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1977 280z EFI Nightmare


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Yup. Details are important and all that kind of stuff is killer on the system. And don't beat yourself up. The good part is you're finding stuff that needs to be addressed. happens to everybody!

The mixed up nipples on the throttle body probably wasn't causing a big issue, but if the lines on the air regulator are leaking, that could be a big deal since some of those lines are on the high vacuum side.

I believe the only function for the TVV is to enable or disable the EGR system in response to engine temperature. When the engine is cold, they disable the EGR system so it doesn't make an already struggling idle worse. And then once the engine warms up and the idle is strong and stable, they allow the EGR system to operate. If you have deleted the EGR, I don't think the TVV has any purpose anymore.

However, about removing the TVV completely... The TVV screws into a heating plate that also warms the idle air regulator, and even if you aren't using the EGR system anymore, the heating plate still adds value to the AAR. So you can cap off the TVV stuff, but probably don't want to take it (and the heating plate) out completely.

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@Captain Obvious

Thank you so much! I will just cap both of the vacuum ports then and leave it on. Hopefully by this upcoming weekend I will have everything corrected and together. If it still runs like trash I will go straight to a compression check and get back with numbers. And then the real fun will begin. Lets hope it doesn't come to that haha. 

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Posted (edited)

Thanks! Got the TVV vacuum ports capped.

Next thing I noticed is that I have no gasket between where the air regulator goes into the intake manifold/throttle body. Is there supposed to be one? The place I am talking about is in the photos below.

 

IMG-0224.jpg

IMG-0225.jpg

Edited by ckurtz2
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What he said. And that gasket is definitely a very important one because it's on the high vacuum side.

Same thing with the cold start valve. If they didn't put a gasket on the AAR connection, maybe they didn't put one on the cold start either?

I'd use a tiny bit of RTV on those gaskets. Some details about that here:
https://www.classiczcars.com/forums/topic/65119-tuning-with-an-airfuel-gauge/?page=2&tab=comments#comment-617333

 

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Posted (edited)

Just pulled it off to double check. Behold... no gasket 🙃  I am amazed the car even ran haha. With all these leaks adding up it had to of had literally zero vacuum.

Looking online I could not find a gasket for the AAR, only for the CSV. I did see there was a gasket for the CSV luckily. Does anyone know where to get the AAR gasket from? Only place I could find it was on MSA and it was unavailable. 

Edited by ckurtz2
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I've used a cereal boxes, scissors and a hole punch for paper to make gaskets similar to that. I coat the gasket with a bit of oil and assemble. I've never had one fail.

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1 hour ago, Mark Maras said:

I've used a cereal boxes, scissors and a hole punch for paper to make gaskets similar to that. I coat the gasket with a bit of oil and assemble. I've never had one fail.

You're who I learned that from!

Take that elbow off and lay it on whatever you choose and lightly tap an impression on the material. Cut it out with an exacto knife and a hole punch. 

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46 minutes ago, Mark Maras said:

 Or lightly coat the part with grease, press it onto the gasket material and cut off the unstained parts.

Another trick that makes things easier! You should write a book. We all could assist by adding our tricks/cheats. LOL

Call it "A to Zs, refurbishing Z cars".

 

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 If I wrote a Z book it would contain all the dumb things I've tried and failed at or worse injured myself than helpful tips. Hmm. maybe combining both subjects, like, when you blow the caliper pistons out with air, after the first one comes out, DON'T stick your hand in the caliper to block air from escaping out of the open cylinder. A hand is an effective method to facilitate the removal of the other piston but the rest of the brake job is very slow and painful.

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We could get Band-Aid to sponsor this...

 

Do like the "Kartrashions" and brand our on band-aid with the Z logo. We'd get sued to hell and back but they'd be cool.

Z-logo.jpg

Edited by siteunseen
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6 hours ago, ckurtz2 said:

Just pulled it off to double check. Behold... no gasket 🙃  I am amazed the car even ran haha. With all these leaks adding up it had to of had literally zero vacuum.

Looking online I could not find a gasket for the AAR,

Agree with the above... For a gasket that simple, I would just pick up some gasket material and make my own.

So did you ever do an intake manifold vacuum test? Would be a good benchmark to see the improvements you're making as you go along.

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3 hours ago, Mark Maras said:

A hand is an effective method to facilitate the removal of the other piston but the rest of the brake job is very slow and painful.

LOL  Ooops!

I assume it grew back?    :excl:

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Posted (edited)

Thanks guys, hahah. Made me laugh. I will take note to not do that when I rebuild the calipers🤣😎

Made a gasket from some old gasket like material I had. Here is my masterpiece of craftsmanship (I cleaned it up a little more after this photo)

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@Captain Obvious  No I never did an initial vacuum check. I am waiting on a part to come in so I can rewire the harness for an AM alternator, so I am just using my time to try and fix the vacuum leaks. Not a bad idea at all though so I could have gotten a benchmark test, bummer. I will do one when it starts though as a benchmark before I start tinkering with other things.

Edited by ckurtz2
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Posted (edited)

@Mike

I got them pinned to the top of my search bar. Definitely going to be handy when I start testing all the AFM and other electronical stuff.

Edited by ckurtz2
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Posted (edited)

So the fun begins. Fired it up yesterday. Still a very unhappy motor even with all the vacuum fixes I did. Also the car knocks when I push in the clutch so somehow I messed up the throwout bearing, and I have literally zero I idea how. Actuates super smooth when the car isn't running.

Anyhow, ran a compression check. I forgot to open the throttle valve to full throttle, but I didn't open the throttle for any so I know the numbers are consistent.

Cylinder # and psi

1:  148

2:  took a few more turns, but 150

3: 153

4: 150

5: 144 (didn't turn the starter motor as much for this one so I am sure it's fine)

6: 150

So the numbers aren't perfect, but I would consider them consistent enough? When I pulled the plugs I noticed they were extremely fouled. So my little bird is running super rich. Odd thing is that if I move the counterweight on the AFM to lean it out, it runs much worse:( So idk what that could mean.

So I am going to do the 35pin continuity check on the harness connector at the control module. Am I supposed to leave the battery connected for this? I am a super noob with electronics, and this will be the first time using a multimeter

Edited by ckurtz2
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1 hour ago, ckurtz2 said:

Also the car knocks when I push in the clutch so somehow I messed up the throwout bearing

Not sure TOB fits a knock.  Does it knock once or continue knocking as the engine rotates?  And does it disengage?

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Just now, Zed Head said:

Not sure TOB fits a knock.  Does it knock once or continue knocking as the engine rotates?  And does it disengage?

It continues knocking only when the clutch is depressed and the car is on. I can feel it in the pedal as well:( I can feel it start knocking when I begin to start applying pressure on the pedal.

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Could be a pressure plate issue.  The levers/fingers that the TOB sits on might be unbalanced, or stuck.  The TOB should be centered on the pressure plate fingers by the nose of the front cover.  Although if the TOB wasn't seated on the fork correctly it might be pressing sideways on the fingers, kocked.  Interesting puzzle.

Bummer though.  The trans must come out.

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UPDATE 2: Resistance Checks at 35pin connector 

Well it looks like we have some work ahead of us. The things that I know failed were one of the AFM tests and the water temp sensor. However, any test where I grounded one of the points to the car it failed. I just grounded it to the bolt on one of the kickplates. Is this how I am supposed to ground it?

Idle throttle switch PASSED? Proper spec should be continuous and not continuous

throttle released it read 0.6. I think that is ok. Throttle depressed it read 1. Not continuous 

Full Throttle Switch  PASSED Proper spec should be continuous and not continuous

full throttle: 0.1 which is close to continuous enough

part throttle: 1 Not continuous

AFM#1 PASSED should be about 180

it read 182

AFM #2 FAILED should be continuous

it read 184

AFM #3 PASSED should be about 100

 it read 101

AFM#4 PASSED there was a wide range depending on temperature. Did just fine within specs

read 1411

AFM#5 PASSED AFM flap at rest should be not continuous. Fully opened should be continuous.

Read 1 so not continuous. Then read 0.1 so continuous

Water Temp Sensor FAILED should read within temp specs

I got 1, so it had no continuity

Control unit ground #1 FAILED should be continuous

62.9k

control Unit ground #2 FAILED should be continuous

62k

control Unit Ground #3 FAILED should be continuous

62k

Control unit ground #4 FAILED should be continuous

62k

Air Regulator and Fuel Pump Relay FAILED should be continuous

64k

Fuel Pump Relay FAILED should be continuous

read 1 so not continuous

 

Let me know your thoughts!

 

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11 minutes ago, Zed Head said:

Could be a pressure plate issue.  The levers/fingers that the TOB sits on might be unbalanced, or stuck.  The TOB should be centered on the pressure plate fingers by the nose of the front cover.  Although if the TOB wasn't seated on the fork correctly it might be pressing sideways on the fingers, kocked.  Interesting puzzle.

Bummer though.  The trans must come out.

Yip, was very disappointing when I felt it do that. Problem for another day though, just won't use the clutch while I try to get the engine running properly:) 

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