suprunner

Finally got to checking fuel pressure. 28 psi at the lowest when the FPR is still plugged in, and goes up to about 36/38 psi when FPR is unplugged. No significant change in fuel pressure when I open the throttle to the normal hesitation range of 1800-2500 rpm. But the fuel pressure jumps to 30 psi when the motor begins to do the hesitation/low-idle/bobbing during idle. I also recently had the CEL come on while driving out of a parking lot at the hottest part of the day. Codes were misfires for all cylinders. CEL went away after a day, then came back while on the highway. Also, it continues to smell rich upon startup. I've also noticed that when I'm coasting with foot off the gas, but in gear, that once I reapply acceleration there's a pop sound that comes from the exhaust at the front of the car. Sound reminds me of engaging the snare mechanism on a drum. Greg

Not since I put in a new pump/strainer/filter about 4 months ago. You want me to check it? Also, if these injectors have many many miles on them, is it worth replacing them? If so, do they need to be OEM, or will something from Rock auto work? Greg

So, I guess my initial evaluation wasn't what I had thought. I swapped #1 and #3 as you had suggested, and there was not change in performance. Unplugging both during idle produced the same effects. After clearing the codes, and taking for a spin, I still experienced the instances of low/bobbing idle.

Sorry for the length, it was hot outside and the engine bay was quite warm, I was fumbling on touching things. There are a couple instances where the motor does stumble on its own without me doing anything. I tried increasing RPMs to show the odd range of motor unbalance, but I'm not sure it shows well in the video. Unplugging injectors 1, 2, and 4, caused the motor to really bog and shake... Unplugging injector #3 had minimal change to the idle. Change it out?

Hi Rick, I'll get a video of it idling tomorrow. I'll try to get it during the hottest part of the day to see if it shows everything I'm trying to describe. I've had this motor build for about 4 years now, with the same symptoms, it's just that I'm now living in the desert heat so the symptoms are always present. The symptoms followed the motor when it was transplanted into the OBW that I'm now driving. The only electronic components that are still on it from the beginning are the injectors, cam sensor and crank sensor. The MAF has been swapped out between two used OEM units, and an AC delco reman. Ignitor and coil are not original either, but there was no change in symptoms. About 4 months ago I had the injectors out, and I cleaned out all the filters, and soaked the tips in some isopropyl alcohol. There was no change after installation. Thanks for your time, Greg

I run a mixture of 100 oct, and 91 oct. The 100 octane is $8 a gal! I usually put in 4 gallons of the highest, and then the rest at 91 octane. I've not noticed any difference in performance if I just do 91. The low idle/bobbing is the worst whenever the gas tank is at or below 1/2, especially if I drive somewhere and park for a half hour or so. If there is an evap issue, is this a symptom? I never hear a positive/negative pressure release when I undue the gas cap... Sometimes I hear bubbling in the gas tank upon startup. Greg

Hi GD, The STFT1 ranged from 2.3 to 10.2 while I was idling. The LTFT1 stayed at 15.6 the entire time. Thoughts? Also, when connecting the computer to the OBDII port, and its startup, the "EVAP" light was flashing on the computer, and in red. Should I be looking at the emissions system(s)?

The OBD-II scanner from the local auto store couldn't show me values for my A/F ratios. For the MAF g/s, at idle stayed at about 3.02 g/s to 3.4 g/s. There wasn't much of a change there when the car started to drop the idle. Alternator output is in the mid 13s on idle, and just below 14v at about 2000rpm. I noticed that the spark advance was 15 degrees at idle, until the idle drop/bob happened, that's when the spark advance jumped to 21 degrees, and there was one time when the vehicle speed sensor registered as 45mph. When I first connected the scanner, I slowly depressed the accelerator pedal (with the key in the ON position only, not running), and I consistently couldn't get the TPS to read over 92% when fully depressed, and without any floor mat underneath it. Does that mean anything, or is it just part of the governor system? I will track down an OBDII scanner that can show me A/F ratios. What values should I be looking for? Is this information in a FSM? Thank you, Greg

GD, for Fuel trims and MAF G's/voltages can I get that information through a computer like those found at the auto stores? Also, what are MAF G/s? Is that grams per second? Do I want to try and read that information when the motor is presenting the symptoms, or just at any time? Have you had any luck with the bluetooth OBD II readers? Thanks, Greg https://www.amazon.com/gp/product/B00652G4TS/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00652G4TS&linkCode=as2&tag=bluedriverweb12-20&linkId=5923cdc63008d567562f7afe37939bf1

Hi all, EJ251 block/EJ25D heads in '98 OBW, 5MT Recent work done in the past year: Plugs (ngk) wires (ngk) Timing belt kit (oem) Timing cam gears (oem) Cleaned and swapped out IACV Swapped out MAF Swapped out TPS New Fuel Pump, Strainer, Filter, Pressure Regulator New OEM Oxygen sensor Compression test cylinders 1-4: 214, 205, 225, 209 (unsure if these numbers are good for a High Compression build, it is consuming some oil. Maybe a half quart to full quart every few months of mostly short trips and some highway) I live in Las Vegas, and the temperatures are now at the usual hot. When city driving during the heat of the day, the engine will idle very low (has approached stalling, entire car shutters/shakes) and will often bob up and down +/- 100 rpm. It seems to be at its worse always when the fuel tank is at or below half-filled. If I use the A/C it helps with the issue because of the idle-up function. I've checked for vacuum leaks with a propane tank, and can't find anything. If I unplug a vacuum line, the engine idles up. Upon startup for the first 5 minutes, the exhaust smells very rich. Should I be looking to test next? The valves are kinda loud, should I do a leak-down test? When I press the accelerator pedal, from 1800 rpm to 2500 rpm, the motor behaves as if it is unbalanced. Anything above 2500, it is smooth and responsive. I am using an air intake from a '96 legacy wagon... is that an issue? Too restrictive? Any help would be appreciated. Greg

Hi, long time without a follow-up. I've recently changed the fuel-pump/strainer/soft fuel lines/fuel filter. No change. When I pinch the return-line, the motor just about stalls. I just cleaned out the IACV as well. I also recently changed out the wiring harness for the motor. I checked it over to ensure there weren't any cracked wires/connectors as well. Symptoms are still present. Upon start-up throttle response is delayed/causes a brief stall when I touch the accelerator within the first 45 seconds of start-up, and there is still a stumbling of the motor at around 1800-2500 RPM, driving or in neutral. Runs very smooth above 3000 rpm. If I give it the goose, the lower rpms it is sluggish, but once it hits 3000-3300 RPM, the car really picks up. Like it's a different animal. I had the Intake manifold off, and there seemed to be a lot of carbon/sludge build-up. around all of the injectors. Like it's running very rich.

Oh dang! It increased pressure by maybe 2psi as I increased the revolutions. . Shoot-dang, I forgot to do the pinch-off test. I'll have to rent the pressure gauge again. Was running out of time and light. Greg

Open-house on the FPR: 36/38psi Closed-hose FPR: 28/29psi where to next?

I just rented the fuel pressure gauge, hopefully I'll get a reading tomorrow after school. Fuel pump is Delphi FE0150. It looks pretty similar, just smaller. The main difference is the size, and the terminals for power. The stock fuel pump has the two separate terminals that you attach wires with screws to. The new Delphi has a male receiver that a female plug inserts to. Funny thing is, the fuel pump I'm currently running is an Import Direct that I bought 6 years ago to replace the OEM pump on my '96... and it has the same plug-type as this newer delphi. I was tempted to try and run it, but I'd have to zip-tie it or hose-clamp it to the holder that inserts into the fuel tank. one of the fellas on the 2nd Gen Legacy facebag group mentioned my symptoms were reminiscent of when his injectors had failed. Think it's connected? I know they have power when I multimeter them, and I've used the noid lights.. Thanks, Greg

Hi, thank you for responding. I apologize for not returning feedback, I've been a bit busy with school finals month. Turns out the fuel pump I had purchased for the car was for a 2000+ subaru. And unfortunately I can't return it to Rock Auto since I purchased it more than a year ago. Do you think it's worth purchasing another pump? Would the pump from the 2000 work? It's much smaller....

Hey, Thank you for taking the time to respond. I've been a bit swamped with finals month at school right now. The car is building static electricity with just idling in place, and not moving. Still normal?

Hi, Thank you for responding and I apologize for not getting back. It's finals month right now at school. I do not have anything left over from the '96. So, I can't swap the ICM, Won't be able to swap the TPS either. I did just check Resistance with the TPS... I followed the above's instructions. I'm attaching the readings that I got. I wasn't sure which terminal was 1 or 3. I figured the center terminal was #2 though. I swapped out MAF for a rebuilt MAF that I had purchased years ago. No change. Still has a dead-spot/hesitation at start-up when I first touch the accelerator, and unbalanced feeling at 2000 rpm +/- 100 rpm all the time.

So it doesn't necessarily mean I have a bad ground somewhere?

Just added a new ground from the intake manifold to the other strut tower, and cleaned up one on the inside of the frame rail on the passenger side. No difference upon startup for the hesitation or the unbalanced feeling at/around 1800/2200 rpm mark. But, I got shocked to hell with static electricity when I got out of the car after backing out of my garage and parking in the street... I'm assuming that's not normal?

Coil is aftermarket. Same symptoms with OEM coil. Plugs, wires are all new subaru, and no oil. I currently have a ground coming from the battery to the intake manifold, to the strut tower, and to the body right behind the headlight. Bare metal for the body mounts listed. I will look over other grounds.

Does it matter that the coil pack is brand new?

Hi all, Working with an EJ251/EJ25D hybrid. Recent work done (in the past 3000 miles): Spark Plugs (OEM Subaru) Spark Plug Wires Ignition Coil New Timing belt Components (subaru oem) New Subaru Camshaft sprockets (OMG $$$$) Group N Motor and Transmission mounts/bushings New Subaru OEM O2 sensor New GrimmSpeed Exhaust manifold gaskets New Subaru OEM exhaust gaskets at Y-collector and right behind rear O2 sensor. New Subaru Air Filter Coolant Temp Sensor (for ecu) replaced about 4 years ago. Motor originally lived in a '96 Legacy wagon, and was recently moved into a '98 Outback wagon (5mt) Symptoms that I experienced in the '96 were as follows: When bringing RPMs up to the 1800 to 2300 range there is an odd imbalance/shudder that takes place. This happens whether I'm driving, or sitting still in neutral. On very hot days (anything above 80, so here in Las Vegas that is a normal...) if the fuel tank is below half, the motor will bob up and down +/- 150-300 rpm during idle for about a minute or two and then settle out. The components that stayed the same with the motor transplant was the entire motor (including intake), Fuel filter (which is about 5 years old), and fuel pump (which is 6 years old). NOW in addition to the above symptoms, upon startup, for the first 5 minutes of driving, when I initially touch the accelerator the motor briefly (maybe .25/.5 seconds) stalls and then gains RPMs. Once fully warmed up this hesitation goes away. I just recently got a CEL for a misfire in cylinders 3 and 4 while driving on the highway for 20 minutes. I bought a propane torch and attempted looking for a vacuum leak, but didn't find anything. I unplugged a vacuum line running from the intake to the FPR, which caused an idle-up, and then I pointed the propane torch into the vacuum and caused another little idle-up. No idle-up happened when putting the propane at any place I tried (along intake manifold/hoses), brake booster hose, injectors, PCV hoses, basically everywhere. Question #1: Could these symptoms be related? Question #2: what plan of attack would you suggest? Right now I was guessing that I should check my fuel pressure since the Fuel Pressure Regulator (FPR) and all fuel components (except fuel lines of the new body) were around before the motor swap. . . What is the likely hood of Injectors being an issue? I do have another (brand new) fuel pump that I could install but haven't had time with grad school. I'm pretty sure they are stock. Compression is good in all cylinders, doesn't leak/consume oil. Thank you for your time, Greg

Might this have caused a belt slip? I guess I'll be looking for new cam gears. Cheapest I've found are $80 a pop.

Rick, my English was poorly worded. The heads had been refurbished by the subaru shop. The cam gears were purchased alongside them. I can't attest to their actual ages, as I believe they were used inventory. Is there no visual inspection that can be done to see if there is the beginnings of failure? Or is it an all-or-nothing fail? Greg

Thank you all for the input. I will only be purchasing a tensioner and belt. These cam gears appear to be in good shape. I picked them up from a subaru specialty shop in Boulder, CO when I bought my heads from them. They were refurbished. Is there a setup process for the tensioner? I'd been told that I'm to remove the pin, then compress the piston, and replace the pin. . . all before installation. I had not utilized this technique when installing the gates tensioner. Take care, Greg