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ecm guru's help please*UPDATE*


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30 replies to this topic

#1 iluvdrt

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Posted 02 November 2005 - 05:29 PM

Ok for some time my 87 gl10 ea82t has had no spark. I have been working on it for ever and nothing.
I changed out the dizzy, coil, and ignition amplifier only to achieve nothing. The other I checked the codes on the ecm and it showed code 11 (no referance pulse from the crank angle sensor). I proceded to follow the steps to find my problem in the FSM's. It said I needed a harness. I pulled the entire chassis harness out and checked every wire with a multimeter. It is ok.
Here is what I have with the key "on"
12 volts going to ECM, Dizzy, and coil. (plug 7 on ECM)
ground has continuity across harness, but not to chassis(possible problem(plug 20))
4 volts on plug 8
and the other 4th wire it said I didnt have to check, but I did anyhow and have continuity.

So what I am thinking is the plug going to the dizzy(crank angle sensor) has a bad connector. I am planning to wire in my own connectors there, and also make a new ground for terminal 20 on the ecm (black wire with a red stripe). That should provide a good connection and a positve ground for everything on that circut.

Today, I did the above mentioned and re-checked the ecm codes. All it does is flash 1......1.......1........1...basically its emissions set up (01 49 states non-cali). which tells me everything is ok. I timed the engine, installed and double checked everything, even through in another new coil. Still no spark.

Can someone please shed some light on this.

#2 Ross

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Posted 02 November 2005 - 05:33 PM

First off, are any of the parts you put in second hand?

#3 iluvdrt

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Posted 02 November 2005 - 05:34 PM

First off, are any of the parts you put in second hand?


The dizzy, and amplifier, but they came off of a running car.

#4 iluvdrt

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Posted 02 November 2005 - 05:35 PM

The dizzy, and amplifier, but they came off of a running car.


I am currently driving a 88 SPFI, I could swap those off it and put them onto my 87. The connectors are the same.

#5 Ross

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Posted 02 November 2005 - 05:52 PM

Did you fix that bad ground?

If only oscilloscopes were a little cheaper.......sounds like you need to find out what signals are getting where. It would certainly make the diagnosis easier if you could hire one or something.

#6 iluvdrt

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Posted 02 November 2005 - 05:59 PM

Did you fix that bad ground?

If only oscilloscopes were a little cheaper.......sounds like you need to find out what signals are getting where. It would certainly make the diagnosis easier if you could hire one or something.


Yes, I fixed the ground. I also made an aditional ground for pin 20 on the ecm.

2 things here that werent mentioned yet.

1) I acidentally grounded out the coil troubleshooting a bad spark problem( the prelude to all this).

2) the car has had a bad ignition problem since I have owned it(3 years).
Black smoke, missing, low power, symptoms of a bad connection on terminals 7, and 8 I think.

I think when I accidentally grounded out the coil, it fried the circut in the ecm, because thats when it actually quit running. Before it ran, just horribly bad...and even that was intermittent.

Keep in mind, the car has been very well cared for, and all general maintenaces have been performed early, and with only the best parts.

#7 hooziewhatsit

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Posted 02 November 2005 - 06:18 PM

1) I acidentally grounded out the coil troubleshooting a bad spark problem( the prelude to all this).


If you grounded the negative side of the coil it should be fine. That's how it makes a spark.

If you grounded the positive side.... I'd check fusible links, fuses, etc.

Have you verified that the negative side of the coil gets pulled to ground while cranking the engine over?

#8 Cougar

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Posted 02 November 2005 - 07:24 PM

After looking at the Subaru troubleshooting guide for a MPFI unit and reading your test results here are some things to check:

The guide says that red wire on pin 7 should have less than 10 volts on it with the key turned to ON. If the voltage is higher, then there is an open on the wire between there and the sensor.

Pin 17 of the ECU should be a white wire coming from the CAS. What is the voltage there? If it is greater than 4 volts and the connection is ok then you need to relace the ECU.

#9 iluvdrt

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Posted 02 November 2005 - 08:54 PM

After looking at the Subaru troubleshooting guide for a MPFI unit and reading your test results here are some things to check:

The guide says that red wire on pin 7 should have less than 10 volts on it with the key turned to ON. If the voltage is higher, then there is an open on the wire between there and the sensor.

Pin 17 of the ECU should be a white wire coming from the CAS. What is the voltage there? If it is greater than 4 volts and the connection is ok then you need to relace the ECU.


I am thinking the ecm is bad.

#10 calebz

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Posted 02 November 2005 - 09:23 PM

I am thinking the ecm is bad.


That could be

Wn you have the diag connectors hooked up, does the fuel pump cycle off and on ever 1.5 seconds or so?

#11 Cougar

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Posted 02 November 2005 - 09:27 PM

Check the voltage at pin 7 before you discard the ECU.

#12 Qman

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Posted 02 November 2005 - 09:41 PM

You have never stated if you checked/replaced any fuses or links.

#13 TheSubaruJunkie

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Posted 03 November 2005 - 12:58 AM

Fuseable links can still look good when they are burnt. You might want to replace them all with verified good links just for good measure.

-Brian

#14 soobscript

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Posted 03 November 2005 - 03:25 PM

Yeah, check the fusible links. I don't remember if you ever got that issue with the hot links fixed...

#15 Adam N.D.J.

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Posted 03 November 2005 - 03:43 PM

Have you opened up the dizzy cap and checked to see if the rotor is turning. If the timing belt has gone south, then the dizzy won't turn and you won't get any spark. Just a thought, didn't see anything about that in the posts.

#16 iluvdrt

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Posted 03 November 2005 - 05:02 PM

Check the voltage at pin 7 before you discard the ECU.


It has 4 volts. Everything wireing wise is OK now. I am thinking the ecm went down the drain. I bought the car with a "spark problem".

I will check the links. I tested them, and they all had voltage going through them. I will replace them anyway.

With the green connectors connected, the fuel pump does cycle, and it also cycles if you manually turn the distributor body back and forth(as if you were adjusting the timing).

As far as timing belts, I dont have timing belt covers, so I can see the belts, they are new.

I have pulled out all fuses and checked them. They are ok. I even went and replaced the ign fuse just for GP.

I was a Subaru mechanic about 8 years ago, so most basic things I have already been through. I think this is more advanced, but keep them coming any way. Usually the attention to detail things is what screws you.

#17 Cougar

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Posted 03 November 2005 - 05:29 PM

From reading your past posts it seems you have covered the voltage checks well. I don't think you are going to make a difference by replacing the fuses but it sure can't hurt and is a simple thing to do. You are going to have to replace the ECU I think. Good job on the trouble shooting, you sound like you were on top of things as a tech.

You may be able to fix the ECU. I have fixed a few of them. Trace the pins that have a incorrect voltage like pin 7 and see if there is a obvious problem with a connection in the unit. You can also do a diode check on the transistors in that circuit area to see how they are.

#18 thealleyboy

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Posted 04 November 2005 - 04:34 PM

I am going to spot Jason my extra ECU to try on his car. It came from a running 87 turbo wagon, and appeared to be good when I junked the car.

Can someone verify that all 87T ECU's are the same? I have ran into some wierd mis-matches on 87 models and want to make sure this correct part.
Mine came off a late 87 model, BTW...

John


#19 naru

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Posted 04 November 2005 - 05:41 PM

Can someone verify that all 87T ECU's are the same? I have ran into some wierd mis-matches on 87 models and want to make sure this correct part.[/color]
Mine came off a late 87 model, BTW...

John
[/QUOTE]

1987 had 4 different turbo ECUs.2for wagons,2 for XTs.
They appear to be interchangable within body styles at least.

Part # for the wagon ones ends in 140 or 141.

#20 iluvdrt

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Posted 04 November 2005 - 07:29 PM

I am going to spot Jason my extra ECU to try on his car. It came from a running 87 turbo wagon, and appeared to be good when I junked the car.

Can someone verify that all 87T ECU's are the same? I have ran into some wierd mis-matches on 87 models and want to make sure this correct part.
Mine came off a late 87 model, BTW...

John


John, I will be over Sat morning.

I thought of something else last night while sleeping. I know if the alt is unplugged it subarus will not start. What if the diode in the alt is fried and its simulating the alt is unplugged? Would that cause a no-spark situation?

#21 iluvdrt

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Posted 05 November 2005 - 03:18 PM

OK, I swapped out the ecm with anopther ecm from another 87 wagon. I have spark now, it is in time, and it still wont start.

It is still showing codes 11,13,23,32,33,51,and 4? . WTF? How can that be possible?

#22 iluvdrt

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Posted 05 November 2005 - 03:55 PM

OK, I tried the other ecu, and it eleminated almost all codes, except the code 23 maf sensor. I put in 2 different sensors, and it still has it.


Does anyone know how to test the circut for a maf sensor? I dont have my fsm's with me. I forgot them at home.

#23 iluvdrt

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Posted 05 November 2005 - 04:46 PM

OK well, Here is what is going on.


code 23. I have spark, I have fuel (which is evedent by the cannon sounding backfires while cranking). I replaced the maf with another one, still same code.

What options do I have at this point to figure out the maf? Are there any ground wires to be weary of, hoses, additional connectors, that would make this sensor cause a fault code?

#24 Ross

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Posted 05 November 2005 - 05:00 PM

Have you tried starting it without the maf? it should start without it, otherwise maybe there is still another problem?

#25 Cougar

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Posted 05 November 2005 - 06:38 PM

I am concerned about the backfiring. Are you sure the timing is ok and the firing order is correct? You could try marking the disty position and then try moving it while it is cranking over to see if that will help get it going.

The MAF should have 12 volts going to one lead at least I think. Check all the leads going back to the ECU and make sure there is no connection problem. Sorry I can't help with a diagram as I am work now.




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