And do you have a quick guide as to how that's done? (Sometimes the MS manual goes over my head) JUST KIDDING, I FOUND THE DIY EXPLANATION, WE'RE GOOD HERE

 

I'm just puzzled because prior to removing all the intake shit, the car idled fairly well without me having to adjust anything. I did remove a few unused vacuum lines that went to the vacuum pump?(above the carbon canister) and plugged them. They weren't plugged to anything since ive started this megasquirt project, but I only plugged the lines and hadn't gotten around to removing them yet.

 

 

When you get home a picture is worth a thousand words.

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You could build a fake foot to set on the throttle pedal.  OR use a broom handle.  Or put the screw valve back on.  Or use an electrical valve controlled by the MS you spent all that money on.  Many ways.

 

Do you have a blueprint for one of those fake feet? I'm very intrigued by that.

 

I haven't hooked my idle valve up to megasquirt because I can't figure out how to wire it up. I'm pretty positive I had only the pwm valve and the aac and no iac. I wired my pwm valve in but the car ran better with it unplugged.

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I believe that the pwm valve was there just so air can bypass the throttle plate and reach the intake directly. I'm thinking of 3 ways I can make it work without an idle valve.

 

1. Weld a bung to the block off plate where the aac valve was and feed a line from the intake pipe bung to the plenum. That'll mean that my intake has ambient air whether the throttle is open or not.

2. Adjust my butterfly valve so it's somewhat open while idling.

3. Replace the block off plate with the aac valve and figure a way to run the pwm valve correctly(as stated above, it didn't run very good while it was connected to the MS) although I like the look waay more without that big ass valve

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Just kidding around.

 

Don't overlook also that idle air and air in the air-fuel mix are not the same.  Don't adjust your tables to add "more air" to try and increase idle speed.  More air for idle speed is just letting air past the throttle blade.

 

You're really going to have to think deeper to make much progress from here. 

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Same here

 

And yeah, it was just a hunch about bypassing the throttle. But how do you suppose people running their stock ecus are doing it? It seems to me that all they're doing is unplugging it and making block off plate for it and it runs great (besides cold startup I guess) but my car doesn't like any setting I give it for air/Fuel wise at operating temp. It will die every time unless I'm giving it a little throttle

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Same here

 

And yeah, it was just a hunch about bypassing the throttle. But how do you suppose people running their stock ecus are doing it?

Later ECU's have the computer control timing and the IACV, and they have air regulators to keep the idle high during initial warmup.

 

Read the EFEC chapters of any of the FSM's and they'll describe the functions of the parts.  Why work from hunches when you don't have to?

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I meant to say, how are their cars running and idling properly with the air regulator and iacv removed only using their stock ecu? You'd think it'd hardly run without any of that. Here's a link to one post.

 

https://z31performance.com/forum/z31-basics/basic-modifications-basic-questions-aka-the-newbie-forum/7356-stock-crap-that-can-be-removed

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The first post in that link describes how you can't just start tearing off ":stuff" without understanding how it works, or how the engine works.  The first post in the link is describing your thread here.  No offense.  You should see that though.

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Wasn't necessarily referring to just the first post. If you read through the first page you'll see what I'm talking about.

 

I hooked up my AAC valve back on to the intake (no wires connected) and ran a line to my intake. Fires right up and idles great. Like I was thinking, the intake wasn't getting enough air to idle properly. I believe I fixed the sporadic pulse widths as well. I adjusted my dead time from 0.7ms to 1.2ms. The PW still tends to jump around by maybe 0.5 How would I be able to stabilize it even further to where it jumps maybe <0.1 at idle. Also my RPMs seem to also jump around by maybe 20-30. Would I stabilize that by increasing/decreasing the latency? Or by adjusting the trim pots on the board?

 

I'm still new to this forum and I understand that some of my questions can be answered by looking at msextra or in the manual. I find it easier to grasp when someone explains it in their terms or points me in the right direction. Do people get pissed off about these types of questions?

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