Desperate for help with code 27

[jtavares]

Hello,

I have searched high and low for a solution to my problem, which many people seem to have had, but none have posted the solution for.

I have a '97 JGC that suddenly started to run very rough and even stalled on a few occasions at stop lights. It starts and accelerates fine, but once it gets up to speed and settles into a gear the rough idle continues.

My husband has replaced all of the spark plugs, all of the plug wires and the distributor cap. He tried disconnecting each sparkplug in sequence and the only one that didn't cause any change in the sound of the engine running was the 6th one. We replaced that one with a new injector. Still, no change. He checked all the wires along the rail, wiggling them while the truck was running to see if it made any hiccups. Nothing.

It had error code 43 when all this started, and the code changed to 27 after replacing the injector.

Any suggestions about what to try next would be greatly appreciated.

Thanks in advance,

Jennifer

[baseball_playa1575]

I looked in my book and for those codes there is a injecor control circuit and a cylinder misfire.

[Caribbean ZJ]

i had a code 27 before. It was the injector wires in the case above the rail. Ones probably broke the insulation and touching another. I had to separate each wire and roll electrical tape over them. Your old injector was probably good. Its the wires.

[jtavares]

Thanks for the responses. We checked the wires already and didn't see any cracks in the insulation but we'll look again. I'll definitely post what ends up working. I also welcome any other suggestions....thanks.

[mac10334]

Possible Causes
Bad connection or wiring - Check the wiring and connections between the fuel injector and the power module (or SMEC) and the injector contol lines between the logic module and power module. Clean and regrease any corroded connectors with dielectric grease and repair any shorts.
Injector driver transistor failure - Check the injector signal coming from the power module (or SMEC). It should rise to about 12V when the injector is off and drop close to 0V when the injector is on. If it is out of spec, you may need to replace the power module.


Diagnostic Method
Trigger Parameters
- Near 0V or near 12V not detected when the injector driver is turned on or off, respectively
Results If Component Fails
Fault code 27 is stored

[jtavares]

Found the problem....there was a hole in the top of the 6th piston. Still being repaired but I've been told that was the cause of the problem. I'll post a follow-up when it's all done to let you know if things are running smoothly after the repair.

[jtavares]

Update: Replaced the piston. Worked great for one evening and now we have code 24. Going to try replacing the Cam Position Sensor.