I have had an old Blitz Dual Solenoid SBC fitted for a couple of years now and it has been 100% reliable. I have set it up with 4 different settings from mild to wild and it works perfectly. Being an old model it has the two wire dual solenoid and only allows one level of gain across the 4 channels although the boost 'set' is variable.

Recently had a chance to get a second hand Blitz SBC iD which has the meter/display and the ability to have variable gain and set on each channel.

I fitted it over the weekend and as I had previously fitted the old one it didn't take too long. All the hoses are tight and the electrical connections fine too. However, dispite having set it up with 4 different settings (similar to the old unit), the boost and rate of boost are the same whichever channel I'm on or indeed if I turn it to 'off'!

I get to 0.95 bar boost with every channel and every gear ( base boost). I know I have the hoses on the right way round as they were that way round on the old unit. I therefore think that the solenoid unit is not working!

I can take it apart but how and what do I test? I can't substitute it for the old solenoid which does work as that is a two wire type and the iD has a three wire loom. The solenoid is obviously the key component and very expensive to replace. Any ideas?

Update:

In attempting to take the cover off the solenoid it is apparent that Blitz prefer the use of painted mild steel bolts and both of the solenoids units from the old Dual SBC and the newer iD unit had bolts which were rusted and seized in. Using 1.5mm drill bit(s)- broken three doing it!- I drilled out all the cover bolts to reveal the working parts inside.

Applying a 12v power source to the solenoid terminals both the old and new solenoid units responded with positive 'clicks' on both units. So both the original Dual SBC (known to work) and the SBC iD (not working) have operational solenoids if 12v is applied. Interestingly the difference between the 2 wire and 3 wire versions is simply seperate wiring to each of the dual units (3 wire) and parallel wiring to the units (2 wire). Therefore the iD unit must alternate between the solenoids whilst the Dual SBC operates both simultaneously.

Whilst they were lying in pieces on my bench I refettled the casework with black satin paint and cleaned out the airways (both were not really mucky though) and then put 316 grade stainless bolts and copper greased the threads in case there is a need to maintain these again. Both are now re-tested and work as they should.

I have also tested them connected to the Blitz loom through the bulkhead so I know that they will operate all the way back to the interface with the Blitz iD control unit. I have yet to road test it yet but it seems to me that in order to work the solenoid should be in the shut position untill the boost pressure is measured to be higher than the set ratio i.e. say 1.35 bar; at which time the solenoids will be activated in pulses to pass air through to the wastegate to maintain the set pressure. However, the units are open in their normal state. So with the unit switched on the solenoids are not operational and air can move freely between in and out- so from turbo to wastegate.

So, I have the iD unit set up with 4 levels of boost and differing levels of gain across each channel. As I said before, on the road, there is absolutely no difference between any of the 4 channels or indeed with the iD in the 'OFF' position; at all times it relies purely on the wastegate to open.

Therefore my dilemma is:-

1. Is it me? Am I not doing something obvious? Whilst the operational manual from Blitz is fine in telling you how to set up the unit it really doesn't tell you HOW to use it on the road! Anybody help there?

2. Is it the control unit? The display works OK and it seems to be measuring the boost levels (compatable with my boost gauge in the car) so if it knows the pressures how can I test to see if it sending controls down the loom to the solenoid?

3.Why doesn't the unit work with power on to the solenoids (i.e. closed) until there is sufficent pressure built up and measured to send controls to release the solenoids?

Before I revert to the old Dual SBC unit (which was working fine and hopefully would again!!!) can anyone suggest what to do with the iD unit? I know some of the "Wise Men" out there have these units and seem to rate them highly- can you help?