I wonder if anyone can help guys..

The car is a 2006 2.5 WRX Hawkeye, and has no mods.

Ive had a dreaded hesitation problem over the last 6 months, and after constantly checking and cleaning things. The problem is still there, bust seems much worse when the outside temp is higher.

This morning I have been having a look at the ECU with my cheapo ELM bluetooth OBD2 reader, and using scantool.net software.

Everything looked normal except that the front 02 sensor, was reading around 2.80 volts but sometimes jumps to 7.995 volts. Could this be why my car doesn't feel right or is it normal?

I used the torque app on my android phone but doesnt show the jump. But when logging whilst driving, when i put my foot down it goes the 5.55 volts on the log.

I want to get a remap but want the car running right before I do, was going to use Jolly Green Monster for the remap.

 

Unusal on hawk wrx.

Is it running the standard dump valve?

What fuel do you use?

 

Yep, the car is 100% standard.

Always use tesco 99.

Is had new plugs, maf cleaned, crank sensor cleaned.

It defiantly seems temperture related, but sound like a misfire in summer weather with the windows down.

 

On cruise this hessitation?

Checked the inlet pipe for splits near the turbo or possible leaks in breather pipes that connect to it?

Is the fuel pressure regulator vac pipe on?

 

Yep, checked all the pipes a couple of times. Might it be worth me spending a few hours looking over it this weekend?

Sometimes it runs perfect, and is smooth and powerful. Just not very often, lol.

 

Looks like it might be worth plugging laptop in to see what the ecus doing.

 

The hesitation is anytime i want to accelerate, it holds back badly, the goes like a rocket. But it seems there are a couple of flat points one about 4500rpm and one at 5500rpm.

 

Okay so unlikely to be o2 sensor although long term fuel trims do effect on boost fuelling.

Sounds like it might be pulling timing if its ecu.

Other possibility which isnt nice but common is ringland

 

Haha, lets hope it not ringland.

Ill have another look over eveything this weekend, how much would you charge to have a look and see what its up to?

Cheers

 

Oh, another thing worth mentioning, if I disconnect the battery, the car runs great for about 10 miles. And It doesnt use any oil.

 

If we could meet somewhere easy then not much at all.

So by disconnecting the battery the learn ignition and fuelling maps are reset (although not all of them, usually clear the lot on the laptop so not 100% on what battery disconnect clears) so the car drives fine and then retards over the 10miles.

Ringland noise will be a tick about 2500rpm holding the revs there in neutral or as it returns to idle a single tick sound

 

Haven't heard any strange noises, except a deep burble when cold but think the is the air pump. Yeh can meet you anywhere tbh.

Could it be anything to do with an oil change? As i noticed it right after an oil change, but just before I changed the cam belt.

Just clutching at straws now? lol

There's lots of posts all over the net about Hawk WRX hesitation but no fix, most end up with a remap.

Do you work saturdays?

 

Not weekends unfortunatly.

Would be interesting to play on a standard car with it, normally its assumed its decat etc related.

 

That's fine, will spend a bit more time tinkering with it and looking for rouge pipes, and see if I can figure ote out.

Will need to take a day off work to see you in the week, but it needs sorting, and would like a torquey remap if theres nothing major wrong with the lump.

 

One last question, just been out to look at the "pipes" is it normal for the breather pipes to have some oil in them? Theres not much but deffo some getting into the intake before the turbo.

Ill leave your brain in peace now. lol

 

yes a little oil in the pipes is normal.

hence people fit catch cans to stop it

 

Cool, going to to a compression test on saturday to hopefully rule that out.