Jump to content
HybridZ

Something shorted out...


JagdStealth

Recommended Posts

'72 240Z with an '81 L28ET in it

 

Yesterday while driving, the battery shorted out and caused the car to eventually die as I was driving. The battery tie down broke off it's stay and let the battery fall off the shelf resting against the block. I'm not sure how long it drove like that, but no more than a couple miles.

 

Initial diagnosis looked like the coil was bad (no spark), so I tossed an MSD Blaster2 out of an old Dodge I have. This got the car to start only if you floored it...and then it only ran on ~3 cylinders if you kept the throttle on.

 

So far I have:

1. swapped to a spare ECU

2. cleaned cap and rotor

3. cleaned plugs and checked all plug wires

4. swapped coil to MSD Blaster 2 (from an old Dodge, I know it works)

5. swapped AFM

6. Checked all fuses under the radio

7. Checked grounds

8. Unplugged what I think is the cold start sensor (passenger side, rear middle portion of block)

 

I'm stumped as I can't get the car to run at all, does anyone have any ideas?

Link to comment
Share on other sites

Dont forget all the alternator and starter wiring on the passengers side of the block. Make sure nothing got disconnected, or the battery broke a connection loose when it fell. Other than that it sounds like your car and a multimeter are going to have a good relationship in the near future :)

Link to comment
Share on other sites

Just checked some more stuff...

 

All original equipment hooked up as it was when the problem started.

 

1. No spark at sparkplugs

2. Checked voltage to coil, only 4V (Ignition switch on, voltmeter from negative terminal to ground)

3. Checked voltage at the positive wire of the ignitor thingie, 12V

 

So I'm thinking the ignitor is bad? 12V going into it, but only 4V when it comes out and connects to the coil?

Link to comment
Share on other sites

Just checked some more stuff...

 

All original equipment hooked up as it was when the problem started.

 

1. No spark at sparkplugs

2. Checked voltage to coil' date=' only 4V (Ignition switch on, voltmeter from negative terminal to ground)

3. Checked voltage at the positive wire of the ignitor thingie, 12V

 

So I'm thinking the ignitor is bad? 12V going into it, but only 4V when it comes out and connects to the coil?[/quote']

 

Check the fusible links too.

Link to comment
Share on other sites

Where would they be on the L28ET? All I hve found so far is old Bus Fuses that the 240 came with...the previous owner installed the motor and it looks like he probably by passed some fuses...

 

It seems to hard to find an ignition module, I can only find one store that carries it and they list it for a CA18DET, which I know isn't right.

Link to comment
Share on other sites

Is there a procedure for checking them? I don't have the shop manual for the car and the Haynes manual I have doesn't list how to test them.

 

It seems to hard to find an ignition module' date=' I can only find one store that carries it and they list it for a CA18DET, which I know isn't right.[/quote']

 

I believe it is the black box infront of the battery...just remove the cover or remove the box from the fender well and get a volt meter. It is just a series of wires that route the 12V power throughout the car...I believe the alternator runs too it, the fuel pump, and I forget what else goes there. If your battery grounded out most likely those wires have burned in half. Should be easy to see.

 

Good luck

Link to comment
Share on other sites

Well, my car has no fuseable links on it, it's all just wired up and there are a couple of inline fuses here and there (nothing on the ignition side).

 

I orderd a new Ignition module and I hope that's the problem.

 

It's impossible to find these stupid things so for anyone in the future who searches here are 2 part numbers I have found:

 

Standard = LX1001

Neihoff = WA913L

 

...both of them are around $200 :(

Link to comment
Share on other sites

Just for others to read...

 

No love on the ignition module fixing the problem.

 

12V go into the module and 0V go to the coil. I tried running the coil straight to the battery and still no spark. I guess something isn't telling the coil to fire...maybe the CAS?

 

ANyone with ideas?

Link to comment
Share on other sites

An 81 get it's signal from the main pulley I believe...I'd check that the 82-83 motors have a built in CAS in the Distributor.

 

 

Just for others to read...

 

No love on the ignition module fixing the problem.

 

12V go into the module and 0V go to the coil. I tried running the coil straight to the battery and still no spark. I guess something isn't telling the coil to fire...maybe the CAS?

 

ANyone with ideas?

Link to comment
Share on other sites

Well I've replaced a bunch of wires and here's where I'm at...

 

12V to the coil when ignition is on, but no spark at all from the coil. I can manually put power and ground to the coil from the battery and it will spark, but nothing when hooked up properly.

 

If I run a ground wire from the negative side of the coil to the body, I get a single spark when going to the accessory position, but nothing when turning over.

Link to comment
Share on other sites

Just an "update"...

 

1. Replaced Coil

2. Replaced Power Transistor (ignition module)

3. Replaced CAS

4. Replaced Ignition Switch

5. Replaced ECU

6. Checked continuity along all wires

7. Checked for proper voltage for fuel injection and ignition system on all wires

8. Checked all fuses (no fuseable links on this car)

9. Ran new grounds from Engine block, intake manifold, power transistor, ECU

 

Not in the order above, but that is all I have done to this point

 

I have 12+V going to the coil when "on", I get ~11.5V to the coil when cranking. I do not get ANY spark from the coil.

 

I'm completely out of ideas at this point. :mad:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...