1991 Legacy Running Terrible after replacing Fuel Injectors - No CEl

[None77]

I need some suggestions about getting my 1991 legacy wagon 122,000 Miles,
running properly. Last Sunday I was driving the car, and CEL came on.
Car started running very rough. I knew it was a bad Fuel injector. I had
a couple of bad injectors over the last year, and I had used a few I
got from junkyard.

 

I was surprised to find the price of bostech injectors
had gone down. I ordered 4 new injectors and replaced them all with new
injectors. The car was very difficult to star, after changing
injectors, and I realized it was flooded. I got it started, but it was
running rough, and smoked a lot.

 

I checked plugs and they were fouled. I replaced plugs,
but it's still running very rough. It runs just fine in my neighborhood,
at slow speeds when I'm getting on highway, If I step on the gas, it
just seems to bog down, and not accelerate. If I very gently press the
gas, it will gradually get up to speed, but doesn't seem to shift at
correct times. It was running great last week before these problems
started.

 

The lack of CEL leaves me guessing.   I started to wonder if the fuel injectors I purchased are teh problem?

 

I did notice the new injectors had a round O ring on bottom, and I think the stock In jectors have a flat rubber gasket?

 

I'm open to any suggestions.

 

Lou

[coxy]

Pull the Injectors and have somebody flow test them and chack they are nor dribbling fuel my guess is dud new injectors or are they Reconditioned ones.

 

Injectors are generally pretty reliable but there are exceptions, have you narrowed it down to any particular cylinder running too rich or are they all too rich in which case maybe the flow rating of the injectors is wrong.

 

Too high a flow rating will mean the injectors are switched on for a set time goverened by the ECU but because the flow rating may not match factory injectors it can end up either supplying too much fuel or not enough if the injedctors are to low a flow rating compared to stock.

 

I think you may well find the injectors supplied are too high a flow rating, aftermarket parts can foul you up like that sometimes.

[None77]

Where can I get ithe injectors tested?  I have never done that before.

 

Thanks for reply.  This problem is very frustrating.

 

Lou

[Fairtax4me]

Possibly one of the injectors is improperly sealed. The o-ring style is very important and using the wrong o-rings can cause leaks.

 

You could also have a broken or loose vaccum line.

[1 Lucky Texan]

yeah, seems more like a vacuum leak, possibly clogged exhaust.

 

vacuum gauges are cheap and there's a decent sized list of failure modes that it help can detect.

 

I dunno when TB changes are due on that model - could be a slipped timing belt I guess.

 

 

has the CEL returned? can you get a blink code?

[None77]

It seems like it's running rich, and bogging down.

 

I don't have any CEL.  I didn't try the blink code... because I thought I had to have CEL, but I'm not sure.

 

I drove it about 50 miles.  It is slow to get up to speed, but will cruise at 80mph.   I had to go up a short steep hill, and it didn't think I was going to make it.

 

I can buy a vacuum gauge, I don't know how to use it, but will try to figure it out.  It has 124,000 miles on it, and Timing belt was done at 98,000.

 

What types of problems would pressure regulator or fuel pump cause?  Do those things throw CEL?

 

This was my Dad's care, and I inherited it in 2001.  The transmission went out in 2011, and it took me a year and two transmission to get it back o nthe road.  I think sitting was bad for it, but it was really hard for me to find a transmission in the Cincinnati Area.

[1 Lucky Texan]

I recall that some older soobs had issues with the Engine Temp Sensor keeping the car in 'choke' mode - fooling the ECU into thinking the engine was cols all the time. And that will usually not throw a code. On your car, I think its the 2 wire sensor. Mounted near a one wire Coolant temp Sensor.

 

 

vacuum gauge probably comes with a few attachments and instructions. Check the web and youtube too.

[john in KY]

Two things come to mind. Pull the vacuum line at the pressure regulator. If fuel flows then the regulator has failed. Wondering if you installed the correct injectors. Very early model Legacys used 2 types of injectors. One for manual and another for automatic transmissions. And somewhere in the early 1990s Subaru changed to another type of injector. What I am trying to convey is make sure the injectors are specifically for your model year. 

[None77]

The injectors look correct.   The 3 types that I'm aware of for 1991 Legacy: Black top - Manual Trans Non-Turbo, Grey top - Auto Trans - Non-Turbo, and Red top - Turbo Models.

 

The replacement injectors are grey, and look exactly like the originals.  I'm going to try and pull the  ECU Codes.   I never cleared them, and I'm not sure if they erase after having battery unplugged, for extended period.

 

The car was hard to start after I replaced the injectors because some fuel had seeped into cylindrers.   It smoked like crazy when I first started it, and fouled the plugs. 

 

I wonder if I could have fouled the O2 sensor, or ruined the Cat.  I'm just reaching for straws trying to determine what to check.

[Fairtax4me]

That engine should have the side feed injectors. If the lower O-rings aren't the correct type, or were damaged on installation, the fuel in the rails will leak around the injector directly into the manifold.

 

I would pull the injectors and check the o-rings carefully.

Before pulling the injectors out clear the fuel out of the rails by removing the fuel pressure regulator, then remove the outlet hose from the fuel filter and blow air into the hose to blow the fuel out of the rails.

[None77]

I checked ECU codes with black connectors, and didn't recieve any codes.   I tried the green connectors and followed instructions driving car,  I got code 32 which is O2 sensor.  I'm still confused why I wouldn't get a regular CEL if there are problems with O2 sensor.

 

I also stopped at Harbor Freight, and bought Vacuum Gauge and Fuel Pump tester.

[None77]

Problem Solved! Fuel Injector Problems. Bosetech Injectors, they look correct with grey tops, but don't work properly.

 

 

Thanks for all the help.  I did check Vacuum and Fuel Pressure along the way.

[lmdew]

Yep, I like good used parts "Subaru" better than new.

[1 Lucky Texan]

good job sorting it out!