not running smooth

Post by **colouredFunk** » 16 Nov 2007, 23:27

hi, van isn't running smooth especially as slower speeds, 30 - 65. it feels slightly juddery or jerky. Anything over 65mph and it feels better. but it's quite bad around 40 in 4th gear.

I've recently replaced -

leads,
distributer cap,
rotter arm,
plugs.
air filter.

initialy I thought it was my injectors but as it does it on petrol and LPG I guess it rules that out. All plugs have a good spark.

oh yeah it's a 2.1i.

Any ideas?

Post by **jason k** » 16 Nov 2007, 23:43

lambda sensor??

Post by **toomanytoys** » 17 Nov 2007, 11:09

Was it doing it before any of those parts were changed?

Post by **strangely brown** » 18 Nov 2007, 19:27

Hi Coloured Funk, i suggest changing the thermostat (fellow 2.1i owner) it totally changed the way my van drove, it's cheap even though it means you have to re-bleed the cooling sytem. Just to add a note my symptoms were pretty bad, give it a go, you might be very surprised.

Strangely Brown.

Post by **hammy44** » 18 Nov 2007, 22:06

try adding redex fuel cleaner it worked wonders for mine would swear by it now

Post by **colouredFunk** » 25 Nov 2007, 18:40

what's and where is the lambda sensor?

I've tried redex fuel cleaner.

Strangely Brown - why would thermostat make a different to the performance, doesn't it just control the water!?

It used to run sweet, but all of a sudden lots of strange things have been going on.. it wasn't firing on all cylinders, hence why I replaced all those parts and used redex, but in the end I found out it was 2 of my injectors that hand packed up. I bought 2 good 2nd hand ones and it's firing on all 4 again. But just running smooth

Post by **Hacksawbob** » 25 Nov 2007, 19:27

Also petrol filter and check condition of fuel filler they can get cacked in the wheel arch and let water in to petrol tank. check for vacuum leaks too

Post by **colouredFunk** » 26 Nov 2007, 09:25

It does it on LPG as well, so it can't be just petrol related.

Post by **Ian Hulley** » 26 Nov 2007, 11:45

colouredFunk wrote: what's and where is the lambda sensor?

The Lambda sensor is set into the exhaust and tells the engine control unit (ecu) what the emmisions are, the ecu then adjusts the mixture accordingly.

colouredFunk wrote: why would thermostat make a different to the performance, doesn't it just control the water!?

The thermostat controls the flow of water from the engine to the radiator for cooling, however if the thermostat is faulty the water temperature is incorrect ... and the ecu picks that up through one of it's temperature sensors and adjusts engine air flow accordingly. e.g. if the thermostat fails open the engine takes ages to get up to operating temperature because the coolants flowing straight away ... the ecu reads this and gives more choke than you need.

On $ierra/Granada Bosch injection systems the cylinder head temp. sender was a weak spot and the ecu often thought the engine was running cold (the default setting) and so assumed the engine required choke, the tick-over was high, as was the fuel consumption. The same applied to the idle speed control valve, that failed and the tick-over became erratic, revving up to the point the ecu realised something was wrong and dropped it down again and repeat etc etc.

Point being ALL the sensors and detectors are equally important to a system with an ecu.

Hope this helps, Ian.

Post by **Martin** » 26 Nov 2007, 17:32

did you gap the plugs correctly?

i would remove them 1st to check

Post by **colouredFunk** » 26 Nov 2007, 23:52

cheers Ian for all the info much appreciated!!

Martin you know what size gap the plugs should have? I did look in the Haynes but no joy....

I will get a thermostat tomorrow see if that makes a difference

Post by **jason k** » 27 Nov 2007, 08:07

if you follow the leads fron the lambda (which is in your exhaust) you can bypass the lambda. if this improves the running then the lambda is at fault. dont get a new one from gsf tho as they are "pooh".