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Pacey

Larger AFM for a 280zx

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I tried mine this afternoon. I had a bit more luck the car wants to run but is hunting on idle. I'm not sure where to look for the cause. Any suggestions? Maybe an adjustment of the bypass?

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Wow, I'm amazed, I had no such things happening at all.

Galderdi, you might need to adjust the coil spring if it is hunting, maybe running to lean or rich at idle, first I would try the idle air adjuster on the Toyota AFM there is a cap in the same position as the 280z AFM has for adjusting the air flow that goes thru the AFM for idle air ratio, if you haven't drilled out that cap, it's time to do so..

Better still if you had and Air Fuel gauge, but you will tell straight away when you adjust the screw..

 

Stevo

I wouldn't be cutting and crimping just yet, pull the original plug to the AFM on the 280z loom apart and check it out. Try a multimeter test for resistance on all pins. Then maybe try and test the wires back to the ECU, maybe a wire broke when you were first changing the AFM.

 

Are the injectors clicking ??

Is there voltage at the AFM when cranking ( test the larger prong in the Toyata AFM with a multimeter, should be a small voltage there when cranking 2 - 4 volts ??

Have you checked the water temp sensor.

 

Let me know how you go guys.

 

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OK so I proved that the AFM was my problem bt leaving it in but pluging the old one in and jamming it open with a screw driver while I started the car....no issue. So I took the new one back out and checked the resistance values, the ranges were similar to the nissan item but the pins were in a different order. So I have made an adaptor out of a spare EFI harness swapped the pins over and I seem to have solved the issue.  Wooo hooo!!!

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there are 7 pins in the camry plug comparing the 5 in the datto. Any improvement using the camry one? To me both look the same except for the plastic lid on the side

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I will be able to answer with a direct comparison of track times after Saturday. The Toyota unit is significantly bigger. The smallest part of the air passage with the flap fully open is (by looks) around 15-20% bigger. So I suspect performance would be unchanged until you exceed the air flow through the smallest part of the nissan unit. In other words it should extend the power at full revs with full throttle.

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Galderdi

Yeah my performance was much better over 4000rpm but also idles much better.

Still love the new AFM.

 

Not sure why the rewiring had to happen, my loom has only five pins that went directly in without change.

I know the Toyota AFM has two additional pins for the fuel pump cutoff but that doesn't come into play on my loom.

 

Glad to hear you've got it going..

Now it's time for a Jaycar Digital Fuel Adjuster, I have had one for a while, and gives me lots of control over the AFM to ECU voltages..

 

Alan

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I will be able to answer with a direct comparison of track times after Saturday. The Toyota unit is significantly bigger. The smallest part of the air passage with the flap fully open is (by looks) around 15-20% bigger. So I suspect performance would be unchanged until you exceed the air flow through the smallest part of the nissan unit. In other words it should extend the power at full revs with full throttle.

 

Not quite Greg, though times will give you an indication if the new AFM has made a difference, but there are way too many variables for a direct comparison of performance. Also will depend on what other mods you have done since the last day out and even down to the number of heat cycles through the tyres you are using.

 

 

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I agree with the logic but in my case it has only been a few months, no other modifications and only one extra heat cycle on the tyres (and that was in wet conditions so I'm not sure if it even counts). The only other variables worth mentioning are track and air temp but we'll have to wait and see on those.

 

By the way I had the bonnet open on my 93 cruiser tonight and the AFM in there looks the same as the 99 camry unit.

 

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About the only way to get a direct comparison on any engine mod is to do a power run on the dyno, swap the component and then do another run as soon as possible after to ensure all conditions are as consistent as possible.

 

Looking at the weather and the rain we have had, don't be suprised if times are a little slower as the track may not have a lot of rubber on it. Air and track temp should be good for the day though.

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