MX5 Turbo 1990 MS1 Lean AFR (Air leak???) - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 07-01-2014, 03:02 PM   #41
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Did you do a free air calibration on your o2?
I have a AEM 35-8460 gauge aparently these dont need calibration unlike the innovate gauges?
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Old 07-01-2014, 03:37 PM   #42
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I have a AEM 35-8460 gauge aparently these dont need calibration unlike the innovate gauges?
Yes, those gauges don't allow calibration. There's still some question as to whether not to actually need it, but that is another thread.
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Old 07-01-2014, 05:31 PM   #43
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Okay so i did a smoke test on the engine tom try and find any vacuum leaks and I found two very very minor leaks one from where the IAT was screwed into and one from a bolt holding the actuator on the turbo.

Both of these leaks were fixed straight away and then i started the car but nothing had changed.

So i then moved on to check all the ECU wiring and I cannot see anything out of place there either so right now im really confused as to what i am ment to do?

The idle wont settle and constantly jumping between 900-1100, and the AFR are lean with the IAT connected and with it disconnected its runnin seriously rich.

When i run autotune its as if the car is trying to fight the autotune and the AFR's constantly bounce erracticly between 14-16.

Any suggestions guys?
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Old 07-01-2014, 05:41 PM   #44
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Look, your MAP and IAT are the 2 most important inputs for the fuel calculation. You can't unplug your IAT and expect to get good results. It's like hooking a power cable up to a PC but not a monitor cable, you kinda need both to work.

Idle 900-1100 isn't that bad, how lean is it when it tries to idle? Have you tried tuning the idle? Maybe try pulling 2 or 3 degrees of timing in the idle area just to see if it will slip down to ~700rpm.

Did you swap the engine harness too, or did you plug the MS into the original harness that came with your shell?
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Old 07-01-2014, 05:50 PM   #45
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Any suggestions guys?
tune the car.
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Old 07-01-2014, 08:01 PM   #46
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Look, your MAP and IAT are the 2 most important inputs for the fuel calculation. You can't unplug your IAT and expect to get good results. It's like hooking a power cable up to a PC but not a monitor cable, you kinda need both to work.

Idle 900-1100 isn't that bad, how lean is it when it tries to idle? Have you tried tuning the idle? Maybe try pulling 2 or 3 degrees of timing in the idle area just to see if it will slip down to ~700rpm.

Did you swap the engine harness too, or did you plug the MS into the original harness that came with your shell?
I know it's not gonna run right without the AIT but if I connect it I'm running 18s on the AFR and no the only difference is I'm using my loom in my shell however the guy is sending down the loom it was running on so I can compare just to see if I have missed a connection somewhere.

I'm taking the car to Alan jefferys tomorrow a local tuning company to see what they say. If he says he just needs to be remapped then I'll get it remapped or I'll autotune it my self but I'm convinced there is a fault somewhere.
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Old 07-03-2014, 12:57 PM   #47
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Okay so I solved the exhaust gasket leak and that is now fine, then i smoke tested the intake and found two very minor leaks not big enough to really effect the AFR's like it has been.

I also went to the tuning shop and they basicly said it sounds as if the car just needs a remap so i decided to autotune the car knowing even if it didnt fix the problem it would atleast bring down the horrible MPG and make the car more driveable.

Well i went to drive the car today and found a fairly noticeable exhaust blow and a lack of boost...

Its safe to say my turbo gasket on the exhaust manifold is shot so I am trying to order 4 new studs and lock nuts as well as a gasket and then going to burn the original map back on the car and if its still way out ill autotune from that point considering that the wideband would have been getting crazy AFR readers from the gasket blow.

And when i say gasket blow its really bad or atleast it is now as i never noticed it before and its certainly must have got worse if it was apparent before.
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Old 07-03-2014, 01:10 PM   #48
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Stop ordering gaskets please, and send your mani and turbine housing off to get machined flat.
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Old 07-03-2014, 03:07 PM   #49
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Stop ordering gaskets please, and send your mani and turbine housing off to get machined flat.
I simply dont have the time to take it off and get it done, with this being my only transport currently due to selling the motorbikes its not viable for me to do it.

later down the road when i start on cleaning up the engine bay ill be getting these sorts of things done.
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Old 07-03-2014, 04:53 PM   #50
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Then take the turbo off and revert to NA. You can take it to be tuned, but it will just blow out the new gasket and **** up your tune.

It sounds like it's not really an option at this point if you want to get the car running well. Even autotuning will only work until the new gasket blows out, and then it will start ******* up your autotuning since as you have found out, the WBO2 readings aren't accurate with a pre-O2 sensor exhaust leak.
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Old 07-03-2014, 09:00 PM   #51
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Then take the turbo off and revert to NA. You can take it to be tuned, but it will just blow out the new gasket and **** up your tune.

It sounds like it's not really an option at this point if you want to get the car running well. Even autotuning will only work until the new gasket blows out, and then it will start ******* up your autotuning since as you have found out, the WBO2 readings aren't accurate with a pre-O2 sensor exhaust leak.
There is nothing wrong with using dam gaskets, what is peoples obsessions with them, its be fine the past god knows how many years with this gasket so im sure after some well deserved new studs, locking washers, nuts and gasket it will carry on for few more years as well perfectly fine...

Just like my manifold is fine with a... Ow a gasket.
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Old 07-04-2014, 10:41 AM   #52
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You are right. We don't know anything. You have all the answers.

Why are you here?
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Old 07-04-2014, 03:19 PM   #53
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You are right. We don't know anything. You have all the answers.

Why are you here?
Didnt say I have all the answers but what I am saying is there is nothing wrong with using a gasket just like there is nothing wrong with not using one if the surfaces are machined flat...

But mine are not so im going to use a gasket.
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Old 07-04-2014, 03:24 PM   #54
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Didnt say I have all the answers but what I am saying is there is nothing wrong with using a gasket just like there is nothing wrong with not using one if the surfaces are machined flat...

But mine are not so im going to use a gasket.


By all means, be a stubborn idiot
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Old 07-04-2014, 08:56 PM   #55
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Originally Posted by xXxKillDogxXx View Post
Didnt say I have all the answers but what I am saying is there is nothing wrong with using a gasket just like there is nothing wrong with not using one if the surfaces are machined flat...

But mine are not so im going to use a gasket.
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By all means, be a stubborn idiot
What he meant was this:

Quote:
Didn't say I have all the answers but what I am saying is I have no ******* clue what i am doing just like there is everything wrong with using a gasket if the surfaces are not machined flat and i am trying to justify my repeating cost for buying them and wasting them instead of doing the correct thing and fixing the root problem...

But I like wasting my money.
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Old 07-05-2014, 01:40 PM   #56
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For the cheap, belt sander? DIY?

You could always stack gaskets upon gaskets and tighten er' down for teh lolz

If you can remove it yourself find a machine shop that'll resurface the parts, save $ that way in labor.

The local automotive/tuner shop also sounds like best bet. Autotune now, save up $$ in the meantime... Rent a vehicle for a week while they send out or resurface the mani/turbine exhaust housing.
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Old 07-22-2014, 04:34 PM   #57
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Default Hmmm.

Okay so last time i replaced the manifold gasket and turbo gasket, both of which are now fixed and I have a lot more boost and a better AFR reading.

Althought I there is still something not right the car is fine above 2K RPM it seems to run awesome and really smooth however if you let it idle which when hot is 1500RPM and when cold is about 1100RPM it will have a slight hiccup and the engine will stumble.

Sometimes it will also sound like a very very tiny misfire and you hear a slight cough sound from the exhaust.

So I did the obvious and checked the coolant temp sensor which according to the laptop its reading perfectly what I would expect, so I am kinda back to thinking I have either a faulty injector or unmetered air entering the system.

So I had a look around the engine bay looking for anything obvious and noticed the bolt that holds the fuel rail to the intake manifold closest to the firewall was loose so I tightend it up along with the other which seemed a tiny bit loose and started the car again.

This made no difference what so ever, also its not the plugs or the leads as i swapped the leads for 2 other sets and also I replaced the plugs yesterday with BKR7E's which are gapped fine for the setup out the box.

Anyone else have any idea what could cause the idle issue?

Also something that may also help is when cold the car will not start sometimes without throttle but once started you can let go of the accelerator and it will idle fine.

Thanks for all the help guys hopefully I am getting near the end now!
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Old 07-22-2014, 04:54 PM   #58
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Come on man, for the hundredth time: if you don't have a MAF or AFM, how can there be unmetered air?

Tune your idle.
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Old 07-22-2014, 04:54 PM   #59
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Originally Posted by xXxKillDogxXx View Post
Okay so last time i replaced the manifold gasket and turbo gasket, both of which are now fixed and I have a lot more boost and a better AFR reading.
Were you able to resurface the manifold flat? I saw earlier you mentioned the AFR going back and forth from 14-16. THIS is normal while in a low load cruise. Even ok at idle. And personally I'd run boost straight to the wastegate if you havent already. That way you're not overboosting it #1 while with bum tune and high idle

Quote:
Originally Posted by xXxKillDogxXx View Post
Althought I there is still something not right the car is fine above 2K RPM it seems to run awesome and really smooth however if you let it idle which when hot is 1500RPM and when cold is about 1100RPM it will have a slight hiccup and the engine will stumble.

Sometimes it will also sound like a very very tiny misfire and you hear a slight cough sound from the exhaust.
Are there any IAC settings on the MS? What is your AFR on cold start, what is it on a hot start.

What does your megasquirt map look like at idle?

Quote:
Originally Posted by xXxKillDogxXx View Post
So I did the obvious and checked the coolant temp sensor which according to the laptop its reading perfectly what I would expect, so I am kinda back to thinking I have either a faulty injector or unmetered air entering the system.

So I had a look around the engine bay looking for anything obvious and noticed the bolt that holds the fuel rail to the intake manifold closest to the firewall was loose so I tightend it up along with the other which seemed a tiny bit loose and started the car again.

This made no difference what so ever, also its not the plugs or the leads as i swapped the leads for 2 other sets and also I replaced the plugs yesterday with BKR7E's which are gapped fine for the setup out the box.

Anyone else have any idea what could cause the idle issue?

Also something that may also help is when cold the car will not start sometimes without throttle but once started you can let go of the accelerator and it will idle fine.

Thanks for all the help guys hopefully I am getting near the end now!
The fuel rail would of been a guess for me too but no fix as you said.

I would try to post Cold/Hot logs of your vehicle showing AFR, RPM, Vac/Boost etc.

Does your car have a BOV? Mine turned out to be the source of unwanted air at idle. It had 'zero' seal on/off boost and turned out to be a ebay rip off (pos came with the car, replaced with greddy fv and AFR's leveled out)
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Old 07-22-2014, 05:22 PM   #60
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Were you able to resurface the manifold flat? I saw earlier you mentioned the AFR going back and forth from 14-16. THIS is normal while in a low load cruise. Even ok at idle. And personally I'd run boost straight to the wastegate if you havent already. That way you're not overboosting it #1 while with bum tune and high idle



Are there any IAC settings on the MS? What is your AFR on cold start, what is it on a hot start.

What does your megasquirt map look like at idle?



The fuel rail would of been a guess for me too but no fix as you said.

I would try to post Cold/Hot logs of your vehicle showing AFR, RPM, Vac/Boost etc.

Does your car have a BOV? Mine turned out to be the source of unwanted air at idle. It had 'zero' seal on/off boost and turned out to be a ebay rip off (pos came with the car, replaced with greddy fv and AFR's leveled out)

No i didnt get the Turbo or manifold machined flat but they are not leaking at all, also i dont have a BOV at the moment and this setup has never had one.

From what i remeber the cold start is usually around high 12s but once it warms up it will fluctuate between 13.5-15.5 and you can actually feel the engine stumble through the gear stick at the same time the idle will also fluctuate.

I also checked around the injectors for any sort of moisture and only found slight moisture on the actual injectors them selfs nothing on the surrounding area and this was on all 4 so it might just be residue oil?

I have MOT for the car tomorrow so once that is done ill get about 10-20mins of logging done and post it here.

It just seems really strange as the map should be fine, since everything is the exact same as when it was mapped in another shell, and I also phoned the guy who I got everything from and he said that the idle was basicly like a stock MX5.

Also i dont know if i mentioned before but if you rev the car at a stand still and let it decel when it gets to about 1800RPM the engine will sort of hiccup its odd.
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