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Acceleration rise and fall. I'm new to Subarus. Help!


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Having trouble with my 90 Loyale. 1.8 not a turbo. Runs fine for a while then, as I accelerate to 3000 rpm to shift, the rpm drops and I have to slow down for the engine to catch up with itself. Occasionally, in neutral on the 5spd, I can depress the accelerator and the engine will rev to 3000 and drop repeatedly at precise intervals. I just bought this thing two days ago. I changed the fuel filter immediately, filled the tank with premium and a bottle of Gumout water treatment. Still does it. Anyone?

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As a matter of fact I do. The person I bought the car from said the light comes on but her mechanic told her there was a short that causes it to come on for no reason. After talking to her about the problem with the rpms, she said that happened once after filling with bad gas but no problems since. I believe, in retrospect, that she's full of it and knew about this problem.

 

The other problem with the light is that any mechanic I talk to says the car is too old to for their systems to identify codes.

Edited by Uncle Don Clark
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Hey you're pretty close. Welcome to the board.

 

Ok about the check engine light... if you pull the piece of plastic off the bottom of the driver side dash (4 plastic screws I think) then you can see a black box. That's the ECU. It should have a small red LED light on it. It blinks codes and that's how you identify.

 

Do a search for the specifics like which connectors under the dash to connect and what the blinks mean exactly.

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http://www.ultimatesubaru.org/forum/showthread.php?t=49918

 

This should help. The longer pulses (exactly 1.2 seconds) indicate 10's and shorter (.2 seconds) indicate singles so if you have 2 longer pulses (20) and then 3 shorter pulses (3) you have a code 23 which is an oxygen sensor. Same example as in the link. And if there's more than one code they will be seperated by a 1.8 second pause. So when you're checking make sure you hang around and get all the codes. There's more to be explained in the link of course, but I thought you might have trouble with that part.

Edited by Subaru_dude
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The other problem with the light is that any mechanic I talk to says the car is too old to for their systems to identify codes.

 

They are lazy or unifromed or both

 

These cars are very simple to read codes on. Blinking light is on the ECU. ECU is bolted to the steering column.

 

turn the key to on, and count long and short beeps to retrieve codes. 2 long, 1 short = code 21 etc....

 

If you want you can also plug in the white connectors to eachother(under hood, above brake booster area) they are the READ connectors, and will retrieve any past codes that were thrown intermittently.

 

The green connectors there put the car into a test mode (d-check) it will throw some codes,(11 and 13) cycle the fuel pump, and a few relays. Good for testing Fuel pump, but not much else in my opinion. Additionally, they are supposed to be connected during ignition timing, but unhooked for regular driving.

 

From the sounds of it though, you should need only to check for current codes. just look at the light with key on. no connectors

 

 

 

 

 

but........I am gonna guess of the top of my head you have a MAF malfunction

 

Clean it or replace it.

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Looks like it's easy enough to identify. What's the process for cleaning it? This part, with core exchange, costs close to $200. If I can fix it without replacing it, it would go a lot easier on my unemployment check.

 

Use MAF cleaner, they sell it at most stores.

 

I have used break cleaner effectively too, but it is said it "may" cause damage in some cases. IDK.

 

Clean it, you might be surprised. Also, make sure all the clamps on the intake are tight,a nd nothing is unhooked

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Ok, I cleaned the MAF and replaced the air filter. Drove it for about 20 miles and the problem started again. Seems that it occurs when I go for a quick acceleration. If I let off the gas and ease the accelerator it does just fine. I'll be trying to locate and read the ECU this weekend. Something's gotta surface!

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FYI, your car is considered "old school"

 

The problem you are having... is the car mostly fine when the engine is cold, but it gets worse when the engine gets hot?

 

I'm thinking it's the coil if it does that... it's on the drivers side front of the fenderwell and it a round can... you can get a new one for like $5-$20 depending on source.

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FYI, your car is considered "old school"

 

The problem you are having... is the car mostly fine when the engine is cold, but it gets worse when the engine gets hot?

 

I'm thinking it's the coil if it does that... it's on the drivers side front of the fenderwell and it a round can... you can get a new one for like $5-$20 depending on source.

 

FYI, King, I know...lol. I was directed here by someone from the "old school" group because he misread the type of car I was posting. I also have this posted under Old Generation but have had only one response. And that was from the fellow who sent me to the New Gen board by mistake...lol Guess it's a good thing I was sent here. Everyone has been so helpful.

 

Now, getting back to the topic at hand, you are correct. Fine cold; bad hot. I'll check into the coil. I know right where that is and can easily replace it. Not too costly. Thanks for your input!

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