handsofftheaudi

I fired it up and as it ran sprayed carb cleaner all around the intake manifold and also the vacuum lines with no response or increase from the engine. I also checked my grounds from chassis to engine was at like 14 ohms. So I took some time and made fresh metal contact between grounds now I have 4 ohms from chassis to engine but I never checked from battery to chassis so that may be an issue as well. I'll check that and maybe even install my own grounding like you mentioned. I do need to recheck all my vacuum lines do you know of a good diagram that tells me what color plastic tube goes to what component. I remember finding one along time ago online but can't find it. As far as grounds how many ohms should I shoot for before its good how many is low enough that I can scratch it off the possible causes list. The fuel is mediocre at best it does need some good high octane fuel and ill fill it up with some. One more thing i bought new fuel injectors for this build and per 12v.org purchased cheaper yet fully interchangeable O2 sensor then spliced them on to my old harness. My question is there are two white wires and one ground ( black) wire per sensor is there a possibility that you spliced them incorrectly. Obviousely i matched the ground wires but when it came to tge white wires i just spliced em there nothing to really indicate wich one is which or if theryre the same. The engine does run rich all the time thats me getting high sniffing the exhaust to see if its running rich or lean, so since its flagging the #2 O2 sensor control unit maybe i got lucky and wired the #1 right and not so lucky on #2 sensor. Thanks for the help rusty.

haraldpost

The two white wires is actually the heater element in your 3-wire O2 sensor. One wire must have +12 V, the other ground. The wires share color because orientation is irrelevant. The heater element is a simple electrical resistor and therefore not possible to wire the wrong way.

The black wire is not ground but in fact sensor signal. Your 3-wire O2 sensor has signal ground through the exhaust manifold.

handsofftheaudi

Thanks for clearing that up harold post. Maybe I need to check the ground from the exhaust manifold to the chassis and make sure I have good ground there.

handsofftheaudi

Alright gents here's the update I had a buddy of mine come over and does some tests with me. We ruled out any bad grounding with a voltage drop test instead of an ohms test so that's good we unplugged each injector one by one and found that cylinder 5 didn't change much when we unplugged so we tested the injector pulse from the harness and that was good. Next compression test and it was coming in at 100 psi running and 120psi with the starter, which didn't seem that bad till we checked number 4 cylinder which was 120 running and 145 with starter. So we talked it over and came to the conclusion that there is a chance that this cylinders rings have not seated yet and all it needs is to be driven. So for the past 3 weeks I've taken it back and forth to work in the Texas summer with no a/c and learned a few things about it. 1 the idle is rough to begin with but once you drive it and say stop at a light its much worse, I typically put it into neutral when stopped at lights. 2 once I'm moving and even getting on the freeway it is very smooth, very gutless but I'm not expecting much from it yet in the power department, but it is smooth driving and accelerating and can't feel a rough running engine at all. 3 there is a point on the gas pedal where you have to push harder to get it to the floor, I know this does two things. The extra effort it takes to get it to the floor is a result of the secondary air port on the throttle body that has a stiff spring attached to it, this also commands the trans to downshift, basically gearing up for high rpms and acceleration. When I do this my engine falls flat on its face. Its pathetic at best. 4 it has died on me three times each while on the freeway and each time I was pushing it pretty hard, Its as if the computer shuts the fuel off or the spark but all of a sudden I have no power and guietly glide to a stop. I then turn the car off and restart it, each time it fires right up and off I go. My question what is causing it to fall on its face? How do I test to see if the intake manifold butterfly valves are operating correctly( not throttle body butterfly valves )I think there called the change over valves? Any other suggestions or advice always appreciated.

haraldpost

How is your fuel filter....?

handsofftheaudi

It's new since the. Installed right before first start up of the new engine.

handsofftheaudi

How much fuel pressure should I have at the rail maybe I need to hook up a fuel gauge on the feed side a see what running pressure I have to my fuel rail. How do verify that my change over valves are functioning if it only opens after higher rpms and driving?

haraldpost

I don't think the change over valves in the IM is a likely culprit. That shorter intake give some extra hp at high rpm, but the car shouldn't fall on its face without it. I am NOT an expert. Anyway, they are supposed to engage at 4100 rpm or so. See if you can get your car to fall on its face before 4000 rpm to clear them of suspicion...

haraldpost

My bet is the injectors. Since you've had the whole engine apart, you've had them out.. it could be injector seals and/or they are not installed correctly.

handsofftheaudi

I did a pressure test of the cylinder in question. I removed the valve cover, rotated the engine so that I could visually verify the cam lobes were not depressing lifters then I pressurized the cylinder through the spark plug hole with air and listened... I heard nothing coming from the exhaust pipes but when I listened to the air hose going to the intake I heard air hissing, then when my buddy hit the gas pedal opening the butterfly valve on the throttle body it was even more obvious my intake valve was open when it should be closthe.
So I yanked the head off it took me about 3 hours and here it is. Now this is easy I just take it back to the machine shop who overhauled these heads and have them fix it. Except I have since then moved to Texas and won't send it cross country to get fixed. So I took it to a friends trusted machinist who said with the cam and lifters off the valve seats are good and holding vacuum really well so it must be the valve wasn't cut enough and holding open once the lifters and cam are installed. I have to do a few more tests to verify some things but it looks like I'll just have the valves trimmed and I should be OK. I also found another gremlin in the head the lifter farthest right had to be pulled out with a vise grip and slide hammer because it had cracked not sure what caused this, the head looks undamaged still looking into it though. :!