Help required i have given up

gemsdad · Jul 4, 2009

wrxfifer said:
when it is idling i can rev it right up all the way no problems and does not die when let foot off pedal just goes back to ticking around 500 rpm rough again

is this on petrol or gas???

kooky_guy · Jul 4, 2009

gavbriggs said:
Mass Air Flow Sensor (X105)
The sensing element of a Mass Air Flow Sensor
(X105) is a hot wire anomometer consisting of two
wires; one heated, one not. The air flows across the
wires, cooling the hot wire and thereby altering its
resistance. The ECM (Z132) measures this change
in resistance and so calculates the amount of air
flowing into the engine.
If the Mass Air Flow Sensor (X105) fails, the engine
will start and then die as the engine reaches 550 rpm
before the ECM (Z132) looks for the Mass Air Flow
Sensor (X105) signal.

Throttle Position Sensor (X171)
This sensor is a variable resistor. The signal informs
the ECM (Z132) of the actual position of the throttle
plate. Failure of the Throttle Position Sensor (X171)
will result in poor idle and lack of throttle response. If
the Throttle Position Sensor (X171) fails in the
closed mode, then the engine will only rev up to
1740 rpm when the ECM (Z132) will initiate over run
fuel cutoff.

Heated Oxygen Sensors (X139, X160, X289, X290)
The heated oxygen sensor consists of a titanium
metal sensor surrounded by a gaspermeable
ceramic coating. Oxygen in the exhaust gas diffuses
through the ceramic coating on the sensor and
reacts with the titanium wire, altering the resistance
of that wire. From this change in resistance, the
ECM (Z132) can calculate the percentage of oxygen
in the exhaust gas and adjust the injected fuel
quantity that as to achieve the correct air/fuel ratio.
This reduces the emissions of Carbon Monoxide
(CO), Hydrocarbons (HC) and oxides of Nitrogen
(NOX) to acceptable levels.
Presently, two heated oxygen sensors are used, one
in each exhaust down pipe just before the catalyst.
In the event of sensor failure, the system will default
to open loop. Operation and fuelling will be
calculated using signals from the remaining ECM
inputs. The fault is indicated by illumination of the
malfunction indicator lamp (MIL). ECM diagnostics
also uses heated oxygen sensors to detect catalyst
damage, misfire and fuel system faults.

Idle Air Control Valve (M112)
The Idle Air Control Valve (M112) controls the idle
speed of the engine by moving the plunger a set
distance, known as a step. Fully open is zero steps
and fully closed is 180 steps. The motor moves each
step by sequentially changing the polarity to each of
the two coils.

thats from rave and it says it will idle then die??? which seems to be on the lines of whats hapening????

I see where you're coming from, but it was running ok before! I can understand the frustration.

Looking at the wiring abortion on the MAF though , that could have something to do with it. I think the idea of cutting the connector of a scrap one is a good one - at least you can be sure of the connections then.

Guy

wrxfifer · Jul 4, 2009

it seems its one of these things that could actually be alot of things thats why my brain has burst i can only go on advice/experiencefrom you guys as i have none

wrxfifer · Jul 4, 2009

this is on petrol im gonna try gas in morning when one of these batteries has a reasonable charge as went through 2 now got another new one today and its dead now too

gemsdad · Jul 4, 2009

wrxfifer said:
this is on petrol im gonna try gas in morning when one of these batteries has a reasonable charge as went through 2 now got another new one today and its dead now too

well if its running ok on revs but ****e on idle,could it be a faulty idle control valve.????

gemsdad · Jul 4, 2009

wrxfifer said:
this is on petrol im gonna try gas in morning when one of these batteries has a reasonable charge as went through 2 now got another new one today and its dead now too

at least when its all running ok you wont be short of batteries will you.

wrxfifer · Jul 4, 2009

but would this cause this sort of mis you hear from the exhaust?

wrxfifer · Jul 4, 2009

na ill always have a spare and where is this valve to check and how would i check?

gemsdad · Jul 4, 2009

wrxfifer said:
but would this cause this sort of mis you hear from the exhaust?

i dont think so,but it would have an effect on your idling problem.

gemsdad · Jul 4, 2009

wrxfifer said:
na ill always have a spare and where is this valve to check and how would i check?

irish is yer man for that.

kooky_guy · Jul 4, 2009

wrxfifer said:
this is on petrol im gonna try gas in morning when one of these batteries has a reasonable charge as went through 2 now got another new one today and its dead now too

I was told by the lpg place that sorted mine out that the car HAS to be running properly on petrol before you even think about worrying about the lpg.

lpg is fussier so if it 's not running properly on petrol then it definitely won't run properly on lpg, although that may depend on the type of lpg system fitted.

Presumably the batteries just need charging?

wrxfifer · Jul 4, 2009

he has sent me an email asking questions but is away for beer now lol

wrxfifer · Jul 4, 2009

i have the same system as gav confirmed to me on the phone earlier

gavbriggs · Jul 4, 2009

the idle air control is one of them on the plenum at the front, other side to throttle links.

starting on lpg is really just to see if the maf has gone as the lpg system doesnt use the maf as far as i know!!

if it missfires etc the same on gas then its ignition related, if not then i would say maf related!

wrxfifer · Jul 4, 2009

and i know we are focusing on the bar/rough idle but it takes a while to start also maybe 30 secs!!
and plenty petrol and spark all new plugs yesterday as well as one looked bad

wrxfifer · Jul 4, 2009

and only starts at all if foot on pedal wont just start using key alone

kooky_guy · Jul 4, 2009

gavbriggs said:
the idle air control is one of them on the plenum at the front, other side to throttle links.

starting on lpg is really just to see if the maf has gone as the lpg system doesnt use the maf as far as i know!!

if it missfires etc the same on gas then its ignition related, if not then i would say maf related!

Apparently my lpg system uses the maf.... (although I've only got the lpg place's word for it). That's why I had to replace it.

gavbriggs · Jul 4, 2009

is it single point? i see no info related to the maf in the instruction and install manual for the aeb 175(leonardo ) that he and me has fitted!!

lambdas are used to sense the mixture and fuel is added as required to obtain the correct mix,

gemsdad · Jul 4, 2009

gavbriggs said:
is it single point? i see no info related to the maf in the instruction and install manual for the aeb 175(leonardo ) that he and me has fitted!!

lambdas are used to sense the mixture and fuel is added as required to obtain the correct mix,

but lambdas are after the fuel has been burnt.

kooky_guy · Jul 4, 2009

gavbriggs said:
is it single point? i see no info related to the maf in the instruction and install manual for the aeb 175(leonardo ) that he and me has fitted!!

lambdas are used to sense the mixture and fuel is added as required to obtain the correct mix,

Actually, you've got me wondering now. It would need an awful lot of splicing to be able to use all the engine sensors and I haven't noticed anything like that. Hmm. I may have misunderstood what he said about it. It was running like a dog on petrol though and the replacement MAF certainly fixed that. It misfired like buggery on lpg - I just assumed it was all related, but thinking about it, that may have just been that the lpg injector blocks were shot.

Anyway, ignore me - I'm just confusing the issue!

Mine's a ovlm (i think) sequential multipoint jobbie.

Help required i have given up

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