Subaru long crank

[Matt]

2000 Subaru Outback

Ever since I have owned it its had a long cold crank condition (~2-3 seconds before a weak start) – switching from regular fuel (91) to premium (98) makes it even harder to start? if I crank it and stop, then crank again it will fire up straight away, if i let the fuel pump prime longer or multiple times it doesn’t make any difference.

Edit:
If the car has warmed up it will start instantly/normally.

There is no check engine light and no codes stored.

The car does seem to be lacking in acceleration? Doesn’t feel as snappy as my older Subaru (1996 liberty/legacy)

Things i have checked:
Timing belt replaced and checked multiple times (even a new tensioner)
o2 sensor (spare in – same deal, put the original genuine one back in)
Coolant temp sensor (spare in – same deal, put original one back in)
Ignition coil (resistance check – to spec)
Fuel pressure (above spec, new fuel filter)
Spark plugs (clean and correct gaps)
Knock sensor (spare in – same deal, put the original genuine one back in)
Valve clearance (adjusted all at 200k km)

Edit:
Battery was checked with a battery tester and passed, and jump-starting the car with another running car doesn’t change the crank time
ECU reset does nothing
Throttle body and IAC spotless and clean
Injector cleaner

Any ideas?

Topic

[zero]

The first step is an easy one, check the cranking voltage at your battery. If the voltage is dropping low enough, it might not be spinning the engine up fast enough to start properly.

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

[Matt]

The battery was checked with a battery tester recently and I tried the jump starting with another running car – exactly the same – do i still require cranking voltage to be checked?

I forgot to mention – if its running for more than ~2 minutes it will start up perfectly

[EricTheCarGuy]

You might find this information helpful.

Please keep us updated on your progress.

[none]

After the aforementioned checks are done, I’d consider vacuum leak testing. Some vacuum leaks can affect a cold start and disappear with a hot engine. Given it’s a Subaru, I’d contemplate eventually doing some diagnosis for a bad head gasket too. I’m wondering if you’ve got a leak between the cylinders causing the lack of power you’re concerned about.

[Matt]

Fuel pressure is fine I thought that at first too

Vacuum leaks – this car has a MAP sensor not a MAF, and new gaskets for throttle body/intake manifold etc

Head gaskets – this engine got a complete gasket/seal kit a few years back (was doing the same thing before the rebuild) – heads checked, new genuine head gaskets, water pump, complete timing kit, new complete gasket/seal kit for everything

[Dmitry Tolstoy]

Check if your Ignition timing marks are spot on with a timing light, they could be off..
Also in my system the car wasn’t storing codes for tps sensor while not running, have you tried checking codes with a running car?
(btw in my case i had an obd1)

[Matt]

Timing marks checked and rechecked however i have not checked timing with a timing light – ill look into that soon

No OBD2 but i do have an adapter to use with “FreeSSM” , no codes and the TPS is smooth from 0% to 100% – ill check for codes when running when i get a chance also

[Matthew]

I agree with DaFirnz and ErictheCarGuy. When you say battery voltage and fuel pressure are “fine” what does that mean? can you provide empirical data? What is battery voltage while cranking engine? what is fuel pressure and how does that compare to manufacturers spec range?

And what does “a long cold crank condition (~2-3 seconds before a weak start)” mean? That when you turn key to start it does nothing for 2 – 3 seconds? or does it crank but slowly for the 2 – 3 seconds before firing? or does it crank normally but takes 2 – 3 seconds before firing? Please provide some specifics.

Without some data to start getting some direction we are all just guessing.

[Matt]

Long cold crank – first thing in the morning or after work if the car has been sitting around all day – turn key to start position, the car cranks and cranks for ~2-3 seconds or longer then finally it splutters and shudders to life then and after its started its fine, never stalls or shudders or anything, i can drive it as normal, if the car is warm (within ~30 minutes of sitting) it starts up fine (within a second).

Fuel pressure is to Subaru service manual specification (30-34 psi, 41-46 psi with no regulator vacuum) – i got ~35psi and ~45psi with engine running, starting pressure was full instantly when key is turned to on position and doesn’t go down on start-up, “throttle snapping” instantly raises fuel pressure to the full ~45psi instantly.

Battery was tested with a load tester at a shop and passed, and like i mentioned earlier I even jump started it with another running car which made no difference at all, again – does this eliminate battery/electrical or do i still have to do more testing (cranking voltage etc)?

Ill post videos of both hot and cold starts when I get a chance.

[zero]

You need to check the fuel pressure during cranking. Key on should put you almost immediately into the spec range and it should sit there through cranking.

[Matthew]

If you want eliminate the battery as an issue, test battery voltage while cranking which is easy enough. Connect DMM to battery posts (not terminals) and try to start car. Then connect meter across starter. Red lead on main starter solenoid power feed post (again not terminal) and black lead to starter mounting bolt (make sure it is clean for good connection). Repeat cranking test. If both numbers are the same and stay above around 10v (9V worst case), then you don’t have a battery or wiring problem. If measurement across starter is a lot lower, then you have a wiring issue to deal with. If a lot lower, move black lead to battery neg post and repeat cranking test. If new readings = same as across battery (>=10v), then you have a grounding wire issue between starter and battery. If voltage drop stays low, you have a power feed side wiring problem. You may want to pull fuel pump relay during tests to make sure you have time to get good readings.

[Matt]

First start (you can hear the fuel pump prime – i always wait for it):
https://www.youtube.com/watch?v=Ralk-rHZ3xo

(Turn car off)

Second start (moments later):
https://www.youtube.com/watch?v=pB6tPMt7-cA

(Turn car off)

Third start (moments later)
https://www.youtube.com/watch?v=_YywElSAn1Y

[Matt]

Key on instantly put fuel pressure to spec, fuel pressure stayed the same during crank (35 psi)

Battery crank load testing – today I used some equipment of mine to pull some numbers (~3000-5000 updates a second) and generate a chart (see attached), I did notice the voltage dived momently to 7v for the initial crank – could this be what i’m looking for?

This chart was generated with data used in the first crank video, for the second and third video the charts looked identical, same 7v dive etc but started much quicker with less cranking.

The initial voltage was 12.6v (overnight, ~30ºC)

Attachments:

• CHART.jpg

[EricTheCarGuy]

It doesn’t seem that you did the leak down fuel pressure test as shown in the video. Do that test and it should reveal if you have an issue with the check valve in the fuel pump or not. You can have ‘good’ fuel pressure while the engine is running and still have a bad check valve. That was outlined in the second video I posted for you. A bad check valve would explain the long crank after sitting.

[Matt]

Hi sorry about the late reply i have barely used this car until recently, fuel pressure leak down tested fine however i inspected the fuel sender unit (plastic!) – it had a small crack in the sender side plug/barb so i replaced the whole assembly – same issue.

Since last posting the issue seems worse, i get hesitation (poor performance) on WOT, seems to run rough and has very little power especially up hills and with the AC on.

Updates – tried NEW battery, crank and cam sensors (from another working Subaru i have), new plugs and leads (other ones were original OEM leads and old plugs that looked fine), upgraded and cleaned up grounding everywhere, coolant temp sensor (from another working subaru) – nothing changes the problem.

This thing shows NO codes at all still, my scanner also tells me on WOT this thing is running lean, fuel trim says -10%?

Any ideas?

[Author]

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