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240DL?

Runs rich, wont rev past 2-3k

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I'm reading the distributor section of the FSM now and will measure the air gap.  If I cant find any problems there ill try running it till it dies then swapping ECU's and seeing if it starts again.  

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Does the tachometer behave normally?  Smooth, seems to correctly match RPM?  The tach needle is a clue to ignition problems.

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I just popped off the cap and rotor, the air gap seems to be .279mm (within spec), while looking at the FSM I see the 2 pickup type has a phase difference. While checking this I am told to remove the red wire from the "water temperate switch". 

My thermostat housing doesn't seem to have this

compon1.gif

Instead it has what I believe to be a colling fan switch from another Datsun?!?

sensor.jpg

sensor2.jpg
 

Another housing I have in a box might have the right one, but I have no idea where this red wire it should be connected to is... FOUND THE RED WIRE

 

Does the "water temp switch" actually effect timing (1976 federal manual transmission car)

 

Edited by 240DL?

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52 minutes ago, Zed Head said:

Does the tachometer behave normally?  Smooth, seems to correctly match RPM?  The tach needle is a clue to ignition problems.

I believe its correct, Ill have to get a timing light with an RPM readout to make sure. But it doesn't seem like it would be 1.5 times the reading like you mentioned before. 

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9 minutes ago, Dave WM said:

have you tried listening to the fuel injectors with a stethoscope? hear the clicking while running?

With a screw driver yes, they are defiantly pulsing as intended, not sure if its too much just by sound

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well lets break it down

fuel pressure right

AFM seems to check out

injectors pulsing

Temp sensor resistance matching FSM guidelines

compression and timing ok

think you said tach seems correct

and you have massive over rich conditions based on spark plug readings.

Testing everything to the FSM at the 36 pin connector should clear wire harness (some of those pics show a lot of nasty looking corrosion).

for EFI issues:

I would think maybe bad or wrong ECU or wrong fuel injectors. Trying to test both those (beyond clicking and spraying) is something I don't really know how you would do other tham substitution, which is a costly way of checking things.

can you take some pics of the overall engine bay maybe something just being over looked.

did you try removing the oil filler cap on the valve cover. A correct setup will run rough and die in a few seconds due to massive ail leak (the PCV system is sealed).

only other thing I can think of is the spark actually getting to the plug? wet fuel soaked plugs could be non firing plugs. I assume you have check for spark AT the plugs.

doing a power load test or just pulling them all out and looking for spark at this point.

 

 

 

 

 

 

Edited by Dave WM

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1 minute ago, Dave WM said:

I would think maybe bad or wrong ECU or wrong fuel injectors. Trying to test both those (beyond clicking and spraying) is something I don't really know how you would do other tham substitution, which is a costly way of checking things.

can you take some pics of the overall engine bay maybe something just being over looked.

did you try removing the oil filler cap on the valve cover. A correct setup will run rough and die in a few seconds due to massive ail leak (the PCV system is sealed).

only other thing I can think of is the spark actually getting to the plug? wet fuel soaked plugs could be non firing plugs. I assume you have check for spark AT the plug.

 

 

 

 

 

 

Ill take some pictures of it, and get some part numbers on injectors just to make sure they arnt the turbo ones. I have the PCV system disconnected because of a vacuum leak at the timing cover that I am yet to correct. I have pulled the wire off the plug and thrown another in it to test and it had spark against the valve cover. 

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4 minutes ago, 240DL? said:

It has black soot until it dies from running rich, then wet and smelling of gas 

so if you put a brand new plug in it, start it idle for 5 min it comes out black sooty and or wet? trying to find an order of magnitude beyond will not rev. also what plugs are you running?

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I'm gonna toss in a new set tomorrow, the ones in it are fouled out after the trip down the road. Ill pull them after idling for a bit and take a look. 

They are NGK BR6ES, on about my 5th set within the 40 miles I've put on the car

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If you can clean plugs enough to start (using carb cleaner for example)  a properly tuned engine will usually clean them in a few minutes.

5 sets are more than enough to get going. 2 sets would be fine.  Just get some carb cleaner and gloves.  Do the work in fresh outside air and a cheap dollar store stainless steel bowl.

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well going thru them that fast, seems like the only things left can be the ECU or the Injectors, I don't know if the wrong injectors can release that much extra fuel.

Does unplugging the temp sensor bullet connectors in the wire harness make it die instantly from over rich? next try subbing a 100hm resistor (I hesitate to say short them together). The way that works is lower resistance should reduce injector on time. How does the fuel pressure reading look when you blip the throttle? should go up with blip, then jump way low as vacuum jumps with closed throttle,  I know you said 36 engine  off 29 idle,  would just like to hear what its doing with actual throttle use.

Edited by Dave WM

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You may want to do some research on part number cross ref to year, and make sure you have the right ECU for your model year. I seem to recall there are differences on pin out.

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11 minutes ago, Dave WM said:

You may want to do some research on part number cross ref to year, and make sure you have the right ECU for your model year. I seem to recall there are differences on pin out.

Great idea Dave!

image.png

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Hmmm... you know the Thermo Time switch and the engine CTS  split into bullet connectors about 12" from the sensors. You can get the bullet connectors plugged in wrong. Then the Thermo Time switch is hooked into the CLT sensor pins on the ECU.  Car will run Pig Rich .

Edit: Oooops... already been covered. You may want to Triple check that. Posts #46 thru #48. Tricked me up on once my 1976 280Z and car ran Pig Rich.  

BTW,  picture in Post #48 is from my 1976 Federal model 280Z... after I sorted out the crossed Bullet connectors. 

 

Edited by Chickenman
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Nissan ZX turbo injectors are a purplish brown color, NA injectors a light green or light tan color.  The numbers don't mean much, it only identifies the design of the injector body plastic.  I think it's the same number for both.  Color is the key.

Unless they're some odd aftermarket injector, which tend to be black or bright green.

Edited by Zed Head

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and just to say it again, make very sure all the connectors to the sensors and AFM are clean and free of corrosion. Checking at the ECU pins should clear them, but then again due to the high impedance of a modern DMM, I suppose its possible to get a reading that would be different in a low impedance circuit, esp things like voltages.

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4 hours ago, 240260280 said:

Great idea Dave!

image.png

I do have the A11 600 000 for federal manual 1976 cars

And my injectors are green, so I would guess they are correct 

1 hour ago, Zed Head said:

Nissan ZX turbo injectors are a purplish brown color, NA injectors a light green or light tan color.  The numbers don't mean much, it only identifies the design of the injector body plastic.  I think it's the same number for both.  Color is the key.

Unless they're some odd aftermarket injector, which tend to be black or bright green.

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A shorted injector wire on the ECU side will cause it to stay open.  Try removing injector plugs, until you find one or two that make a difference.

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If I hear them all pulsing (individually) would that rule out stuck open injector? 

 

edit  - Not mechanically damaged of course but stuck open because of the ECU

Edited by 240DL?

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Kind of rules out a direct short keeping them open.  But the ECU also determines time open.  So they might be opening and closing correctly, just staying open too long.

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