Volvo 480 Club Europe

Short intro,
I'm driving a 1990 480 turbo, with an orange labelled ECU.

For two weeks, I bought a second hand tuned ECU.
It worked fabulous!

But...

A couple of days ago, I drove back from work and all of a sudden, the boost wouldn't go up towards the 'red area' anymore.

I was affraid i'd trashed the Turbo or someting, but, when I changed the ECU for the original ECU, the problem was gone!
The turbo pressure is higher with the orignal ECU, compared to the tuned one...

So everytime I drive my car, the turbo pressure boosts up, only once (and even then not to the max). After that, it will go up for about 2/3 of the maximum. So I thought, that the ECU is in some sort of protect mode.

A bit strange, cause it all worked fine when I installed it at first and it (turbo pressure) still works fine with the original ECU.

Could someone tell me what is going wrong? Or give me a clue where to start with?

Thanks,

Greets, Thijs

who tuned the ecu?

lee wrote:who tuned the ecu?

Well, that's something I dont know (yet?)
I already contacted the previous owner, but did not get an answer so far.

I believed it was BBF that describes a similiar problem when he did the R207 mod (search the forum, you mod the air pressure signal).

Does it helps to reset the modded ECU by disconnecting the battery ?

Well, when I restart the engine, the boost will go up one time again. So it seems it 'resets' itself every time I stop the engine.

When I accelerate in second gear, the boost is ok, till the engine reaches about 4500 rpm, then the pressure drops to a certain value and the 'fun' is gone...

It will probably be a Rica chip, you can consult them. They do know a thing or so of tuning ECU's.

Does it matter if you floor it with full throttle?
If it only occurs @ half throttle it could be your lambda sensor.

Ettore Bugatti wrote:It will probably be a Rica chip, you can consult them. They do know a thing or so of tuning ECU's.

Does it matter if you floor it with full throttle?
If it only occurs @ half throttle it could be your lambda sensor.

In an earlier stage, before I bought this ECU, I contacted RICA and they told me they did not tune orange labelled ECU's, only the ones with the double print inside.
So I think it is not likely to be that RICA tuned the ECU.

Concerning the lambda sonde, the original ECU works fine. If the sonde is broken, the original ECU should also give problems, or is that 'to straight forward'?

Hmm, that is correct thinking I assume.

The EZK can cut boost when it sees problems. You only have to find out what it sees as a problem.
Boost, knock are two phenoma, but it can detect more.

Hi

I had this same problem with 2 different cars. First one was with Richmodded ecu and later with standard ecu. The problem is inside the ECU but i dont know what kind of problem is it. Richard fixed the first ecu i had. Maybe he can tell more.

Ettore Bugatti wrote:Hmm, that is correct thinking I assume.

The EZK can cut boost when it sees problems. You only have to find out what it sees as a problem.
Boost, knock are two phenoma, but it can detect more.

Boost spikes (iffy hoses on the boost control valve, or broken valve), throttle position sensor, dodgy temperature sensor wiring or sensor, knock sensor done up too tight, air leak (if one of my ecus, load signal is out of spec for boost pressure), leak between manifold and ECU (or pipe to boost gauge) failed recurculationg valve on turbo and failed, or iffy MAF.

Try unpluging all sensors and replugging, this cleans the contacts, same with both ECUs including the fuel one, particularly if the car has leaked at all.

Think that about covers it.

Richard

Ok, I'll try to clean the contacts first.

I also found, that one of the pipes on the EVAP system is missing... Could that be causing some problems? It's making a sissing noise, so I presume it's connected to the inlet manifold.
I'll try to fix it in the weekend...

Still thinking it's strange when everything works fine with the original ecu...
I mean, when a sensor is broken / dodgy or something in between, it shouldn't work with the original ecu should it?
Or are the sensors more severe loaded (don't know how to put this in 'proper' English...) with the tuned ecu?

Other question (just curiosity):
How does the ECU measure (calculate?) the load?

t_w wrote: Still thinking it's strange when everything works fine with the original ecu...
I mean, when a sensor is broken / dodgy or something in between, it shouldn't work with the original ecu should it?
Or are the sensors more severe loaded (don't know how to put this in 'proper' English...) with the tuned ecu?

rpruen wrote: load signal is out of spec for boost pressure

t_w wrote:Other question (just curiosity):
How does the ECU measure (calculate?) the load?

It is based on the MAP signal. Although MAF and rpm do play a role. The ECU calculates/ looks up in a table what the appropiate timing, fuel and boost should be.
That's the short version

t_w wrote:Still thinking it's strange when everything works fine with the original ecu...
I mean, when a sensor is broken / dodgy or something in between, it shouldn't work with the original ecu should it?
Or are the sensors more severe loaded (don't know how to put this in 'proper' English...) with the tuned ecu?

The airflow, and boost pressure are both higher for the tuned ECU, so yes the extra load could drive something towards failure, where the normal ECU would not.

t_w wrote: Other question (just curiosity):
How does the ECU measure (calculate?) the load?

Ok.... Not easy to answer simply but I will try.

First off, there are two ECUs (that comunicate with each other)

Fuel ECU

The Fuel ECU measures the airflow (via the MAF), and that gives it enough info to supply the right fuel to go with the air. It uses the RPM signal to time the injection pulses. There are other sensors, but these are just used to fine tune the fuel mixture for operating conditions (i.e. cold start, acceleration)

The fuel ECU has two major inputs, airflow (from the MAF) and RPM (from the ignition ECU). It also has engine temperature, throttle closed (idle), and two further inputs from the ignition ecu (Acceleration and Enrichment).

The Fuel ECU is quite 'stupid' and apart from oxygen control (closed loop), and idle speed control (sometimes), it doesn't do much other than look up in a table to see how much to open the injectors given particular airflow reading. There is some 3D maping, but not much. Most 'maps' are 2D.

Temperature compensation for a cold engine is based on temperature and RPM only.... etc.... etc

The fuel ECU has only two major outputs, the injector pulse, and load signal to the ignition ECU. Ok so it switches on the fuel pump and stuff, but that is just some logic.

Ignition ECU

The ingition/boost ECU is the brains of the outfit. It drives the fuel ECU enrichment and aceleration inputs, as well as mapping ignition timing to load.

The ignition ECU has for the time an advanced processor, that is capable of keeping track of a lot more information than the fuel ECU. It has for the time a lot of internal RAM, and (EP)ROM. Even with the ECUs fitted with an external EPROM, most of the program is in fact stored internaly. Only the MAP data, and some interupt routines are stored on the EPROM.

The ignition ECU is able to calculate the aprox torque output from the airflow (load signal from Fuel ECU), and internal tables. It can then adjust the boost to give the desired output (the torque request comes from the throttle position sensor). The manifold pressure also changes the ignition timing, as does the load signal.

The ignition ECU also uses the knock sensor to vary the timing for each cylinder, creating a per cylinder 'map' in it's internal memory. The ECU can both retard and advance the timing for each cylinder within set limits. Knock is controlled first by retarding the timing, and then by adding extra fuel (acceleration and enrichment signals to the fuel ECU), and eventualy by reducing boost pressure.

The ECU will addapt to the fuel octane rating (low), and will try to maintain performance by retarding ingition timing, but increasing boost and fuel enrichment. If a high octane rating fuel is used, the ECU will advance timing and reduce boost, as well as keeping enrichment low, leading to greater efficiency.

The ignition ECU has the following major inputs... Crank position (from crank position sensor) and thus RPM also, Load (from fuel ECU airflow), Load from MAP sensor, Engine temperature, throttle position and Knock sensor.

These are the outputs.... Coil firing signal, RPM to Fuel ECU, Enrichment, Aceleration, PWM to boost control and the diagnostic output.

Hope that helps!

Richard

Thanks for the explaination!

wow!
nice explanation!
Is this for LH2.2 or LH2.4? what are the differences?

bbf wrote:wow!
nice explanation!
Is this for LH2.2 or LH2.4? what are the differences?

The 480 ecus are not exactly like any other LH system, the Porshe 928 is the only other car I know of with these ECUs (they are clearly not identical, but near enough to use the same diagnostic gear from Bosch)

The fuel ECU is more or less LH2.2, heading for LH2.3, the EZ210K (ignition ECU) is not quite like anything else, apart from the Porsche, ours with boost control (the K for kompressor?)

Hope that helps

Richard