mus1

Hi

My 99 turbo has a strange 'pulsing' kind of effect when driving 'normally' not hard acceleration etc just on general driving either at 40 or 80 ish the problem stays.
I've tried to clean out the boost solenoid but nothing happens. It's fine on idle.

Anyone else had this issue ??

LewisScoob

iTrader: (5)

Does it idle ok?

Have you checked for fault codes?

Tried cleaning the MAF?

mus1

hi
it idles fine. no engines check light.
I assume electrical cleaner spray would be ok for the maf.

Thanks for the advice,i'll keep you posted

Gambit

iTrader: (6)

uk my99 all had that trait of pulsing on light acceleration/coasting on std ecu - spraying the maf will do nothing - and if anything is more likely to damage it.

how did you clean the boost solenoid? with the diagnostic plugs connected so that it was pulsing the boosting solenoid?

mus1

Hi

Disconnected the pipes then sprayed cleaner in to each port. turned ignition on but nothing happened.
I assume the solenoid is the upper most one, there is something below it which has one hose connected.

1509joe

iTrader: (2)

Don't hold me to this and I can't really remember what cured it but I think it was a slack actuator.

Gambit

iTrader: (6)

you need to connect the 2 sets of plugs underneath the dash. it will put the car into diagnostic mode - the rad fans will turn on/off continually but more importantly the boost solenoid will be also switching on/off - spraying cleaner inside it then will let it clean it out completely

good point - i remember setting the preload also on mine based on old Harvey posts on here
https://www.scoobynet.com/general-te...e-preload.html

mus1

thanks Gambit and 1509joe, ill try that at the weekend.
not so sure about wastegate bit but i'll try the solenoid first

cheers

Bazil_SW

iTrader: (4)

How subtle is the pulsing?

I've had subtle pulsing on several cars (turbo and non turbo) and subtle pulsing in light throttle, I.e. off boost and in closed loop fuelling was caused by a failing o2 sensor. It's possible they get gammed up over time and become laggy. Not necessarily out of tolerance (so the ecu can not detect it and flag the MIL, at least initially) but laggy enough to cause wider AFR fluctuations than normal. The car will drive normally under boost because it's in open loop fuelling where the ecu uses the maf sensor to see how much air is going in and squirts the amount of fuel it thinks it needs and does not use the 02 sensor to mark its homework.

Anyway, on wife's Corsa recently it had this pulsing, and I soaked the O2 sensor in petrol over night and it sorted it. Alternatively you can buy a new sensor for about 100 quid on flebay. Either way buy a proper 02 sensor socket to make the job easier, they are pretty cheap.

If you reuse the sensor it's worth replacing the seal oring, and I had a post recently with some advice on doing so.

Hope it helps!

mus1

Thanks Bazil_sw
Yes it's more noticeable off boost but then just as turbo starts spooling it's a bit lumpy.
Wondered if the Ninja downpipe with sports cat might cause it also.
I'm not sure if its been mapped either !

Appreciate the advice.

ps just had a b road blast on way home, no issues when driven quickly

mus1

Hi All

Cleaned out the boost solenoid. What I have noticed is that the 'pulsing' is quite obvious until warmed up. but not so noticeable at higher speeds.
Maybe a few blasts I've done have helped somehow ??!!!

tjmatt

iTrader: (1)

They tend to lean on lambda sensor a bit too much and quite soon while engine is cold and sensor slow. Disconnect it and test drive it and see if its better. However don't expect a new one to be much better if there is a difference.

mus1

Thanks tjmatt, i'll try it today.
I noticed yesterday that even when warmed up and doing 80 ish it's still 'pulsing'.
A bit annoying cause it seems to be making the turbo spool up.
Cheers for the advice

mus1

Hi
Disconnected Lambda sensor, no pulsing. hooray !
Reconnected after my return from work, as the engine light had come on. The next day the issue returned.
Have just removed the sensor and trying to clean it.

mus1

Hi
Cleaned Lambda sensor seems a lot better but now the idle from cold fluctuates. Guess it could be idle control valve joining the party !!!

Gambit

iTrader: (6)

if you clean that out, just be careful not to nip the O-Ring when refitting

they are this style of ICV/Stepper motor on the MY99/00 cars compared to previous years

mus1

Thanks Gambit.
Cheers for the 'heads up'

mus1

Hi, cleaned Idle Control Valve, didn't make any difference.
At least it's been cleaned, guess i'll just leave as is or bite the bullet and get a new Lambda.

Thanks for all the advice

semih

my 99 classic has same issue too(prodrive ecu) when the engine warmed nice, pulsing was gone. i changed lambda sensor(bosch one), original maf and cleaned iacv but nothing changed.(engine about 95k kms)

and i have aem wideband on dp.

at light throttle afr is very unstable (about 13,5-16,5) but when i went WOT afr is rock solid about 10.9-11

maybe try another lambda sensor(denso one)

mus1

Thanks Semih
I bit the bullet and order a new Lambda sensor from Lambdapower, first run today seemed ok.
Fingers crossed it cured.

Thanks again to everyone who offered advice.