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Gary
Gary, ASE Certified Technician
Category: Subaru
Satisfied Customers: 999
Experience:  Senior Technician
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Vehicle: 1998 subaru impreza 2.5rs auto Condition: crank but

Customer Question

Vehicle: 1998 subaru impreza 2.5rs auto
Condition: crank but won't start, no power at the cam shaft and crank position sensors.
Background: Car originally started fine. Went to change coil pack and realized new one Would not fit. Bolted old one back on but forgot to plug in. Went to start and cranked around 10 times before realizing the issue. Plugged it in and went to crank. Car would only crank over twice then would stop even if key help in cranking position.
I then noticed smoke coming from starter. I figured I had blown it so got an oem replacement. In the process I had found the previous owner did not have the MAIN ground wire attached only the secondary one which is much smaller. I then went and got new cables and terminals for both the power and ground. I also charged and tested the battery.
Now the vehicle cranks better but, it will not start. It will pop occaisionally but that's it. There is power at the injectors and fuel is flowing to them. I also pulled off a spark boot and noticed voltage change during crank but do not know if that is a proper test. I do know that there is no power at the crank and cam position sensors with the key in the ON position.
I checked all of the fuses in the main and interior box and they check out. This lead me to checking the main relay. When I went to test it per subaru recomendations I first got an overload on the multimeter. I then tried a couple more time and would intermittently get .1-.7 ohms. Subaru stated it needed to be under 10 ohms. I could also here it clicking when the power was supplied but would only get an ohm reading part of the time. Could this possibly be the issue. Thanks for your time and I appreciate it.
Brad
Submitted: 10 months ago.
Category: Subaru
Expert:  Gary replied 10 months ago.

Hi Brad,

Suprised it cranked at all with the main ground disconnected.

Now we need to get a scan of the ECM to see what codes are set.

Can you get this done please?

Gary

Customer: replied 10 months ago.
I was actually able to drive it around the block with it disconected! I was stunned when I found it. I will pull codes but last time I checked I did not have any. Would having no power to these trip a code without a physical start up? I can try to start it again and see if any codes will pop up or if you have a test that can help pull codes.
Expert:  Gary replied 10 months ago.

Hi Brad,

Yes, I bet you were stunned.

Do you have access to a scan tool?

Gary

Customer: replied 10 months ago.
I do have an obd scan tool.
It's this one to be exactBAFX Products 34t5 Bluetooth OBDII Scan ToolI have used it in the past to diagnose some other issues and has worked great. Showed the throttle position sensor code and a few others that I have had issues with. Last time I scanned only thing that comes up is the egr valve and I currently have it unplugged. It needs to be replaced as well.I can check again though if you have other suggestions.
Expert:  Gary replied 10 months ago.

That's interesting if it doesn't log a code.

Can you disconnect the crank sensor and then try and start it, to see if it logs a code for crank sensor?

Gary

Customer: replied 10 months ago.
I will give that a try. It will be around 6:00am est before I can give it a go. I will unplug it as well as the cam position sensor since it did not have voltage as well and give it a go. I'll report if they toss a code. My concern was that since It cranked so long without the main negative being connected that it could have surged something.
Expert:  Gary replied 10 months ago.

Yes, that is my concern as well.

Gary

Customer: replied 10 months ago.
Hey I cranked with the connectors unplugged and did not get a fault code for either one. I noticed when reinstalling the main relay that connectors had white looking corrosion on them.
Customer: replied 10 months ago.
Here the connector.
Expert:  Gary replied 10 months ago.

That's good in a way, since the crank and cam sensors aren't the cause.

I would clean that corrosion out, contact cleaner works well.

The females might need a tighten up.

Does the relay operate ok?

Do you smell fuel in the tailpipe?

Gary

Customer: replied 10 months ago.
Yeah the cam and crank sensors are brand new.I cleaned out the contact with contact cleaner before reinstalling. It got some of the corrosion out.I already ordered a new relay as well just in case.I'm testing the relay it will intermittently show overload. The other times it reads around .1-.7 ohms.I have smelled some fuel and also tested the connectors for the injectors and they are getting power. I also pulled the feed fuel line and had it dump into a milk jug. During cranking it was flowing fine.
Expert:  Gary replied 10 months ago.

Hi Brad,

Where is this relay? Under the dash?

Perhaps you have a small water leak that has damaged the relay?

Do you smell fuel in the tailpipe after attempting to start?

Gary

Customer: replied 10 months ago.
Yeah this relay is under the dash. It's been in the garage hasn't seen rain so doubt it's from water. Could it have gotten surged.Smell some fuel I'll check again though.
Expert:  Gary replied 10 months ago.

I would say that a major ground not connected could zap the ECM.

If you smell fuel out the tailpipe, can you now check for spark from all the leads?

Gary

Customer: replied 10 months ago.
Yeah that was my main worry.I'll check both of those things and get back with you.
Expert:  Gary replied 10 months ago.

Ok Brad.

Gary

Customer: replied 10 months ago.
I pulled a plug and got spark on cylinder 1.I also smelled fuel when cranking as well.
Expert:  Gary replied 10 months ago.

Hi Brad,

Time to check the valve timing.

If if has spark and fuel the engine should run.

Sounds like the timing is wrong.

Can you check the timing belt please, condition and correct timing?

Gary

Customer: replied 10 months ago.
Yeah I can check it. I just installed a new timing belt and all components a month ago and ran correctly until this incident.
Expert:  Gary replied 10 months ago.

Yes, ok.

You know what to do now.

I'll hear from you soon.

Gary

Customer: replied 10 months ago.
Hey the timing looked and components all look in order. I had read that if the car is still getting spark then the ecm is telling it to but not at the correct time since the cam and crank sensors arnt getting power which seems like the case. Is there a particular relay that controls these functions. Or which wires at the harness should I check. Any other suggestions?
Expert:  Gary replied 10 months ago.

Hi Brad,

I can't see how you are getting spark and fuel, and the engine doesn't start.

If the cam timing is correct, the ignition timing will be correct.

Have you had the spark plugs out? they may be wet with with fuel, when you had no spark.

Gary

Customer: replied 10 months ago.
Well if it's getting fuel or spark at the correct time then that could be the issue. If the ecm doesn't know where the crank and cam position is at because they have no power then it's just firing In the dark. The engine could be in time but if it doesn't have the sensors to correlate with that Then it won't run.
Customer: replied 10 months ago.
If it's not getting at the correct time. The engine will still fire spark even if it doesn't have those sensors. It just may not be at the correct time.
Expert:  Gary replied 10 months ago.

Hi Brad,

You are saying it has spark from the coil pack, with cam and crank sensors disconnected?

Also, if does fire at the wrong time and it has fuel, the engine will backfire, cough etc.

Gary

Customer: replied 10 months ago.
Ok went and did some more testing. If I pull the crank and cam sensors it doesn't spark.I went and tested all of the boots and am only getting spark on cylinder 1 and 3. 2 and 4 did not spark using the same plug for all of them. Also it only cranks like 2 to 3 times and then stops intermittently.
Expert:  Gary replied 10 months ago.

Yes that's correct, that now proves the crank sensor and ECM side for spark.

My bet is the ECM is damaged.

Have you had the spark plugs out yet?

They are probably drowning in fuel, and you could hydraulic the engine.

Gary

Customer: replied 10 months ago.
I had two the plugs out they were wet and smelled like fuel. I had my wife only crank it a couple times so it didn't get completely dumped with fuel.The plugs are also brand new ngk plugs.
Customer: replied 10 months ago.
Should I pull all the plugs and let it evap some?
Customer: replied 10 months ago.
The boots were also new as well.
Expert:  Gary replied 10 months ago.

Yes, I would pull all the plugs out, let them all dry out, and the let the engine dry out.

While you are there, I would measure EVERYTHING with a multimeter for resistance, leads AND spark plugs.

I have had BRAND NEW spark plugs open circuit out of the box.

Still concerned why you have no spark for one pair.

Have you got another stock coil to test with?

Gary

Customer: replied 10 months ago.
I have another coil pack to use but it is older. I will see if that makes a difference. I can get new boots as well if you recommend that. I will check all the plugs and see whats up. Thanks for your help I will update again after i go through some more testing. If you have any more recommendations just let me know.
Customer: replied 10 months ago.
big update**
Checked all the plugs, leads, pack etc all looked great. I then went and checked the connector that goes to the igniter and got zero volts on the left 2 wires! This has to be the issue the other two had 12 volts.
Expert:  Gary replied 10 months ago.

Ok Brad,

All the best in the next lot of testing.

There's not much more to offer at the moment.

Can you measure the coil resistances prior to swapping them over?

Do you have a a workshop manual?

Gary

Customer: replied 10 months ago.
It's the left two wires that are the issue.
Customer: replied 10 months ago.
I have the subaru fsm.
Expert:  Gary replied 10 months ago.

That's great.

Do you have the circuit diagram for the ignition coil circuit?

Gary

Customer: replied 10 months ago.
I could find it will have to do some digging.
Expert:  Gary replied 10 months ago.

Hi Brad,

When you get your circuit from your manual, you will see that there will be 12v on one or two wires as the positive coil primary feed. The negative side will be switched on/off grounded by the ECM, hence why you see zero volts.

Gary

Customer: replied 10 months ago.
Alright well back to zero. I'm not really sure where to go from that point. I got resistance on all the components of the ignition system. Smelled fuel on each of the plugs. Yet for some reason cynlinder 2 and 4 is not firing.
Expert:  Gary replied 10 months ago.

Hi Brad,

It will be difficult to fix this remotely, since I am not with you.

Two heads are better than one, as they say.

You have an unusual fault here, and I am leaning towards an ECM.

But I would like to see same more diagnosis from the coil wiring to the ECM to be sure.

To me, you have two faults in one.

You have fuel on all four, you have spark on two.

The engine should at least have a cough and try to fire up, even on 2 cylinders.

It should also backfire if the spark timing is incorrect.

I will open the question to another tech if you like.

Gary

Customer: replied 10 months ago.
Thats fine with me if you would like to open it.It will cough and have a heavy fire intermittently. I will see if anyone local can lend me an ECM to test to rule that out. I also have that new relay on the way.Thanks again
Expert:  Gary replied 10 months ago.

Ok Brad,

All the best to you.

Hope you get it sorted.

Kind regards

Gary

Expert:  Gary replied 10 months ago.

Hi Brad,

I see that you haven't been attended to as yet.

Have you had any success with your problem?

Gary

Customer: replied 10 months ago.
I havent I got the relay in but haven't installed yet.
Expert:  Gary replied 10 months ago.

Ok, I'll leave it with you until you have more time.

Gary