ECU Error codes

[TiddlesRX7]

Hi all. I\'ve just pulled the ECU error code off my car. I\'ve been having problems with the idle again this week, and after Rotorstock I found out just how bad it was overfueling hence error code check time. Anyway the codes were as follows

13/ Pressure sensor (intake manifold pressure) fixed @29.9 inHg
17/ Feedback system (possible o2 sensor) feed cancelled
34/ Solenoid, BAC valve

So 17 could be the o2 sensor (Lambda sensor in English?) could be contributing to the overfueling situation. 34 solenoid, BAC valve could be causing the lumpy idle. But what the hell does the code 13 effect? anyone know?

[TiddlesRX7]

Although I was loosing boost on the dyno. Something like 14psi down to around 5psi. maybe thats related to it.

[Prof]

The lambda sensor on the FC only does cruise and low boost tuning - running the ECU in closed loop - once you boot it hard, the lambda can\'t keep up anyway, so the ecu goes to fixed maps using the MAP sensor and MAF / temp sensors to sort out fuelling.
 
The BAC solenoid is used to control stable idle when loads are placed on the engine, like power steering, air con, lights, heating - so again once you are under any kind of boost, the BAC isn\'t really doing anything.
 
The worrying one is the MAP sensor - the code 13.  If it\'s fixing pressure at a set value, and you are running higher boost - then the engine will run lean - which will explain your dyno figures.
 
The BAC error code may be the cause of your rough idle

[TiddlesRX7]

It\'s running rich though not lean. Hmmm its all very confusing isn\'t it! So the MAP sensor is the pressure sensor. I take it the easiest fix is to swap it with another one. Looks like a trip up to my spare car. What do you mean by fixing pressure at a set value?

[Prof]

It\'s running rich though not lean. Hmmm its all very confusing isn\'t it! So the MAP sensor is the pressure sensor. I take it the easiest fix is to swap it with another one. Looks like a trip up to my spare car. What do you mean by fixing pressure at a set value?

It\'s running lean under boost - that\'s what your dyno sheet was saying.  If the ECU thinks the MAP sensor is faulty, it will assume a set pressure, and fuel accordingly - if the car is making more boost than that, then there is more air than fuel - hence lean.
 
It may well be running rich on idle - there\'s any number of reasons for that - aftermarket fuel pump, pressure regulator set wrong or seeing air pressure not vacuum on idle...

[TiddlesRX7]

I get a good vacuum on idle. I\'m new to all these graph data sheets but I thought it was running rich pretty much all the way through. I know it drops off when the boost kicks in but I thought it was still above what it should be. At least that is what I was led to believe. I take it that advice was wrong?

[Prof]

You need to compare the graphs of boost versus AFR - from what I remember - and there was a thread on here about it - the AFR\'s are close to 14 when you are running about 0.9 BAR boost - which is VERY lean.  It should be below 12/11 ideally.  It\'s ok to be about 14.7 on cruise - it will be rich on idle as all rotary\'s are.

[TiddlesRX7]

Ah right I see. I think! I really need to get these faults sorted pronto and get a air/fuel controller of some sort. Then all will be good.

[pdtaylor18]

One on ebay for £250 !!   spoke to the chap and he will not budge on price. I ideally need one to go with the rest of my setup but would much rather put that sort of money into a apexi and sell the other HKS bits I have already.