noob valve adjusting on 1978 280z

[FastWoman]

Fascinating! Another mystery solved. Great job!

I just have to say, though...

YOGURT CUP TEST

Such an easy thing to do, and it would have revealed your leak. It might have been hell tracing it down, but it would have revealed to you that somewhere in the recesses of the engine... somewhere in that thing... there was a leak. In this case, a leak directly from the exhaust to the intake, bypassing the EGR valve.

Anyway, you found the problem, and that's what's important. Soon you'll be be taunted no more by the drivers of those VW bugs!

Edited May 9, 2011 by FastWoman

[argniest]

aaaaaaaaw goshhhh, exactly about the bugs and minivans. I wont be putting up with that crap anymore hehehehehehe. ! There was nothing I could do before. but now.....ohhhhhhh yeah, watch out. This car, with everything that has been done to it now on my long journey, in some ways, better than almost new.

I was still gonna do yogurt cup test. During my most likely final and drawn out set of testing everything else that I hadnt done (and maybe retesting a few other things). Thankfully none of that will be needed now!

I stuck a small led light with a flexible head on it, right down into that EGR housing....and the hole I could see was sort of jagged shaped, but at least size of nickel, and probably in total, the size of a quarter. hows that for a massive intake leak!!!!!!!!!!!!!!!!!!!!! right into the frigging intake and cylinders.

They no likey likey eating full amounts of exhaust for breakfast lunch and dinner. They will like fuel much better!!!! This explains so much. All the data I have collected can be traced to this problem. I NEVER knew something like that could happen, or I would have been looking for it.

From now on, in my life, if I ever encounter something like this on other cars I plan to acquire, I will never forget this. It is very rare for something like this to happen from what my cousin says, and another online mechanic friend of mine. I just cant believe there are no other Z people who have seen this happen to their cars. Why o why did I have to be the lucky one. The really good thing in all of this is it forced me to learn soooooooooooooooooooooooooo many things about my Z car. Stuff I dreamed about learning but didnt know if I ever would have time. And now I have good tools, procedures, ideas for future.

Im very happy on this day. Now I just cannot wait to get it fixed. I am going to try to talk my cousin into fixing it on tuesday. To do the welding of that pipe/(and insert some kind of plugs) and closing it off for good, until I get a new intake and a few months in the winter to carefully take it all apart, put on the new (well good used anyway) intake manifold.

If I knew how to weld I might fix it myself, but we both agreed taking that pipe off from the exhaust manifold and the EGR housing could be risky. It is possible to break off the back of the intake manifold which would render the car useless until I got a replacement, And then the time to replace it....ughghghghghghgh

I will let you know how it goes....

Edited May 9, 2011 by argniest

[Zed Head]

It's still odd that only three cylinders were affected by the breakthrough in to the EGR channel. All six intake runners are exposed to the channel so all six should have had excess exhaust gas coming in. The EGR ports in to the runners of your intake manifold might be messed up also. If your band-aid fix is to disable the EGR entirely, you'll probably get back to balanced running, but it might be worth checking the individual EGR ports, if you can get the plugs out. I've never seen one myself so don't really know how much gas they flow.

[FastWoman]

Argneist, I meant that you should have tried my patented yogurt cup test in the first place. You would have found that you were blowing air from your intake directly out the exhaust. That would have told you something weird was going on with the internals of the engine.

I agree with Zed. There's likely a blockage in your EGR ports somewhere. Maybe disabling the EGR is the path of least resistance. Perhaps you can weld the EGR pipe closed and have a baffle plate on the EGR mount to block off the valve. If you leave the components still mounted (but nonfunctional), then it might not look tampered with, and you'll be able to pass inspection with it. Or maybe you live in a non-inspection state. Dunno.

[argniest]

Here is what the Z jedi master told me to do, just in case someone else runs into this,....they will know what a 30+ year z mechanic would do to fix this. I want it fixed as quickly and easily as possible. So I can drive it finallllllly:

That's great you found it out. I've seen that happen before and it's not a hard fix to do right on the car. The hard part is diagnosing it as you found out. It's all academic at this point, the diagnosis is sound. As soon as you mentioned something about understanding the EGR system, I knew instantly what the problem is before you described it.

It's pretty uncommon, but it does happen. I haven't seen it for quite a few years and it didn't even come to mind until now. I've ran across that scenario probably 5 to 10 times in the last 25 years but haven't seen it for the last 5 at least.

You can cut a section out of the egr tube and weld both ends shut. Then you'll be good to go until you weld the manifold shut.

DON'T TRY TO TAKE THE TUBE OUT OF THE EXHAUST MANIFOLD UNDER ANY CIRCUMSTANCES OR YOU'LL REGRET IT! They usually won't come out of the exhaust manifold without ruining the tube, and the nut. Then you won't be able to get it to seal on the exhaust manifold. Cut and weld the tube right on the car. Once you cut the tube, then you can take the fitting off of the intake side and weld it on the bench.

DON'T TRY TO TAKE THE EGR TUBE ADAPTOR OUT OF THE INTAKE MANIFOLD EITHER. Be sure to put a wrench on the adaptor, and another wrench on the nut for the tube and break the nut loose that way. If you try to back out the adaptor, IT WILL EAT THE THREADS!

I usually take the intake manifolds, and cut the egr section off of it and weld a plate over the end. Then weld the egr tube down by the exhaust manifold closed and it's a done deal.

For now just do the tube and don't worry about the long term fix. If you ever need to change the head gasket or exhaust manifold, then worry about fixing it permanent. I can modify an intake manifold here and send it to you. Then just send me your old one for the core charge. I'll take your old one and save it for the next guy.

****************************

EDIT: No I live in the middle of nowhere USA, and no emissions to worry about.

FASTWOMAN: Yes, :-) I was going to do yougurt cup test. I have been going banannas about this...and had too many things I was trying to do. But sooner than later I was gonna do that test, so I would have noticed something was odd. And would have reported it to my guru's.

IT IS A VERY GOOD IDEA TO DO THAT YOGURT CUP TEST. I even have th yogurt cup sitting right near the car. Im tellin ya I was gonna do it.

Edited May 10, 2011 by argniest

[FastWoman]

I think if I were to name the yogurt cup something else more technical sounding, people might actually be more inclined to do it. Maybe...

Intake Leakdown Test

Intake Pressure Retention Test

Intake Positive Pressure Leak Detection Test

Translumenal Pressurization Procedure

I just named it the yogurt cup test because that's what I did it with. I have tons of Yotastic yogurt cups in the garage for mixing epoxy and doing odd jobs. The cup fits perfectly.

I agree with your guru. Just weld it up for now. FAIW, I was able to detach the EGR tube from my intake by putting a huge crescent on it, tying a rope through the hole at the end of the wrench's handle, tying the other end around the intake manifold near the throttle body, and pulling up on the rope (which creates enormous mechanical advantage). However, I don't think there's any way of dealing with the other end of the tube. I'd just follow the advice you cite: Cut the tube in situ and weld both ends closed.

Be warned that if you have annual inspections (not meaning emissions testing, but just a general non-emissions inspection, like here in VA), your EGR might be an inspection item. I think it's illegal to tamper with the emissions equipment. While I don't think you will get fined, I don't think your car will pass inspection. The way around this is to make the EGR tube LOOK like it's intact, perhaps by slipping a tube over both welded ends and wrapping it up with exhaust tape.

Edited May 10, 2011 by FastWoman

[grantf]

If it were a "beer can test" people would listen I'll bet. (:

[grantf]

I am a little confused on how the repair will be done, will you post pics?

[Bonzi Lon]

Your

Oxygen

Gas

Union

Regurgitation

Test

Bonzi Lon

[240260280z]

Bonzi

[FastWoman]

YOGURT test. Yeah, I like it, Bonzi!

But I'm going to check whether a beer can fits the boot.

Breath

Exhalation

Experimental

Retention

[argniest]

GREAT NEWS!!!!!!!!!!!!!!!!!!!!!!!!!!!!! All the blood sweat and tears have come to end on this part of the project. I worked with one of the mechanics (at my cousins garage) that has worked on other stuff on my z car. The fix is done, and the car drives night and day different!!!!!!!!!!!!!!!!!!!!!!!!!!!! My wife just drove it for 2 hours and she was really enjoying it. She was patient and knew I would tell her when it was *ready* to actually enjoy. Let me tell you it was fun being over in the passenger side to. I could just listen to the engine purring like I thought it should, and feel the new found power too. It was a complete transformation. We did a lot of little stuff too, that needed to wait for this moment. BUt the main thing is the EGR tube is welded shut. An intake manifold replacement is not expensive, and whenever I feel like it, I will get it, and start tearing into the engine to replace it. It will teach me some more new things. But that aint gonna happen until I get in month and months of driving this year.

Also I got my kick butt stereo done around the same time. So I popped in one of our old favorite DVD's and she didnt know it, and looked down and was like OMGGGGGGG you werent kidding. It was a kodak moment for sure. It rocks.

This isnt the end of the story, but it is the end of a book in a series for sure.

My cousin said engine is sounding sooooooooo much better, and it doesnt stink of course, anything like before. I just need to drive it a lot now and recheck plugs a few times. And tweak the AFM screw, because I think that needs to be done. I feel some heistation or maybe its flooding in the power band between 3000 and 5000. I mean dont get me wrong, but I feel like it has more to give and more smoothly at the higher rpms, but also we can climb up huge hills just fine while acclearting in 2nd gear. But on the interstate it seems doggy in the higher end.

I am not complaining at all. I just want to make this engine run as exactly to specs are possible. Yes I will do valves pretty soon. But my 3 Z experts are telling me, its OK if I put it off a little longer anyway. I mea my god, there have been so many little problems that have added up to one BIG problem. The car ran like S*i%

Oh well I could go on and on, as you know. I am going out to check the AFR's with my innovate meter, and see how they are and start the tweaking process.

He figures the more I drive it, it will clean up those valves that were being assulted by the extreme amount of exhaust GOING RIGHT INTO THE ENGINE!!!!

I am also going to use a little seafoam at some point, but maybe not for a month.

WHAT WAS DONE

================

• EGR housing fixed/remedied,
  
• Reserve light switch replaced (it was leaking because we found out the gasket on it was in bad shape)
  
• Fixed a bolt I broke off holding on the ignition coil
  
• oil change
  
• spark plugs cleaned
  
• New distributor adaptor (because of the other people working on the timing, broke the adjustment bolt off)
  
• They checked the distributor while they had it out, and reset timing
  
• They put oscilliscope on the car again-->primary and secondary ingition looked good/fine
  
• Removed the fuel pressure guage from the car, it doesnt need that anymore
  
• I hooked my vaccum lines for HVAC system again (and its still working - unbelievable)
  
• tweaked the idle and AFM bypass screw a little (backed it out a lot)
  
• Checked engine vacuum was between 16 and 17, and that was before they tweaked AFM, so I think it go even higher once I get AFM dialed in better
  
• Installed all new premium connectors on the fuel injector connectors (soldered on), they are bosch styl quick disconnect :-)
  
• New plugs, rotor and cap (Yec brand from japan, supposedly very high quality
  

No more stinky exhaust either. Now that the engine is running fine. :-)

Well this is already getting too long. I will post more later in a few weeks, I need time to test and tweak things.

THANKS AGAIN FOR ALL YOUR ADVICE AND TIPS!!!

Edited May 12, 2011 by argniest