EJ25D Fuel Cut? 98 Outback 5 speed

[torxxx]

Just scored a 98 Outback 5 speed over the weekend for 500 bucks. Sat in storage for a few years, all it took was a jump start to get it going. Car runs great, but I've noticed one thing... It feels like a fuel cut @ 4500 in first gear. Rev rev rev no fuel, rpms get below 4k and it powers right back up. Shouldnt be a limited since redline starts @ 6k.. One would assume the engine would pull at least to the start of redline before fuel cut occured.

 

The 5 speed didnt have a fuel cut system to stop overreving did it? I've never noticed it on any other 5 speed before, just wondering if this is a common issue with the DOHC engine/fuel system? I'm sure it needs a tuneup, but its starting to make me wonder if its just old gas or the fuel pump dying maybe? Anyone else have fuel cut like issues, and if so what was the fix?

 

And whats with the whistle that comes from the exhaust? I've seen it do this almost EVERY 5 speed Outback I've worked on, and on a few of my friends Outbacks. We started calling it the simulated turbo (as a joke) since it whines like one under high RPM. I am planning on getting rid of the muffler and resonator and running straight pipe because I like to hear my exhaust, not my engine. Easier to listen for misfires IMO.

 

Thanks in advance to anyone who responds

[Fairtax4me]

Nice score!

 

The muffler noise seems common on the older EJ Subarus. I think there must be some holes that rust out on the baffles inside the muffler that cause it. My auto wagon did it, and I've heard several other soobs around here making the same noise. Doesn't seem to be specific to any certain model.

 

Never heard of a 4k fuel cut on these. Might just need some tune-up love. Filters and such. Check all the usual vacuum hoses and intake/breather/pcv tubes.

[torxxx]

You guys are gonna laugh at me for this one. After posting this, goin back to the shop and fixing the F150 blocking the door, I got mine in the shop and checked out the entire car.

 

Ends up being, I drove the car for damn near a full day never noticed that the speedo didnt work. ( My SVX and my 86 wagon speedos are so far off with the bigger tires/different gearing I dont ever look at that side of the dash lol)

 

Replaced the Instrument cluster and the fuel cut issue stopped.

 

So I guess the vehicle speed sensor in the speedo cluster controls fuel cut. No speed sensor = no high revs. I pushed the car well into redline in several gears after the VSS was replaced and no more fuel cut. Oh the joys of ODB2 systems. Reminds me why I love the SVX... Check engine light comes on, no fail safe mode.

 

Thanks for the info on the exhaust, good thing I did some favors for the exhaust shop last week. I'll buy some 2 inch exhaust tubing and hit them up this weekend and get rid of that muffler. IMO Subaru's weren't made to run mufflers. If you use the right size tubing you can create enough back pressure to avoid the nasty pops on aggressive decel, and still have the bottom end power like running a full exhaust. Once the lift is on, I'll do full catback and ditch the O2 sensors/cats

 

Don't really see the point of the 02 sensor system Subaru uses on a MPFI system. Whats the point of reading the entire exhaust system and letting the computer adjust all 4 cylinders. Be a different story if each cylinder had an o2 sensor, but with the stock header setup I dont think it'd be possible unless someone scored a set of equal length N/A headers. And then at then by then, why bother with the Subaru fuel management system? MegaSquirt time!

[nickb21]

Nice, glad to hear you sorted that out!

 

I had the same problem with no VSS signal and hitting the cut-off (02 OBW). I did happen to notice the speedo not working and my CEL was on though . Did you get a CEL and just not take a look at the codes?

 

If you use the right size tubing you can create enough back pressure to avoid the nasty pops on aggressive decel, ...

 

Interesting you mention the pops - I get these quite a lot on lift-off (5spd), wonder if the hole(s) in my exhaust make the problem worse. Interesting...

[Fairtax4me]

Subarus O2 sensor setup isn't any different than any other manufacturer of the time. They pretty much all worked that way. Even now car makers use one sensor per bank to adjust mixture. For the most part any sensor that's behind the cats is going to be for checking catalyst efficiency. Some newer cars use A/F ratio sensors behind the first cat, which can play a small part in mixture adjustment, but don't generally cause drive ability problems like a front sensor would if they go bad.

[edrach]

You're right about the instrument cluster being the issue since the VSS signal comes from there on the '98s.

 

Also, the whistle is standard on early Imprezas; my '97 has done it for all the time I've owned it; a loose or missing baffle in the muffler.

[torxxx]

Well, I noticed a CEL coming on and off a few times which I thought was odd. I'm just too used to my SVX (ODB-I) and the system glitches now and then so you'll get a random CEL while driving and 10 sec later it goes off.

 

I guess I need to start carrying my scanner in the glove box since ODB-II actually pops legit codes unlike the early SVX.

[Fairtax4me]

OBD2 is more sensitive because of emissions regulations.

With OBD1 the engine could be on fire and the ECU wouldn't set any codes. You can have sensors fail almost completely and the ECU wouldn't know, or wouldn't set a code for it.

 

OBD2 came about because of pollution laws. OBD1 was more of an "in between" while manufacturers were working out the OBD2 bugs and getting them system implemented.

But the whole idea is to prevent excessive pollution in the form of high carbon and NOx emissions. To do that, it needs to be sensitive enough to alert the driver immediately when there is a problem, by illuminating the CEL.

 

Generally when the CEL blinks on and off several times, it's due to a misfire (not a glitch), which is a major source of emissions and can damage the cats, which then compounds the emissions problem.

If the misfire clears up the CEL turns off, the ECU should set a "pending" code, which may clear or may not when the key is cycled. But if it continues for a certain time the CEL will stop blinking and stay on, and the ECU will set a current code.

[torxxx]

ODB and emissions... Lol its a clean burning gas engine to begin with. I love how the EPA has made it strict on clean burning gas engines, but yet diesels blow coal all day long and there is no restrictions on them. Fact that one could run a subaru inside a shop with the door down for 30 minutes and you dont get sick. Try running a diesel for 3 minutes with the door down..

 

Guess I shouldnt complain too much, our state just got rid of the entire emissions program because it really wasnt making that much of a difference up here.

 

 

Anywho, since I've replaced the VSS, I've put 200 hard miles on it, and it seems to run like a champ. Kinda starting to like the DOHC engine, guess its a good thing the SVX spark plug location got me into shape to do the 2.5 spark plugs lolololol.

[Gloyale]

The whistle is intake noise, not exhaust.

 

It's from the ribbed tube section of the intake snorkus.

 

sometimes unclamping it from the MAF, bending it a hair, and reclamping will help.

 

It's worse if the fenderwell airbox is removed.

[Fairtax4me]

Not in my case. The ones that I've seen the whistle clearly comes from the muffler.

 

EPA mandated new diesel emissions regulations in 2007 for all highway operated vehicles. The catalytic converter regulations do not apply to vehicles made before 2007, but any diesel highway use vehicle made for the US market for model year 2007 and later has to have catalytic converters. Because of that diesel fuel has new refinement requirements. The biggest change is the amount of sulfur allowed has been decreased from >500 ppb to >15 ppb. Makes a big difference in how much smoke comes out of the pipes.