End of Turbo Swap woes

[jaromgi]

Hey guys, this is my first post in HybridZ, but I have been lurking for a while.  I posted this same question over at Zdriver, but I haven't gotten much of a response.  I'm hoping you guys can help to crack the problem.

 

So, I have been doing a 280zx n/a to turbo swap.  In an effort to keep things as simple as possible, I purchased a 1981 280zx turbo donor car to put the motor into my 1981 280zx N/A 2+2.  Both cars were in running condition before the swap.

 

I am using the stock harness, stock 1981 turbo ecu, and stock distributor.

 

Everything went pretty much according to plan until it came time to fire it up.  I used the wiring diagram from here.  I have everything in place and hooked up, but the car just won't start.  The starter motor engages, and I can tell I am getting fuel pressure, but the car starts dumping the 12V into the ground wires.  The first time I started to fire it up, one of the ground wires burnt through its insulation in a cloud of smoke.

 

I took out the entire harness again and replaced the wire that had burnt.  I rewired everything with the help of NismoPick, to make sure I didn't goof anything up.  Despite this, it is still running voltage through the grounds, and I am getting nothing in terms of spark.

 

I'm pretty dense when it comes to wiring and electronics, but I've checked and rechecked everything, and it is all set up according to the diagram in the site I linked to.  I can post pics to verify if that would help.

 

Any suggestions?

[skirkland1980]

If you're getting power on your ground wires it usually means the grounds aren't grounded good.

[jaromgi]

So what do you recommend?  I've taken it out once, and tried grounding it in 3 separate places.  I don't know what else I can do to get a better ground.

[NewZed]

the car starts dumping the 12V into the ground wires.  The first time I started to fire it up, one of the ground wires burnt through its insulation in a cloud of smoke.

That's what ground wires are for.  Follow the wire that burned backward toward the battery.  It must be short-circuited, or it's too small for the current it's carrying.  Ground wires should have a device or electrical component between the grounding point and the battery or alternator.  The component is what limits current flow.  Check the wires connected to your starter since it happens when you try to start the car.

 

As for the hand-written wiring diagram you used, it's full of question marks and un-needed wires.  Look at the turbo swap threads on this forum and see if you can find better instructions.

[dexter72]

Make sure your using the correct wiring diagram as was suggested before, You said you had an 81 zxt engine and harness going into an 81 ZX. Make sure you installed the dropping resistors.

 

Look at another wiring diagram, go over it again and again and again. I added the engine wiring harness and efi from an 82zx into my 260z. Wired everything up and no spark. Went over the wiring diagram 7 or 8 times. Took me two weeks to figure out that i didn't add a ground wire. I figured that out helping someone else out. Go over the wiring diagram again, make sure your using the correct year diagram.

 

The write up that you followed was for an 82-83 ZXT engine and Harness into an 81 ZX.  The wiring diagram is not the same as the 81.

[motomanmike]

I've seen terrible starter postive wires do this or terrible battery to chassis, battery to block grounds. Sounds like your battery ground isn't good.The current draw at start up makes the grounds smoke all over the vehicle because its supplying the ground to the starter with those instead of the big ground like it should. Make sure your spacer plate on your trans isn't causing it if you grounded on that side of the trans bell housing.  I usually run the battery ground right to the starter bolt though since the starter gets its ground through the starter body. 

[NewZed]

motoman's theory makes the most sense.  Take his suggestion first.  The big cable from the battery negative post isn't passing the current it should be.

[jaromgi]

Update.

 

I spent a good portion of today trying to go through everything one more time.  I should mention that after replacing the burnt out wire the first time, none of the grounds have had the same issue.  Following motomanmike's suggestion, though, I tried to improve the ground running from the battery.  I have included pictures of the setup that I have below.  If you guys can see something wrong, let me know, and I'll be happy to fix it.  I have thick wiring between the positive battery terminal and the starter, and the negative terminal does go straight to the same bolt as the starter motor.

 

As far as wiring diagrams go, I did find another thread where it was a 81 280zx na to turbo swap, where both cars were from 81.  In the thread here, they use the same diagram as is on the website I linked to above.  That person did modify it, however, in that they also grounded a blue wire with a green stripe by the ECU (I believe it is to the inhibitor relay).  I think I found the correct wire, but for whatever reason, I am still getting zero spark.  I will upload pictures tomorrow of wiring connections to see if I have missed something from that thread, but between the diagram, and that thread, I think I have things linked up the same way they did.

 

Here is the setup for the starter and ground.

 

 

[NewZed]

Read motoman's post again.  The end of the cable from the negative post should be attached to the starter case using a starter mounting bolt.  This gives the shortest path for current back to the battery.  You have it attached to the body, so that current has to flow through the starter case, in to the block, then through those small melting ground wires to the body, on its way back to the battery.  Move the cable end to the starter mounting bolt.

 

Your positive cable end looks pretty nasty also.  It will give you problems in the future.  RockAuto has cheap OEM-style cables.

[jaromgi]

NewZed, thanks for clarifying Motoman's post.  I am sorry for my confusion, but I am still fairly new to working on cars, so I got the starter solenoid and the starter motor bolt mixed up in my head.  I did go out and purchase a new cable to do what Motoman said.  I have put the new picture below to show the new ground wire.  It sounds like it is much closer to starting; the starter engages much more readily.  It was definitely part of the problem, so thanks for the help with that.

 

 

The cable is a bit long, but you can clearly see that it is going from the starter motor bolt on the battery box, and then to the bolt on the starter motor.  I changed it to go straight from the battery terminal to the bolt on the starter motor.  

 

However, I am still not getting spark!  I checked the YW wire and the BW wire that connect to the ignition coil, and the coil is getting around 12V when the car is ON, and about 10V when the starter engages.  I am taking the ignition coil to autozone today to have them test it to see if it has somehow gone bad.

 

Also, while I was taking the ignition coil off for testing, I came across a small capacitor(?) attached to the coil bracket.  It says Shizuki 250-0.47 on it, and on the top it has a blue wire with a male connector that connects to a BW wire on the ignition wiring.   Out the bottom it has a black wire that leads to a female connector that I don't see an obvious place to connect anything to.  I can't even find the stupid thing on the wiring diagram.  Anybody know what I am talking about, or where that black connector goes?

[NewZed]

Study up on how spark is created and how the ZXT ignition system works.  It's a little bit complex and will take some thought. 

 

The Shizuki component is probably your ignition transistor, aka "ignitor".   That would explain why it won't spark. 

 

The 82 Electrical chapter will have to do.  EL-32.  Power transistor.  The case needs grounding, so there are actually three electrical connections.

[jaromgi]

Update on the car.

 

I took the unit to autozone for testing, and it ended up failing both tests.  I bought a new one and will get it hooked up today; hopefully it will fire up this time.

 

As for the piece, I saw it referred to in another thread as the "RF resistor."  The picture below is not mine, but the part I am talking about is the one in the red oval.  You can see the blue and black wires I was talking about.  I thought the ignition transistor was the part on the left of bracket in the picture, is that not right?  The plug that goes into there is where I tested the power before to see if the coil was getting power.  That has been plugged in every time.  It is possible the ground wasn't very secure, so I have tightened it down.  I will try again and let you guys know how it goes.

 

[NewZed]

You were right, capacitor/condenser/RF resistor.  The black wire connects to ground.

 

The other side of the ignitor is round.  Thought you might be talking about that.  The specs. for the coil are in the FSM but you'd need to understand primary and secondary circuits.  Hope the auto parts guys knew what they were doing.  Looks like you're making progress.

Edited August 3, 2013 by NewZed

[jaromgi]

Update #2.

 

So, put in the new coil, got it plugged in and when I turned they key, it actually got spark and ignited; it then died after a second or two.  I was excited, and went to get the wife to show her that it was starting to run.  Tried it again, and nothing; same as before, the starter motor engages easily, but the spark plugs don't seem to fire.

 

When I put a spark plug on the wire from the coil to the distributor, it sparks, but usually as a short from the base of the plug to the body of the car.  If I hold the plug away from the body of the car, there is no spark in the plug.  I made the mistake of holding the wire once and it shocked the crap out of me.  I am not even more confused as to why I am not getting spark, because it is obviously getting power!!  Same results happens when I use of of the spark plug wires coming from the distributor to the spark plugs.

 

Took off the distributor to see if anything was obviously wrong there, but I couldn't really see anything.  I will be putting it back on tonight to try again.

[jaromgi]

Put the distributor back on, still won't start.  I am going to go back through the wiring to see if I have missed anything in the connections on the battery side. where the EFI harness connects to the body electrical harness.

[jaromgi]

update.  I took a couple videos so you can see where it is getting spark, and not getting spark.  The first video is of the plug placed directly in the wire from the ignition coil.  The next video is at the plug #6 spot.

 

You can clearly see that the plug is jumping to the body in video 1, and the plug is not sparking at all in video 2.  Any input will be welcomed.

 

Video 1

 

Video 2

[Tony D]

All spark originates at the battery, and all must return there.

That means the 12 v steps up in your coil to 30,000 volts...but if its not got a path to the battery...or earth... Ultimately, you won't get a spark.

 

If you have it out the coil, and not at your plugs WHILE THEIR BODIES ARE GROUNDED AGAINST BARE METAL AT THE MOTOR, then your coil wire or distributor rotor is bad.

 

If you get nothing when holding them away from their referenced ground, that is normal.

 

Your Video 1 shows a good coil wire, you don't need the plug to test that. It shows good spark.

 

You are now down to, in order of test:

 

Distributor Cap Carbon Button

Distributor Rotor

Individual Plug Wires (if they exceed 1000 ohm/foot, they're bad, throw em out. If they are even close, chuck em!)

Plugs wet fouled from excessive cranking.

 

I would dry out your plugs and burn off fuel in the cylinders before trying again. Once they wet foul from excessive cold start cranking attempts, they will NOT dry out for days!

 

The "glow plug" procedure is elsewhere, I won't repeat it again.

 

That should do it.

Good Luck.

Edited August 6, 2013 by Tony D

[evildky]

CAS? I know the 81 is unique in that is uses a crank mounted CAS whereas the 82-83 have an optical sensor inside the distributor. I've seen the optical 82-83 fail intermittently, just wondering if your cas signal is consistent?

[jaromgi]

Thanks for the additional suggestions, guys, a couple of points of clarification, though.

 

1. When checking the carbon button on the distributor cap, what exactly am I looking for?  I has some play, but it should because it is spring loaded, right?  Am I checking for Ohms, or just that it is there?  Tried searching the forum and then google, but couldn't really find any answers on what I am looking for.

 

2. Rotor appears to be in good condition with no excessive wear or corrosion.  I'll post a pic later today.

 

3. I will check the plug wires today as well.  Just in case, I've got ahead and ordered the NGK blue wires, as I've heard really good things about them, and they are

 

4. A friend suggested checking the plugs, so I tried last night.  I pulled the #4 plug and it smelled faintly of gas, and had a slight wet spot, but overall was not damp.  I will pull each plug today, though and try to burn off the excess fuel.  Any suggestions on how?  Just stick a lighter in there (the kind with the long neck)?

 

5. glow plug procedure - looked on the forums, couldn't find anything under "glow plug procedure."  I'll keep looking, but a link would be very helpful.

[Tony D]

Propane or mapp gas torch, heat until ground electrode glows red and orange flame off plug stops, stick flame to POOF!" The cylinders clear (no puddled fuel in the manifold, right?) and stuff them in while still hot and fire it off.

 

Disconnect any cold start valve through clamping line shut and removing electrical plug.