ey guys!

I have a 1977 280z which used to have the California specific emissions tech. I recently "refreshed" the engine after I got it. I completely redid the fuel tank and fuel system from the tank back going as far as to replace all the hoses for the vapor tank as well. 

I am just going to list off new things.

• rebuilt fuel injectos
• new fuel pressure regulator
• new fuel damper
• fuel lines
• fuel pump
• rebuilt fuel rail
• rebuilt head and new headgasket
• all new seals around the engine
• spark plugs
• rotor
• distributor cap
• plug wires
• oil pressure sender
• water temp sendor
• water pump/ radiator / fan clutch / thermostat etc
• cold air intake
• intake hoses at AFM
• vacuum lines
• new fuseable links
• new fuses inside the car under the passenger dash area
• several cleaned up grounds throughout the car

 

I also modified the EGR system by removing it, along with the BPT system. I just did this to simplify things. I also have a 6 to 1 header from MSA going back to a 2.5 in exhaust. This deleted the catalytic converter it had.  Other major change is I removed the AC. Might still be some things left over like the vacuum canister, but they aren't hooked up.

Anyways, I am positive the mechanical timing on the engine is solid. I also set the ignition timing as the sticker on the hood. I think it recommended 10degrees BTDC, could have been after tho. The car starts beautifully like a top. However, cold or warm it cannot rev the car. If I hold the gas pedal down it will slowly rise, but then it sounds terrible and won't go further. My assumption could be it is misfiring. In addition as the car heats up it will begin to stumble, buck, and eventually die.  Quite sad to watch. I would also like to mention it idles right around 850rpm. Even when cold.

So I went to troubleshooting. If I unplug the water temp sensor the car will die pretty much immediately, so I know that it is at least getting connection. I tried adjusting the idle speed and it pretty much has zero affect until i close it, and then it will choke out and die. I also tried to test vacuum. People recommended removing the oil cap and see if the engine runs worse. I did, and it made zero affect to how the engine ran. Which made me think a vacuum leak, although I can't find one for the life of me. Except that maybe I did not plug the EGR right.

Next came the AFM. I noticed that as the car warmed up I could watch the counter balance thing on the AFM begin to bobble (representing the vane itself inside bobbling). As the car got to operating temp the AFM bobbles more and more until I can see it making extreme movements to stay alive. Then the car dies. So I thought, lets help the little bugger out. So I had a friend slightly hold the AFM open so it would run a little richer. The engine immediately ran SOOO much smoother. I tested further and had him open it slightly more as I followed with my foot on the gas pedal. And the engine would rev up with it. I actually could get it to rev all the way to 6k rpm. Sometimes it took a while to get there, other times it would rev there super quick. Never would reach redline though, most likely because the mixture was still way off.  So to me this rules out that spark as an issue. But I just have no idea what it could be. I really don't know where to start. I never got to see the car start before I redid it, because it was so crusty and likely had a blown head gasket.

I actually drove the car about a quarter mile, by running the AFM about 3 cog teeth richer. Although I had what felt like 50hp. Can't say it was a great idea, but I needed a pick me up.

I will provide some photos and let me know if you see anything immediately wrong with how I hooked things up. This is my first z car and I am on that initial steep learning curve. 

I also am based in Phoenix, Arizona. If you or anyone you know would want to help I'd be happy to host. 

 

Edited March 29, 20213 yr by ckurtz2

 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.

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.

Edited April 27, 20213 yr by siteunseen

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.

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.

  Ooops!

I assume it grew back?    

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)

@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 April 28, 20213 yr by ckurtz2

Check to make sure you have these files to help with your EFI system..

 

@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 April 29, 20213 yr by ckurtz2

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 April 30, 20213 yr by ckurtz2

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?

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.

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.

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!