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Old 11-16-2007, 02:27 PM   #1
entropy138
Scooby Newbie
 
Member#: 87446
Join Date: May 2005
Chapter/Region: NWIC
Location: Burlington/Bellingham WA
Vehicle:
2005 STI
3 second start club

Default Hydra: Car won't stay running

My car stalled out a couple weeks ago on the way to work and when I started it back up it would idle but when I'd press on the throttle the rpms would drop and the car would die. I towed the car home at this point and now I can't get it to start up or keep running unless I disconnect the vac line that goes from the intake manifold to the Hydra.

If I disconnect this line the car will start up and run at 10:1 afrs (of course it isn't reading any vacuum) and giving it some throttle the car responds like normal (just really rich). It will run like this until I hook the vac line back up to the intake manifold. When I plug the MAP line back into the manifold the hydra registers vacuum and starts pulling out fuel. Over about 10 seconds after connecting the line the afrs go from 10:1 -> 17:1 in small increments and the rpms drop from 1500 to ~400 in the same fashion at which point the car dies.

If I give it some throttle during the point where it is leaning out it kind of chokes off and tries to die/lean out faster. If I pump the throttle rapidly it pops in the intake like it is 'lean firing' according to one of my buddies who is used to working on older cars. If I keep pumping for a bit I can eventually get the RPMs up to 3000+ at which point I can hold the throttle and it responds more like normal.

I have tried reuploading the map I had in it and an older one as well with no luck (a couple of times they have gotten corrupted and just reuploading them to the hydra has fixed all the issues.) I have a log of the car's behavior either in my email or on my home PC that I can post a little later. What is everyone's preferred method of posting these, host the .xls file and attach it to a post?

The hydra box is a 2.17 that I've been running for almost 2 years with relatively no problems. It was professionally tuned by Phil probably 15 months ago and there have been relatively few changes to the car since - none in the last 3 months. I'm running a Perrin GT30r, Perrin FMIC, PE 850ccs, Alki injection (can't think of the mfg right now - it's the $500 kit that replaces the windshield washer tank) DTEC BC and a bunch of other mods that are probably mostly unrelated.

Is it possible that it is an 02 sensor going bad? I have probably 30k miles on the wb02 but it seems to be reading afrs just fine - it just doesn't seem to quit trimming fuel after it hits ~14.7.

Any ideas of where I should start looking?
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Old 11-16-2007, 04:03 PM   #2
Element Tuning
Former Vendor
 
Member#: 54918
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Gaithersburg, MD
Vehicle:
673 WHP Element
Tuning Pro Comp Engine

Default

Quote:
Originally Posted by entropy138 View Post
My car stalled out a couple weeks ago on the way to work and when I started it back up it would idle but when I'd press on the throttle the rpms would drop and the car would die. I towed the car home at this point and now I can't get it to start up or keep running unless I disconnect the vac line that goes from the intake manifold to the Hydra.

If I disconnect this line the car will start up and run at 10:1 afrs (of course it isn't reading any vacuum) and giving it some throttle the car responds like normal (just really rich). It will run like this until I hook the vac line back up to the intake manifold. When I plug the MAP line back into the manifold the hydra registers vacuum and starts pulling out fuel. Over about 10 seconds after connecting the line the afrs go from 10:1 -> 17:1 in small increments and the rpms drop from 1500 to ~400 in the same fashion at which point the car dies.

If I give it some throttle during the point where it is leaning out it kind of chokes off and tries to die/lean out faster. If I pump the throttle rapidly it pops in the intake like it is 'lean firing' according to one of my buddies who is used to working on older cars. If I keep pumping for a bit I can eventually get the RPMs up to 3000+ at which point I can hold the throttle and it responds more like normal.

I have tried reuploading the map I had in it and an older one as well with no luck (a couple of times they have gotten corrupted and just reuploading them to the hydra has fixed all the issues.) I have a log of the car's behavior either in my email or on my home PC that I can post a little later. What is everyone's preferred method of posting these, host the .xls file and attach it to a post?

The hydra box is a 2.17 that I've been running for almost 2 years with relatively no problems. It was professionally tuned by Phil probably 15 months ago and there have been relatively few changes to the car since - none in the last 3 months. I'm running a Perrin GT30r, Perrin FMIC, PE 850ccs, Alki injection (can't think of the mfg right now - it's the $500 kit that replaces the windshield washer tank) DTEC BC and a bunch of other mods that are probably mostly unrelated.

Is it possible that it is an 02 sensor going bad? I have probably 30k miles on the wb02 but it seems to be reading afrs just fine - it just doesn't seem to quit trimming fuel after it hits ~14.7.

Any ideas of where I should start looking?
Disconnect the power to your "Alky" kit as it sounds like it could be on flooding your engine. Check fuel pressure to make sure it's adequate and you don't have a bad fuel pump, fuel pump controller, or regulator.

Start there.

Thanks,
Phil
www.elementtuning.com
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Old 11-16-2007, 09:07 PM   #3
entropy138
Scooby Newbie
 
Member#: 87446
Join Date: May 2005
Chapter/Region: NWIC
Location: Burlington/Bellingham WA
Vehicle:
2005 STI
3 second start club

Default

Ok the alky kit is the SMC kit and it isn't the problem. It wasn't spraying and I unplugged it just to be sure.

I don't have a way to test the fuel pressure tonight but with the MAP sensor taken out of the loop the car seems to get fuel just fine - revving freely.

Tonight I noticed that the driver side fan was trying to kick on - like it'd turn a few degrees then recenter then repeat. All of the relays next to the washer fluid tank (fan a/c etc) are clicking rapidly and loudly. This is definately not normal as they can be heard even when the hood is shut.

I'll work on testing the fuel pressure this weekend but what would cause the relays to spaz out?
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Old 11-17-2007, 03:19 AM   #4
Element Tuning
Former Vendor
 
Member#: 54918
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Gaithersburg, MD
Vehicle:
673 WHP Element
Tuning Pro Comp Engine

Default

Quote:
Originally Posted by entropy138 View Post
Ok the alky kit is the SMC kit and it isn't the problem. It wasn't spraying and I unplugged it just to be sure.

I don't have a way to test the fuel pressure tonight but with the MAP sensor taken out of the loop the car seems to get fuel just fine - revving freely.

Tonight I noticed that the driver side fan was trying to kick on - like it'd turn a few degrees then recenter then repeat. All of the relays next to the washer fluid tank (fan a/c etc) are clicking rapidly and loudly. This is definately not normal as they can be heard even when the hood is shut.

I'll work on testing the fuel pressure this weekend but what would cause the relays to spaz out?
If your WB sensor is bad then you can un-check the "closed loop" option in your map to make sure it's not interfering if dead. Typically though I don't run the WB until after 1500 rpm so there shouldn't be any feedback while at idle. If the car runs excessively lean with the MAP sensor plugged in it could be any of the fuel related issues I mentioned.

You didn't mention the relays in the first post but typically those will have nothing to do with the Hydra with exception to the fan relay and the AC compressor relay.

If you upload and email me your map I can just make sure nothing is out of the ordinary. It's not normal for you to ever have to download your map periodically. This could be a sign of low voltage or a short out which can "zap" the map off or corrupt the map file. Email me your map and I'll have a look to see if anything jumps out at me.

Thanks,
Phil
www.elementtuning.com
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Old 11-29-2007, 10:24 PM   #5
entropy138
Scooby Newbie
 
Member#: 87446
Join Date: May 2005
Chapter/Region: NWIC
Location: Burlington/Bellingham WA
Vehicle:
2005 STI
3 second start club

Default

Update - the relay issue went away with a new battery. The Hydra is reporting 14.7v while the car is running.

Fuel pressure is sitting at 15-20psi with the car running and it takes cranking it over a dozen times to get it running. Plugging the MAP sensor back in didn't have much effect on the pressure - the car dies too fast.

Would this be a fuel pump or controller issue? It has a walbro 255 in it currently.

Thanks for your help Phil...
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Old 12-03-2007, 10:33 AM   #6
Element Tuning
Former Vendor
 
Member#: 54918
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Gaithersburg, MD
Vehicle:
673 WHP Element
Tuning Pro Comp Engine

Default

You definitely have some sort of fuel pump, regulator, or fuel pump controller issue at hand. The reason it was running better without the MAP sensor signal is because it just increased the injector pulse width in the Hydra so it was delivering more fuel. Typical OEM base fuel pressures are from 42-48 psi at idle so yours are way off.

You can bypass the fuel pump controller and wire your fuel pump directly for testing. If there is no net change in pressure then you have likely narrowed it down to regulator or the pump. If the pressure jumps up to normal the fuel pump controller is likely the culprit.

Thanks,
Phil
www.elementtuning.com
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