Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

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nmibaja
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Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

I've got an issue. My Baja Turbo accelerates normally, as long as I don't give it more than 1/3 throttle, or so. Any more than that, and it bogs down, until reaching 4000 rpm in any gear, where it misfires, and I let off immediately. Acts like some kind of a fuel/air mix problem to me. The car has no mods to speak of, other than some silicone intake hoses.

I have replaced all the spark plugs with new. I replaced the in-tank fuel filter. I installed new silicone hoses on the intercooler (y-pipe and throttle body). I put in a new set of fuel injectors.

It still does it, and if anything is slightly worse. :(

I have a new fuel pump coming.

The power wire to the MAP sensor has a 1/2" bare area, with a broken strand. Though I did test it with a vacuum tester, and it seems to give proper readings. I'm fixing this as soon as I get a replacement connector in the mail, hopefully today/tomorrow.

The only strange thing I noticed, was when I did some data logging, I did several WOT pulls (only to 4000rpm....) and my pressure seems high? LIke a slight overboost? I calculated it out to be about 14psi of boost, and I read somewhere that the Baja's only boosted to 11.4psi? Could slight overboost be causing any of these problems? All told, the MAP pressure maxed out at about 57 inHg at WOT and 4000rpm, when it started misfiring.

Oh, and the MAP with KOEO was reading 28.8 inHg; but I was actually at an airport, and the airport altimiter was reading 29.9 inHg. I don't know if that would matter.

I looked really hard for damaged vacuum lines, and didn't find any. Sprayed all over with starting fluid, while the engine was running, and it just idled smooth the whole time.

I saw that the BOV return hose is pinched somewhat (at least half restricted) at the bend where it hooks back into the turbo inlet area. Looks like when the previous owner installed the silicon inlet, the BOV hose needed a little trim on the end to fit right, but he didn't do that, just squished it on.

Maybe. I'm going to pop off the intercooler again this weekend. I have a fuel pressure regulator I want to try and install, and I have some new BOV hoses, that I will trim to fit on that end if needed to avoid any pinching.

What do you all think? I know I've just thrown a lot of parts and $$ at it so far. I'm not the best troubleshooter, unfortunately, and this is my first turbo, and first Subaru.

I can try to post some of the data logs if anyone thinks it might help? I attached one. Thanks everyone.
Data Log WOT pull
Data Log WOT pull
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

Well, latest update: I changed the fuel pressure regulator over the 4th of July weekend, and also installed a new Denso brand MAF sensor, replaced some vacuum lines, and some clamps.

And, it runs worse. Or, I should say, it ran worse. Because this morning, it didn't want to start at all.

There are additional details to this new behavior, and if someone shows interest in helping me, I will post all I know.

I'm just so frustrated. It seems like every time I touch it, it runs worse than before.

I guess I'll put the old MAF back into it, and see if that helps; check the fuel pressure again. Say a prayer for me.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by Guacamole »

Hey there, sorry about your problems. I'm not much a turbo nor engine guy so I won't be much technical help... but are you using the correct fuel? Baja Turbos require at minimum 91 octane to function properly.
Also is the ECU throwing any codes when it misfires?

Also stumbled on this NASIOC thread while researching:
sounds like a similar problem you had, turns out his issue was a pinched 02 sensor wire.
https://forums.nasioc.com/forums/showth ... ?t=1660526
Granted this guy's using a hybrid 2.5L block and 2.0L head setup, and I have no idea where the O2 sensor(s) on a WRX are located.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

Hi, thanks for responding.

Yes, in the month or so I have been driving it, I've been using nothing but premium fuel. I even tried a couple of tanks with premium fuel + octane boost, thinking it may help. But it did not.

The ECU does not throw any codes, unless I "persist" with my full throttle action, and get it to ping for more than a second or so. If I back it off right away, no codes. When the code does pop up, it is two codes usually, for cylinder 1 & 2 misfire.

Rolling back the clock to when I first got it: Before I touched anything at all, I could give it full throttle, and get it up over 5000 rpm (I think I could hit maybe even 5500 rpm). The engine kind of surge-stepped its way up there, before I'd get the misfire. So things at that time were disappointing, but not disastrous.

So first things I did, were oil change, air filter change, and spark plug change. When I pulled the plugs, they looked perfectly normal to me. A nice flat tan color, with just a little black oil staining on the end of the threads. I also changed one of the coils, because I had one, and one of the old ones had the connector locking tab broken off. The one I replaced was the #1. But, instead of a straight swap, I shifted the #3 up to the #1, and put the new coil in the #3 spot. My thinking was that I wanted the newest coil in the hardest to reach spot. Not thinking that I was creating a troubleshooting headache for myself down the road.

Car ran no better, just slightly worse. RPM before misfire was a little lower.

Since then, I have replaced the fuel filter, all four fuel injectors, the fuel pressure regulator, and some vacuum lines and clamps, and the MAF.

This latest situation, has happened after doing the fuel pressure regulator, and vacuum lines. First, the test drive on Saturday, the car was absolutely no better: Bogging if I gave it over 1/4 throttle, and misfiring at just under 4000 rpm. This time, I got the two same misfire codes; but I ALSO got P0102 (MAF sensor "A" circuit low); P0113 (Intake Air Temp Sensor 1 Circuit High Bank 1); and P0108 (MAP sensor circuit high).

So, a lot changed suddenly. Or, it just got bad enough to finally trip the codes. My thoughts were, that my vacuum line and clamps tinkering had tightened up the manifold finally. And this was maybe showing the real issue. But I had put a new MAF into it too, so this wasn't a realy scientific test. I was going to put the old MAF back in, just to see what the numbers were. But then the 4th, and family, etc. No more testing.

I cleared the codes Monday morning, and limped into work. No further codes.

Monday after work, getting in to go home, I found I had to crank the car for almost 4 seconds to start it, and it stumbled slightly before settling into an idle. This was unusual. As the car up to now, had always been a quick starter, and good idler. Trip home was uneventful.

Tuesday morning, got in, and had to crank at least 5 seconds this time before it fired off; and immediately I noticed it was clearly missing on one cylinder. I tried to clear it, but nothing, and it died. Repeated this one time.

Then, the kicker: I tried starting it a third time, and it didn't want to turn over at all. So i played with the key, and got it turning over for a second, before it stopped with a "PING!".

Hydrolocked.

I got out, and drove my old car into work. And here we are.

Now I've got the thing so full of fuel somewhere, that it hydrolocked. And all this time, I was thinking that I was having a problem with not getting enough fuel. Because all this time, my mpg has been around 23 24 mpg, which isn't bad for this thing, or so I've read.

I'm kind of at a loss here. I've done so many different things to the car, that I'm not sure what caused this.

My assumption, is that either I did something wrong, or put in a defective part, or I finally fixed it enough for it to show the true problem.

From what I have read, hydrolock at start could be caused by a stuck fuel injector; or the fuel pressure regulator getting a bad diaphragm, and leaking fuel back into the intake manifold.

Could it be happening because of a MAP or MAF issue? Making the fuel/air mixture so off the wall, that one cylinder gave up, and filled with fuel?

I just don't know.

I'm going to try talking to some local Subaru people, and see if I can get some help. I think I need it. I'm in over my head.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by ZUBAJA »

IF (and I say if) you are hydrolocked because of fuel, I would suspect injectors. For diagnostic starters, pull the vacuum hose from the FPR and see if fuel squirts out of the nipple. If that stays dry, consider (yes, consider, because we can't be sure over the internet - I've see way too many folks saying "replace XXX" and then see some poor person throw money away). You could pull all 4 plugs and see if one comes out dripping with fuel.
If you decide to crank it to blow the fuel out, UNPLUG the low voltage plugs from the coils. You don't want any chance of a spark if it's squirting fuel all over. Is this "coil on plug"? I think all my Subies have a single coil (haven't looked too close at the 2010 Forester yet).
A cylinder that's running too rich, can cause the others to run lean. The ECM sees a rich mixture, and tries to compensate by leaning.
We hope not, but it COULD be a head gasket. It IS a Subaru.
What about the timing belt? Has that been checked? Only 3 bolts on the driver side timing cover to have a quick look at condition of the belt. (OOPS! I forgot. You have a turbo. Is it DOHC, that may be a little different. If it's like the early DOHC, there could be valve interference if the belt slipped (this could be more bad news). Been a while, maybe the DOHCs had a cover over each side that came off????? Dennis
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by kamesama980 »

ZUBAJA wrote: Wed Jul 08, 2020 1:15 pm IF (and I say if) you are hydrolocked because of fuel, I would suspect injectors. For diagnostic starters, pull the vacuum hose from the FPR and see if fuel squirts out of the nipple. If that stays dry, consider (yes, consider, because we can't be sure over the internet - I've see way too many folks saying "replace XXX" and then see some poor person throw money away). You could pull all 4 plugs and see if one comes out dripping with fuel.
If you decide to crank it to blow the fuel out, UNPLUG the low voltage plugs from the coils. You don't want any chance of a spark if it's squirting fuel all over. Is this "coil on plug"? I think all my Subies have a single coil (haven't looked too close at the 2010 Forester yet).
A cylinder that's running too rich, can cause the others to run lean. The ECM sees a rich mixture, and tries to compensate by leaning.
We hope not, but it COULD be a head gasket. It IS a Subaru.
What about the timing belt? Has that been checked? Only 3 bolts on the driver side timing cover to have a quick look at condition of the belt. (OOPS! I forgot. You have a turbo. Is it DOHC, that may be a little different. If it's like the early DOHC, there could be valve interference if the belt slipped (this could be more bad news). Been a while, maybe the DOHCs had a cover over each side that came off????? Dennis
Turbos have coil-on-plug (one coil per cylinder)

Depends on what's causing the rich cylinder but generally it won't lean out overall. A leaking fuel injector causing a cylinder to run rich will NOT fool the ECM into leaning out the other cylinders because even wideband sensors don't detect mixture, they detect O2 in the exhaust. A rich cylinder will not affect fuel trims significantly until it causes a misfire. when you have a misfire, you have unburned fuel and air in the exhaust, the 02s sees the unburned 02 (not the mixture), and tells the ECM to richen things up.

Subaru head gasket failures are (NA) generally external oil leaks. Turbos have multi-layer-steel gaskets from the factory so very unlikely to fail (but not impossible)

Until you said you hydrolocked it (Follow Z's advice about pulling ALL the plugs to check and clear it) I suspected maybe you had something going on like mine: I went to TGV deletes and the fuel rail hold-down bolts didn't fit right so it ran great in vacuum but when boost hit, the injectors lifted (like a check valve) causing massive misfires till I figured it out

I'd also suggest double checking the cam timing and do not crank the engine until you can bar it over by hand a few revolutions.

If it's hydrolocked with fuel, change the oil as soon as you fix it, fuel does not lubricate nearly as well as oil.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

Thank you both very much for your answers, and suggestions. Everything is so very helpful.

I have reached the end of my rope, figuratively. I'm going to have it picked up and taken to a Subaru specialty shop.

I've just put so much of my time into this every weekend since I bought it back at the end of May, and having it behave so badly after so much attention, has me rethinking my level of auto mechanic expertise.

As a last update to what I have done: I pulled a few vacuum lines, and didn't detect any fuel in them, so I'm thinking it isn't a ruptured fuel pressure regulator diaphragm (better not be, since I just put a new one in a week ago!). And I checked the oil, and it reeks of fuel.

So I'm going to have the shop first, solve the possible hydrolock situation, whatever it may be. Then, troubleshoot the original problem, of "can't give it full throttle/misfires at 4k rpm"

I'm so very frustrated. I needed to offload this problem, before I start to dislike the car. I don't want that to happen, as I plan to keep it for a long time.

I promise to relay any notes I can get from the mechanics back to everyone here, so it can be a source of information for us all.

Hopefully my next post in a week or two, will be that the car is 100% fixed; and details.

Thanks!

EDIT 7/15/2020: I've decided to tinker on it a little more, before I give it up to a shop. :)
Last edited by nmibaja on Wed Jul 15, 2020 9:01 am, edited 1 time in total.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by jaxed »

Some of those symptoms scream out "plugged catalytic converter" to me.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

You, sir, must be listening in to our conversations!

The "guy at NAPA who has a Subaru" listened to my problems, and he too, said that plugged Cat could be a cause...... the crap acceleration with misfire, that has seemingly only gotten a little worse over the course of about 1600 miles of driving.

Also, spoke to the owner of SSI Subaru in Traverse City, who said Cats could be an issue, but he'd have to test it out to see.

So that suggestion may well hold water in the end.

First, though, I still need to address my "hydrolock" problem, which I may have self-induced with all my un-needed maintenance.

I checked the oil, and it reeks of fuel, so a fuel hydrolock seems more likely. I pulled off a couple of manifold hoses, and couldn't smell fuel in there, so probably (?) not the diaphragm vacuum line off the regulator.

I replaced the fuel injectors a few weeks ago. Not with new ones. The "rebuilt/tested" variety. So those are my prime suspect. Maybe I damaged an 0-ring when I installed them; as I recall one of them didn't want to seat as easily. I would love it if it was something like that, actually. Something that I could actually see, causing a problem.

This weekend, I'm pulling the plugs to see which cylinder (s) are full of fuel. If I get a culprit cylinder, I'm going to re-o-ring the old fuel injector, and replace it, see if that makes it any better. So it can run at least.

I should take the time to do a compression test while I'm there, since I did not when I swapped out the plugs a month ago.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by ZUBAJA »

An injector O-ring is only going to give you an EXTERNAL fuel leak, or a vacuum leak. Pressurized fuel is on one side of the injector, and goes into the intake THROUGH the injector. raw fuel getting into the intake / cylinder(s) will only be through a leaking injector or a leaking FPR. Usually, the reconditioned / tested injectors are okay. Hopefully, thay came with some kind of guarantee. Definitely get the fuel pumped out of the affected cylinders and change that oil. If you crank it to remove the fuel, try unplugging the coil pack(s) from the low voltage wires so there is no chance of one firing a spark and toasting your vehicle.

Result of a leaking injector O-ring on the pressure side
0324181704 burning love.jpg
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

Uhh, guys? Did I really screw something up?

I installed new fuel injectors a few weeks after I got the Baja, and the new ones had this grey plastic collar around the tips.

Was I supposed to remove those???
New.  Old.
New. Old.
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New.  Old.
New. Old.
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I just removed the front passenger side one, because after removing all the spark plugs, I cranked it over and lots of fuel came out of that plug hole.

When I pulled the injector. There is no sign of that grey plastic thing from the injector tip anymore.

Oh boy.

EDIT: Okay, after reading some other forums, I’m understanding that the plastic cap is there to hold the oring in place on that style of injector. When I was installing that particular injector, it went in the hardest. So I must have damaged the plastic retainer, and when it did fall off, the oring went out of place, and allowed some unmetered fuel into the cylinder. Causing my hydro lock.

That theory will be put to the test.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

Ok. Good news.

Baja is back running. One fuel injector was bad, via the bottom seal losing its retainer. I put new seals on one of the old injectors and it’s back to basic running order.

Changed the oil, of course, and wow was it highly flammable smelling. Yikes.

It still has the original problem, no power, etc etc.

At least I can drive it to the repair shop now.

I just don’t feel up to possibly hacking up a 15 year old exhaust on my back in the driveway.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

The news is in, as far as probable cause. The repair shop performed some tests, and concluded that the engine is kind of worn out.

Some excessive gap on the rod bearings; and not great compression numbers:

Cyl 1 - 133 psi
Cyl 2 - 105 psi
Cyl 3 - 135 psi
Cyl 4 - 110 psi

Determined all that through a leakdown test, and compression tests.

Looking at an engine rebuild. They are working up an estimate for me right now.

Disappointing, definitely. But at 184,000 miles, not totally unexpected either.

They also checked for plugged or failing catalytic converters, and they were fine.

In a year, all I will care about is that it is running properly. I'm going to keep telling myself that as I pay for the rebuild. lol
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by sparebeer »

Just throwing out there that the cat that usually plugs up is the one in the up-pipe, between the exhaust manifold and the turbo, on the passenger front side of the engine. I've had this cat plug up a 2003 WRX and my 2005 Baja turbo. A catless up-pipe is highly recommended, as they can also fall apart inside and the catalyst ends up in the turbo. That happened on my Baja after the cat was already plugged. It was that way when I bought it, non-running. The WRX wouldn't run much above an idle, as it was still intact, but plugged up. Also, remove the screens in the banjo bolts that feed the turbo and AVCS valves, as they can plug up and kill the turbo and cause cam timing issues. Lots of youtube videos and forum posts about that.
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Re: Baja Turbo No Power over 1/3 Throttle Then Misfire at 4000 rpm

Post by nmibaja »

The basic problem was what most of you suggested.

The cat in the up pipe was plugged. So we cleaned out all the catalyst material.

We rebuilt the engine while I had it there. She runs smooth and strong now.

Thanks everyone.
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