Jump to content
Ultimate Subaru Message Board

94 loyale running rough


Recommended Posts

I have a 94 loyale. When I got it the previous owner had the hose coming into the fuel pressure regulator clamped off. When I took the clamp off the motor ran rough and would eventually die at idle. I replaced the regulator, still having same problem. If you clamp the hose shut it runs fine. Take the clamp off rough idle and dies.

 

Any suggestions?

  • Like 1
Link to comment
Share on other sites

I have a 94 loyale. When I got it the previous owner had the hose coming into the fuel pressure regulator clamped off. When I took the clamp off the motor ran rough and would eventually die at idle. I replaced the regulator, still having same problem. If you clamp the hose shut it runs fine. Take the clamp off rough idle and dies.

 

Any suggestions?

 

Post a pic of the hose aand surrounding are. Way too vague for me ti know which hose you are talking about.

  • Like 1
Link to comment
Share on other sites

 It could be the fuel pump  is subpar in supplying pressure so to compensate, they blocked the return line. Only way to know for sure is to measure the pressure as stated above.

 

A clue to the fuel pump might be to listen to how long it takes to charge. With the car off, turn the key to just before starting and you should hear the fuel pump charging the line. It should take about 3 seconds. If it is going much longer, suspect the fuel pump.

 

ETA: Sometimes a failing fuel pump can be brought back temporarily by gently rapping on it with the HANDLE(wooden preferred) of a hammer. So one test would be to remove the clamp and wait for it to die then go in back and gently tap the body of the fuel pump. Try running again. If after a few "rap sessions" (OMG the puns just flow out lol), if the car appears to run OK even for a few minutes, then I would strongly suspect a failing fuel pump.

Edited by MR_Loyale
  • Like 1
Link to comment
Share on other sites

Ok so I had the ol lady turn the key while I listened to the pump. It did run for roughly 3 seconds or so.

 

Little background on the car, I picked it up for 400 bucks. Body is clean But ran rough, previous owner said it had sat for a while.

 

I did a complete tune up on it, plugs, wires, cap, button etc.

It did run a lot better after that but still didn't idle well and wouldn't start when the engine was warmed up. No check engine light codes.

 

I will try and find a gauge and t it in on the supply line. Anyone know what the factory pump is supposed to put out?

Edited by Loyale#1
Link to comment
Share on other sites

  • 2 weeks later...

New update, wound up replacing the fuel pump because I was having to tap the old one with a hammer handle to get it to spin. After replacing pump I still have to keep a clamp on that return hose for the car to idle well and be driveable.

 

Is there a way to test the dampener?

  • Like 1
Link to comment
Share on other sites

Could be the pressure regulator is stuck open.  Fuel pressure is supposed to be 21PSI.  A gauge would help.

 

Not a whole lot in the FSM to help troubleshoot, which surprises me, as they usually have a lot of info.  I think the regulator is the shiny thing the return line is connected to.

I'd swap a spare one in place to test.

Link to comment
Share on other sites

That is a new regulator on it. Im kinda stumped.

 

Thanks for all the good suggestions though.

 

Think I could have a vaccum problem? I sprayed starter fluid around all the vaccum hoses and fittings, engine didn't rev. Is there another way to test vaccum?

Link to comment
Share on other sites

Update!

 

So today I got a gauge t'd in my fuel line. With the clamp off the return line gauge reads 22 psi, clamp the return line and the gauge hits 70psi.

 

Another thing I did was pull the vaccum line off of the fpr at idle and nothing changed. So that tells me I'm not getting vaccum there? Should I have vaccum at a idle?

 

This is begining to be very frustrating

Edited by Loyale#1
Link to comment
Share on other sites

Want to add another thing I unplugged the coolant temp sensor While the car was running and up to operating temp and the idle increased a little. I tested the sensor and got 241 ohms.

 

I read in my chiltons manual the denote should test 2-3,000 cold and around 1,000 at operating temp.

Edited by Loyale#1
Link to comment
Share on other sites

Sounds like the fuel pressure is good, I would not use the clamp to make it run, or realize that the pump is being overloaded. That might not be good for it.

 

22psi without the clamp is on normal range.

 

Maybe something wrong with the injector? I suppose a bad vacuum leak could lean it out so much it wouldn't run, but the overpressure then makes up for it sort of.

 

I would think you would be able to hear a vacuum leak that big.

 

 

A thing to try would be capping off the vacuum taps like the brake booster, the port that goes to the solenoids, etc.

 

I'm trying to think of how to narrow down your problem. I'd just swap in a spare injector.

 

I have yet to have a problem with the mass air flow sensor or the throttle position sensor that caused this trouble. Maybe some else has?

 

The coolant temperature sensor can really screw up running well when it fails in some ways, and it won't cause the CEL to come on. Might be worth putting an ohmmeter on that one, since it's simple to check.

Link to comment
Share on other sites

I did meter the cts. 241 ohms at operating temp. Have yet to test it cold (waiting on engine to cool down)

 

I don't hear any vaccum leaks, I have even held a small piece of hose to my ear then followed as many vac lines as I could find and didn't hear a single leak. Like I said before I sprayed starter fluid around be vac lines also and engine did not revv.

 

I do not have a spare injector and the parts stores around me do not hardly carry anything for my car so I normally order online. I found this on parts geek part #408-05172345. Is there one you recommend?

 

I have not tried capping off vac lines to narrow down a leak yet. Maybe tommorow after work I will try that.

 

Thanks for the quick reply's and good advice DaveT

Link to comment
Share on other sites

I have not tried capping off vac lines to narrow down a leak yet. Maybe tomorow after work I will try that.

 

A vacuum test is easy to do and can help you diagnose engine problems and tell you a lot of information about the health of your engine.

 

YouTube has plenty of info on how to use/read a vacuum gauge.

 

http://youtube.com/watch?v=SdlNwm8OHco?version=3

Edited by Dee2
Link to comment
Share on other sites

Loyale#1  wrote:  I did meter the cts. 241 ohms at operating temp.

 

That isn't good.  Way lower than anything I've seen.

Table of temps vs ohms from FSM:

 

14F    7K to 11.5K ohms

68F    2K to 3K ohms

122F  700 to 1000 ohms

 

From measurements on sensors I have, made a while back:

 

77F    2390  new sensor

185F  400 new sensor

190F  454 1990 sensor

Link to comment
Share on other sites

Need more data points. But if it is say, stuck at 240 ohms, that would be telling the ecu the engine is very hot. It would then not supply enough fuel to get and keep a cold engine running. One of the things it does is control the fuel system like the choke did on carburetor systems.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...