Luke's Minibus 1st V6 24v cosworth now fitting a 2JZGTE

[dieselhead123]

Glad you got the chargecooler fitted mate, you won't regret it

See you, AND the van at Weald

TIM

[Luke]

we'll see Tim

next development - ive fitted the air fuel gauge and the needle bounces wildly - ive taken a video of it https://www.youtube.com/watch?v=JpLZorm ... e=youtu.be

ive never fitted one of these before and im not sure how they behave but i was expecting it to be a lot more stable

does anyone have any experience of these and think this may be a problem or confirm its normal

cheers

[limitedblack]

Looks normal according I this clip?

http://youtu.be/rw5TIty2TK4

[limitedblack]

Found this on the web, looks like this is a normal characteristic with an ECU controlled engine:

The stoichiometric (STOICH) air/fuel ratio is the chemically correct ratio, theoretically all of the oxygen and all of the fuel are consumed. The mixture is neither rich nor lean. However, due to the fact that combustion is never perfect in the real world, there will always be a small amount of oxygen left in the exhaust. This small amount that is left is what the oxygen sensor measures. The smaller the amount of oxygen that is left in the exhaust, the richer the A/F ratio is, and the higher the oxygen sensor voltage is. The on-board computer or Powertrain Control Module (PCM) monitors the voltage from the oxygen sensor. If the PCM sees an oxygen sensor voltage greater than .450V, it immediately starts to reduce the amount of fuel that is metered into the engine by reducing the on time to the fuel injectors. When this happens, the A/F ratio starts to go in the lean direction, and the oxygen sensor voltage starts to go down. When the voltage drops below .450V, the PCM immediately starts to increase the fuel metered to the engine by increasing the on time to the fuel injectors to produce a richer A/F ratio. This occurs until the oxygen sensor voltage goes above .450V. This repeating cycle happens very fast (many times per second). The PCM is said to be in closed loop. It is constantly monitoring the oxygen sensor voltage and adjusting the on time of the fuel injectors to maintain a stoichiometric A/F ratio. This A/F ratio produces the lowest harmful exhaust emissions, and allows the catalytic converter to operate at peak efficiency, therefore reducing the exhaust emissions further.

Since the oxygen sensor output is non-linear and very sensitive at the stoichiometric A/F ratio it will cause the A/F meter LED's to bounce back and forth rapidly. A very small change in A/F ratio causes a large change in oxygen sensor voltage as can be seen on the graph. This causes the A/F ratio meter LED's to rapidly cycle back and forth, and is normal operation when the PCM is in closed loop and trying to maintain a stoichiometric A/F ratio. The oxygen sensor is very accurate at indicating a stoichiometric A/F ratio. It is also very accurate at indicating an A/F ratio that is richer or leaner than stoichiometric. However it can not indicate what exactly the A/F ratio is in the rich and lean areas due to the fact that the oxygen sensor output changes with the oxygen sensor temperature and wear. As the sensor temperature increases, the voltage output will decrease for a given A/F ratio in the rich area, and increase in the lean area as shown on the graph.

During wide open throttle (throttle opening greater than 80% as indicated by the throttle position sensor) the A/F ratio will be forced rich by the PCM for maximum power. During this time the oxygen sensor outputs a voltage that corresponds to a rich A/F ratio. But the PCM ignores the oxygen sensor signal because it is not accurate for indicating exactly what the A/F ratio is in this range. The PCM is now in open loop, and relies on factory programmed maps to calculate what the on time of the fuel injectors should be to provide a rich A/F ratio for maximum power. The A/F ratio meter should indicate rich during this time.

During hard deceleration the PCM will command an extremely lean mixture for lowest exhaust emissions. This may cause the A/F ratio meter not to indicate anything. The A/F ratio is so lean that it is outside the range that the meter will indicate.

A bit of clarification on how they work and what they look like when they are working.

We get tons of calls, emails, and letters about what this gauge does and how it works, and what it is supposed to look like. In its simplest form, the gauge is a color coded voltmeter, which lights up the LED(s) that correspond to the voltage that the gauge is sent via its signal wire. On most late model vehicles, the sensors are quite sensitive, and capable of responding very fast to a change in A/F ratio. This makes it appear that the LED's flicker in the different ranges, and this is normal. The gauge is showing the voltage it is receiving from the sensor, so more often than not it will appear that more than one of the LED's are lit, or that the readings are being shown to be in more than one section. Provided the gauge is connected properly (good power and ground) and that the connection to the O2 sensor signal wire is SOLDERED, this operation is normal.

[g-man]

sounds a load of bollocks to me

[Luke]

Looks normal according I this clip?

http://youtu.be/rw5TIty2TK4

ive spoke to someone on the supra forum and they say its not normal - if you look at mine compaired to that one mine goes from rich to lean almost full scale that one stays in the stoich zone although it does move a lot

this could well be the problem all along

[limitedblack]

Could be, is your gauge analogue?

[limitedblack]

Is the lambda in the same place as the standard engine??

[Luke]

if you look at this one he's complaining it's all over the shop https://www.youtube.com/watch?v=PU6444T3U-E looks positively static compaired to mine

[Luke]

Could be, is your gauge analogue?

it takes a 0-1v signal from the sensor

Is the lambda in the same place as the standard engine??

no put not a million miles off - i had to have a custom exhaust on mine - originally the engine was on twin turbos and i have it on a single

what i think i will do next is try this gauge on my brother in laws supra TT then if the gauge is stable its my engine if its the same its the gauge

[Luke]

I've tried the gauge on the supra and it's exactly the same - so it's either a faulty gauge or not compatible with the stock oxygen sensor

so i'll try it on another o2 sensor next see how it behaves

i'm also looking at installing a fuel pressure gauge

[limitedblack]

I've tried the gauge on the supra and it's exactly the same - so it's either a faulty gauge or not compatible with the stock oxygen sensor

so i'll try it on another o2 sensor next see how it behaves

i'm also looking at installing a fuel pressure gauge

Well that's good news really, it looks like the engine is ok (ish).

[Luke]

i've ordered a fuel pressure gauge and a special banjo bolt with a 1/8" npt thread in the head of it so i can fit it direct onto the fuel rail, the gauge is electrical so i dont need to have a petrol feed direct to the dash they are from usa so just waiting for them to arrive now

[martynx]

There's an AEM Series One standalone plug & play Ecu on eBay at the mo. 600 squids.

[limitedblack]

There's an AEM Series One standalone plug & play Ecu on eBay at the mo. 600 squids.

Do these fit any engine Martyn ??

Guessing they do 3D injection and ignition???