ECU repair

[emmessegi]

hello to all users,

I have a problem with the ECU of an Esprit 2.0 Turbo (for the Italian market).
I should have the electronic control unit checked because there is no fuel in the cylinders.
Probably the MOS controlling the injectors are faulty.
Can anyone tell me who can control the control unit?

Thank you!

Marco

[Barrykearley]

Are you sure the fuel cut off switch hasn’t taken a knock?

[emmessegi]

Thanks for your answer. I need to check what you wrote to me. Another clue. The injectors have been overhauled. They have the correct impedance (I don't remember well if it is 4Ohm). With low impedance the control unit must deliver a lot of current to open the injectors. In fact, I have read that ECU failures are not uncommon.

[emmessegi]

the fuel pressure has been checked and it is ok.

[Bibs]

An ALDL cable and Freescan or Espritmon might be helpful here...

https://www.thelotusforums.com/forums/forum/85-ecufreescanespritmon/

[emmessegi]

using freescan i have these errors.

Canister has been removed from the previous owner

 

Edited February 9, 2022 by emmessegi

[Bibs]

Try Espritmon too, might give you a better idea on the Quad-Driver error. 

[sailorbob]

ECU failures are uncommon. Loss of both primary injector circuits is pretty rare but if the primary injector impedances are about 4 ohms then that is too high and will cause a problem.

[emmessegi]

I will also try Espritmon.
What is the correct impedance of the injectors?

[fjmuurling]

The correct impedance of the primary injectors is around 2.0 ohm, they are peak and hold injectors.

[emmessegi]

ok many thanks.

I check the impedance of the injectors again

[emmessegi]

 

update.

The injectors are ok.
The sw that I downloaded signals me these problems.
Flag 26 should be due to the vapor recovery which has been removed.
Is the 33 due to the high pressure sensor?
Can I carry out the test by exchanging the high pressure sensor with the one on the lower part?

 

Regards,

Marco

[sailorbob]

Error codes 26 and 33 should not affect the primary injector firing. Have you checked the injectors are getting voltage?

[emmessegi]

Hello sailorbob,

the injectors have the correct impedance.
The doubt is that the control unit (the driving part of the injectors) has some fault.
This is why I am looking for someone who can check it to see if everything is ok in terms of electronics.
Do you know anyone who can do this?

[sailorbob]

Have you checked the injectors are getting voltage?

[emmessegi]

The injectors have voltage, the engine starts.
The carburetion is lean, a clear symptom that the control unit is unable to drive the injectors.
Probably the power part of the ecu, the one that drives the injectors, is faulty.
So I'm looking for someone who can check and repair the ecu.

[sailorbob]

You are giving conflicting information about the problem; in your first post you said there was no fuel but now you are saying there is fuel but there is insufficient fuel delivery and this is causing a lean condition.

It is almost unheard of for an injector driver to partially fail so, if it were me, I would check the fuel pressure next.

[emmessegi]

It can happen that a person expresses himself poorly.
Summarizing the engine starts but, when you push a little, the carburetion is lean.
The injectors are ok, the pump too.
If you do a couple of maths (12V battery and 2 Ohm impedance of the injectors) you can understand that the ECU must deliver 6A for each injector to open them completely (there are 6 injectors in total, 1 for each cylinder and 2 on the manifolds).
The current is not low and over time it may happen that the power part of the control unit suffers and is unable to deliver all the required current.
Result the carburetion is lean only in certain conditions.
It will be a coincidence but the low impedance injectors, on modern cars, are no longer used.
My problem is to find someone who is competent in verifying the ecu and its eventual repair.

[Chillidoggy]

If you’re convinced your ECU is faulty, just buy another one. 
 

https://www.rockauto.com/en/catalog/oldsmobile,1991,cutlass+supreme,2.3l+l4,1223165,electrical,engine+control+module+(ecm+computer),2896

[emmessegi]

Thanks for link.

The engine is 2.0 for the Italian market.

[Chillidoggy]

https://www.pnmparts.co.uk/lotus-ecu-fix

[fjmuurling]

3 hours ago, emmessegi said:

The engine is 2.0 for the Italian market

The ECU's for the various esprit models are the same, it is the MEMCAL (which contains the calibration for the specific engine) inside the ECU which is different. If you buy a new (remanufactured) ECU then you have to take out the MEMCAL from the old and put it into the new ECU.

4 hours ago, emmessegi said:

The injectors are ok, the pump too

Spray pattern OK? filters inside the injectors OK? What is the fuel pressure at the fuel regulator?

4 hours ago, emmessegi said:

If you do a couple of maths (12V battery and 2 Ohm impedance of the injectors) you can understand that the ECU must deliver 6A for each injector to open them completely (there are 6 injectors in total, 1 for each cylinder and 2 on the manifolds).
The current is not low and over time it may happen that the power part of the control unit suffers and is unable to deliver all the required current.

Above is not correct.

Yes there are 6 injectors, 4 primary ones and 2 secondary ones and they are not the same.

• The primary injectors are peak and hold (low impedance, around 2 ohm). One for each cylinder. They are driven in pairs (1 &4) and (2 & 3). Each pair is driven by a single MOSFET in the ECU. When they are commanded to open a "high" current is used (for quick opening), however the current is measured and after opening of the injectors the current is regulated down to a much lower value by the ECU in order to keep them open for the desired length of time (right amount of fuel).
• The secondary injectors are high impedance injectors (around 14 ohms). They are also driven as a pair. They are driven by 2 (out of 4) outputs of one of the QUAD drivers. These injectors only come into play in the high power regions.

 

For injection of the right amount of fuel the ECU relies on information from the outside.

As the car is starting (idling) it looks like the ECU is doing its job, but relies on information from the outside. If that is wrong then...........................................

You seem to have an error 33 (MAP voltage) so fix / investigate this one. (check cabling etc).

Also make sure that the fuel system (pressure, filter etc is well into spec).

Reconnect the solenoid of the CCP back, see if the error 26 goes away. (BTW the descriptions in Freescan of error 26 are wrong).

 

5 hours ago, emmessegi said:

Summarizing the engine starts but, when you push a little, the carburetion is lean.

 This can also happen if the lambda sensor is not OK. (among other things)

 

[emmessegi]

thanks for the info