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ea82 stumbling/surging

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My loyale stumbles at times especially under load. The clutch is only a few yrs old and the spark plugs and fuel pump have been relaced within the last 6 months. Its a non carburated ea82. Are my timming belts on the way out?

It's not a huge issue, I just romp on the gas more and it smooths out.

Any ideas?

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I have the same issue. I was noticing it yesterday morning. If I accelerate slowly or if I really give it the beans, it doesn't seem to have the issue as much. But when I accelerate normally that's when I notice the problem the most. I'm interested to see what kind of feedback there is on this.

 

I replaced my air filter, plugs and plug wires thinking it was a weak spark issue but that didn't seem to help. I'm suspecting a coil issue but I'm not certain.

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my GL was doing that. The fuel pump ended up going out not too long after and i replaced it with a universal pump that i bought off ebay. The pump was like 40 or 50 dollars. The car sure runs great now with the new pump. Easy as pie to replace as well, didn't even have to jack the car up.

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I was just writing the same thing as above. Definetly a fuel delivery problem. It can also be a clogged fuel filter so that's a good place to start looking before replacing the pump itself.

Edited by -tombba-

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OH! Forehead slap! The fuel pump/filter. The filter right next to the pump was always the problem with my EA81. I wonder if the different fuel blends (in the US) are having an effect too.

 

New fuel filter tonight!

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When you replaced the spark plugs, did you replace at least the plug wires?  I have seen lots of bizarre issues as wires go bad.  I would not expect this to be a fuel pump or filter problem, which usually would worsen with increased throttle.

 

Other possibilities are ignition timing, O2 sensor, and coolant temperature sensor (CTS; their wiring/connectors tend to corrode). Plus other, less likely sensors and injector(s).

 

Timing on fuel-injected EA82s need to be set/checked with green diagnostic plugs connected; don't forget to disconnect them afterwards. 

 

The O2 sensor can be bypassed by disconnecting the sensor:  This will put the ECU into open-loop mode, which uses "conservative" (generally richer A/F) fuel mapping.

 

Timing belts generally don't give any warning about needing replacement.  The tensioners can slacken and allow some sloppiness in the valve timing or a belt to skip a tooth, but idle is generally worsened by stuff like this.

 

My bet is ignition related.  Part-throttle usually is set to run leaner than other running conditions, and leaner mixtures are harder to ignite.

Edited by NorthWet

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My fuel pump is a brand new one made for a ford truck, and the filter is a new one made for a mazda FI motor. The loyale has been running fine with these parts. The stumble has gotten progressively worse over the last few months. I had a simmilar problem w/ my brat and I swapped in a different coil and plug wires and that seemed to do the trick. I guess I will try that and see what happens. The motor runs great I just have these annoying dead spots/stumbling, It's getting to the point where I can't ignore it any longer. I almost wish it would completely die, so I could definitively know what the culprit is.

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Unless you have a cheap source of good coils, I would suggest not assuming a bad coil.  Realistically, they do not go bad very often.  Much more likely are the plug wires, distributor cap, rotor, grounding of the coil bracket, and ignitor.

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whats the pressure and flow rating for the ford fuel pump?  with non standard gear it might be out of spec.    

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That is probably the Ford transfer pump that is commonly recommended as a replacement.  Plenty of flow and pressure, just much cheaper than original.

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I have a plentiful supply of coils, wires, plugs ect. Going to try swapping different wires, this weekend. The fuel pump is a generic aftermarket listed for a direct replacement for a ford f-150 FI motor (30$ at rockauto) It has been working fine. I don't susspect it is a fuel issue, but I will find out this weekend. last nights commute was the worst. skipping/stumbling at highway speeds, and realy stumbling going up through the gears(like a bucking bronco). I'm back to driving my GL now until I get this issue w/ the loyale sorted out. May also try swapping some fuel filters first just to rule out the fuel issue.

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Well so far I have swapped out the following parts: 

 

Coil

plug wires

plugs

fuel filter

cap/rotor

Air Control Valve

 

I have also checked the timming, and done experiments running it a litte advanced, and a little retarded.

 

End result..................still running like poo.

 

Stumbling on acceleration, stumbling at cruising speeds. 

 

When swapping the plugs they all looked pretty clean, so I dont think one of the cylinders is bad.  

 

So what is left that could be bad, Vacuum leak? bad distributor?

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So I was looking at my intake manifold gaskets this weekend while trying to find a coolant leak. I noticed the gasket material that extends beyond the metal was flaking off and a small chunk that was sandwiched between the head and intake came off in my hand. I'm beginning to wonder if there's a leak in my intake manifold gaskets.

 

I did a little research here and it sounds like others have had issues with that gasket as it pertains to the coolant passages, but I wonder if this could be your issue.

 

I guess the logical test would be to spray some kind of fluid near the point where the manifold joins the head to see if it effects the engine speed. Maybe someone else here can chime in on a good test for that.

 

My 86 Honda Civic suffers from a temperamental MAP (Manifold Absolute Pressure) sensor and that causes some pretty 'bucking bronc'-like situations. Higher vacuum situations would probably be worse if there is a manifold leak.

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Just a question, have you looked to see if there is an internal screen inside your fuel pump? The original to the Loyale had  a brass screen which could become clogged, before anything gets to the fuel filter. 

 

I had to drop the tank in my loyale, as it was full of trash, and after I cleaned it up and cleaned out my pump, and replaced the fuel filter, it nows runs like a top!

 

Since the pump is so easy to get to, if it were me, I would consider pulling it to see if it too has a screen, and if it is clogged, and if so, maybe putting a filter before the pump.

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Rust,Is it missing at idle?Take a can of carb/brake cleaner and spray where the intake man.goes onto the head when it"s running... if it starts to run better the intake gaskets are shot! The X GFs car showed up running on 2cyls. I could hear it  missing when it pulled in the driveway-Had a Bad intake gasket!! She Puts Gas in And Drives <_< Spray the intake if not that check the pickup screen Good Luck

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The engine idles normally.  I will check the intake gaskets.  I'm leaning towards the fuel pump as the culprit.  while it is virtually brand new (less than 6 months) it is a generic el'cheapo unit designed for a ford f-150.  Perhaps the quality inspector at the factory in mexico, or whatever 3rd world country this part was made in, was out back having a siesta when this turd was dropped in a box for shipment to the USA.  Or the 5 yr old child assembling it, stuck his chewing gum inside it. 

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Did you try swapping the distributor?

I know... I've posted this before.  If your tach is jumping around... probably the disty.

Let us know if the fuel pump replacement works.

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Well I have not tried swapping distributors or fuel pump.  The stumbling has not been as bad lately.  Since I did all the swapping of plugs/coli/wires/ect..  it now primarilly stumbles when accelerating from 1-3 gears.  4-5 gears not so much. It also stumbles on de-acceleration in 5th gear going down hills(but no back fire.)

 

Basically it is running beter than before, but not as good as I would like it,  but also not so bad that I have to fix it.

 

Its doing it's job of running like a bear (but with a splinter in it's paw) Unless it gets worse I will keep on driving it.

 

Perhaps there was/is a clog somewhere in my fuel line that is slowly workingh its way free.

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ive run into this with a few different cars but never a subi yet, it was always an never failed...i replaced the distributor with a serviceable or new unit and work everytime.... im not saying go buy a new one just go get a used on of a runner and dont forget to time and mark befor removal... just a thought...  its the electronic ignition sensor in the dist is what im getting at... if not that still sounds like ignition symptoms... any slight load on a ignition system will cause all kinds of funny behavior

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