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EA82 Puzzle, SPFI too rich, Why?


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OK, Here's my puzzle.

 

Components:

Low mileage EA82 Motor from Japan, SPFI, everything stock

New plugs, rotor, wires, cap, gaskets, filters, belts.

 

Symptoms:

Fuel runs too rich at mid rpm range 2500-3500

Low rpm seems ok

Motor seems to flood out when given full throttle at mid range.

When accelerating, it has more power at 1/2 throttle then full

Fuel injector seems to be pumping too much gas.

Occasionally it will almost die from richness and emits black smoke out the exhaust.

 

What I've done so far:

Replaced throttle body-fuel injector twice with other known good ones.

Includes all the electrical devices attached to intake system, throttle postion sensor, air flow sensors etc.

Replaced plastic/rubber intake ducting, all clear and firm.

Checked intake route into air filter, all clear.

Blowned out all fuel lines back to the tank.

Checked timing belt, timing is correct.

Checked cylinder compression, all are good.

Replaced electric fuel pump with known good one.

Ignition timing set correctly.

Checked inside of catalytic converter, no restrictions.

 

Still exactly the same problem, nothing I did made a difference.

 

Things I haven't done yet:

 

Check muffler for restrictions or clogging

Check or replace sensor on Cat, What effect does it have?

Replace Computer, Why would it be the problem?

 

At this point I'm open to any suggestions you might have.

I'm even williing to try something that doesn't make sense.

 

Any Suggestions?

 

Thanks

Rollie

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The Oxygen sensor on the cat controls the mixture. This could be the problem. If you have replaced everything else, try a new O2 sensor.

 

Could try resetting the computer. I can't remember the sequence, do a search.

 

Good luck.

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Yep, CTS will do it too. I thought you tried it already, but a closer read of you post show you haven't looked at it yet.

 

Apparently , the connector gets corroded. Try cleaning it. Lots of posts on here about this device.

 

Good luck.

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The Oxygen sensor on the cat controls the mixture. This could be the problem. If you have replaced everything else, try a new O2 sensor.

 

I disagree. I've ran many SPFI and MPFI cars with the O2 sensors unplugged. the CEL doesnt even come on.....

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Without the O2 sensor these computer controlled engines have no reference to go by for fuel control. When they are unplugged or nonfunctional they go fat causing poor mileage and a number of other problems. That's why they are there!

 

Temp sensors are the biggest cause of drivability problems of all. Idle, cruise and WOT issues can be attributed to a bad temp sensor.

 

A code check should reveal these issues.

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He didn't mention a CEL, so that is why I suspect the O2 sensor, since they are famous flor crapping out without setting one. The car will run, just not efficiently. The car won't set any MPG records, that is for sure.

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Thanks guys, for your comments.

I'm trying to track down a good used O2 sensor for cheap or free and then I will try it to see what happens. It is a one-wire device.

I'm also looking for a computer to try. It's an 88 GL Wagon 4x4 built in 12/87

Computer says:

 

22611 AA392

MECF-022

4E 42

 

Meanwhile I just keep driving.

Fuel mileage has been hovering around 20mpg after adjusting the odometer reading for running 27" Swampers.

 

Rollie

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20 MPG with 27" tires is about normal. Sorry dude.

 

My wagon - same engine, same carb went from 32 MPG with 175's and 2WD 5 spd with 3.7 diff, to 20-22 MPG with 215/75R15's (28") and 4WD with 3.9 diffs.

 

Swampers are wider than my MT's, and being bias-ply your mileage will be teh suck.

 

GD

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If your coolant temp sensor is working fine and actuallly functioning..you will notice idle up at cold start..after engine is warm..it will drop to normal idle..if it is hoovering above normal idle..that will be the problem.....i run a few ea82t,s and the oxygen sensor does not make the cel come on..if you disconnect it.... and will not let black smoke belch out the rear when disconnected..diesel will do this though..lol:lol: :lol: so i would look elsewhere for the problem.....cheers

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If your coolant temp sensor is working fine and actuallly functioning..you will notice idle up at cold start..after engine is warm..it will drop to normal idle..if it is hoovering above normal idle..that will be the problem.....i run a few ea82t,s and the oxygen sensor does not make the cel come on..if you disconnect it.... and will not let black smoke belch out the rear when disconnected..diesel will do this though..lol:lol: :lol: so i would look elsewhere for the problem.....cheers

 

Hmmm.

 

Coolant temp sensor could be it.

I do notice a high idle problem, somtimes as high as 3000 rpm. Adjusting the throttle stop down to the limit where the butterfly is all the way closed still results in a 2000+ rpm idle when hot. Is this the same sensor used to run the dash temp gauge, because the gauge seems to go up and down normally with temperature? Where is the above mentioned temp sensor located?

 

Thanks for the continued input. When we get this one solved the rest of the engine should run just about perfect considering all the new parts and adjustments I've been doing.

 

Rollie

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