Barxy

I have an odd issue with the car !
Its an MY00 UK turbo, running a few mods (exhaust decat remap v8 intercooler), now ive had some issues with the car mainly idle problems which has now been sorted... by replacing the maf and the o2 sensor.

The last issue to sort out is something strange. It tends to be mainly when the engine is cold, but when im gradually / gently accelerating (i.e joining the motorway or just generally accelerating slowly - not pushing the car hard) it seems to have a constant hesitation, then its fine, then hesitation, then its fine, for about half a second each in a 'heartbeat' kinda way?

Is this what ive read as surging? as im struggling to find out what surging atually is, and if this is it?

I know its difficult to explain but im sure its happened to other scooby owners?

BTW it doesnt really do it anywhere near as noticeably when its warm, and it boosts perfectly smooth when warm (dont know about cold as i dont use boost when cold) its just like its holding back for a half second then fine, then holding back again in a constant motion...

really odd ... any ideas?

TonyBurns

iTrader: (3)

Any particular gears?

Tony

Barxy

Doesnt seem to matter which gear im in, which i can only image is not a gearbox issue?
its as if it stops accelerating for half a second then carries on thens tops again, all in a constant motion...

TonyBurns

iTrader: (3)

Does it do it in 1st and 2nd?

Barxy

Im pretty sure it does it in all gears... dont spend too long in 1st to notice it but it definatley does it when im in 2nd 3rd and 4th (usually not accelerating by the time im in 5th)

overboostUK

Mine does something similar, I put up numerous posts and got no help I'm putting it down to coil pack or the map itself.

Barxy

From some research I think it could be an issue with the ecu...? But I'm not sure what?
Can't see why a remap would cause this?

TonyBurns

iTrader: (3)

It could be a remap issue if its only started with the cold weather, though try cleaning out the boost solenoid and check to see if it does do it in 2nd gear, if it doesnt and only does it in 3rd/4th/5th then definately has to have the map looked at and adjusted slightly, take it your car was mapped in summer?

Tony

Barxy

I'm not too sure a previous owner mapped it. It's done it on warm days though ? Out if interest why would it be okay in 2nd gear if it was a mapping issue ? (It definatley does it in 2nd gear btw)

TonyBurns

iTrader: (3)

1st and 2nd are lower boost levels so if its doing it on those you have another issue which means its not overboosting because of the map (though that doesnt mean the map is correct, it could still be at fault).
Check the boost solenoid first and clean it out, was the maf sensor you replaced brand now out of box or 2nd hand?

Tony

Jolly Green Monster

iTrader: (4)

99/00 cars follow the lambda sensor ie. alters the fuelling to lambda one.

You can often feel them surging on light throttle. Its horrible.
Some are worse than others.
Worth getting the map checked if there is any chance the maf wasnt 100% when it was mapped.

Simon

Barxy

The maf sensor was a brand new Subaru part, about a month ago if that? And in The case of the lambda is it not weird that its just been replaced, and the problem still exists after changing both of these.
Jollygreenmonster yeah it's only on light throttle and is fairly annoying !
It was mapped at power station a few years before I owned it so I cannot comment on the map, but is it likely a new map will fix this?
What other causes can there be?

Jolly Green Monster

iTrader: (4)

Genuine lambda sensor?

It sounds like a normal 99/00 but difficult from txt on here to be sure rather than seeing it.

Maf should have been fine when originally mapped then

Barxy

Not I replaced it with a second hand Bosch sensor, but it was doing it before and after, and the replacement sensor fixed my idle problem so i presume it's working correctly.
The car seems to have been well cared for and according to its history everything has been fixed when needed, it's got a huge wad of paperwork.

Possibly just something that these cars do at this age? It doesn't affect driving really and it's on noticeable on very light throttle, I'm just very very picky with any car issue.

Jolly Green Monster

iTrader: (4)

Exactly that.

If its the hessitation from following the lambda sensor then not every drive notices it and some cars are worse than others

Barxy

I see, thanks for the info mate.

sonic93

iTrader: (16)

Barxy you get this prob sorted?

Barxy

Nope mate, car runs beautifully in every aspect but this, but it's so minor and picky, and very hard to notice, missus doesn't even notice it so just gonna live with it. Doesn't seem to do anything wrong and I can't find any info other than people saying its something that these cars do and isn't a problem ?

Richy P1984

I also experience this slight hesitation, but not all the time. It was happening yesterday and was quite noticeable. At first I thought it was me, not accelerating properly, but after a couple of experimental runs, and reading this, the car may well have a small issue.

My car is completely standard (apart from back box and centre pipe replacements) - No maps, and the engine bay is as the day it came out the factory.

One thing that may not be related, but I have recently noticed, my car after full service (new belts etc) seems to rev much more freely, and every time I go to change gear it 'over revs' or carries on revving, making it sound like you still have your foot on the gas whilst the clutch is in. It never used to do this except, just after the previous service.

Its almost like the car is blipping itself ready for a downchange, makes great driving though when going up the gears, as its like having my own version of anti lag!

simscoob

iTrader: (1)

Hi gents - i had hesitation issue on my wrx ppp and it turned out to be the turbo to ic hose. Damn thing bugged the hell out of me but i eventually identified it and bought a second hand prodrive hose from one of the good gents off this very forum.

Issue occurred slowly - so much that upon curing it the car felt very different and full of beans.

Worth checking the basics if you haven't already.

Cheers
Simon