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EA81 SPFI Idle Issues


SuperNova
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So now that the SPFI conversion is done ive been getting ready to take it back to the smog ref. But ive noticed something getting progressively worse. Its been having starting issues sometimes, at idle its kind of rough and after a few minutes of running at idle it will just all of a sudden die. When i come to a stop while driving and try to get going again it feels like its running rich and i have to clear it out before i can take off smoothly. But it only occurs sometimes. I ran D-check and it did not through any codes. Kinda confused on this one. Any Suggestions?

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So now that the SPFI conversion is done ive been getting ready to take it back to the smog ref. But ive noticed something getting progressively worse. Its been having starting issues sometimes, at idle its kind of rough and after a few minutes of running at idle it will just all of a sudden die. When i come to a stop while driving and try to get going again it feels like its running rich and i have to clear it out before i can take off smoothly. But it only occurs sometimes. I ran D-check and it did not through any codes. Kinda confused on this one. Any Suggestions?

 

Coolant tempature sensor. Probably a bad connection or just a bad sensor. Classic symptoms. Here's a tip. The sensor for the SPFI models is $75 bucks. The one for the MPFI(turbo) models is about $25 bucks. The only difference is the connection. The SPFI has 2 wires and a plug. The MPFI has pins right on it and uses a standard old Bosch/JECS Fuel Injector connector.(available new on ebay or in good imort shops) Switch connectors and save $50 bucks. Note I'm refering to the 2 wire, ECU temp sensor, not the one for the gauge with just a single wire/tab.

 

You can test the one you've got. IIRC Cold it should have 2-3k ohms. At running temp should be less than 100 ohms.

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  • 2 months later...
Coolant tempature sensor. Probably a bad connection or just a bad sensor. Classic symptoms. Here's a tip. The sensor for the SPFI models is $75 bucks. The one for the MPFI(turbo) models is about $25 bucks. The only difference is the connection. The SPFI has 2 wires and a plug. The MPFI has pins right on it and uses a standard old Bosch/JECS Fuel Injector connector.(available new on ebay or in good imort shops) Switch connectors and save $50 bucks. Note I'm refering to the 2 wire, ECU temp sensor, not the one for the gauge with just a single wire/tab.

 

You can test the one you've got. IIRC Cold it should have 2-3k ohms. At running temp should be less than 100 ohms.

 

So i just got back from the junk yard. I got the water temp sensor off a 4 door legacy. Just want to get your opinion on it to see if the one i got would work. Here is the pic.....

 

100_1268.jpg

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Legacy one won't work. Different resistance range.

 

Ok, so if that one wont work than what year/model will work that isnt gonna cost me a hell of alot of cash. Do i just ask for a EA82 turbo model? Can i ask for the GL-10 turbo sensor? This stupid sensor is the only thing keeping me from the car running perfect and getting my smog done.

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Legacy one won't work. Different resistance range.

 

ok, so, just got back from kragens and i picked up a 90' Loyale ecu water temp sensor for $17. Got the loyale sensor because thats the year and model i got the SPFI stuff off of to do the conversion. So now that ive got the sensor i had to come up with some way to integrate it into the car. Since the Loyale sensor was located in the radiator and on my car the temp sensor for the guage is there and i dont want to move it. So here is what i have come up with, i took a galvanized 3/8 T and threaded 2 ends into it, got a 3/8 to 1/4 adapter and threaded the sensor into the adapter and into the T. I was planning on putting it inline with the heater core since the sensor just needs to touch water, right? Another question i have is which pin goes to the ecu and which goes to ground?

 

100_1272.jpg

100_1271.jpg

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Hmmm. Except that's the sensor for the gauge or fan, not the one for the ECU. That's not gonna help you much. The one for the ECU is in the thermostat housing, and has a green connector.

 

From what ive been told the gauge sensor is a single wire and the ecu uses 2 wires. Is this wrong? Is the sensor in the intake right below the thermostat housing on a 90 Loyale, not in the housing itself?

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The sensor in the radiator is only to turn on the fans. You're looking at the incorrect one.

 

The sensor you want is in the thermostat housing, on the side of it. It'll have two wires leading off of it into a green plug. THIS is the temperature sensor you're looking for.

 

There will be one other temperature sensor with a single pin on it. This is the gauge one.

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The sensor in the radiator is only to turn on the fans. You're looking at the incorrect one.

 

The sensor you want is in the thermostat housing, on the side of it. It'll have two wires leading off of it into a green plug. THIS is the temperature sensor you're looking for.

 

There will be one other temperature sensor with a single pin on it. This is the gauge one.

 

OK, cool, thanks for clearing that up a bit but when i went to get the new one from kragens they only had 2 sensors, 1 with 2 pins (the one i picked up) and 1 with only 1 pin (which i figured was for the gauge). Do you know of any part # or autoparts store that might have this??

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Ok, lets try this again. I went to AutoZone and had them look up the sensor, they found the exact one i need but its $97. So i asked for the MPFI Turbo model sensor which is supposed to work just have 2 pin connectors instead of wires and a plug. It was $20 but it was the same one that i got from Kragens that i posted a pic of. So this is where im at, any ideas? Dont really want to spend 100 bucks on this.

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  • 4 weeks later...

have you checked the wires going to the sensor, in other words, the harnass? I know that most problems with this temperature sensor are connection related and not the sensor itself going bad. Also check a few inches of wire "behind" the connector, this could also be corroded.

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OK, so, ive checked the wires coming from the coolant temp sensor to the main harness plugs and tested the sensor itself. The sensor was within limits and the wiring was fine. So now the problem is getting worse, it dies whenever i come to a stop and let it idle. Also, when i can get it going if i push the gas pedal to far it will act like its going to stall out but as soon as i let off it will keep running and i can only accelerate if i push on it slowly. Flashing the ECU no longer has an effect on the problem, it used to clear it up for a while but now its always there. Im guessing it might be the MAF or TPS sensors. Anybody have any suggestions??

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OK, so, ive checked the wires coming from the coolant temp sensor to the main harness plugs and tested the sensor itself. The sensor was within limits and the wiring was fine. So now the problem is getting worse, it dies whenever i come to a stop and let it idle. Also, when i can get it going if i push the gas pedal to far it will act like its going to stall out but as soon as i let off it will keep running and i can only accelerate if i push on it slowly. Flashing the ECU no longer has an effect on the problem, it used to clear it up for a while but now its always there. Im guessing it might be the MAF or TPS sensors. Anybody have any suggestions??

 

I believe daeron posted a write up not so long ago on how to check the TPS, it may be in the USRM but I don't know, otherwise use the search.

 

it boils down to measureing the TPS with a analog resistance meter and checking for irregularities in the sensor

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Try disconnecting your O2 sensor for a while.....

 

Does it do this while cold or warmed up? Any difference between the two?

 

Clean your MAF, and check operation of the TPS using an analog meter.

 

Hard starting - you have the ECU's start signal wired into the ignition switch harness?

 

GD

 

I'll try disconnecting the O2 sensor. When its cold it doesnt do it because the choke keeps it running at a higher idle, if i kick the choke down it will slowly die. And it dies whenever i come to a stop and let it idle. I'll clean the MAF, this was done when i did the conversion but i'll check it and do it again. I also have the FSM so ill follow the TPS testing procedures. It never usually has trouble starting, but this morning it would not start, i figured that it was because i flashed the ECU yesterday and did not drive it around. Maybe, Maybe not!?!

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When its cold it doesnt do it because the choke keeps it running at a higher idle, if i kick the choke down it will slowly die.

 

I understand your meaning, but for future reference fuel injected engines do not have "choke's" - those are the exclusive domain of carbs. What you have with SPFI is a coolant temp sensor that tells the ECU to change the mixture when the engine is cold - this is known as "cold start enrichment".

 

 

And it dies whenever i come to a stop and let it idle.

 

Have you cleaned and adjusted the Idle Air Control Valve (IAC)?

 

I'll clean the MAF, this was done when i did the conversion but i'll check it and do it again.

 

Make sure you clean the bypass hole so that air can flow past the hot-wire and sensor wire. Gunk gets in the slot and air can't flow past it to cool the hot wire.

 

I also have the FSM so ill follow the TPS testing procedures. It never usually has trouble starting, but this morning it would not start, i figured that it was because i flashed the ECU yesterday and did not drive it around. Maybe, Maybe not!?!.

 

Generally shouldn't matter much - the SPFI doesn't "learn" like newer fuel injection computers. It just goes off what it sees when it's turned on. It has a small capacity to remember previous faults but that doesn't come into play as far as it's actual running parameters.

 

GD

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So, i kinda feel like a retard. I was so caught up in that new SPFI sensors and possible problems, i didnt look to the super simple basics. I started tearing the top end apart starting with the MAF, and i ended up reading threw a few wiring diagrams and it made me remember that the ignition coil is wired to the fuel pump relay. And since i have been hearing the fuel pump itself change pitch, which i figured was a varying voltage problem, i tested the coil and wouldnt you know it, BAD COIL. Still made the car run, but crappy. It was a new coil when i did the SPFI swap, also a new cap and rotor, that were also pretty messed up. These parts have only been on for 5 maybe 6 months. Goes to show i should have never bought the cheap Kragens special parts just to get the car running. So i bought a Accel Super Stock coil, and i new cap and rotor, and she's back on the road. No problems, no stalling, voltage seems cool. It fuctuates when i turn the turn signals on with the blinking but i just figured that was normal. The only thing that kinda bugs me is that the idle isnt as smooth as i would like it. I cleaned the MAF, it was pretty clean to begin with. And im gonna clean and adjust the IAC, i cleaned it when i did the swap but never adjusted it, so that could be an issue. Any other thoughts?

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Really? Well ive only had it on for one day. I have time to return it. What have been the problems with them in the past? And where do i get a Hitachi Coil? I know i cant just go to any local parts store.

 

Accel switched their manufacturing to mexico, and since the quality has been terrible. Do a search there's several threads here about them with lots of folks having had them fail.

 

The Hitachi coils can be had at the dealer, and probably from other sources such as rockauto.com. Here I get the locally at Discount Import Parts. http://www.discountimportparts.com/

 

GD

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