Hey group been a minute since ive posted.  

I have a customers 06 LLbean forester 2.5 NA engine. 

Its having an issue where sometimes it will crank ( normal speed)  but not start. 

The weird thing is If you put a jumper pack or charger on it it starts right up. 

I swapped in a different battery before i did the swap but that didnt seem to change anything 

It doesnt seem to matter how long the car has sat but temp might have an issue. 

I just put a 50-60k JDM engine in the car and had hoped that with the engine swap the start issue would go away. 

when we installed the engine yesterday it fired right up and then an hour or so later when i went to run an errand but today. 

Hope someone here has seen this and can shed some light on the issue. 

Thanks, Craig 

denso starters can have worn contacts/plunger in the solenoid when old. Rebuild kits are available.

or, iffy batt cables or ground connections???

23 hours ago, logic23 said:

Hey group been a minute since ive posted.  

I have a customers 06 LLbean forester 2.5 NA engine. 

Its having an issue where sometimes it will crank ( normal speed)  but not start. 

The weird thing is If you put a jumper pack or charger on it it starts right up. 

I swapped in a different battery before i did the swap but that didnt seem to change anything 

It doesnt seem to matter how long the car has sat but temp might have an issue. 

I just put a 50-60k JDM engine in the car and had hoped that with the engine swap the start issue would go away. 

when we installed the engine yesterday it fired right up and then an hour or so later when i went to run an errand but today. 

Hope someone here has seen this and can shed some light on the issue. 

Thanks, Craig 

Seems like overkill but hey if ya got a spare engine laying around... Thanks for the laugh.

Good luck hunting down the gremlin.

18 hours ago, 1 Lucky Texan said:

denso starters can have worn contacts/plunger in the solenoid when old. Rebuild kits are available.

or, iffy batt cables or ground connections???

the starter is fine... it cranks fine but wont fire until you put a jumper pack on or battery charger. Then it fires right up

 

2 hours ago, brus brother said:

Seems like overkill but hey if ya got a spare engine laying around... Thanks for the laugh.

Good luck hunting down the gremlin.

The car was in to have the worn out engine replaced   it had been having the issue but i didnt want to start diagnosing until i had a fresh engine in and made sure all contacts were good. 

 

5 hours ago, logic23 said:

the starter is fine... it cranks fine but wont fire until you put a jumper pack on or battery charger. Then it fires right up

 

 

nvrmd

Edited January 14, 20215 yr by 1 Lucky Texan

On 1/12/2021 at 4:00 PM, logic23 said:

The weird thing is If you put a jumper pack or charger on it it starts right up.

That really is a weird problem. Here are a couple thoughts.

When cranking, something is starving for power until you connect the jump pack. That will supply extra current and keep the voltage up when cranking with the starter. Once it is running the ALT outputs over 14 volts so the amperage is up and it keeps running.

Maybe it wants a higher amperage battery. What does the voltage drop to when cranking. And what is the drop with the jump pack connected?

The starter motor could be drawing more current than normal. After all, it is an electric motor.

My first thought was battery negative grounds to the body. Add a few and see what happens. The ECU gets several grounds off the body.

Fuel or spark would be next.

When it doesn't fire check for spark from the coil.

And see if the fuel pump is running while cranking. Or, better check the fuel pressure with a gauge.

Hmmmm.....if it IS cranking but not starting, here's a coupla things to try;

spray some starting fluid into the intake to see if it fires - if so, some odd issue with fueling.

measure the voltage while cranking, really should be 10 or more volts I think.

are any codes stored? even pending codes?

 

Edited January 14, 20215 yr by 1 Lucky Texan

1 hour ago, 1 Lucky Texan said:

...measure the voltage while cranking...

Measure the voltage twice:

- First, at the +ve battery-post

- Then again at the starter-motor terminal (where the large wire is connected).

There shouldn't be much of a voltage diffetence between these 2 readings.

15 hours ago, Rampage said:

That really is a weird problem. Here are a couple thoughts.

When cranking, something is starving for power until you connect the jump pack. That will supply extra current and keep the voltage up when cranking with the starter. Once it is running the ALT outputs over 14 volts so the amperage is up and it keeps running.

Maybe it wants a higher amperage battery. What does the voltage drop to when cranking. And what is the drop with the jump pack connected?

The starter motor could be drawing more current than normal. After all, it is an electric motor.

My first thought was battery negative grounds to the body. Add a few and see what happens. The ECU gets several grounds off the body.

Fuel or spark would be next.

When it doesn't fire check for spark from the coil.

And see if the fuel pump is running while cranking. Or, better check the fuel pressure with a gauge.

ill check the voltages the next time it does it.  

I cleaned all the pos and neg connections at the battery, starter and right next to the battery.  

It also has the 2 extra grounds that go from the body to the block ... they are in good shape. 

I dropped a 1 month old battery in from my 2002 forester to see if that changed it.. 

Its warmer ( 40 deg ) today but will drop next week.. will be interesting to see if its temp related.

Thanks for all the support

 

10 hours ago, forester2002s said:

Measure the voltage twice:

- First, at the +ve battery-post

- Then again at the starter-motor terminal (where the large wire is connected).

There shouldn't be much of a voltage diffetence between these 2 readings.

Ill check this next time... my daily is a 5sp 2002S in. silver... its my favorite subaru so far. 

12 hours ago, 1 Lucky Texan said:

Hmmmm.....if it IS cranking but not starting, here's a coupla things to try;

spray some starting fluid into the intake to see if it fires - if so, some odd issue with fueling.

measure the voltage while cranking, really should be 10 or more volts I think.

are any codes stored? even pending codes?

 

i have a can of start fluid in the car , jumper wires and a test light for the next time it acts up.  

Thanks

 

11 hours ago, logic23 said:

I dropped a 1 month old battery in from my 2002 forester to see if that changed it.. 

Sure hope that fixes it. Wait and see.

If it acts up again here is one more thing to check. Voltage on fuse 11 or 14 with Key ON and when cranking. That is the voltage out of the IGN SW when ON and Cranking.

So the "new" battery fixed the issue. The newer drive by wire setups must be more sensitive to voltage/amperage drops. 

I took the battery out of the 06 and dropped it into my 02 forester S and havent had an issue. 

Thanks for the support and answers

 

1 hour ago, logic23 said:

So the "new" battery fixed the issue. The newer drive by wire setups must be more sensitive to voltage/amperage drops

Wow... So, it does like the newer battery. Sure beats poking around with meters.

Gotta remember that next time it happens.