Motor transplant. Chasing odd RPMs, Acceleration Hesitation

[suprunner]

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

[1 Lucky Texan]

I think live data could be very helpful. Check into an ELM327 BT adapter and an app like Torque for your smartphone.

 

I Think cyls 3 and 4 share half the coil (dues to waste spark ignition) so, maybe try a coil pack?

[suprunner]

31 minutes ago, 1 Lucky Texan said:

I think live data could be very helpful. Check into an ELM327 BT adapter and an app like Torque for your smartphone.

 

I Think cyls 3 and 4 share half the coil (dues to waste spark ignition) so, maybe try a coil pack?

Does it matter that the coil pack is brand new?

[1 Lucky Texan]

Of course, it's extremely rare for new stuff to be bad - not impossible. Is it from the dealer or aftermarket?

are the plug wires original, aftermarket replacements or new? Will they swap 1-2 for 3-4 as a test?

any oil on the plug wire boots?

was the original coil bad? Do you still have it? try it.

grounds are critical - got any missing or corroded? try refreshing the ground connections.

Edited September 24, 2019 by 1 Lucky Texan

[suprunner]

1 hour ago, 1 Lucky Texan said:

Of course, it's extremely rare for new stuff to be bad - not impossible. Is it from the dealer or aftermarket?

are the plug wires original, aftermarket replacements or new? Will they swap 1-2 for 3-4 as a test?

any oil on the plug wire boots?

was the original coil bad? Do you still have it? try it.

grounds are critical - got any missing or corroded? try refreshing the ground connections.

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. 

[suprunner]

3 hours ago, 1 Lucky Texan said:

Of course, it's extremely rare for new stuff to be bad - not impossible. Is it from the dealer or aftermarket?

are the plug wires original, aftermarket replacements or new? Will they swap 1-2 for 3-4 as a test?

any oil on the plug wire boots?

was the original coil bad? Do you still have it? try it.

grounds are critical - got any missing or corroded? try refreshing the ground connections.

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?

[Rooster2]

I would question how well the fuel pump is working. Seems like your problems could be fuel related. Install that fuel pump that you have. See if that helps.

[1 Lucky Texan]

I've never owned a car that didn't shock me in dry weather - as to levels of severity...could be the Subaru fabric is a worse offender than other cars you've driven?

try to keep one hand or finger on some metal of the car AS you exit. That should allow comfortable discharge of any static produced.

[suprunner]

1 hour ago, 1 Lucky Texan said:

I've never owned a car that didn't shock me in dry weather - as to levels of severity...could be the Subaru fabric is a worse offender than other cars you've driven?

try to keep one hand or finger on some metal of the car AS you exit. That should allow comfortable discharge of any static produced.

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

[1 Lucky Texan]

23 hours ago, suprunner said:

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

completely different issues.

[Rampage]

You may want to try swapping these two parts. They are the same on the 96 and 98.

For the misfire, swap the Ignition Control Module. It is located at the center of the firewall. It is the same size as the plug connected to it. The ECU sends signals to it and it controls the coil.

For the rpm thing, swap the Throttle Position Sensor from the 98 intake to the 96 intake you are using now. It is mounted on the side of the throttle body with 2 screws. It is adjustable, so you will need a volt meter. Turn the ignition switch to ON, do not start.  Measuring from a good ground on the meter, the center wire on the plug should be adjusted to .5 volts (half a volt) with the throttle fully closed. The bottom wire is ground and the top wire is hot from the ECU.

Which Mass Airflow Sensor are you using?

[suprunner]

On 9/26/2019 at 6:29 PM, Rampage said:

You may want to try swapping these two parts. They are the same on the 96 and 98.

For the misfire, swap the Ignition Control Module. It is located at the center of the firewall. It is the same size as the plug connected to it. The ECU sends signals to it and it controls the coil.

For the rpm thing, swap the Throttle Position Sensor from the 98 intake to the 96 intake you are using now. It is mounted on the side of the throttle body with 2 screws. It is adjustable, so you will need a volt meter. Turn the ignition switch to ON, do not start.  Measuring from a good ground on the meter, the center wire on the plug should be adjusted to .5 volts (half a volt) with the throttle fully closed. The bottom wire is ground and the top wire is hot from the ECU.

Which Mass Airflow Sensor are you using?

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. 

[suprunner]

On 9/26/2019 at 3:23 PM, 1 Lucky Texan said:

completely different issues.

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? 

[suprunner]

On 9/25/2019 at 9:54 AM, Rooster2 said:

I would question how well the fuel pump is working. Seems like your problems could be fuel related. Install that fuel pump that you have. See if that helps.

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.... 

Edited October 9, 2019 by suprunner

[Rampage]

Try a new fuel filter first. See if it makes a difference.

You mentioned having a problem at half a tank of gas. A dirty filter will slow down the rate of fuel flow through the lines. AWD vehicles have a saddle tank because of the driveshaft. The fuel system uses a jet pump to move fuel from one side of the tank over to the side with the fuel pump. It uses the return line to run the jet pump. If the flow rate (GPH) is low the jet pump won't move the fuel and the fuel pump could be getting air.

Do you have access to a fuel pressure gauge?

What brand is the fuel pump you bought?

[1 Lucky Texan]

it has to do with you and your clothes and possibly your shoes, etc.

not much different than scooting your sneakers across carpet and touching some metal in the house, except it's probably your sweater/shirt/coat rubbing across the seat cushion or similar friction.

[suprunner]

On 10/8/2019 at 8:11 PM, Rampage said:

Try a new fuel filter first. See if it makes a difference.

You mentioned having a problem at half a tank of gas. A dirty filter will slow down the rate of fuel flow through the lines. AWD vehicles have a saddle tank because of the driveshaft. The fuel system uses a jet pump to move fuel from one side of the tank over to the side with the fuel pump. It uses the return line to run the jet pump. If the flow rate (GPH) is low the jet pump won't move the fuel and the fuel pump could be getting air.

Do you have access to a fuel pressure gauge?

What brand is the fuel pump you bought?

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

[Rampage]

1 hour ago, suprunner said:

Fuel pump is Delphi FE0150. It looks pretty similar, just smaller.

I know the plug, our 95 RHD had it on the pump. Glad your pump is not a Carter, those skinny pumps only lasted 11 months in my wife's wagon. The car went through 3 of them warranty replacements until I found the larger diameter pump with the two studs for the wires. They last quite a few years in her car. I had changed the fuel tank, so it is clean.

It's funny, but other people do not have a problem with the skinny pumps.

I don't know if I would try the new pump. It has more pressure but the flow rate is way lower.

80 PSI for the 98 pump and 94 PSI on the Delphi pump you bought.

The flow rate is 40 GPH for the 98 pump and only 26 GPH on the Delphi you bought.

The pumps use a rubber gizmo on the bottom to hold it in place on the bracket. Hook up the short hose and push down on the pump and tighten the clamps.

I would replace the fuel filter before doing a pressure test. I have replaced fuel filters that I could not blow air through and yet the car ran.

When using the fuel pressure gauge hook it up between the fuel filter and the pipe on the engine. NO leaks allowed. 

This is from a 97 FSM.

Start the engine.
Measure fuel pressure while disconnecting pressure regulator vacuum hose from collector chamber.
Fuel pressure:235 — 265 kPa (2.4 — 2.7 kg/cm2, 34 — 38 psi)

After connecting pressure regulator vacuum hose, measure fuel pressure.
Fuel pressure:177 — 206 kPa (1.8 — 2.1 kg/cm2, 26 — 30 psi)
WARNING:Before removing fuel pressure gauge, release fuel pressure.

Another test I do to see what the pump is capable of is this. Using needle nose pliers "momentarily" pinch the return line. The pressure should shoot up to the rated pump pressure 80 PSI.

Injectors do plug up. Pour a can of Sea Foam Motor treatment in the tank. 1 OZ per gallon of gas. Read the can, it's good stuff.

[suprunner]

23 hours ago, Rampage said:

I know the plug, our 95 RHD had it on the pump. Glad your pump is not a Carter, those skinny pumps only lasted 11 months in my wife's wagon. The car went through 3 of them warranty replacements until I found the larger diameter pump with the two studs for the wires. They last quite a few years in her car. I had changed the fuel tank, so it is clean.

It's funny, but other people do not have a problem with the skinny pumps.

I don't know if I would try the new pump. It has more pressure but the flow rate is way lower.

80 PSI for the 98 pump and 94 PSI on the Delphi pump you bought.

The flow rate is 40 GPH for the 98 pump and only 26 GPH on the Delphi you bought.

The pumps use a rubber gizmo on the bottom to hold it in place on the bracket. Hook up the short hose and push down on the pump and tighten the clamps.

I would replace the fuel filter before doing a pressure test. I have replaced fuel filters that I could not blow air through and yet the car ran.

When using the fuel pressure gauge hook it up between the fuel filter and the pipe on the engine. NO leaks allowed. 

This is from a 97 FSM.

Start the engine.
Measure fuel pressure while disconnecting pressure regulator vacuum hose from collector chamber.
Fuel pressure:235 — 265 kPa (2.4 — 2.7 kg/cm2, 34 — 38 psi)

After connecting pressure regulator vacuum hose, measure fuel pressure.
Fuel pressure:177 — 206 kPa (1.8 — 2.1 kg/cm2, 26 — 30 psi)
WARNING:Before removing fuel pressure gauge, release fuel pressure.

Another test I do to see what the pump is capable of is this. Using needle nose pliers "momentarily" pinch the return line. The pressure should shoot up to the rated pump pressure 80 PSI.

Injectors do plug up. Pour a can of Sea Foam Motor treatment in the tank. 1 OZ per gallon of gas. Read the can, it's good stuff.

Open-house on the FPR: 36/38psi

 

Closed-hose FPR: 28/29psi

where to next? 

[Rampage]

Those readings look good. Do they stay there when you rev the engine?

Did you replace the fuel filter?

Did you pinch the return line? If the pressure does not immediately jump up to 80 PSI, then the pump is not as good as it should be and may not keep up when driving.

[suprunner]

17 minutes ago, Rampage said:

Those readings look good. Do they stay there when you rev the engine?

Did you replace the fuel filter?

Did you pinch the return line? If the pressure does not immediately jump up to 80 PSI, then the pump is not as good as it should be and may not keep up when driving.

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

[Rampage]

Understand.

Opening the throttle reduces intake manifold vacuum and that controls the fuel pressure regulator, like when you pulled the vacuum hose off of it. Less vacuum, more pressure.

[suprunner]

On 10/10/2019 at 8:50 PM, Rampage said:

I know the plug, our 95 RHD had it on the pump. Glad your pump is not a Carter, those skinny pumps only lasted 11 months in my wife's wagon. The car went through 3 of them warranty replacements until I found the larger diameter pump with the two studs for the wires. They last quite a few years in her car. I had changed the fuel tank, so it is clean.

It's funny, but other people do not have a problem with the skinny pumps.

I don't know if I would try the new pump. It has more pressure but the flow rate is way lower.

80 PSI for the 98 pump and 94 PSI on the Delphi pump you bought.

The flow rate is 40 GPH for the 98 pump and only 26 GPH on the Delphi you bought.

The pumps use a rubber gizmo on the bottom to hold it in place on the bracket. Hook up the short hose and push down on the pump and tighten the clamps.

I would replace the fuel filter before doing a pressure test. I have replaced fuel filters that I could not blow air through and yet the car ran.

When using the fuel pressure gauge hook it up between the fuel filter and the pipe on the engine. NO leaks allowed. 

This is from a 97 FSM.

Start the engine.
Measure fuel pressure while disconnecting pressure regulator vacuum hose from collector chamber.
Fuel pressure:235 — 265 kPa (2.4 — 2.7 kg/cm2, 34 — 38 psi)

After connecting pressure regulator vacuum hose, measure fuel pressure.
Fuel pressure:177 — 206 kPa (1.8 — 2.1 kg/cm2, 26 — 30 psi)
WARNING:Before removing fuel pressure gauge, release fuel pressure.

Another test I do to see what the pump is capable of is this. Using needle nose pliers "momentarily" pinch the return line. The pressure should shoot up to the rated pump pressure 80 PSI.

Injectors do plug up. Pour a can of Sea Foam Motor treatment in the tank. 1 OZ per gallon of gas. Read the can, it's good stuff.

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.