280Z Difficulty starting

[Zed Head]

They look great.  Have you moved on from the starting problem?  Plug condition is more of a running engine thing.

 

If you wanted to try something on the starting problem, you could wire your CSV to a switch and give the engine a shot of gas before every start.

 

My engine takes longer to start if it's been in a cool garage overnight compared to sitting out in the sun.  If it's been sitting in the cool garage it takes noticeably longer than if it's been sitting in the sun for a while.  In the sun, it fires up right away.  I move my car in and out of the garage often by rolling it, since it's easy, so I've noticed this garage-effect.  Residual fuel pressure would be about the same so I'd guess that it's just the rate of vaporization of the fuel.  The engine and manifold are warmed by the sun so the fuel vaporizes and lights off faster.

 

This is actually a problem that the government and fuel companies have addressed with "winter-grade" gasoline.  They increase the volatility so that engines start faster and run well sooner.  I've never seen the exact reasoning described but I would think that a poorly running engine blowing some unburned fuel out the back on startup is a bad thing.  Your problem might go away in the fall and winter.  Fuel quality varies across the country.

 

You might also check your timing and the distributor advance.  If the vacuum advance is stuck it might affect starting behavior.  Just one thing I haven't seen mentioned.

[Marios280Z]

Zed Hed, I have not moved form the starting problem yet. It's quite annoying. Captain Obvious has asked how my spark plugs looked like, so I did a check. I've never done either of the two things you mentioned at the end of your post.  I know I would need a timing light to check my timing, but I'm not even sure how to do it. Neither do I know how to check the distributor advance. Will I find info about those two things in FSM? I think I recall reading something about the timing, but that's about it. I will do some research on World Wide Web about those timing and distributor advance.

[Zed Head]

Yes, it is described in the Engine Tune-Up chapter of the FSM.  The initial timing number should also be on the inside of the hood of the car.

 

But inspecting the breaker plate for sticking is not.  It's just one of those old Z car things, they tend to get rusty eventually.  But the first thing to do is to check your timing.  If the breaker plate is stuck it will be advanced.  

 

If you do check timing with a light, you can spend some time revving the engine and watching what happens to the timing.  There are two mechanisms to advance (increase the number) the timing, once is centrifugal (RPM-based) and the other is controlled by intake manifold vacuum.  It's the vacuum controlled piece that gets stuck.

[Marios280Z]

But inspecting the breaker plate for sticking is not.  It's just one of those old Z car things, they tend to get rusty eventually.  But the first thing to do is to check your timing.  If the breaker plate is stuck it will be advanced.

 

Zed Head, is the location of the breaker plate also described in the FSM? If it is , I will find it. If not, can you point me to it?

 

Also, this morning after first unsuccessful attempt at starting. I went in and unplug the water temperature sensor as it was suggested few posts earlier. The result was that the car started right up on but as it was also mentioned (forgot who said it) that the car would run like crap, and it did started to stumble shortly after it fired up nicely. I then turn the car off, reconnected WTS and the car started nicely again followed with smooth operation. I will perform this test couple more times to make sure it wasn't just a fluke. Perhaps the new WTS I put in isn't really working correctly(just a reminder, the starting problems began before I replaced the WTS), or the signal between the sensor and ECU gets corrupted in some way.

[Captain Obvious]

OK, so on two different days it was giving you trouble starting and on those two different days you tried two different things things... First day you gave it a shot of starter fluid and it fired right up. Second day you unplugged the WTS and it fired right up. Seems pretty clear that it really wants more fuel in order to start. The question now is "why?"

 

And this test:

 

this morning after first unsuccessful attempt at starting. I went in and unplug the water temperature sensor as it was suggested few posts earlier. The result was that the car started right up on but as it was also mentioned (forgot who said it) that the car would run like crap, and it did started to stumble shortly after it fired up nicely.

 

Did exactly what it is supposed to do. With the WTS disconnected, your ECU put in WAY  too much fuel. The engine liked it at the very beginning, just  to start the engine. But once the "starting process" was over, it was way too much fuel for the engine to burn and it probably belched black eye burning smoke.

 

But your reminder that the problems started after you put in a new WTS is interesting. The water temperature sensor is what they call an RTD ("Resistance Temperature Device" or "Resistance Temperature Detector") and it is made up of a piece of something (often a short length of platinum wire) that changes resistance with respect to temperature. There are lots of different RTD's with different R vs Temp curves and it's possible you accidentally got one with the wrong curve.

 

Do you have an Ohmmeter you can use? Take some resistance measurements to compare your old and new water temp sensors? Here's the FSM page that lists a couple temperatures and the corresponding resistances. The ranges are pretty wide, but it might highlight an anomaly:

 

 

And I agree about the plugs, they look pretty good. A little rich maybe, but not enough that it would be at the top of your priority list. They certainly aren't scary lean that would make you be looking for a huge vacuum leak. I would reevaluate the plugs again after you get the starting issue worked out and have some miles on the car.

[Marios280Z]

Thanks CO. Just a correction, the starting problems have started BEFORE I replaced WTS , NOT after I replaced it. I have performed the resistance test as you indicated in the FSM snap shot and the result I got seemed to be correct. That being said I'm using a crappy volt meter that I don't know any more how much I can trust. I do have the old WTS, so  I will compare them when side by side when they achieve same ambient temperature. I will try retrace the signal from the WTS to ECU and also perform the WTS resistance/voltage test at the ECU connector.

 

I do agree with you.The fact that on two different occasions/tests the lady acted way more enthusiastic when she got an extra amount of fuel (starting fluid in one case, fuel in other) does indicate that I'm running lean on start up.

 

Just a note,  I will be going on vacation tomorrow morning for a week and I will be off the grid. So there will not be any updates for a while.

[Chickenman]

Throughout this thread, I've noticed that you always seem to use this " Priming " method of turning the key on and off multiple times before actually trying to start the car. Have you recently tried just getting in the car and just starting it by just turning the key once?

 

I'm wondering if you are triggering a " flooded engine " procedure in the ECU by turning the key multiple times or something similar?

 

Edit: And don't let go of the key so quick. Let the engine catch first. I sometimes have to hold the starter in on my 280Z ( on Hot starts ) till she clears a few cylinders and catches.

Edited August 20, 2015 by Chickenman

[Chickenman]

 

Keep in mind that the car has not been driven in few days now and all I have been doing was starting it cold and running no longer than 1 minute at the time, never reaching operating temperature.

That is not a good thing to do. That will Carbon foul plugs and make it difficult to start the engine all by itself.  Even new plugs can get Carbon fouled in short order by repeated short runs with the engine not reaching operating temperature. A fresh set of plugs often works wonders. What's you plug gap set to?

 

BTW..  I just noticed that you use 8MM Taylor ignition wires. Taylor has had a bad reputation for poor quality plugs leads. Especially their standard, Universal  " Carbon core " resistance wires . They ( resistance core )  are just junk. I'd take those plugs leads off and check them with an Ohm meter. Post the results here. I've seen new Taylor " Resistor " wires with incredibly high resistance values. Their spiral core wires should be OK... but the resistor core ones.... well lets just say there are better products available.

 

Spiral core or Helical core wires by NGK, Magnacore or MSD are some of the best brands to buy. Aurora leads ( Custom built ) are also very, very good....and have a lifetime warranty.

Edited August 20, 2015 by Chickenman

[Marios280Z]

Throughout this thread, I've noticed that you always seem to use this " Priming " method of turning the key on and off multiple times before actually trying to start the car. Have you recently tried just getting in the car and just starting it by just turning the key once?

 

I'm wondering if you are triggering a " flooded engine " procedure in the ECU by turning the key multiple times or something similar?

 

Edit: And don't let go of the key so quick. Let the engine catch first. I sometimes have to hold the starter in on my 280Z ( on Hot starts ) till she clears a few cylinders and catches.

What originally triggered me to do this priming approach was the fact that after installing inline fuel pressure gauge it was very clear that the fuel pressure in my fuel line was dropping to 0 after few hours. I did have the problem BEFORE I installed the gauge and therefore before I was priming the fuel pressure.  I could try few times without the priming and see if it makes any change now that I have cleaned so many of electrical connections under the hood. Just keep in mind that at this point we are leaning towards the theory that I'm actually running lean on start up, not rich, because with an extra fuel (starting fluid squirt) or disconnected WTS (ECU provides more gas) the engine starts much easier. 

 

The reason why I let go off the key so quickly is because as soon as the engine tries to catch the starter makes this "grinding" noise just like it would if you attempted to crank already running engine. I'm not too familiar with an operation of a car starter so I don't really know what happens inside when I crank the engine and right when it caches. I just don't want to destroy my starter. I know one of the guys Capin Obvious or Zed Head, I think,  has mentioned something earlier that in the videos he was noticing that my starter was acting strange but later on somebody else said that he didn't see anything wrong with how the starter operated...

[Marios280Z]

That is not a good thing to do. That will Carbon foul plugs and make it difficult to start the engine.  Even new plugs can get Carbon fouled in short order by repeated short runs with the engine not reaching operating temperature. Sometimes a fresh set of plugs works wonders.

 

BTW..excatly what plugs do you have in there now?

My plugs are currently NGK B6ES 11, one of the plugs listed in FSM. They are just few months old.

[Chickenman]

( Snip ) Just keep in mind that at this point we are leaning towards the theory that I'm actually running lean on start up, not rich, because with an extra fuel (starting fluid squirt) or disconnected WTS (ECU provides more gas) the engine starts much easier. 

 

The reason why I let go off the key so quickly is because as soon as the engine tries to catch the starter makes this "grinding" noise just like it would if you attempted to crank already running engine. I'm not too familiar with an operation of a car starter so I don't really know what happens inside when I crank the engine and right when it caches. I just don't want to destroy my starter. I know one of the guys Capin Obvious or Zed Head, I think,  has mentioned something earlier that in the videos he was noticing that my starter was acting strange but later on somebody else said that he didn't see anything wrong with how the starter operated...

I understand it's not getting enough fuel. What I was trying to communicate is that by turning the ignition switch on and off multiple times you may have accidentally  triggered the " Clear flooding " circuit in the ECU. That will reduce the the amount of fuel injected during start-up. Since the engine is not actually flooded, you get very little fuel injected and thus it's hard to start.

 

I haven't checked all the Parameters for the " clear flooding " flow chart... but the ECU does have that capability.

 

As mentioned before. There is something wrong with your starter. It shouldn't " kick out " like that. Usually it's because of a bad Bendix or  a weak pull in solenoid. But the " kick out " is not normal.

Edited August 20, 2015 by Chickenman

[Zed Head]

Pretty sure that in 1978 the closest thing to "clear flooding mode" that the EFI system has is the "avoid flooding" feature of the heating element in the thermotime switch.  The technology is primitive.

 

And CO has proposed that the "priming" that is being done is actually an artifact of a slow-reacting fuel pump control relay.  It's not a design feature, it's an error.

 

I think that the starter licking out doesn't show up on all of the videos.  But my 1978 parts car did that and it made starting a pain.  I had to keep trying until I got a good catch.  If I recall right, the starter had some damaged teeth.  Cause or effect, I'm not sure.