injector volatge

how many volt, is needed for xj injector to work?

thanks
Emil

As I recall, pretty much all automotive injectors take a pulsed +12VDC signal.

However, if you tell us what year your XJ happens to be, we can tell you better. There are three basic control systems - RENIX (1987-1990,) HO/OBD-I (1991-1995,) and HO/OBD-II (1996-2001.)

Granted, they all use the same injectors - or can - but if you are going to ask technical questions, you should consider this a critical datum to include with your posts and questions, since it will save us having to ask.

Welcome aboard! Seems our circle is ever widening...

5-90

Re: injector voltage

it's 96 xj HO with automatic trans

Yeh - you should see pulsed +12VDC at the injectors. If you want to test the injector coil proper, you should measure about 16 ohms (+/- 15% or so) with a decent ohmmeter.

If you find you need replacements, it is common to get a set of Ford 5.0 fuel injectors (or equvalent) and use those - it gets you two spare injectors and the V8 set costs, oddly enough, about half as much as spec'd 4.0 fuel injectors.

5-90

I have a set of 99 WJ 4.0 injectors that I was going to install along with the 99+ style intake manifold... I pulled out my $3.00 multimeter and I was getting an average of 12.8 ohms on all of them, none were above 13, and none under 12.5, now you say they should measure at 16ohms, does that mean my injectors are bad or just my $3.00 multimeter sucks??

Thanks
Chris

In my experience with a bad wiring harness, it seems that the injectors need just about all of those 12 volts to fire correctly. A drop of 2 or more volts will probably stop the injector from opening even if the harness lights a 'noid light or injector tester.

bzdel2441 said:

I have a set of 99 WJ 4.0 injectors that I was going to install along with the 99+ style intake manifold... I pulled out my $3.00 multimeter and I was getting an average of 12.8 ohms on all of them, none were above 13, and none under 12.5, now you say they should measure at 16ohms, does that mean my injectors are bad or just my $3.00 multimeter sucks??

Thanks
Chris

Click to expand...

Your meter probably just sucks. Don't get too hung-up about "exact" numbers with regard to electronics. There's always some variation between any meter and circuits but the important thing is that you are in the ballpark and all of the injectors are close to the same resistance measurement with your meter.

Are you having issues? The '96 should throw codes and any parts store can retrieve them for free.