...it seems the injectors don't want to get out of bed and throw some fuel in ..

I have modified a standard loom using the neccessary resistors, it cranks over, has fuel travelling through the rail, and have great spark but plugs are as dry as the sahara ...

Does anyone have any suggestions as to what the crucial input to the standard ECU is to signal injectors to work..... I've been studying the wiring diagram all day to double check that all ECU cables are correctly connected (which they area) and i've have now started to strip the loom sheathing to look for any other possible faults.... Myd

Just a thought

Have you checked continuity between the correct pins on the ECU plug and the Injector connectors ?

Set of Noid lights would help to see if the ECU was pulsing the injectors correctly aswell, if you could get hold of a set..

quote:

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Originally posted by perksy
Just a thought

Have you checked continuity between the correct pins on the ECU plug and the Injector connectors ?

Set of Noid lights would help to see if the ECU was pulsing the injectors correctly aswell, if you could get hold of a set..

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Noid Lights

http://cgi.ebay.co.uk/noid-light-electronic-fuel-injection-tester-inc-vat-/370398646264?cmd=ViewItem&pt=LH_DefaultDomain_3&hash=item563d7acff8

Sorry,Not too sure if they do a Bike engine version or not though

Hello Myd,


Gary Evans site may have an answer for you if you do not get one here.

http://azbiketech.yuku.com/directory


Read here


http://azbiketech.yuku.com/topic/492/t/Fuel-Injector-Circuits-and-Drivers.html





Is there anything showing in the harness when your cranking it over ?

There should be current in the harness to the injectors.

My Saabs injectors are live and when the ecu grounds each injector out, the spring closes the injector.


Is the ecu earthed ?

Is it getting all the sensor inputs , otherwise it cannot work out the fuelling.


ct/cps/tps/map and so on, I dont know Busa there is bound to be more.


Is your battery ok , Saab ecu doesnt like less than 11.5 volts or it wont play.


Good luck.


Ps The Fiat build is kicking off this week.



Ivan

[Edited on 18/7/10 by T66]

Are you running a fuel return?

Do you have sufficient pressure at the injectors?

Are you running a pressure regulator?

Injectors are wired with an ignition live supply to each and the ecu 'fires' each one by switching it's earth 'on' for a mapped time.
You say you have the necessary resistors. I think Busa uses high impedance ?12-15ohms injectors and doesn't need resistors unless you have fitted low impedance (3ohms) ones. Put the multi meter across an injector and measure the resistance to see if resistors are needed. I may be wrong.
If you have spark then the ecu is seeing the crank sensor and switching the coil earth so should be switching the injector earths too!

Right I've done this myself so check that you have the fuel flow and return hoses on the correct end of the fuel rail.
If you put them on the wrong ends the regulator will stop the fuel getting to the injectors.

Thanks to you all for your valuable input, i've taken it all in to account and this is the current state of play as of this evening:

Connected multimeter to Injector harness plug and no resistance recorded when either battery connected, ignition on or cranking over;

Also, connected a single LED to injector plug harness for all above and nothing;

I have continuity in all cables within the harness - from ECU to end outputs. The only resistors in place are a 100ohm between common ground and Orng/Yell to ECU; The other is a 6.4k ohm between one Blk to Blk/Brown (both to ECU)

I have modified the standard loom to a tried and tested spec.

I have also tried another ECU and Rectifier to no avail.

I have modified the fuel rail to have a -6 JIC entry on one end and same on opposite end connected to a quality SYTEC race fuel pressure regulator, fuel is travelling through via a low pressr fuel pump to swirl pot then a SYTEC HP FI pump.

Battery is a brand new Varley Red Top 30, fully charged.

The mystery goes on.....

quote:

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The only resistors in place are a 100ohm between common ground and Orng/Yell to ECU

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It's alive.....!!! yes, it has finally fired up.

I managed to obtain a 32 Bit ECU Pin diagram late last night only to find i had not properly connected one cable which on my original drawing showed it going to Earth when according to my new drawing in needed a + supply..... fingers crossed its now sorted.... ..........not bad for 20p worth of Resistors and a Saturday cutting down a stock loom.

Thanks for all the help all, it certainly gets you thinking laterally

Nice one !


So where are the pictures.

Here are some... linkies ok?













Myd

looks great!