Dustin Dove

Ok from the top things I have done so far. New fuel pump, new fuel pressure regulator, cleaned grounds on dipstick and added one from battery to body. Replaced both battery terminals. Replaced battery. Replaced starter solenoid. Repaired all broken fusesble links. Replaced CPS. Checked for broken wires. Map sensor vacuum and wiring look good. Bypassed fuel ballast resistor. It's getting good pressure at the rail. Pump is good and loud. It has spark. Pretty strong and even pulses. Plugs look good. Newer cap and rotor. It'll fire as long as you spray down the intake but won't stay running on its own. I used the multimeter on an injector and not showing any voltage at all..

nujeepguy

meter wont show much with short duration pulses. need a scope.
or "noid" lights that i know nothing about

jake92

Who in there right mind would break out a scope on an XJ? I don't normally agree with the YouTube mechanics but ScannerDanner is a great resource (and an XJ owner) on testing fuel injectors with basic tools.


Stop trying to scare people away from diagnosing their XJs nujeepguy. These aren't anywhere near the technology that would require a scope.

cruiser54

Bull****. It's just a 5 volt signal.

More "help" from the Master Of Misinformation.

cruiser54

Each injector has it's own driver in the ECU. . Test another one or two.

nujeepguy

great video, the guy said you could use a scope or a noid light. thats what i said. he used a voltmeter just to verify the 12v supply for the injectors was there.i said the meter wouldnt show pulses. he used a test light to show that.

djgrayxj

Note from DJ for cruiser
We know for a fact that if you unplug the MAP on a Renix that the Engine will stop running.
I just went out and did the same thing on by 88; only I tried starting it up with the MAP unplugged.
It will start for a couple of seconds but then dies; which is what Dustin is describing his Renix is doing.
I had no more time to go any farther with the test because it’s time for my evening meal.
If you have the time after your evening meal can you verify my test on your Renix?
I don’t know if it kills the fuel pump circuit or if it stops the in the injectors from firing or what.

nujeepguy

no fuel? injectors working huh

i meant spark!!!

djgrayxj

Note from DJ
nujeepguy your statement is without proof.
Engine is running on starting fluid that means it has spark only of some sort.
The question is lack of fuel pump suppling fuel or do the injectors stop firing.
I had no more time for more testing and minimal knowledge of the system.

67 GMC

OK, so if it runs on starter fluid, then the spark is probably ok. You have fuel pressure on rail so fuel pump and relay probably good too. Sounds like injectors are not firing. Download the Renix fuel injection manual. That has a complete description on how things work and what sensors do what etc.

http://www.pirate4x4.com/tech/billav...ion_manual.pdf

nujeepguy

oops!! i meant spark, my bad...

djgrayxj

Note from DJ
nujeepguy you are still making a false statement
Look at Post #75 by OP Dustin and then you reposted in your post#76 as a quote; OP Dustin States” It has spark”.

Dustin Dove

Tested two more injectors and still nothing at all. I may snag another ECU from the wrecker. Wouldn't hurt to try it I guess. I am going to go through that injector manual and get to the bottom of this.

cruiser54

I've never had one lose all drivers at once, but I guess anything is possible.

nujeepguy

are you checking for 12 v on all injectors,on one side?as it should be.