Testing Injectors

[hcmini1989 16]

right ive had my car running now for a couple of days on megasquirt.had it started the other morning and it cut out .i noticed it had a fuel leak from top of the fuel filter so i sorted that .and still wouldnt start so i put some fuel in and it poped into life for a brief couple of seconds .now it wont go its sparking ok allso tested the coil .that came back ok .

 

checked all the wiring that all looks ok and all the sensors are working ok cps, clt ,air temp.

 

so i moved onto the injectors tested the resistance and there reading 0 ohms now from what i can find they should read 15 ohms .is this right is it possible ive knackerd all my injectors there mi16 yellow ones .

 

ive set them up so they were high impedence and 217 cc

[Tom Fenton 1,548]

And this is why you buy an Emerald or DTA and not a Megasquirt. Here endeth the lesson.

 

Regarding your injectors it sounds quite possible that they are fcuked. Try connecting a earth and 12v to one, it should make a feint click when you connect to indicate its working. They are usually very reliable, I've certainly never had one that didn't work, but that is with a standard ECU or Emerald/DTA/Omex.

[DrSarty 90 1 Cars]

I agree with Tom 99.999%. I think MS still has a place, but there is only one way to get it done right, and that's the way we go about things with the other ECUs he's mentioned.

 

Anyway: I'm no electronics guru, but 0ohms is an open circuit, i.e. the 2 pins you are testing are simply not connected at all. If all of your injectors read 0ohms then either you are measuring something wrong or you have miraculously fried 4 injectors. The latter I struggle to believe is possible!

 

They have a coil inside (in simple terms) and that, just like any item, or even a length of wire between 2 pins has a resistance, so you must get some reading. Something's not right.

 

To test this logic, go test an injector on a known working car the same way. If that comes up as 0ohms too then I suspect your measuring technique is at fault.

 

Good luck solving this, but I suggest we know what we're working with first before we try and help.

 

But yet again, this is another case of the Megasquirt route being riddled with pot-holes, and when it doesn't work, trying to rectify the problem over the interweb becomes a depressing affair.

Edited December 23, 2009 by DrSarty

[hcmini1989 16]

ok cheers for the help i tried it on some old injectors wich were working when removed and there reading 0 ohms aswell so ill have to boroow another meter and try them again.

[pugpete1108 62 1 Cars]

have you tested all four injectors? there should be +10 ohms at least. assuming they are high impedance ones? did you check them before setting them up as high impedance? green gti6 ones are but im not sure on mi16 ones?

 

have you got a switching voltage at the injectors?

 

tis' true ms is a nighmare to get right, but there are alot of sucess stories so it cant be all bad (he says trying to convince himself )

 

i have finally managed to get mine starting and idling everytime, even cold, which is almost triumph in my book

 

stick with it liam, best thing is to take a break and go back to it otherwise its gets really frustrating.