83 280ZX won't start, won't fire. Just turns over.

[jmw_man]

Hi all,

It's been a while since I posted.

Anyhow, my Z has started giving me problems after running pretty good for the last year. This problem started about a couple months ago. One day I got in it and tried to start and it just turned over and over and over and I never heard the sound of ignition as if there was no fuel or spark. Then moments later it fired right up.

As the days progressed since then, those moments between not firing to firing right up increased to the point now that it won't fire at all.

First off I want to point out that I've done some browsing around the internet for other people having this problem and I have found forum thread of such people. The PROBLEM is, those threads were largely unanswered or the OP never came back to update as to what was causing his Z's problem.

Spark, air, and fuel right? Well,...

Air - Nothing looks suspicious there.

Fuel - I hear the fuel pump. I haven't checked the pressure yet but the pump is definitely working. Fuel is also definitely making it past the filter too. I say this because I noticed a tiny fuel leak near the injectors. More specifically, the number 3 or 4 injector. The line that goes to it will get soaked which I find really odd. I need to look into that further but I think that might be a separate issue. Let me ask this. Is it possibly my injectors are clogged enough that this could happen? Also, maybe someone can shed some light on this question but does the injector ONLY squirt fuel when it receives a signal from the computer? This is something I need to look into. I have pulled the control unit or whatever it's called and checked all the pins and everything that's supposed to have battery voltage does have battery voltage including the 6 pins that go to the injectors. FYI, I have the E.F.I engine I believe because I have a cold start valve. If I remember correctly the E.C.C.S engine doesn't have the cold start valve. Anyways, I was going through the EFEC section of the FSM, particularly pages 83 and up to check the control unit. All of the injectors had voltage. As far as diagnosing a possible fuel problem, I just need to know if it's possible for 6 injectors to all clog in the same timeframe. I also need to learn how to test each individual injector. I can't imagine that all 6 injectors have stopped receiving voltage at the same time. Maybe someone knows what I'm talking about.

Spark - It's not the coil, I changed it out, still experience intermittent starting with new coil. I doubt all spark plugs went out at the same time. Is it possible that the timing could be soooooo faaaar off that it won't fire? I can't imagine that being possible. Everything looks normal under the distributor cap. Can someone point me in the direction of a list of steps to further my diagnosis?

Thanks,

jmw

[Zed Head]

Check for spark first. Make sure it's a good solid blue spark, not a weak thin yellowish spark. If you have no spark...

A bad ignition module or dirty connections at the ignition module are a possibility. They're in a dirty. dusty spot and the rubber seals and wire insulation tend to get baked and cracked. The module and coil need a good voltage supply to create a good spark. When the engine is cranking voltage drops. A few more lost volts due to dirty connections could be enough to weaken the spark during starting.

Finally, when did you last give it a tune-up? Worn, dirty spark-plugs can cause problems.

[jmw_man]

Check for spark first. Make sure it's a good solid blue spark, not a weak thin yellowish spark. If you have no spark...

A bad ignition module or dirty connections at the ignition module are a possibility. They're in a dirty. dusty spot and the rubber seals and wire insulation tend to get baked and cracked. The module and coil need a good voltage supply to create a good spark. When the engine is cranking voltage drops. A few more lost volts due to dirty connections could be enough to weaken the spark during starting.

Finally, when did you last give it a tune-up? Worn, dirty spark-plugs can cause problems.

What's the best method for checking for spark if you are alone and don't have a second pair of hands to rotate the engine?

I'll inspect the ignition module. Um, can you point me towards the section of the FSM that covers this? I'm browsing it right now and I can't seem to find any mention of the ignition module.

I put in new plugs maybe a year or so ago if I recall correctly, along with new wires, dizzy cap and rotor.

I also have the IC type distributor, anything in there I need to check?

Edit: I just saw a google image that shows the ignition module is attached to the distributor, I'll look there.

Edited October 10, 2014 by jmw_man

[EuroDat]

The IC's I have played with generally don't give problems when cold, but Zed Head said is a good point. They need good voltage to work. If the voltage drops off to much they will stop triggering. You should run through the checks in the FSM and make sure all the wiring for the ignition is ok.

I would also invest in a gauge to messure the fuel pressure. It could also be suffering leak down through the check valve in the pump of FPR and it taking time to build up pressure again. A gauge can tell you a lot here.

Goodluck

Chas

[jmw_man]

The IC's I have played with generally don't give problems when cold, but Zed Head said is a good point. They need good voltage to work. If the voltage drops off to much they will stop triggering. You should run through the checks in the FSM and make sure all the wiring for the ignition is ok.

I would also invest in a gauge to messure the fuel pressure. It could also be suffering leak down through the check valve in the pump of FPR and it taking time to build up pressure again. A gauge can tell you a lot here.

Goodluck

Chas

The sucky part is that I noticed many of those tests require a second pair of hand to crank the engine while you use a voltmeter. I wish there was another way. Anyways, I can at least inspect the wiring.

I have the fuel pressure gauge, just haven't gotten around to checking the pressure (or been spending too much time on the mustang). What does FPR stand for?

Edited October 10, 2014 by jmw_man

[Zed Head]

One of the handy features of the Z's and ZX's is that the hood opens forward. Get some 1 - 2' test leads with alligator clips on each end and set the meter up where you can see it from inside the car.

[jmw_man]

One of the handy features of the Z's and ZX's is that the hood opens forward. Get some 1 - 2' test leads with alligator clips on each end and set the meter up where you can see it from inside the car.

That's exactly what I did, .

Well, I did two tests. Although, I need guidance.

I went out there and first inspected the ignition module and the two connectors that are plugged into it. They looked dirty but I didn't clean them yet. The two tests I did are from pages EL-28 and EL-29 from the FSM steps number 5 and 7. First I want to point out that the FSM doesn't seem clear to me whether I'm supposed to connect the lead to the female or the male connector.

Step 5: When I hooked it to the connector that's on the ignition module side, the voltage read .7 volts. When I hooked it to the connector that's on the wire side, the voltage read 11.98 volts. Which side was I supposed to connect it to? I'm guessing the latter.

Step 7: When I hooked it to the connector that's on the ignition module side, the voltage read 0 volts. When I hooked it to the connector that's on the wire side, the voltage read 11.98 volts. Again, which side did they mean for me to connect it to?

In both of the above scenarios it was supposed to read between 11.5 and 12.5 volts so if in both scenarios I'm supposed to connect it to the wire side then both tests were good.

I also want to point out that a couple weeks ago I had already tested the coil secondary and primary resistances, step 4 and step 8. Step 4 was good as it was in the range of 8200 to 12400 ohms. However, step 8 had a reading of 2.1 ohms. 2 weeks ago I assumed my coil was faulty so I bought a new one. The new one had a primary resistance of 2 ohms as well and so did the second new one. So, I returned the two new coils and just kept the old one. That particular reading was supposed to be between .84 ohms and 1.02 ohms. I'm not sure why the primary resistance is so high on the new coils.

Anyways, after doing the step 5 and step 7 tests, I used my can of electronic cleaner and cleaned all connectors attached to the ignition module and retested. I came back with the same results. So far I feel like I haven't really narrowed down to anything. I then decided I'd give her a try and crank her up. Well she fired right up. So I don't know if that means my tests were null and void. That's why I hate intermittent problems like this.....

Next I plan to test the fuel pressure. Since I got it running I unplugged the wire that goes to the fuel pump and let it die to depressurize. I'll try to get back out there to hook up my fuel pressure gauge.

[Zed Head]

The test connections are at the connector/plug ("receptacle" = receiver) so your second tests were correct, and results look good. I would do Test #6, since that measures voltage during starting. Your starter could be drawing too many volts or your battery could be weak.

I would also do something similar Test #9, since the module grounds through the distributor body, except Iwould just measure resistance to ground. The ground is the other important part, that allows current flow. You can have correct voltage but low current and have problems. Measure resistance from the distributor body to the engine block. I don't know why they test voltage drop with the coil discharging. It seems like a good way to make a mistake and damage the module. Check the ground first.

[jmw_man]

The test connections are at the connector/plug ("receptacle" = receiver) so your second tests were correct, and results look good. I would do Test #6, since that measures voltage during starting. Your starter could be drawing too many volts or your battery could be weak.

I would also do something similar Test #9, since the module grounds through the distributor body, except Iwould just measure resistance to ground. The ground is the other important part, that allows current flow. You can have correct voltage but low current and have problems. Measure resistance from the distributor body to the engine block. I don't know why they test voltage drop with the coil discharging. It seems like a good way to make a mistake and damage the module. Check the ground first.

On test number 6 and 9, I didn't do because I wasn't sure if there was a specific way I should ground the coil wire. Isn't the coil wire some kind of positive voltage and grounding it would be bad for the battery or something? Do I just use my jumper wires and connect it to the coil wire and a ground somewhere and not worry?

[Zed Head]

Oops, I missed the fact that Test 6 asks the same thing.

What they want you to do is to ground the center wire of the coil, the big one that's the same size as a plug wire, to the block so that the current from the coil has somewhere to go. So that you can crank the engine over without the engine starting. So pop the wire out of the distributor cap. leave it connected to the coil, and place or clamp the metal end against a solid piece of metal on the engine block. Just make sure that it's solidly placed, if it gets loose it can spark to things that shouldn't get spark. And if it's too far away to spark, the electrical pulse can do other damage if it has no way to discharge. As I understand things. The spark from that wire will be a big one.

[jmw_man]

Fuel pressure readings:

Turn key to on, fuel pump turned on for 5 seconds, pressure went up to 32 psi. Started car, fuel pressure was steady around 28 psi.

[siteunseen]

How old is the fuel filter? They're $15 at chain parts stores and always better than the one you have now.