Fuel Injectors for Z32 ECU Maf/swap for N/A

[dj paul]

Alright guys. I have almost everything done on my 300ZX MAF/ECU swap to my N/A 280ZX. My stock system went out and always had problems so i just decided to go ahead and do this. Im using a Crane Cams Optical ignition instead of the 300ZX crank angle sensor. (#1 if anyone knows that this is wrong let me know because no one has done this before)

My main question though is, since i have the 300ZX computer. Should i put the 280ZX turbo injectors on? i keep getting backfire through the intake and when i manually turn my coldstart valve on it runs better. Also on the straight 6 the firing order is just 1,2,3,4,5,6 but on the 300ZX its 1,3,5,2,4,6 so i swapped the injectors around. Ill try it with the original firing order. Any help would be great though because when im done i am going to do a writeup of how to do it and if its worth it.

Thanks,

Paul

[BRAAP]

Well, the firing order of the L-6 is actually 1-5-3-6-2-4. Make absolutely sure that your ignition system is sparking in that order! The firing order of the L-6 is something that you can not change or alter! If your spark plug wires are NOT wired in the firing order I just listed above, then that IS why you are getting intake back fires, (also could be injector pulse width being too short, i.e. lean misfires.)

 

Your crank trigger might also be an issue. For the Z-32 ECU to work properly, it really needs the Z-32 optical CAS. The Z-32 unit has 2 rows of slots, (see pics below). One row has 6 slots, all of which are different lengths. The other row has 360 slots in one degree increments. The Z-32 CAS can and has been succesfully adapted to the L-6. Ron Tyler has done just that on an L-6 powered show car in our shop currently.

Here is that actual Z-32 wheel with an extra “sync” hole drilled to be used with the WOLF Stand alone EMS, and an excerpt from the factory Z-32 service manual…

 

 

 

 

 

 

That same info can be found in the “online” Z-32 factory service manual here..

 

http://www.300zx-twinturbo.com/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=14&design=default&total=190'>http://www.300zx-twinturbo.com/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=14&design=default&total=190

 

Here is the index. If you don’t have the Nissan Z-32 manual, this is your new best friend…

 

http://www.300zx-twinturbo.com/cgi-bin/manual.cgi

 

 

 

As for your injectors and the order/sequence in which they pulse, your engine will run just fine with them in any firing/pulsing order. If they are out of sequence in any manner or combination whatsoever, that alone will NOT cause your engine to misfire, I repeat, that alone will NOT cause the engine to misfire or run substandard. In fact, as long as everything else is as it should be, (i.e. the ignition firing order and the Injector pulse width matches what the cylinder need in regards to keeping the proper air fuel ratio, i.e. not too lean or too rich), the engine will run just fine with the injectors pulsing in ANY combination or sequence, (remember the OE Datsun EFI fired ALL the injectors at once, i.e. batch fire, even though the intake valves were opening in the 1-5-3-6-2-4 sequence)! As for the engine being able to run and run well, the engine really doesn’t care WHEN the injectors are open and closing as long as they are all supplying the correct amount of fuel. If the mixture is too lean, you can get random lean misfires out the intake.

 

The benefits of properly sequenced sequential injector firing, is a slightly cleaner/crisper idle, slightly cleaner emissions, and possibly, but not necessarily, crisper throttle response. Over all engine performance and drivability, (as felt/heard by the driver), will be the same no matter what the sequence/order the injectors are pulsing in. The driver of the car would NOT be able to tell the difference!

 

Hope that helps,

Paul

[RTz]

Im using a Crane Cams Optical ignition instead of the 300ZX crank angle sensor. (#1 if anyone knows that this is wrong let me know because no one has done this before)

 

 

In addition to the item's mentioned by BRAAP, I would ask...

 

...a Z31 or Z32 ECU?

 

...One of the things the Z32 ECU is looking for (and likely the Z31) is a 5-volt square-wave from the CAS. Another thing its expecting is increasingly longer slots per cylinder, as well as a 360 tooth 'outer count'.

 

I haven't personally scoped the Crane optical system... is it a square wave? What voltage? Are you getting this wave-form straight out of the pick-up?

[dj paul]

Im really sorry guys. I was in a hurry. It is a Z31 ECU/MAF. Your all's info still helped me out. and about the CAS, Isnt the CAS just making the firing pulse the correct length? I dont even have the ECU hooked up to the corresponding spots for the CAS to go since the Crane Cams box controls it. It essentially is supposed to eliminate any stock ignition, so does the ECU need this signal for anything else besides the ignition itself?

 

Ahh and my bad about the firing order, i knew that doh! lol. Yes that is the sequence the spark plugs are in but not the injectors currently. Basically, im thinking that the 280ZX N/A injectors dont provide enough fuel at the pulse the ecu is trying to give it. I have 280ZX turbo injectors and 300ZX injectors lying around (all good) so I was just wondering if i should go to the trouble to put those on to fix my backfiring problem, because like i said, when i manually turn on my coldstart valve (hooked up to a 9volt on a switch) it starts to actually try and run, but when u press on the throttle it still kind of backfires, but less. What do you all think? I'll figure it out pretty soon ive just been really busy. And Today is Oaks, and the Derby is tomorrow!!

 

Oh and about the TPS. How am i going to hook that up. I dont know what signals the N/A 280ZX one gives and it has 3 wires where as the 300ZX has 2. I was going to play around with it till it worked but i rather save some time.

Thanks,

Paul

[RTz]

and about the CAS, Isnt the CAS just making the firing pulse the correct length?

 

Not at all... its job is to provide positional information to the ECU.

 

 

so does the ECU need this signal for anything else besides the ignition itself?

 

Yes. It needs it for 'everything'... its the KEY component. You can't replace it with a categorically different sensor and expect the ecu to 'understand'.

 

If I correctly understand which Crane system you have, it will not provide the information that the ECU needs to function correctly.

 

A more direct approach would be to start with a 280zxt (late model) distributor, which has a CAS built in. This dizzy will 'bolt on'. Then, per this thread... http://forums.hybridz.org/showthread.php?t=91250&highlight=z31+MAF+swap, adapt it for your intended use.

 

HTH,

[dj paul]

cool thanks i have looked at that but i was hoping i wasnt going to need to find a turbo dizzy. i find that now i can only have it running when im cranking it and when i turn on the cold start valve it straight up dies. I found out that it ran better previously because one of the backfires blew off one of my vaccuum lines and it had a vaccuum leak. I readusted the timing from 0 to 10 where it was set at stock and it seemed to help a little so that makes me think the problem is with the wrong information to the ECU for timing. Can anyone help me out with these items? 280zx turbo dizzy and Z31 CAS chopper wheel?

[dj paul]

alright i got a couple of chopper wheels and a couple of optical triggers from some maximas with the same motor in it. Now i just need to get a hold of a 280ZXT dizzy. I had a spare NA one that i tried to modify but it didnt turn out as i planned.