Engine Hesitation When Cold

R

RX Wagon

Sunday Drivers
Hi Guys,

Does anybody have any ideas on a problem I’m having, I’m getting a hesitation( lack of power) from the car when the engine is cold or when the engine is stressed, going up a steep hill etc.

I started feeling it soon after I bought the car, it got progressively worse and I thought it was the plugs, I changed the plugs to Denso ones and this seemed to fix the problem. It has started again (about 4 weeks since I changed the plugs) but only when the car is cold its fine once its warmed up but I’m guessing it will only get worse as it did last time.

The plugs I removed where NGK plugs and had a small build up on them which I assumed was causing the problem...

Its a 2.0 litre non turbo hawh eye wagon

Any ideas?
 
hey, that sounds pretty similar to what I am experiencing, check my thread few topics lower, low RPM acceleration knocking. I yet dont know what it is, but to me it happens when car is warm as well, and I dont blame spark plugs as I changed them not that long ago. I will drive my car to Dave tomorrow and will see more. I have too non-turbo 07 hawkeye...
 
Interesting, mines an 07 too.

I did read your tread, the only difference is mine isnt making a knocking noise and when i changed the plugs it did fix the issue for a few weeks.

What mileage is on your car? does your car feel down on power when ur getting the knocking sound?

Let me know if you get an answer :thumbsup:
 
Not a fan of denso plugs ngk would have being Better but it's still not your problem . Are you sure it's lack of power and not just a hesitation around 2500/ 3200 revs And it seems to be a common problem with the 2.0 not turbo legacys and imprezas
 
[quote author=scoobysub link=topic=42820.msg490775#msg490775 date=1411462504]
Not a fan of denso plugs ngk would have being Better but it's still not your problem . Are you sure it's lack of power and not just a hesitation around 2500/ 3200 revs And it seems to be a common problem with the 2.0 not turbo legacys and imprezas
[/quote]

I would have gone for the NGK ones too but the motor factors had the denso in shock so I said id give them a go.

It does at the moment feel like just a hesitation around that rev range alright.

Before I changed the plugs it was worse, and you could feel a small kick as power came back on.

I wasn’t aware it was a common problem for the non turbo car... maybe just getting a turbo is the way forward :)
 
Hey,

I do not think the knocking sound is anyhow related to the power loss, but I might be wrong, I have driven her to Dave few days back and I will see what his results of diagnostics are. He mentioned, that it might be just some sensor. The car shows 147 000km at this moment. I have had the same issue with the hesitation earlier on as well, and I thought it might have been a airflow issue, but I managed to get it 'fixed' temporarily by just hard driving her in high revs, but I dont want to do that again, since it happened again. I originally thought that something might be stuck in the fuel intake that limits the amount of petrol getting in or something.

Considering what you said, that changing spark plugs helped for a while, I might suspect Ignition Coils. Dave said over phone, that those should be changed every 100k km, but who knows if mine were changed at that point. I doubt it. Well, lets see what Dave finds out and I will let you know. It feels like we are looking at exactly same issue.

Only difference I can see is, that to me, its happening all the time, no matter if cold or hot. If I manage to get somewhere between 2500-3200 RPM the car is just lazy, after that, when I get above, its like magical whip and I get pushed deep into the seat and the car flies again...
 
Ah okay, as mentioned above maybe its just the 2.0 non turbo engine is 'lazy' between 2500-3200rpm. Mine has about 130k klms and I doubt the ignition coils have been changed either.

What part of the country are you in? it would be interesting to see if they drive the same...
 
Well, I can assure you that the kind of hesitation I am getting is not the laziness of the car, I know how it drove before, and it happened instantly that there was massive loss of power. I am living north Dublin city. My car is at Dave's now, but if you drove me arround, I could tell you whether its normal, or you experience the same thing as I do
 
Thank you Tommy, as always great post of yours, apparently based on what Dave called me with, the ECU Coolant temperature sensor was giving 220c degrees to the ECU. Which according to the topic you posted might have caused that hesitation
 
Thanks Tommy :yellowthumb:

I see, so whats your plan Zheiko? change the coolant temp sensor?

What about the knocking noise ur getting?
 
So, it seems to be a bit more complicated than that. The sensor had been changed, but ECU is still receiving weird numbers(160degrees after start). Dave said he never seen that before. Anyways, Dave will now look at compression as he is trying to find what the fault is. So far all that Dave checked, he said that all sensors and everything shows good numbers and there is apparently yet nothing wrong...

Thumbs up for Dave and his efforts on the car, I really wish he can find the cause.
 
Very interesting and it does make alot of sense. I wonder would anybody in subaru ireland know of this 'hesitation remap'

Also the post quoted below sounds very similar to mine, almost like a small turbo kick... i must look at the air flow sensor


I have a 2004 Subaru Legacy 2.0R (enigine is a JDM EJ204 - 190HP model) that developed a similar problem. Horrible power down low and would then surge (sort of felt like a turbo - no power then power).

Turned out to be the air flow sensor, it was giving error codes so the Subaru people gave it a clean and so far so good. It drives like a completely diffirent car. Power everywhere :D

Something to consider if you are having similar issues.
 
So, I was also thinking. Last time when I had this issue, it suddenly disappeared after I got a new petrol. Now the latest one, started happening when I got full tank from Applegreen petrol station. Just out of curiosity, what petrol stations are you using? :bump2:
 
So, to keep you updated, I have my car back, big thanks to Dave that he had the patience with me, he changed the coolant sensor, and after ECU reset it started reading good values, so that could be the issue I had, but at the same time, I had my spark plugs a bit loose as he said, so he tightened them up, it might possibly be the issue, but he said it was unlikely. Anyways, currently car drives great again. Drove off the rest of Applegreen petrol, and on Dave's recommendation went to Maxol and got full tank there today.. so lets see how the car drives. I will give it several weeks now and will monitor closely and see if that comes back or not.
 
[quote author=Zheiko link=topic=42820.msg492701#msg492701 date=1412894883]
So, to keep you updated, I have my car back, big thanks to Dave that he had the patience with me, he changed the coolant sensor, and after ECU reset it started reading good values, so that could be the issue I had, but at the same time, I had my spark plugs a bit loose as he said, so he tightened them up, it might possibly be the issue, but he said it was unlikely. Anyways, currently car drives great again. Drove off the rest of Applegreen petrol, and on Dave's recommendation went to Maxol and got full tank there today.. so lets see how the car drives. I will give it several weeks now and will monitor closely and see if that comes back or not.
[/quote]



All values were correct on live diagnostic and within subaru parameters. maf, avcs, tps, air fuel sensor, nps, manifold relative pressure (vaccum leak), intake air temp, etc. Coolant temp reading incorrectly. Replaced with genuine Subaru.

Leak down test carried out to cylinders and all cylinders within acceptable areas. Spark plugs loose.
Timing covers removed, timing checked and all in order.

Live reading and coolant temp back in normal values.

Test drive. Misfire/Flat spot not present.
 
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