Alternator not powering battery

[Dave WM]

9 hours ago, jlenownnab said:

Is there an upgrade fuse panel like on the 240 or is this not a problematic area usually?

I don't think so unless it has a lot or corrosion on it. On the fuse links, you can buy them or make them (I have done both). They work fine IMHO I know there are a lot of folks that like to mod this area, but not sure why. I had one melt when my Alternator diodes short out, Fixed the alternator, put in a new one (after making one to get me on the road while waiting for a factory replacement) and have not had a problem since. I do have one fuse that runs hot (the AC fuse) not sure why as the current seems to be correct. Again just my opinion less mods are a good thing, as it makes you figure out what the problem is vs covering it up with non factory solutions. If everything is right, the fuse links and fuses should be fine.

Edited July 3, 2016 by Dave WM

[jlenownnab]

Can I carry this on to my next issue? With all the great help so far, maybe this super clean original 75 wiil be on the road again soon. I mentioned I may have a vacuum leak. I Sprayed down with brake cleaner and inspected vacuum lines. I could not get a change in idle and all lines are clean and pliable. I went ahead and changed plugs, wires, cap and button. No help?? If I didn't mention what the car is doing, the car starts and idles perfect, when you push the gas pedal to rev the car there is a delay, it sounds like it sucks air and will pop and backfire in the intake? The car appears to run nice at speed?

[Dave WM]

fuel pressure check is next, sounds like its running lean. a little hesitation is ok, will never notice while driving it, but backfire thru intake is bad, can damage the AFM. oh and make sure you are not running out of gas. When I 1st got mine I was low on fuel and it started doing exactly that backfire thru intake, up until it completely ran out of gas. Your tank gauge may not be accurate.

Everything with my Z so far has been simple dumb stuff (fuse blows cause I short out the VR while adjusting, fuse link blows due to shorted 40yr old alternator, back fire due to running out of gas).

What you don't want to do is start messing with adjustments of things you don't understand. You should read the EFI bible and know it inside out and backwards.

stuff like changing plugs, wires rotor all that is not the way to correct problems you must diagnose the issue and use a systematic way of checking things.

The problem with replacements is you can introduce and new problem by not doing the fix correctly (like mixing up plug wires just as an example). the more variables added to a problem the harder it is to fix.

Also modifying to fix a problem is not good either. These cars are very simple and in stock trim run very well. No need to replace the entire FI system with a modern after market unit.

Bottom line is if you want to own a 40 yr old car you need to find a good mechanic or become a good mechanic (not that hard really) for your specific vehicle.

Example why was the spark wires replaced? was there a mis fire, was it spark related, did you look for leakage and see/hear it? if not no reason to replace the spark wires to fix a problem. Now if there is no problem and you want to replace them cause they are old, fine, but do it when the car is running fine, and then if it does not run after the replacement put the old ones back. That way you can retrace your steps.

If you are skilled at diagnosis you can get away with shot gunning parts (replace everything old just cause its old), and then if the car does not run right you can still diagnose the issues. But if you are not skilled this can lead to a near impossible to resolve issue without finding a skilled person to do the work of figuring out what the problem(s) maybe.

 

 

 

Edited July 4, 2016 by Dave WM

[Dave WM]

As to the issue of the backfire, if the tank has sufficient fuel in it (good fuel)the fuel pressure checks out, I would start by checking the water temp sending unit (for the EFI not the temp gauge). This sender is responsible for fuel enrichment when the engine is cold, if its not working properly it could mess up the amount of enrichment, its all covered in the EFI portion of the FSM as well as hot to test it (you don't just install a new one, what if the new one is bad?).

oh by the way how does the inside of the tank look?

Edited July 4, 2016 by Dave WM

[Patcon]

Also I believe the EGR line connects on the bottom of the manifold. They can rot out if I remember correctly so the vacuum leak could be there. Use a mirror to look around under the rear of the intake manifold

[jlenownnab]

I changed the plugs and wires because of a test we did. With the car idling we pulled one plug wire at a time to see if a particular cylinder was or was not affecting the idle. Cylinder number 2 didn't seem to affect the idle the way the other 5 did, we pulled the plugs and the plug was in worse condition then the others. The wires were from 1984, when we replaced them we verified the order. In hopes of it being something as simple as a tune up, I wanted to try a few things. I know out sourcing this job is on the horizon, I was just trying some basic maintenance. My plan is to tear this car down after summer. it will include removing, cleaning and treating the gas tank, a new fuel sending unit, poly urethane bushings, all suspension components gone through, brakes etc... The crappy thing is that I paid good money for this car and it was supposed to be in good running condition. I don't have any interest in learning everything about these cars, but I wanted to throw it's problems out there just in case they were common and easily repaired. I'm at a point where I want to do what I am capable of and what I know how to do and enjoy doing.

[Zed Head]

Use this book to verify that the coolant temperature sensor is correct and connected, and the AFM.  Your symptoms sound a little bit like the AFM isn't connected, and the engine is running on the idle enrichment only.

http://www.classiczcars.com/files/file/31-efi-book-1975/

 

[Dave WM]

12 minutes ago, jlenownnab said:

I changed the plugs and wires because of a test we did. With the car idling we pulled one plug wire at a time to see if a particular cylinder was or was not affecting the idle. Cylinder number 2 didn't seem to affect the idle the way the other 5 did, we pulled the plugs and the plug was in worse condition then the others. The wires were from 1984, when we replaced them we verified the order. In hopes of it being something as simple as a tune up, I wanted to try a few things. I know out sourcing this job is on the horizon, I was just trying some basic maintenance. My plan is to tear this car down after summer. it will include removing, cleaning and treating the gas tank, a new fuel sending unit, poly urethane bushings, all suspension components gone through, brakes etc... The crappy thing is that I paid good money for this car and it was supposed to be in good running condition. I don't have any interest in learning everything about these cars, but I wanted to throw it's problems out there just in case they were common and easily repaired. I'm at a point where I want to do what I am capable of and what I know how to do and enjoy doing.

Ok that is a good start (checking by pulling the wires) did that smooth things out? also does the replacement plug look the same as the others now? You could have a bad injector on that cylinder, oil fouling from a bad ring. A good baseline check of the cylinder pressure should be done. Checking the new plugs again will help confirm that the plug wire was the issue. I would have swapped the wire to another spark plug to see if the problem moved with the wire, but its ok to replace as long as you go back and make sure the plug is not re offending. If it looks fouled again you should listen for the injector to see if it sounds any different than the others (that's assuming the pressure test is ok).

The problem you are likely to run into is you need someone that understands the EFI unit. As Zed and I both alluded to the #1 check would be the temp sensor checked AT THE EFI 36 pin plug. If you want to read the EFI book then you can follow along with the diagnosis, OR find someone that knows these cars. Again its not hard to learn I knew nothing about Z cars 8 months ago, some reading a few basic test tools are all you need.

Since you are look for common problems

Get the coolant system pressure checked to make sure you don't have any leaks. Check the condition of the fan clutch and water pump. Water pump failure will ruin your day. Warning if you do need to replace the water pump read up on how to try to avoid breaking bolts if stuck. I would not replace it if its ok, this is an item best left alone unless in needs replacing to avoid bolt breakage.

Fuel tank, put a G-3 Fram fuel filter ahead of the fuel pump. It will allow you to see if you have junk in the tank (clear plastic filter).

Check the fuel lines for pressure and flow capacity (they can rust from the inside restricting fuel flow) Mine were a bit stuffy (that's a FSM description BTW). I cleared up the fuel line with some evaporust and compressed air.

Check the vent line that goes to the carbon canister, mine was completely blocked with rust. Does the fuel cap have suction or pressure when opening?

Check all electrical connectors associated with the EFI Corrosion is a common problem. check all the Grounds associated with the EFI. Make sure you have GOOD battery cables and grounds to chassis off the negative lead. Check fuse links for corrosion where the plug in.

Listen for valve noise. Valves will need periodic adjustment (easy).

Make sure valve cover gasket is in good shape (can cause vacuum leak)

Make sure Oil cap on valve cover has good gasket (vacuum leak)

Brake booster, Listen for leaks, see if depressing brake causes idle to change (the booster can leak when pressing the brake).

Oil dip stick firmly in place

EGR working only when car is warmed up

Vacuum gauge, get a base line vacuum at idle, report back.

Start a service manual if you don't have one to document what was done and when. (I need to do this too).

Sounds like a lot of but its really not, you just have to recognize its a 40 year old car, way past normal expected life of many of the parts so you have to be extra diligent about staying on top of things. Plus compared to modern day cars that are designed to go 100k with practically no service other than oil changes, the era these were made in assumed regular service intervals that were much shorter.

Hang in there its well worth it once you get it sorted out.

 

 

 

 

 

 

 

 

[Zed Head]

58 minutes ago, jlenownnab said:

. I don't have any interest in learning everything about these cars, but I wanted to throw it's problems out there just in case they were common and easily repaired. I'm at a point where I want to do what I am capable of and what I know how to do and enjoy doing.

Dave gave a good list.  It looks long but each item is simple.  Things get overlooked like the fact that the crankcase (the valve cover) is connected to the intake system, through the PCV system.  So even a missing dipstick is a vacuum leak.  

And the tests at the EFI plug are simple "poke and read the meter" tests.  Just resistance measurements.  Grab a pen and paper and write down what you measure also.  People often come back and say the numbers checked out, but don't say what they were.

 

[jlenownnab]

Thanks for ideas/list. Having troubles downloading book, will get done in morning. I will report back but it may be a day or two waiting on my friend/mechanic. Also, not many shops in Cincinnati to work on these type cars.

Thanks,

Stewart

[Dave WM]

check and see if there is a Z club near by, could be a good group to contact.

[jlenownnab]

I did a quick search the other night for nearby clubs... nada. I have downloaded book and my brain is swimming after about page 31 or so. So far I definetely have a way better understanding of how the system works and will recognize components I normally would have just looked at and wonwered what does that do. I am meeting my guy this evening and will post update, thanks.