Fuel injector connector voltage question ?

Technical Area Engine, Transmission, Exhaust etc
2

Hi all,

Today i changed fuel filter and air filter  and car still not firing. Checked again i have spark at all four plugs just no fuel getting through injectors ?

Checked with a screwdriver onto injector body and cannot hear any audible clicking ???

I have put a voltmeter across connector  injectors and am getting a slight kick with meter on 250 v DC, then moved dial to 5v DC expecting a big kick ?? but the needle just went about a 5th of the way across the scale ? i’d guess that’s about 1v ? but can’t be sure ?

I think i have gone about as far as i can now and am totally baffled. Really need verification on the voltage that should be present at the injector connectors until then i am stumped as to why she is not getting fuel.

So far i have changed 

Plugs / both fuel relays / fuel pump (now working) / fuel filter / air filter

Fuel present at 2 rubber hoses that go into fuel injectors but fuel not getting past injectors ???  Dont know if this is electrical or fuel injectors blocked ???

Any help much appreciated

Thanks again Paul

3

Well a big thanks to Muppet here for giving me that very comprehensive workshop manual Big Smile 

After reading very carfully how to fault diagnose the injectors i was putting my voltmeter across the wrong points Embarassed.

The positive needed to go on the r/w (red/white) wire and the negative to ground. I set the voltmeter to 250DC and got a reading  very difficult to verify the excact voltage  on that scale so i put the voltmeter on 5v DC scale and “bingo” the needle flew across as soon as i found a good earthing point Big Smile

I cannot cerify the excact voltage  but am now sure it is the injectors !

Thanks again for all your help i will keep you posted.

Paul

4

She’s running !!!

A little tap on the “Fuel Regulator” and i heard a splutter Big Smile … A few more taps and she sounded like she was firing on 3 cylinders. A couple of trips around the block and she sounds sooo much better.

Still plenty of work to do but i am over the moon Big Smile

thanks again all

Paul

5

Unfortunately it’s not quite that simple. The injectors get a 12v supply via the fuel injection relay, so , when the ignition is on you should get 12v on one side of the injectors. The way it works is that, in order to ‘open’ the injector the ECU will ‘pull’ the other side of the injector to ground, so, when the engine is not turning, you should have 12v on both sides of the injector with respect to earth. Problems occur when either the 12v feed to the injectors is lost, or the ground for the ECU is interrupted. One easy check is to take apart and  clean the earth connections underneath the wiper motor, as this is one of the main earths for the ECU. To do this properly you need to undo the bolt to the body, and dismantle and clean the multiway spade connector.

Good Luck

 

6

Thanks ralphf crikey ! this has already turned into a full time hobby Big Smile

Well i did want a “Little project” {#emotions_dlg.indif} 

Another one to add to the list then Wink

Cheers

Paul