No Start - Then Running but Rich?

[78-280Z]

Hi all,

 

Yesterday I replaced all of the fuel lines from the injectors to fuel rail. 2 of them were starting to leak. I replaced with the proper FI hose as well as clamps. After that, I started the engine up and it started and ran great. Once it warmed up, I noticed a pinhole leak in a short coolant line that was squirting a little coolant out (maybe I nicked it with a screwdriver). After that, I turned the car off, replaced the line and when I tried to start it up again - it would not. It would crank but not start. With a line on the carbon canister disconnected it would start though and idle very rough. I gave up for the night. This morning, I went to start it with everything hooked up and it started right up. However, it idles very rough - very rich it looks like by the smell and smoke. 

 

When I replaced the fuel injector hoses, I did not fully remove the fuel rail, just loosened it up everywhere and tilted it back. I had to remove the distributor cap to get access to the coolant line as well. After some research and based on the fact that it started cold this morning (probably 55F out this morning), could it be the water temperature sensor? Perhaps it thinks the engine is very very cold and it's supplying too much fuel? Can I jump the prongs on the Water Temperature Sensor (with a paperclip or something) and see if would stop supplying so much fuel? I'm weary of thinking it's the WTS only because why would it break all of a sudden? But perhaps I hit it when I was moving stuff around. I will check the resistance when I get home but would like to have some other ideas on what to check when I get there.

 

NOTE: The engine is getting fuel, spark and air. Because of this, I think it's some electrical sensor issue. I verified all of them. I pulled the spade on the starter, turned the key and saw fuel coming out of the fuel supply line. I checked all spark by pulling the spark plug wires one by one while running. Spark would jump the gap and make it from the wire to the plug. 

 

See below for pics:

 

This is the short coolant hose I replaced.

 

Engine bay in case you see something I missed or re-connected incorrectly.

 

 

The line I disconnected on the carbon canister and it ran the first day. AGAIN, this morning when it started no problem (but rough), this was connected and idled.

 

What my car looks like... so you can feel my pain about how I can't drive it right now! And I just got new tires (old ones were dry rotted). I'm ready to enjoy the open road!

Edited June 9, 2016 by 78-280Z

[78-280Z]

Disregard. Can't figure out how to delete this post.

Edited June 9, 2016 by 78-280Z

[NewZed]

You can't delete the post but you can delete all of the stuff in it.  

 

Get your thermotime and coolant sensor plugs mixed up?

[78-280Z]

I didn't disconnect them so that can't be it. I'm really hoping I just pulled out one of those bullet connectors for the WTS that's right by the fuel rail.

[NewZed]

Funny, I thought you wanted to delete the first post so I ignored it.

 

You really need to break out a meter and measure things at the ECU connector when you have those kinds of questions.  The 1980 Fuel Injection Guide is the book, very clear illustrations and instructions.  Or the 1978 FSM, Engine Fuel chapter.

 

The bullet connectors seem likely.  (Didn't see your second sentence 'til now).

Edited June 9, 2016 by NewZed

[NewZed]

http://www.xenonzcar.com/s130/other.php

 

http://www.xenonzcar.com/s30/fsm.html

 

http://www.nicoclub.com/FSM/280z/

[78-280Z]

Hi Zed,

Thanks for sticking through these problems with me. I was at work when I posted that. I knew that's what I'd do next but in case I missed something I wanted to be ready with things to try.

I replaced the bullet connectors for the WTS and it helped. Sort of. The car now runs and idles great when it's cold and up to operating temps. It hauls and is a ton of fun to drive. Up until the temperature arrow is a little past halfway on the gauge then it starts to sputter at low rpms and at idle. In the higher rpms it gets a little power back but struggles. I pulled the plugs after a drive and they are nice and brown. Much better than the black plugs from yesterday. This confuses me because the only thing that could cause the engine to stumble would be something happening in the combustion chamber. If there is a good burn happening in the cylinder, why would it stumble like that? 

 

I do own the FSM and the fuel injectio bible. I've read through them and it's how I avoid posting all of the issues I have on here. 

 

Side note, maybe related, maybe not. I checked all the spark plug wire resistances because it's the only thing (aside from the ignition coil) that I haven't replaced. The previous owner gave me a receipt that they say they are new and were replaced 6 months ago. However do not have a brand name on them - looks like someone just made them to length. 

 

Resistances were read cold after sitting all night and are:

1 - 6.96k Ohms

2 - 9.40k Ohms

3 - 8.14k Ohms

4 - 8.65k Ohms

5 - 10.43k Ohms

6 - 8.27k Ohms

 

The FSM says "Above 30k Ohms, replace". I also recall reading that they should be ~11k ohms but I can't find that page again. My question is, should these wires be replaced? Could they be a problem?

Edited June 10, 2016 by 78-280Z

[78-280Z]

PS - I was just trying to delete the second post with nothing in it.

 

Also, I'm getting a buzzing from my engine bay and it sounds like it's coming from my distributor. My cap and rotor were replaced. I tried a search and didn't find anything. When you give it gas, it changes then goes away. See below for the video: 

 

Edited June 10, 2016 by 78-280Z

[78-280Z]

I found a ton of threads of similar issues as mine but no one ever posts back with their fix...

http://www.classiczcars.com/forums/topic/30120-78-280z-rough-idle-when-hot/

 

http://forums.hybridz.org/topic/113290-77-280z-rough-idle-after-warm-up/

 

 

and so on...

[NewZed]

That noise sounds more like an alternator whine or maybe a vacuum leak in a hose.  Kind of high frequency.  Have you checked the air gap on the distributor reluctor?  Might be rubbing.

 

Have you checked fuel pressure, and the vacuum hose to the FPR for fuel?  Sometimes the diaphragm leaks, making things rich, even though fuel pressure looks right.  Pull the hose and see if it has fuel in it, or pull the hose and run the pump to see if it leaks.

[78-280Z]

Zedd,

 

I'll have to check the air gap tomorrow. It could be that. When I retard the timing on the distributor, the sound goes away. It must be there somewhere.

 

Also, it seems I figured out what my problem is. When you unplug the harness for injector 1 and 2 when the car is running (but stumbly), nothing happens. When you disconnect another one, car dies. So this tells me injectors 1 and 2 aren't functioning. I did the tests from the Fuel bible. There is battery voltage going to the harness for each injector. Each injector has ~3-4ohms of resistance which I guess is normal for a low impedance injector. I can also hear them clicking when i supply 12V to each. This tells me electricals are all in order. I guess they must both be clogged? The reason I'm hesitant to believe it is because the PO gave me a receipt that he had them professionally cleaned 6 months ago. The car also runs great half of the time. Then all of a sudden it gets stumbly and that's when I pull the injector connector and nothing changes for 1 or 2. Is there any test I'm missing?

 

I did check fuel pressure a few weeks back and it was within range ~32psi or something like that. I remember verifying at the time.

Edited June 13, 2016 by 78-280Z