Cascade Crew

[83Z28BlackBetty]

So here's how the story goes,

the car originally had a massive leak after i forgot to plug a half in plug in the intake manifold under the throttle body, plugged the hole car ran great for about a week.

car started to run like crap, found plugs were totally fouled. replaced plugs and car ran great once again.

car started to run crappy and idle around 1700 again and was throwing an o2 code, p0152 (B2, S1, high voltage) So i replaced the o2 since it was almost brand new and didn't cost anything to warranty it out.

no change since o2 replacement. Same code comes back P0152 and idle creeps up. Tonight i hooked up the scan tool to read o2 data and see that bank 1 voltage is around .02v and bank 2 consistently around .95v. thinking that the sensor may have been defective, i swapped them side to side. still same info. B1 .03-ish and B2 .95v.

Am i correct in thinking that i may have a wiring issue with my harness?

~JAKE

[Twilightoptics]

Hmm it's possible. Or you've got the wrong heat range of spark plugs in.

The opti sparks were known to take a crap too.

[iansane]

That's where I'd go with it. Pull the connector out of the PCM and the connector out of the o2 and ohm it to check for a break. Then chase that break down!

[aaron_sK]

[iansane]

Wasn't the opti unit new? They usually douche themselves with age/corrosion/coolant.

[83Z28BlackBetty]

i don't want to jump and condemn the opti yet, since its brand new.

My next day off i'm going to start checking the harness. Also as a point of interest, all the other sensor data seems to be accurate. tps, maf, iac, iat, cts.

~JAKE

ps. I thought it was crazy that the o2 code would cause a high idle issue. I can clear the code with the scan tool and watch the idle come back down to 800.

[Twilightoptics]

First thing you should do is check what the o2 voltage is when the car is cold, and not running.

[chevymad]

Also on the same idea, what does it say with the sensor unplugged?

[Twilightoptics]

Indeed. ^

[83Z28BlackBetty]

voltage with ko-eo was the same both sides around .03v but that was after i was driving around for a while. does this suggest that my harness may be intact?

[Twilightoptics]

If they read the same with the engine off.... for a period of time after the exhaust has cleared out.

I'd be inclined to believe the harness is intact.

If you clear the code, how quickly does it return?

If the o2 signal was shorted to voltage in the harness, it would be active all the time.

[chevymad]

Sounding like it. Reason I said unplug the sensor and check the reading too, if it was shorted wires then you'd still have high voltage. If the reading changes then it shows a connection is being made at the sensor. To me I think you have an actual mixture control problem on that bank. Whether its a misfire, vacuum leak, shitty injector whatever..

[83Z28BlackBetty]

after i cleared code, it came back after about 10 min of driving.

Some other interesting points of info, when i pulled plugs to replace the first time, bank 2 plugs were WAY worse than bank 1.

I'll try to get readings with sensors unplugged tomorrow sometime.

~JAKE

[Twilightoptics]

How's your fuel pressure?

[chevymad]

Can't beleive I just had to look up if high voltage meant rich or lean.. Think my brain is running on 6 or 7. The things I forget..

Anyway, high should mean its seeing a rich condition on that bank. An ignition misfire will do this, so will a stuck on injector perhaps. Some reason its not burning all the fuel on that bank.

Check plugs to see if they're all clean or if you can narrow it down to a certain cylinder.

[chevymad]

So all the plugs were fouled/black? If the ecm is seeing that o2 as rich, it should be trying to lean out that bank. So if it was a single cylinder problem, i'd have expected to see 3 plugs being very white.

Fuel pressure should affect both sides equally.. I'd be looking for things that would only affect bank 2.

Lt1s are sequential right? So all the injectors should be seperately wired to the ecm.. not wired in a batch of 4?

[83Z28BlackBetty]

correct brandon, its fully sequential. each injector is wired to ecm on its own. however, each bank receives 12v separately. b1 and b2 injector fuses. I'll look into that and make sure they are both getting power as they should.

When i pulled plugs the first time the entire bank 2 side were BLACK! i wouldn't thing that an opti could cause a complete bank misfire since it is still a distributor.

I'll check fuel pressure again but i checked it when i first fired the motor and it was ok. 40psi if i remember right.

how do i go about checking injectors?

~JAKE

[chevymad]

Doubt it with an entire bank acting up.. but there's been stranger things.

Start out just ohming each one. Make sure they're all the same or nearly. Then with your fuel pressure gauge make sure they hold pressure. There's a fancy machine you can use to test fire each injector for a set period of time while watching the fuel pressure gauge. This is to make sure they each flow a similar amount. This test can be faked by wiring an injector to the battery and just closing the circuit by tapping your jumper wire. A quick tap each should flow a very similar amount.

An injector problem causing a whole bank to act up when wired sequential is about as likely as the optispark doing it though. Any other things that would be common to that bank only? Do you have a injector duration or duty cycle pid on your scanner for that bank? Is the computer asking for more fuel on that bank even though the o2 says its allready rich?

[chevymad]

OH I just had a thought. . You couldnt have gotten the bank 1 and bank 2 sensors mixed up when you wired them could you? When that happens the computer thinks the wrong side is lean and pours the fuel to it.. Feedback never responds.

[iansane]