348 purge valve code=1124

hi All,

after re-installing the engine on my 348 i am getting this error code under the 5-8 bank.
i saw that Ernie has a writeup about troubleshooting these but first off:

-does anyone know how the computer knows that one of the purge valves is bad?

-there are two valves, one per bank. i assume that each side throws it's own code,
therefore can i assume that the one on the 5-8 side is bad? (i swapped the connectors for valve
actuator and the code stayed on the same side so it must be the valve right?)

-i understand from Ernies post that the electric power is always on during running engine
so the valves are closed, correct? i.e. engine off - valve open but engine running - valve closed...

is there any other way one gets this code besides a bad valve? (or no power to the valve)
would appreciate your feedback!

 

Not to my knowledge.

Actually I have a sneaking suspicion that the purge valves always have power running to them. Why? Well, because when I was waiting for the new valves to arrive I left the purge valve unplugged. I had to wait over the weekend for the valves and I also left my battery connected. Normally my battery will show sign of being low on power after about 3 days. But this time it didn't seem fazed, cranked over like it was full.

Now I haven't tested this theory out yet but I think it is a possibility that the purge valves have constant power.

Having said that, I think that it's the ecu that CUTS power to the valves to let them purge the fumes off. It could be that the ecu doesn't get the required resistance needed to keep the valve closed, and that's how it "knows"????? What is that resistance, or what every the ecu is looking for? I haven't the slightest clue? I never got into testing the resistance of the connectors, I just did the suction test with my thumbs. Maybe that's something you can tackle and let the rest of the Brotherhood know what you find?

 

thanks for the info Ernie. i ended up fixing this issue by realizing that there was a connection problem to the 5-8 purge valve. Once i had re-connected the power, the check engine went away. What is confusing about this is the fact that when swapping the connectors to the two purge valves the CEL stayed on the 5-8 side...
maybe it's measuring resistance on the circuit??

regardless, the CEL is off and the car runs fine, better than ever, and not a drip of oil/coolant/brake fluid under the engine!! naturally i am pretty proud of myself right now ...

new timing belt, water pump, cam seals, hills tensioners, wheels powder coated black etc. etc.

I'm off to Angeles Crest tomorrow!

 

Did you check the valves with the engine idling? You need to make sure that the valve isn't open/drawing suction. I'm assuming you did since you said that you swapped the connectors. If the valve is stuck open when the engine is idling it will likely be open all the time, and the vacuum can crash the gas tank, especially at full throttle. The other thing to check is that you do not have negative pressure sucking shut the gas cap, and making it difficult to remove it when it is in screwed.

I just don't want you to think everything is okay and then end up with a crushed gas tank.

As for your bad contact, was it the female pins being loose, or was it wiring, or was it not even fully clipped in place?