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Power to injectors


DC871F

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2 hours ago, DC871F said:

SO, I just went out and checked with the noid with the ECU grounded, and yes, pulsing, a long road to this discovery, but I'll take it. Still no fire off.

Injectors next.

Did you mean no clicking?  That's one thing, that indicates the injector solenoid is moving the injector pintle.  Whether good fuel squirts when that happens is another thing.

The key to troubleshooting the EFI system is to isolate the various actions that are supposed to happen.  Sounds like you've done that with the ECU grounding process, which also confirms the signal from the coil negative terminal.  If "pulsing" means the noid light flashed as the engine turned over.

One of the hardest things about talking on the forums is describing what's happening.

p.s. the ECU is grounded through its own pins in the harness.  It doesn't need the ECU case grounded.  But that does bring up the other end of the power circuit - the ground point for the EFI harness.  Sometimes people have problems if that connection is dirty or broken.  You can check the ground at the ECU connector also, the pin numbers are on the diagram.

ZX ground.PNG

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1 hour ago, Zed Head said:

Did you mean no clicking?  That's one thing, that indicates the injector solenoid is moving the injector pintle.  Whether good fuel squirts when that happens is another thing.

The key to troubleshooting the EFI system is to isolate the various actions that are supposed to happen.  Sounds like you've done that with the ECU grounding process, which also confirms the signal from the coil negative terminal.  If "pulsing" means the noid light flashed as the engine turned over.

One of the hardest things about talking on the forums is describing what's happening.

p.s. the ECU is grounded through its own pins in the harness.  It doesn't need the ECU case grounded.  But that does bring up the other end of the power circuit - the ground point for the EFI harness.  Sometimes people have problems if that connection is dirty or broken.  You can check the ground at the ECU connector also, the pin numbers are on the diagram.

ZX ground.PNG

No Clicking. I have also pulled some spark plugs to see if they were wet, and they are not. So if ECU has its own ground, I may have missed the noid lights in the bright conditions in the shop yesterday, they are kind of dim.

If the noid shows pulsing, I'm going to assume the ECU is doing its job, correct? The injector harness is intact, then the next place to look is going to be the injectors. It's bothersome though that all 6 would be bad/clogged, but I guess its not outside reality.

Thanks again. I'll figure this out eventually. 

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Removed injectors, all were stuck, got them to finally click after a lot of coaxing from a 9v battery, one of them wouldnt budge at all. 

I'm glad I found something.

Edited by DC871F
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Stick a Q-tip up in to the fuel rail and see if it's rusty.  My sticky injector engine had rust in the rail.

My first engine started and ran pretty well, but when I tested the injector with a home-made testing rig, they were all unbalanced.  You could really feel it when the engine was running too.  So, odds are, you'll be best off to get "new" injectors.  I put the parens on because I've had old Nissan injectors that were in great shape internally, even though they were all rusty on the outside.  If you wanted to look for used.

But, several people have used the Standard FJ707 injector and like them.  But it looks like the price has gone up quite a bit over the years.  Ouch.

http://www.rockauto.com/en/catalog/nissan,1982,280zx,2.8l+l6,1209350,fuel+&+air,fuel+injector,6224

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55 minutes ago, Zed Head said:

Stick a Q-tip up in to the fuel rail and see if it's rusty.  My sticky injector engine had rust in the rail.

My first engine started and ran pretty well, but when I tested the injector with a home-made testing rig, they were all unbalanced.  You could really feel it when the engine was running too.  So, odds are, you'll be best off to get "new" injectors.  I put the parens on because I've had old Nissan injectors that were in great shape internally, even though they were all rusty on the outside.  If you wanted to look for used.

But, several people have used the Standard FJ707 injector and like them.  But it looks like the price has gone up quite a bit over the years.  Ouch.

http://www.rockauto.com/en/catalog/nissan,1982,280zx,2.8l+l6,1209350,fuel+&+air,fuel+injector,6224

How about the cheaper ones? The FJ707 might eat into the budget for a few other things for the car. I have zero knowledge about what are good or bad injectors.

Thanks so much for the help. Years ago I would just go to the junk yard and throw them in, maybe I just got lucky, but that was also 20 years ago when most ZX's were in the junk yard at that time for just a few years.

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siteunseen used the T series and had good results.  They were less expensive.  I don't see them on the page though.  BWD makes good stuff, I used a set of theirs  for a while.

Found the 707T on Amazon.  Prices have really gone up.  I got my BWD injectors for $34 each at OReilly.    https://www.amazon.com/Standard-Motor-Products-FJ707T-Tru-Tech/dp/B002ELMUCE

You might try eBay, there are people out there that flow test them and resell used.  I built a tester using a junkyard fuel rail then found junkyard injectors that still had fresh gas n the system.  About $6 per injector, I think.  But that was back when there were typically a few Z's or ZX's in the yards at all times, just a few years ago.  Now I hardly ever see a Z or ZX go through they yards.  I have notifications set and they just don't roll through anymore.  The hobby's getting expensive. Good luck.

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Those FJ3's look like a good deal.

The cheapy BWD's are still available at OReilly.  

There are a variety of Bosch injectors that will work also, with hose length modifications.  The Bosch EFI system was licensed by a bunch of manufacturers.  They all the same basic injector.

Edit - that picture reminds me that hose clamps can be expensive also.  And you'll need new seals and maybe insulators.  Nickels and dimes.

BWD i.PNG

Edited by Zed Head
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8 hours ago, Zed Head said:

Those FJ3's look like a good deal.

The cheapy BWD's are still available at OReilly.  

There are a variety of Bosch injectors that will work also, with hose length modifications.  The Bosch EFI system was licensed by a bunch of manufacturers.  They all the same basic injector.

Edit - that picture reminds me that hose clamps can be expensive also.  And you'll need new seals and maybe insulators.  Nickels and dimes.

BWD i.PNG

I'd bet those come with the rubber and the clamp is on the hose in the picture.  That looks to be the best deal on new ones plus they look an awful lot like my Standard FJ707Ts.  You might even find a coupon code for O'reilly's and get an extra 10% off?

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