2007 Hawk STi with EJ257 does not want to idle/run

[Rozsko]

Hey guys,

I am not sure if this is ECU related or not, but I need some advice if possible.

Long story short, car was running fine on one day while I was doing some cruise logging, then next day made some adjustments in Fuel table2 based on the logs and car won't start any more. More precisely it starts very hard and doesn't want to idle at all. Pedal response is horrible and does not take RPM, even if it takes, it does that only momentarily. If I play with the accelerator pedal like crazy, then I can keep it alive, but runs horribly unstable and wants to die badly.

Here are couple of links to check out.

• video: https://1drv.ms/v/s!Ale4oyMCOgLThOYAFgJCuOEx_CyNsA?e=RUUZGJ
• rom: https://1drv.ms/u/s!Ale4oyMCOgLThOV8ENECSxApAWCy6w?e=tUtYWX
• data log trying to keep engine alive: https://1drv.ms/u/s!Ale4oyMCOgLThOV_SbCmk6n707bC0g?e=ABjoJD
• data log with brake cleaner: https://1drv.ms/u/s!Ale4oyMCOgLThOV-q7ODvC_ZXMMumQ?e=y4lG5O
• trigger scope: https://1drv.ms/u/s!Ale4oyMCOgLThOV9dCMUpY9L-U2BlA?e=GiOx8d

So, things that I checked, tried so far:

• Fuel pressure is good (you can see in the log)
• Disconnected the injectors one by one and started the car each time. Did make any noticeable difference in how the engine is running.
• Did a quick scope test of ignition, injectors, crank and relative compression, and all looks good. In the injector signal I can clearly see the pintle bump and the signal did not miss once. Same for the ignition. Crank signal is nice as it can be with ~1.5v Min peaks at the no tooth section. Relative compression test is perfect.
• Checked timing belt, did not jump, lined up well.
• Tried to run the engine with electronic throttle disabled, and actuate the plate by hand. When I did that, engine started, but when I manually opened the plate, engine died right away. This led me to think it is a fueling problem probably.
• So I connected a can (spray bottle) to one of the vacuum hoses and as I started the car, I sprayed brake cleaner into the intake manifold. Engine was running nicely and happily like that.
• Checked the logs, including an older one to see if IPW is not good, but actually it is kinda the same. 1.5 to 1.9 ms, depending on RPM and MGP.
• I obviously tried to upload an older rom that worked just fine before, but that did not help at all.

To sum up, it seems like fueling issue, but injectors open and close, fuel pressure is good, and IPW didn't change compared to old logs. I am out of ideas, so I would appreciate any new ones.

Thanks,

Béla

[Adamw]

Yeah looks like lack of fuel to me.  It runs when you constantly work the throttle as that adds acceleration enrichment.  

A quick test to increase fuel would be to increase the engine capacity setting, see how much larger you need to make it to bring the lambda right and that may give you a clue how much fuel is missing.  

I notice in your tune the MAP sensor was reading 7.5 kpa lower than BAP when you last saved it so that may indicate the sensor is drifting or has mositure in the hose.  7.5kpa doesnt sound like enough to cause your problem though.

[Rozsko]

26 minutes ago, Adamw said:

Yeah looks like lack of fuel to me.  It runs when you constantly work the throttle as that adds acceleration enrichment.  

A quick test to increase fuel would be to increase the engine capacity setting, see how much larger you need to make it to bring the lambda right and that may give you a clue how much fuel is missing.  

I notice in your tune the MAP sensor was reading 7.5 kpa lower than BAP when you last saved it so that may indicate the sensor is drifting or has mositure in the hose.  7.5kpa doesnt sound like enough to cause your problem though.

Thanks Adam.

That's an interesting way of adding more fuel, but certainly worth a try before I disassemble all the intake and fuel lines.

I recently fitted this 4bar map sensor, and I still have the old one, so I can try to fit that and see what's happening then.

[Rozsko]

Quick update - PROBLEM SOLVED!

First I tried the engine capacity increase, and that worked well. If I increased the capacity to 4700cc, lambda was bang on.

This obviously confirms that no mechanical issue is present, and yes it is a fuel related problem.

Now back to your MAP sensor comment Adam, what stick out to me, but previously I did not pay attention to, is that idling this time happened around 30kpa, while in the past, that was more around 47kpa.

So, I replaced the 4bar OMNI sensor with a 3 bar OE sensor I used in the past, changed the calibration, and voila. Engine runs perfectly.

Couple of more things I checked/did. I put back the OMNI, calibration (liner)was good, but baro pressure was shown as ~70kpa, so the MAP sensor calibration function did not work due to the 5kpa max difference allowed.

By changing the calibration to a 6bar sensor, I could get the baro pressure read 0 and do a calibration, but I guess this clearly confirms it is a faulty MAP sensor.

I also looked back the log with the brake cleaner and actually I should have paid more attention there, since when the engine stalled, the MAP sensor was reading ~70kpa.

One more thing I had in mind is if this is a wiring problem, but since the 3 bar OE sensor with the Subaru V9 calibration works just perfectly, I think we can rule that out.

 

Long story short, big thanks again for your help. Beyond the G4X being an awesome product, this is why I love Link! Awesome support!!!

[dx4picco]

You will not be the first to have bad Omni map sensors out of the box