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Engine code 27

ILLXJ

NAXJA Member
NAXJA Member
Location
Louisville, IL
I,ve got a 92 4.0l that is giving trouble code 27. The book says Fuel Injector Control Circuit. What does this mean & how do I fix it. The only reason I pulled the code is a stall condition when slowing down while coming to a stop & a "bucking" at speed. These conditions do not happen all the time. At this time I have changed cap & rotor, plugs, & fuel filter. TIA. JIM.
 
I believe the ECU issues this code as a result of ....

When the ECU switches an injector ON, it attempts to 'confirm' that the injector has turned ON by measuring the current through the injector. If it does not 'see' the expected current flowing, it reports an fault.

A fault may be caused by a bad driver(switch/transistor) in the ECU, a bad connection in the harness from the ECU to the injectors, or a bad injector(s) .
 
According to badge714 resistance across the injector terminals should be 3-6 OHM. Checked all the injectors & they read between 13.2 - 13.7 OHM. Does this mean the injectors are all bad? Can I check the ECU to see if it is bad? If so how? Thanks again. JIM.
 
Chilton's says 3-6 Ohms.....'91 FSM says 12.8 to 15.2 Ohms. FSM always wins.

Despite the coils on the injectors being within range, that does not rule out a bad injector(s). They may still be sticking ???

There is not much that you can do with the ECU.

Have you tried fiddling with the wires and connectors going to the injectors (and ECU) while the engine is running to see if it hicups?
 
No I haven't tried that yet. Working 10 to 12 hr. shifts at night & 3 kids, I get to work on the XJ's about an hr. a day. Will try this in the morning. JIM.
 
Will the ECU from my 96 work in the 92? If it will I will swap them & see what happens. JIM.
 
Got it put on a scanner. Injector #3 circuit & #6 circuit faults. I checked the wires between the injectors & the ECU, it test OK. If I swap injectors 3 & 6 with 1 & 2 & then get faults with 1 & 2 that should mean the injectors are bad. If I still get faults with 3 & 6 that should mean the ECU is bad. Am I correct in assuming this? If not let me know where I should go from here. TIA. JIM.
 
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