Problem with Air/Fuel Ratio gauge?

[typerdevil]

Hi guys,

I filled it up my DC2R it had half of the tank left was BP Ultimate 98 and filled with 95 to make it full 2 days ago, i was in a hurry to uni so yeah and now my gauge is not moving backwards or forwards like it should when idling, it's been stuck on Lean since last night, i am very worried, maybe it's the fuel mixture or it might be a loose connection, i doubt it though it's all taped up to the sensors etc, so i have no idea what may be the problem........any clues why is this happening? I want to resolve it A.S.A.P, damn cars !!! lol it's fraustrating.....

[NSPYRE]

do u have a narrowband or wideband A/F meter?

if you got a narrowband, they arent really all that accurate...

[typerdevil]

well, i have a O2 sensor obviously, lol i hope errm it's a drift gauge, doesn't say if it's narrowband or wideband ???? .....

[NSPYRE]

does it give u numbered readings or is it like a pretty flashing light that goes up and down and ur gauge says LEAN STOIC RICH

[typerdevil]

it's a mechanical one with a needle, Lean and stoich, rich as the back face display, no clue why it's stuck hmmm

[NSPYRE]

sounds like a narrowband to me... honestly, they arent the most accurate things. have u done anything to ur car lately?

[typerdevil]

just changed the brake fluid a day ago

[NSPYRE]

yeah, dont think thats related... are u getting any pinging/knocking?

[typerdevil]

yeah i stopped at a servo, i don't think i could hear any pinging, just a high pitched hissing squeeling sound over the engine running....:confused:

[NSPYRE]

hmm... well ur ITR has a knock sensor anyway so if it detects knocking/pinging it will automatically retard ur timing... honestly mate, i dont think its something to worry about. if your serious about it, take it to the dyno and get some A/F print outs on paper. if ur on a stock tune, it would probably be pretty rich and be in the 12.5 ratio or so... if you're around 13.5 then ur meter might say lean but its still safe to run at that point since its NA

[nd55]

[Internet mechanic in the area]

> it had half of the tank left was BP Ultimate 98 and filled with 95 to make it full 2 days ago,

95 Octane E10 fuel?

> i have a O2 sensor obviously, ..... doesn't say if it's narrowband or wideband

If it's a wideband, you'd know. The hole in your wallet would tell you. :eek:

Besides, wideband sensors normally need and O2 sensor and an interface box between it and ECU.

Nick.

[omgzilla]

it might be a loose connection, i doubt it though it's all taped up to the sensors

Did you just twist the gauge wiring around the oxygen sensor wires and tape them?

If so, i'd be double checking the connections. You should wire things up properly using wire strippers, solder, heatshrink (or electrical tape tightly at least).

Once you've taken off (from idling) does the gauge operate as normal?

Is your water temp getting high when idling or whenever the gauge is reading lean constantly?

If it truly is running that lean:
1) The engine will Ping / Knock - If this occurs you should hear it. You may also see the gauge quickly flick to rich once a knock occurs (as the ECU retards the timing it may also enrich the mixture to counteract the pre-ignition).

and/or 2) Engine/Water Temperature may increase - As there is a lack of fuel to cool the combustion process and cylinder walls.

[typerdevil]

no the gauge is flicked to rich at midnight, i have no idea what the hell is going on with it, it use to operate normally, eg. backwards and forwards, i loosened the bolt to my gauge cup and it starting moving backwards and forwards, so weird....i might check the oxy sensor today and the wiring again.....

by the way i didn't do the installation... i took it to a performance shop near me....

[omgzilla]

It might be worth checking the wiring for any possible shorts along the circuit.

Might also be worth checking with another gauge to test that the gauge itself isn't faulty.

[sheppsz]

a narrowband setup like yours will only have 3 results i believe

rich, stoich, and lean (where as a more expensive and sophisticated wideband AFR gauge will show many values from around 10 to 19 AFR)


basically when idling, the stock o2 is used to get a AFR of around 14.7. So the ecu uses the stock O2 sensor and if it is richer than around 14.7 (or so) then it will lean it, and vice versa.

My point is that when idling the ecu, if it is too lean the ecu will richen it up.. so you should really worry


it is only when you put the throttle down a bit, that you goto pure injector duration values..


so yeah dont worry
and your gauge is cheap and a little dodgey

[omgzilla]

Another note: The reading of the air/fuel gauge should be ignored until the car is at operating temperature.

The 02 sensor doesn't provide any (correct) feedback until it reaches a certain temperature (until it is hot - normal operating temperature).

So whatever is displayed on the gauge before it has warmed up is incorrect/inaccurate.

[e240]

Aren't DC2R pre-2000 where they mostly have only started introducing '98?
So the DC2Rs were actually tuned from the factory to have premium, which was 95.

unless you have a programmable computer tuned to '98, I don't see how fueling up on 95 would harm the car in anyway.


Hi guys,

I filled it up my DC2R it had half of the tank left was BP Ultimate 98 and filled with 95 to make it full 2 days ago, i was in a hurry to uni so yeah and now my gauge is not moving backwards or forwards like it should when idling, it's been stuck on Lean since last night, i am very worried, maybe it's the fuel mixture or it might be a loose connection, i doubt it though it's all taped up to the sensors etc, so i have no idea what may be the problem........any clues why is this happening? I want to resolve it A.S.A.P, damn cars !!! lol it's fraustrating.....

[dumped echo]

As you said it usually swings around stoic at idle right?

Sounds like you have a narrowband and it sounds like you just have a wiring problem. Check the wiring to the gauge and don't worry about damage to the engine. It will throw a code if there's something wrong that bad (like detonation).

If you really want to monitor your air/fuel ratio properly get a good wideband sensor and yeah as stated above....feel the hole in your pocket. There's a review somewhere on the net about good quality ones.

[omgzilla]

Unless you've got an aftermarket computer and/or are constantly tweaking with performance bits narrow-band A/F gauges are pretty much pointless.

I wouldn't be running a DC2R on anything but Premium 98 Octane. My EK4 fuel lid says only to use P.U.L.P - I would have thought B18C's would be the same...

[Lerlo]

Anyway, if your car is still running smoothly, its probably your guage thats gone, so just throw it away, or buy an autometer one with LEDs, the needle ones just dont last with it moving about so much, narrow band guages are pretty much useless, but good to check if your O2 sensors are running well.
Another thing is your car should be running 4 wire heated O2 sensors and from my experience they run straight after u start the car.
So if your car still runs well, dont worry about it.
Also I believe its alright to run 95, its not like your turboed it or high comped it rite? Maybe there would be slightly more pinging, but thats what the knock sensor is for.

[typerdevil]

i have fixed it , i re-wired it and it 's working fine now, thanks guys for all the advice and help , if it goes again i will buy another gauge with LED's etc, nah i'm preparing it for track by mid next year so, it's not turbo'ed, i'm doing it the N/A way, though it's going to burn a very big hole in my pocket but yeah

[aaronng]

unless you've got an aftermarket computer and/or are constantly tweaking with performance bits narrow-band a/f gauges are pretty much pointless.

I wouldn't be running a dc2r on anything but premium 98 octane. My ek4 fuel lid says only to use p.u.l.p - i would have thought b18c's would be the same...

p.u.l.p. = 95 ron.