Noobie here needs Fuel pump help!

[JRSGTS]

Thanks Sarah. Wondering when I'd find you on here... I'll try those tips. It will start better with the CSV unplugged. However I still am clueless on this coolant switch. Can't find one anywhere easy. I'll call Zcar source but it will be a week out...

Came up with another question.. Should this car have an O2 sensor? Cause it doesn't....

[Zed Head]

Looks like you're using the EFI Handbook for your testing. The Handbook is a generic document for the 280Z's and/or the 280ZX's, depending on which version you have (1975 or 1980). You should start working from the FSM, with its information and diagrams that are specific to 1976. Read the first few pages of the Engine Fuel chapter and the Emissions chapter. They describe all of the weird little devices that you're working with. Then do your circuit testing from the ECU connector. Then you'll know if the wires and connections are adding resistance or shorted.

Many people remove the CSV system entirely, the switch, the valve and the fuel lines. Cars are designed for a very wide range of environments, and I think that the CSV is for people in the mountains or the midwest. If you're worried about it being stuck open causing richness, just block the fuel line for a test.

Index of /FSM

[JRSGTS]

I'll try that. I was able to move it. Starts like crap, but sorta clears at higher RPM. The owner came by and I tried to show him...It started on 3 cyl. then never cleared. Now it won't even try!! UGH. and that was with the CSV disconnected. With the plug off it can it still spray fuel? I suppose if it was stuck open right? I don't think that's my big problem any way because I was seeing such a bright"Noid" light. Could my AFM be the culprit?

Also, have tried nearly everywhere for a coolant switch...Not in production for the 76 anymore....UGH!B I'm walking away to get the fuel fumes out of my head...

[Zed Head]

It's really hard to emphasize!!!@@@## how much better and smarter you'll feel!!! if you run the resistance test for the coolant temp. circuit from the ECU connector!!! Once you know that the ECU sees what it should see!@#$#% then you can stop guessing and buying parts @#%%$

Seriously, just unplug the ECU connector, measure resistance to ground at the right pin (13? I believe, it's in the Engine Fuel chapter) and compare the number you get to the chart in the FSM (it's in the Handbook too I think).

You can do many of the other component checks also, like the injector circuit, Pin 1 to coil, etc. It's much easier than it seems and really, it's where everyone should start.

[JRSGTS]

I promise I'll do that as soon as I PUSH it back in the shop... I had to move it out to finally get some other work done around here.... I did go back before dark after leaving the plugs out a while and letting it dry out a couple hours. It was probably in the upper 30's by then. Put the plugs in, lots of battery, rolling over fine. It barely tries to start maybe twice, then nothing, just spinning won't even sputter. This is with the fuel line to the CSV removed and plugged. I check the inj. #1 and #6 I'm getting wicked bright flashes every third....Then it goes to dim flashes. First time I have ever seen it do this. Checked both inj. Same result, so I think great it won't flood out. Keep trying to start, won't even try... Figure it's already flooded, pull the plugs. They're not that wet....Blow out the Put all the plugs back in the wires and spin the motor. My sparks all F'd up! I got fire on 6 and 1, intermittent on a couple others, The battery starts to tire by then, I just threw some hair at it and walked away...

I will do the resistance test. But the sensor is new now. I doubt there is any issue there. Something is/was firing my injectors way to much. I do plan on pulling the whole rail off and see how they fire and if they leak. I wish the damn thing could at least spit out codes. I'm wondering if the ECU was hurt from being wired wrong? Who knows who jumped power and grounds where before I got here.

I really am sorry for how long this has dragged on. I'm very grateful for all of your help and patience.

JR.

[superlen]

JR,

You may be at the point it's time to swap out with a known good ECU and make sure it didn't get tweaked a little too much with whatever crazy wiring combinations it had before it reached your shop. If you don't have one available, pm me. I have a few and can ship you one to test with. I just need it or your old one back after you test.

Also the resistance check will confirm the wiring connection from the sensor to the ecu. The pigtails up there are a problem area & this test will confirm that they are either good/bad.

Lenny

[FastWoman]

A worse problem spot than the pigtails, IMO, is the (very likely) crusty and half-rotted Bosch-style connector that mates to the spanking new coolant temp sensor. It takes quite a lot of abuse up there at the front of the engine. The connectors on my thermo housing sensors were in crumble-in-your-fingers condition, with a lovely green patina on what was left of the metal bits. Replacements are plentiful enough. Check out this ebay auction for a complete EFI harness connector replacement kit! Woohoo!

A10B1F1 Datsun L6 Wire Harness Connectors Repair Kit afm TPS Fuel Injectors | eBay

And I've bought the two-pin connectors from this guy, who is an upstanding gent:

Injector Connector Kit 6pc Datsun 280z 280ZX 300zx | eBay

There would be no reason I can think of for the injection pulse to be very long (bright flash) and then drop to very short (dim flash), OTHER THAN an intermittent open circuit on the CTS circuit. Well, either that or the ECU is bad. My vote would be for the bad connection.

[Zed Head]

I've had one bad ECU and its death characteristics were to die instantly, come back to life for about 1/2 mile, die again, start again, die again, flood the engine with fuel, then never start again. I replaced the two injector transistors and got it to work again (just for fun, not because I knew what I was doing) but have only taken it for a test drive since then.

Something to consider is that the transistors used for the injectors are very similar to those used in the ignition module, and ignition modules do weird things before they crap out for good.

[JRSGTS]

Len, That sounds very helpful! After I get it back in the shop and do those other tests, I will let you know. Sarah, The connector was intact with a Minor bit of visible oxidation. I have some micro files, so I cleaned it up real good. The plastic and the wire clip are still in decent shape. I will confirm all condition with the resistance check. I did see the connectors on Ebay. I was looking for a temp. switch. (They don't exist anymore). I think I can buy those connectors at Advance also should I need one.

Zed, I am concerned about the ign. Module, and or the dist. pick ups. Z car source just rebuilt this distributor, so I really hope its ok. Don't know if all this abuse has hurt it. When I pulled it out of the shop it would run, terribly, but it would run. I was trying to start it for the owner, it tried then stopped even trying. Something let go. Not surprising. This thing is beginning to get to me...

[JRSGTS]

Another thought, What about the air temp sensor in the AFM? The AFM passed the resistance checks and a saw change on my meter with flap movement. Though I didn't watch it carefully to see if it was perfect or not. I saw resistance drop so called it functional, but doesn't the temp sensor have bearing on inj. pulse?

[FastWoman]

The air temp sensor plays a much more minor role in fine-tuning the mix. I doubt a problem with that sensor would result in the magnitude of problem you're having. Besides that, I don't recall anyone ever having a problem with the thing going out or suffering a bad connection (via the AFM connector). FAIW, I think it has the same thermistor as the CTS, and yet it lives a much more sheltered life.

Regarding the distributor pickup: If you've got spark, it's working fine. Apparently the biggest problem with the distributor pickup is setting the gap correctly. Some rebuilds have too wide a gap. Worse, some rebuilds come back with a bent shaft that wobbles and yields an inconsistent gap.

Reason to believe your ignition is working fine: You're getting the "noid" flashes once per rotation, right? Without the ignition firing (which requires triggering by the distributor pickup), the ECU wouldn't count and wouldn't inject. As RPMs increase, the distributor pickup should put out a cleaner, higher-voltage signal, so if the pickup works well enough when you're cranking, it should work even better when the engine is actually running.

Edited December 4, 2013 by FastWoman

[FastWoman]

But honestly, you should just read the #13 pin resistance at the ECU. Just remove the interior driver kick panel, and there's the ECU. Pull off the big, hunkin' connector, and the world's your oyster. We can't emphasize that enough! (Well, Zed gave it a pretty good try, I think -- post 52. ) Nothing will tell you what the ECU "sees" like measurements taken from that connector.

Oh, and you had asked about the O2 sensor. (Had that been answered?) The Z don't need no stinking O2 sensor (to paraphrase the movie). The ECU only has open-loop mode, with no lambda feedback. Primitive!

Edited December 4, 2013 by FastWoman