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Guest Message by DevFuse
 

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Spark #1 and #2 NO spark #3 and #4


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49 replies to this topic

#26 jimshih

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Posted 27 October 2004 - 10:37 PM

Got a replacement ECU today. Plug it in...still the same output..:lol:

Started checking all the wires again.

Cam sensor: engine cranking: 3,4,5 volts.
checked cs resistance to body both wires= OL (no shorting out condition) spec is greater 1 M min ohm
checked cs wire connector to ecu connector resistance = low and within spec

Crank :
crank sensor: engine cranking: 4,5,6 volts.
checked crank resistance to body both wires= OL (no shorting out condition) spec is greater 1 M min ohm
checked cr wire connector to ecu connector resistance = low and within spec

So both cam and crank are putting out signal to ECU and the connection between them are OK.

One thing I noticed, If i leave any one of the sensor disconnected, I will not get any spark at all. Once both connected then it is spark at 1 and 2 only.

Contiued to check voltage between ECU and body
(B58) NO12 - body /10V min good
(B48) NO15 - body /10V min good
(B48) NO2 - body /10V min good
(B58) NO13 - body /10V min good

(F47) No 24 -- Body/ 0 ohm ?
(F47) No 25 -- Body/ 0 ohm ?
(F47) No 14 -- Body/ 0 ohm ?
(F47) No 15 -- Body/ 0 ohm ?
(F48) No 11 -- Body/ 0 ohm ?
(F48) No 22 -- Body/ 0 ohm ?


I got some high numbers here some low some as high as 70 ohm so I ran ground wire from battery to each above connections to avoid any possible bad ground.


Checked crank again and still the same??


What now? :banghead:

#27 Legacy777

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Posted 28 October 2004 - 08:18 AM

hmm.....I'll have to think about this....

#28 Legacy777

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Posted 28 October 2004 - 02:40 PM

Ok....I guess let's recap some things here.

It sounds like the ECU ground and power supplies are good.

It also looks like the cam and crank sensors are working properly.

I don't remember if you told me, but have you tested the ignitor signal directly at the ECU pins? They should be pins 9 & 10 of the F47 connector.

You should see voltage varying while cranking.

If you only get the one output working there....I'm really lost....

#29 jimshih

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Posted 28 October 2004 - 05:32 PM

Ok....I guess let's recap some things here.

It sounds like the ECU ground and power supplies are good.

It also looks like the cam and crank sensors are working properly.

I don't remember if you told me, but have you tested the ignitor signal directly at the ECU pins? They should be pins 9 & 10 of the F47 connector.

You should see voltage varying while cranking.

If you only get the one output working there....I'm really lost....


I checked the F47 plug to ignitor wires for high resistance and that tested OK.

Now I unplugged the F47 and measured the voltage at 9 and 10.
They came out about the same ~11.6 volts.

Crank the engine with the plug off ans measured it, it's about 6,7,8 both pins.

Plug it in and measured at the ignitor and it's oV. Crank it and the 1&2 Bank wire is .24,2,3 and back to .23. The point is the signal goes over 3 and it sparks.


The other bank also have signal but never go over 3 so it won't fire.


One interesting thing is while plugging it back I had the key to on and it sparked so I wiggled the F47 in and out and was able to have spark at all 4.
In and out at different angles and it all 4 will spark.

I though I was on to something and test it somemore but I think it is just because I am cutting or providing power to ignitor during this quick connect disconnect that caused coil to fire.

The problem is still something in there not just a bad connection at the connector.


So now the 2,3 bank wire has some signal but won't go over 3 V like 1&2 bank
???

Just not sure how it is controlled??

#30 Legacy777

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Posted 28 October 2004 - 06:13 PM

It's controlled all in the ECU. If you replaced the ECU, it shouldn't be that......but something just isn't adding up....

#31 jimshih

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Posted 28 October 2004 - 09:02 PM

Here is something else I found. While removing the crank sensor I heard the fuel pump realy clicks on and off. So I took out the CS and see what's going on.

The body of the CS is being used as ground somehow. I cut and wired the sensor direct to the ECU to see if it is still the same.

It's the same so no short in between. Maybe the CS is bad so I took the cam sensor out and wired that in to the ECU crank location since the wires are the same three wires and they perform the same function. Tried it and samething happens.

So sensors should be OK. Not sure is this is suppose to be or something wrong.

Putting a wrench to the cam sensor is ok but putting a wrench to the crank bolt and somewhere on the engine and the fuel relay clicks on.


Not sure if this somehow affects the 3&4 not firing??

#32 Legacy777

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Posted 28 October 2004 - 09:05 PM

Hmm....have you looked through all the engine and wiring diagrams in that manual.....just to make sure everything was wired properly?

#33 Cougar

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Posted 29 October 2004 - 07:06 PM

This problem still sounds like you have a broken tab on the crank sensor gear. Have you checked that to make sure that none of the tabs are broken off? It would be nice to have a oscilloscope to look at the input signal to the ECU. My bet is the input signal has a missing pulse(s). Going from Josh's wiring diagram it looks like you have verified all the circuitry from the ECU to the plugs. That just leaves the input to the ECU or am I missing something?

Josh, do you know how many signal tabs are on the gear? From your pictures you can't see the whole perimeter.

#34 jimshih

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Posted 30 October 2004 - 12:41 AM

Got a pair of used cam and crank sensors today. They are a little different where the originla have wires connected and these unplugs at the sensor head.

They look and fit the same though. Two connection on them only with three on the original where the numbe three is the shielding.

I soldered and wired them up to give it a try.

After a few cranks the engine started up..it was running..:brow:

I pulled the cam sensors and try it again. Still runs. So it was the crank sensor.

Unplugged one wire at the crank connector to shut it off. Got out my timing light to check if all 4 wire ares sparking.

Oops..couldn't get it started again.. something is wrong again...

Is something burning out the crank sensor??

It was dark and I couldn't see anymore so need to ck it tomorrow.

At least I know the engine mechincal is all good now.

#35 Legacy777

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Posted 30 October 2004 - 10:35 AM

I've never known crank sensors to just burn out.......something weird is definitely going on.

#36 Cougar

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Posted 30 October 2004 - 12:31 PM

I'm not sure what you did by pulling the wire. It sounds like the orignal problem you had though was due to the crank sensor not picking up on one of the position tabs somehow. This is why I asked you to check those tabs.

The sensor itself seems to be working ok to me. It is picking up positions, but one of the position tabs doesn't seem to register for some reason. Whether this is due to a broken tab or sensor adjustment I can't say. Since it worked for a little bit perhaps the tab is ok.

#37 jimshih

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Posted 01 November 2004 - 12:31 AM

Ok, something that I did at night where I put one of the wire into the sheilding connector by mistake (yellow wire) and caused the no start again. Once I can see better during the day I fixed the problem and it started right back up.

Now it is idling but somehow when I rev it, it doesn't reponse. The engine just idle that's it. I check the TPS and MAP and all the readings checked out.
The TPS puts out the right voltage sweep with the opening of the throttle.

I am not sure what is going on but maybe the crank sensor I am using from a different model is not a good fit but it shouldn't cause this problem since the crank just provide timing info. I also read in the manual the fuel pump circuit is also related to the crank sensor so maybe that has something to do with it.

#38 Cougar

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Posted 01 November 2004 - 02:14 AM

I am having a little trouble understanding what you are saying but from what I think you are saying it sounds like you may have a damaged ECU now. Do you have the original unit still to replace it with?

#39 jimshih

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Posted 01 November 2004 - 02:46 AM

Both ECU acts the same. The car idles but when you hit the gas or manually open the throttle there is no rev. The engine rpm does not change at all.
The engine has a two wire crank sensor now which I got from a junk yard for testing and the original cs has three wires. That is the only differance I see. The third wired is shielding but also connects into the ECU as grounding or somthing..not sure.

#40 Nug

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Posted 01 November 2004 - 08:39 AM

There are 2 different crank position sensors for 90-94 2.2's. But i doubt there is much difference between the two, besides the connector.


Which ecu do you have? Hitachi or, um, the other one (forget what it's called)? You need to have the MAF sensor of the same make. Also, there is a 1 wire difference between the two. Vrg3 (I think that's his username) at legacycentral.org knows what the difference is. He pointed that out on my project. He's the man.

#41 Legacy777

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Posted 01 November 2004 - 09:07 AM

There are two ecu manufactures. JECS and Hitachi. The Hitachi ECU's are used with the manual tranny cars or silver MAF's. The JECS ECU's are used with the auto tranny cars or black MAF's.

#42 Cougar

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Posted 01 November 2004 - 10:08 AM

Since replacing the ECU didn't help get things working again then it may be good to check the signal going to the fuel injector(s). It sounds like the input signals are ok. Check the output signals. Also, have you checked for any codes that may have been stored?

#43 jimshih

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Posted 01 November 2004 - 07:36 PM

Once the engine was running and I noticed the non revving condition, I manually open the throttle plate while injecting starter fluid into one of the intake hose.

The RPM should change regardless of anything almost. Air and Fuel although not the correct amount are feed the engine should react.

The weird thing is no differance. Weird?:confused:

#44 Cougar

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Posted 01 November 2004 - 07:46 PM

I take it that all cylinders are now firing at least.

#45 jimshih

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Posted 02 November 2004 - 10:36 AM

Yes before when only two coils had spark the engine would not start.

Now I used a timing light's induction pick up to check all 4 wires and all have power going through them.

#46 Cougar

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Posted 02 November 2004 - 11:36 AM

This may not be relevant but have you checked for any blown fuses? Also did you say the cam sensor was the same as the crank sensor? If they are, maybe you should try replacing the crank sensor again as you may have damaged it by tieing the lead to the shield connection.

#47 subaruVWnut

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Posted 17 February 2006 - 09:29 PM

What finally happened with this problem.. did it get solved.

I have the same issue in a 98 Outback with the DOHC 2.5L. Ignitor and coil have been swapped.....none of the intricate voltage and resistance checks done here.....an ECU swap fixed it once...but now the problem is back. No fire on 3 and 4.

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#48 Cougar

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Posted 18 February 2006 - 09:09 AM

You could try swapping the coils to see if that makes a difference. If that doesn't help then I would suspect there may be a connection problem causing this to occur and swapping ECU's happened to correct the real problem at the time.

What finally happened with this problem.. did it get solved.

I have the same issue in a 98 Outback with the DOHC 2.5L. Ignitor and coil have been swapped.....none of the intricate voltage and resistance checks done here.....an ECU swap fixed it once...but now the problem is back. No fire on 3 and 4.

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#49 subaruVWnut

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Posted 18 February 2006 - 11:15 AM

Already swapped coils and ignitor with no effect.

Warren

#50 a97obw

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Posted 18 February 2006 - 01:32 PM

"There are 2 different crank position sensors for 90-94 2.2's. But i doubt there is much difference between the two, besides the connector."

Au contrere mon frere!! One of them is about $28 to replace, the other is about $350!!

And when your Legacy with the 2.2 hasn't been run for several months, and a mouse or meeces has taken up residence on the top of your engine where they eat, poop and pee......if they peed on your crank angle sensor it is going to be severly corroded to the housing, and will only come out by being destroyed! That thing must have 4 miles of white thread in it for some reason! And mine was the $350 flavor! ($50 at the salvage yard and I was back in business!):banana:




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