Alltrac with st215 motor running rich.

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Alltrac with st215 motor running rich.

Postby UtahSleeper » Sun Oct 11, 2015 1:03 am

I have an 88 Alltrac with a st215 motor. Runs, starts and drives, but is running pig rich. I can share the emission numbers if wanted.

[url="https://www.youtube.com/watch?v=_lP7lxU-PYU"]Torque Pro recording of readings[/url]

So, I made a short video of what my ecu is showing while idling. No audio, but figure the gauges tell the story. I did idle and 2500 rpm hold.

I have replaced o2 sensor and plugs. Not sure where to look next. The fact it shows a high load makes me wonder if that is tied to the issue.

Thanks for any feed back.
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Re: Alltrac with st215 motor running rich.

Postby zaluss » Sun Oct 11, 2015 1:27 am

UtahSleeper wrote:I have an 88 Alltrac with a st215 motor. Runs, starts and drives, but is running pig rich. I can share the emission numbers if wanted.

[url="https://www.youtube.com/watch?v=_lP7lxU-PYU"]Torque Pro recording of readings[/url]

So, I made a short video of what my ecu is showing while idling. No audio, but figure the gauges tell the story. I did idle and 2500 rpm hold.

I have replaced o2 sensor and plugs. Not sure where to look next. The fact it shows a high load makes me wonder if that is tied to the issue.

Thanks for any feed back.


Based on a quick google search, I would check the turbo pressure sensor and ECU.

http://www.6gc.net/forums/index.php?showtopic=93897
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Sun Oct 11, 2015 2:59 am

zaluss wrote:
UtahSleeper wrote:I have an 88 Alltrac with a st215 motor. Runs, starts and drives, but is running pig rich. I can share the emission numbers if wanted.

[url="https://www.youtube.com/watch?v=_lP7lxU-PYU"]Torque Pro recording of readings[/url]

So, I made a short video of what my ecu is showing while idling. No audio, but figure the gauges tell the story. I did idle and 2500 rpm hold.

I have replaced o2 sensor and plugs. Not sure where to look next. The fact it shows a high load makes me wonder if that is tied to the issue.

Thanks for any feed back.


Based on a quick google search, I would check the turbo pressure sensor and ECU.

http://www.6gc.net/forums/index.php?showtopic=93897


I had seen that link. My problem is that the ecu sells for 200. Dont want to spend that much if it isnt a guarantee fix. I did have a dent in my ecu that was causing grounding, but fixed that. The board didn't seem to have any issues in the ecu
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Mon Oct 12, 2015 11:45 pm

Pardon me as I keep looking at things.

I decided to connect with torque with the key on, but not started to see what my readings were and here is what I saw.

Image

Am I correct in my assumptions that vacuum and intake psi should be zero when the engine is not running?
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Re: Alltrac with st215 motor running rich.

Postby ___Scott___ » Tue Oct 13, 2015 3:16 am

The intake manifold should read atmospheric pressure, but "vacuum" should be zero.

I'm not sure why you even have a "vacuum" gauge. The ECU doesn't have any need to know about it. All that matters is the absolute pressure.
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Tue Oct 13, 2015 4:16 am

Think torque just does the calculations from the ecu and displays it. Either way, it tells a little. Wanted something to compare to mechanical.

I figured intake pressure should be zero since the car wasn't running.
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Sat Oct 31, 2015 9:20 pm

So, update and recap. Still looking for suggestions.

I have replaced the coolant temp sensor(at water neck), MAP and TPS. No changes in readings interpreted by the ECU and it still reads and smells rich.

I unplugged the fan for troubleshooting. Got the engine temp up to 200 to 220 F and took it around the block. ECU still shows rich(.9v from o2).

Got my fuel rail/injectors flushed, just in case they were getting stuck open. No change in performance and richness.

Fuel pressure at rail shows around 35 psi at idle.

Torque shows 35%-ish load at idle.

Motor will occasionally pop in the exhaust an declaration.

As per the previous video, feels great driving and accelerates well.

ECU had a dent when I got my motor. Caused power issues for the ECU during initial install. After removing dent all "seems" fine. I have checked the board, but there seems to be no burn marks or popped caps.
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So, I am at the point of just replacing the remaining electronics/sensors that deal with fueling. I know the ECU could be an issue, how ever unlikely, and hope to save that for last as its a steep cost for a hope.

I keep thinking electronics cause it seems to mostly be an issue at idle, but I am shooting in the dark honestly.

Does anyone use torque that has a st215 motor? Curious what your o2 and load show at idle, just to see if I am barking up the wrong tree.

Any other suggestions?

Again, thanks for the help so far.
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Re: Alltrac with st215 motor running rich.

Postby underscore » Sun Nov 01, 2015 3:21 am

Your O2 sensor shows rich but your ECU isn't doesn't anything to correct that? Sounds odd to me.
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Sun Nov 01, 2015 4:25 am

underscore wrote:Your O2 sensor shows rich but your ECU isn't doesn't anything to correct that? Sounds odd to me.


Yea, thats what is wierd. The ECU shows a negative -20% fuel trim, so it seems like the ECU knows and may be trying to remove fuel...........but I dont know enough to understand. When driving it adds fuel when under load.
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Re: Alltrac with st215 motor running rich.

Postby underscore » Sun Nov 01, 2015 5:16 am

Is your fuel system modified in any way, or is it stock? If the ECU knows it's overfueling but can't correct it then I'd imagine it could only be the fuel system, injector wiring, or the ECU.

edit: stupid idea, does the 215 have a cold start injector or no?
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Sun Nov 01, 2015 5:58 am

underscore wrote:Is your fuel system modified in any way, or is it stock? If the ECU knows it's overfueling but can't correct it then I'd imagine it could only be the fuel system, injector wiring, or the ECU.

edit: stupid idea, does the 215 have a cold start injector or no?


I dont think it does have a cold start. No extra fuel lines.

Fuel system is mostly stock. Walbro pump and an inline fuel filter. Nothing special.

That could be right, just not sure what other fuel related systems I can mess with.
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Re: Alltrac with st215 motor running rich.

Postby ___Scott___ » Sun Nov 01, 2015 1:49 pm

You haven't mentioned the intake air temperature sensor, but in a speed-density engine management system it is an important input that the ECU uses to determine load.

If the ECU is getting good IAT info, then excess fuel suggests either a leaky injector, incorrectly too large injectors, or fuel pressure that's way too high (which you've already checked.)
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Sun Nov 01, 2015 6:41 pm

___Scott___ wrote:You haven't mentioned the intake air temperature sensor, but in a speed-density engine management system it is an important input that the ECU uses to determine load.

If the ECU is getting good IAT info, then excess fuel suggests either a leaky injector, incorrectly too large injectors, or fuel pressure that's way too high (which you've already checked.)


Thing is, there are 2 intake temp sensors, from what I understand. One pre turbo and one on the intake manifold. I know I have 1 valid intake reading, but not sure which one. I may need to look at torque again and see if there is another sensor I haven't noticed.

Injectors appear to be stock. I plan on pulling the injectors again and verifying if there is leakage.
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Re: Alltrac with st215 motor running rich.

Postby Gibs » Sun Nov 01, 2015 8:04 pm

Sorry for the out of topic but, which device is connected to your ECU ? :shrug:
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Re: Alltrac with st215 motor running rich.

Postby UtahSleeper » Sun Nov 01, 2015 9:33 pm

Gibs wrote:Sorry for the out of topic but, which device is connected to your ECU ? :shrug:

A Bluetooth obd2 adapter connected to my phone
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