JAM Ecu Info needed

[richardc9052]

Right i have been told by someone that they where advised by their tuner that the jam ecu needs the car to have a lambda connected as it uses the lambda readings constantly. so effectively never goes into open loop.

I call bullshit but the guy says his car now runs like crap on boost when it should be in open loop.. (the guys decat cracked and the bung for the lambda and the sensor fell out and lost on the road)

Now from the information ive gathered 02/lambda sensors become inaccurate when aiming for anything over or below stoich and dont react quick enough for this to be true.

Please tell me im wrong because then ill need to understand why lol

Edited June 9, 2014 by richardc9052

[Whitenoize]

See tbh dude when I ran a plug and play my lambda was loose and my car ran like shit

Edited June 9, 2014 by Whitenoize

[richardc9052]

When though? down low and cruising i can understand as that how any ecu would react as run rich because they are in open loop without the lambda but up high and on boost i cant understand..

[Whitenoize]

It was more on start up low revs ran like shit didn't want to boost I get what your saying would prob be the same on any ecu.. I don't know the ins and outs but how would you even run no lambda without a full standalone y would you want to run no lambda with a plug and play?

[richardc9052]

I wasnt running a lambda until i plumbed in my widebands 0-1v feed to the ecu. Your ecu doesnt use the lambda once you put your foot down in a normal ecu as it enters open loop and doesnt need to hit 14.7afr

[Whitenoize]

See mate you obviously know a lot more than me I just thought that a lambda reads afr plug and plays arnt really anything special expensive fcd and rrfpr basically a standard ecu with extra features imbedded in them if they dont get an afr signal sent back to the ecu would they not run like shit? I'm prob talking a load of balls haha that just how I thought it worked

Edited June 9, 2014 by Whitenoize

[richardc9052]

Basically yeah. If you google Open loop vs Closed loop ECU you will find loads of stuff on it and youll understand how they work a lot better.. still loads that you cant find on google but thats why im asking here lol

You should deffo look it up. its really handy to know

[Whitenoize]

So was I compleatly wrong and talking shit haha? Cheers for the advice dude will look into that always like to learn new stuff

[richardc9052]

no you werent. in a way they do but only under certain circumstances. its too late for me to explain though hahaha

Yeah me too. i could spend hours reading random stuff haha

[Stu]

Just remember the narrow band sensor only tells the ecu that its either rich or lean side of stoich (14.7), but not how rich or how lean. That's why its not much help for tuning but can be useful for cruise map adjustments.

[richardc9052]

Actually it can be used for more than that but its not very accurate if you do.. it is a 0-1v sensor and it is variable. not just a 3 way switch to say lean.good.rich

You can harness it to aim for a different afr if you have a piggyback you can use it as the load and aim for 11.0 and add or subtract fuel depending on which way it goes...

[gorganl2000]

what i can tell you is that from my experience the stock ecu needs to have the o2 sensor connected or else the car will run very poorly (felt sluggish/hesitant and just not a smooth drive)---happened to me when the o2 wire connector was off accidentally

and seeing that the JAM ecu (and other Plug and play ecus) are basically modified stock ecus, then i suspect the same "crap" operation will happen if the o2 sensor is not connected. the stock ecu uses it for some of its functions as outlined above

i'm not sure, but try a diagnostic with it disconnected and see if a code shows up

[richardc9052]

Of course a code will show up.. the car is missing the o2 sensor.. your missing the point entirely. the standard ecu used the lambda sensor but ONLY and cruise/low throttle. after that it goes into open loop and does not use the sensor any more.. SO if you unplug the lambda it will run crappy because its supposed to be in closed loop but cant so it runs rich and off the open loop map. Once you floor it though it will run the same as usual because it doesnt need the lambda for that.

And yes i know that the p&p ecu's are modified standard ecus. the take some of the readings fromt he standard chip but others are directly re-routed to the tuners chip, which then feeds all its info into a decryption chip which then tells the engine what to do.

What i want to know is if the tuner that told my mate this is full of shit. I think he is, but who am i to question him??

He said that the jam ecu uses the o2 sensor all the way through the rpm range and that without the lambda plugged in (it got ripped off as above) he should be careful and not boost etc because his engine will fail somehow..

Id love to have a jam ecu and a wideband soo i could unplug my lambda and show that the afrs are the same when in open loop but i dont have one, so i cant..

i know how the standard ecu runs without a lambda down low. ive done it many times. I also know how they run in open loop without a lambda and i understand, for the most part how it works and why, which is what is causing me to argue the tuner is full of shit.

Any other input here? if he is right please show me proof and if you know he isnt i also would like to see proof so i can show them.