riche

You can test the o2 with a volt meter, however I can not tell you which wire. You need to find the signal wire it will produce a 1 volt signal.
Anything bellow 0.4 volts = lean
Anything above 0.4 volts = rich

Unplug your mass air (that way it ignores closed loop and goes into limp mode) get it up to temp and test o2 running.

I don't know about tune ports but when my stealth ram is rich and the idle air control valve is above 30 to 40% it makes a heck of a loud whistle noise like a wicked vacuum leak.

gta_knight

I sent my original memcal to Brian (Tuned Performance) to be reprogrammed so i havnt even got the original one to swap in and try now

So i have to test the o2 sensor with the engine running, well that should be fun trying not to burn myself etc, i also hate keeping the car running too because of the vibration and noises its making too

riche

There are some ways to test the O2, you can look into that if you want a piece of mind that the O2 is working correctly (search the net)
I am more concerned with what the O2 is telling the ECM while the engine is running.
I see it 2 ways, the ecm is telling the car to run rich or there is an exhaust leak and the o2 as told the ecm to compensate, now the ecm has this correction stuck in its long term fuel trim. That is why it continues to run rich even at cold startup before it goes closed loop.
A good scan tool would show you this info.

gta_knight

thanks Richie, very helpful stuff

Im in the garage now and ive just been turning the engine over by hand, and i can hear air pressure somewhere, is that normal ? its hard to tell if its escaping somewhere or if its coming from inside the engine

All the plugs are in by the way

gta_knight

looks like i can test the o2 sensor easily as the connector is up in the engine bay and its only a single wire one, so i can just probe the wire with the car running..........if it will start, havnt tried yet !

gta_knight

Ok then, Riche ive tested the o2 sensor without even starting the car, i jacked it up a bit and clamped the ground lead of my meter to the body of the o2 sensor, then probed the wire, switched the ignition on and i got back out of the car to make sure the multimeter was secure so it wouldnt fall over when i started up and the reading was going up and down with just the ignition on ????

Shouldnt it just read zero until the actual sensor starts heating up then it produces a voltage ? i even checked the pin on the ECU that the right wire was going to the o2 sensor and it is.

I had the meter set at 2V as per the video instruction and it was from as low as .003 upto .187 and everywhere in between, all over the place

riche

Not 100% sure but that sounds right, 0 volts would be the outside air. So if you are saying it is reading less than 0.1 or 0.2 volts I would say that is close to open air. Maybe it is picking up on some fumes from the engine. 0.4 volts is 14.7:1. Not sure what 0.2 or 0.1 volts would equal Air fuel ratio wise.
Seems like it is working. But what is more important is what it reads while it is running. Is it a 3 wire O2?(never mind I missed your first reply) If it is a single wire it may not read correct until it is heated up...
While your Mcal is gone might want to take this time to re-seal or double check that side of the exhaust. And it couldn't hurt to run a compression test on each cylinder to rule out any engine issues.

riche

Yes, it is the cylinder pressure leaking past the piston rings.

gta_knight

hmmm, ok i will test it with the car running then. Its just the bench test video i watched it was reading a big fat zero on his multimeter until he started applying heat to it, so i just figure with the car off and it being cold it should be zero too instead of bouncing around

riche

Could be picking up on fumes from the engine. If I am right you are running rich, and there is un-burnt gas fumes lingering in your engine.
Do you have a compression tester? Might not be a bad idea. Would give you a piece of mine that nothing is wrong. all of the cylinders should be with 15 lbs of each other

Dakota W.

How much smoke at startup and what color? good amount of white smoke is too much fuel and the right amount of air, blue smoke at startup is the right amount of fuel, but not enough air. Assuming your engine isn't leaking oil internally anywhere.

gta_knight

the few times ive started it i havnt really noticed any smoke out the back to be honest, i could smell fuel though

I will check that too if i can get it started tomorrow, i didnt even get a chance to run the engine tonight to check the o2 sensor, while i had it up in the air to put the clamp on the o2 sensor i checked the exhaust was tight then noticed a leak on the passenger side, im sure its a bit of coolant as there was a drip forming on one of the bolts from the starter so i was trying to trace that but couldnt see anything.

Dakota W.

I hope a thread sealer was used on those head bolts, coolant can walk up the grooves between the bolt and the head.

gta_knight

I hope so too because if this engine place has screwed anything else up i will be straight up there asking for my money back.

im hoping its just what was left over from my leaking heater hose, after letting it run a while the other week i had a leak from that side which just needed a jubilee clip nipped up, so fingers crossed its just what had dribbled down and was lingering on that bolt

gta_knight

STOP EVERYTHING !..... lol

turns out the guy from the engine place that adjusted my valves overtighened them, so we sorted that this morning, and what do you know, after rechecking the timing the car fired right up, runs smooth, sounds great, idles great and i even tried going through the gears, all is well so far !


In dying to road test it so i need to hurry up and get the front end all back together

gta_knight

STOP EVERYTHING !..... lol

turns out the guy from the engine place that adjusted my valves overtighened them, so we sorted that this morning, and what do you know, after rechecking the timing the car fired right up, runs smooth, sounds great, idles great and i even tried going through the gears, all is well so far !


In dying to road test it so i need to hurry up and get the front end all back together

riche

Glad you found it!