LH2.2 tweaking diary

[alfaromeo]

How much power do you have in. that x19?

[lookforjoe]

How much power do you have in. that x19?

I don't know - significantly more than stock. I will be taking it to the dyno once I have the idle/surge issue resolved.

[lookforjoe]

The one niggling problem I have had since adding the EZK ignition back in October, was a idle surge when warm. If I stepped on the brake, put it in reverse, turned on the lights, etc., it would cause the idle rpm to surge. I tried isolating the switched power supply to the LH ECU, and then the supply to the EZK edu & the power stage, and it still did it once warm. What I finally found, was that the circuit that was used to feed the coil is also used for way too much other crap, so the voltage drops below 13.5 at 850rpm idle speed, this clearly effects the coil and subsequently the ignition system, causing the surge.

So, the last thing I need to do is relocate the switched supply to the coil to a dedicated supply not tied to other current -consuming devices.

I also received another 514 ECU, so I can try the Saab MAF/ ECU combo again on Monday. I would like to tweak a few settings, even though it runs really well as is.

[lookforjoe]

Fixed the current supply issue.

Problem I have with the Saab 514 ECU is that it is supplying over 9v at the idle offset line, and is holding the filament in burn off mode. I've tried two different MAF's and two different ECUs, same issue. There must be a difference in the wiring between SAAB/Volvo LH2.2, I can't figure out any other explanation.

[lookforjoe]

Found the problem, after looking at Volvo LH2.2 (plastic case MAF), LH II wiring (metal case MAF) and Porsche 928 LH2.2 schematics. Couldn't find a frikkin Saab Wiring Diagram anywhere.

Volvo LH2.2......Volvo LH II......Porsche LH2.2
MAF.................MAF................MAF
1 - (-)..............1 - ECU 8.........1 - ECU 8
2 - ECU 6........2 - ECU 9 (+)
3 - ECU 7........3 - ECU 6.........3 - ECU 6
4 - ECU 8........4 - (-)
5 - ECU 9(+)...5 - ECU 7.........5 - ECU 7
6 - ECU 14......6 - ECU 14.......6 - ECU 14

So, the (Saab) ECU is held in burnoff mode when connected to the harness configured for the Volvo LH2.2 - I witnessed this when I connected the new replacement MAF. Hopefully I didn't toast another MAF. I'll add a 'pigtail' with the MAF connector in Saab configuration, so I can switch between the two setups (Volvo/Saab).

[lookforjoe]

Got the car running with the 514 ECU, with a chip flashed with the Volvo 554 bin, and the 005 MAF. Added a 12v feed to pin 4, and removed the grounds used by Volvo for pins 14 & 19 at the ECU. Now I need to figure out how to get rid of the rev limit. I already set the limit to the max setting in the bin, and it still cuts out at around 6K rpm.