Airflow sensors

General information about the first-generation Nissan Maxima in the US. What was the Datsun 810 became the luxury leader Maxima in the US in 1981.

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kassim503
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Airflow sensors

#1

Post by kassim503 » 14 years ago

Does anybody know if the airflow sensors on the L28 and the L24 are compatible?


Also is there any MAF's that can be compatable with a L24?

Im planning on running a bigger throttle body on my gasser and im trying to find a better flowing MAF because the stock one seems like itll restrict alot of flow
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012

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83_maxima
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#2

Post by 83_maxima » 14 years ago

I don't think that it would work for the simple fact that the L24E AFM is designed to work in conjunction with the Bosh L-Jetronic FI system (which is a far cry from the engine management of the LD28).

Even though I have never seen an LD28 AFM, I think that it would be pretty safe to assume that there wouldn't be a crossover there.

But who knows, I have been wrong in my life. ;)

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asavage
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#3

Post by asavage » 14 years ago

83_maxima wrote:(which is a far cry from the engine management of the LD28).
I think that he's referring to the L28, not the LD28.

Kassim, a Q like that is probably better asked over at zcars.com or similar. Certainly, I don't know the answer.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

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83_maxima
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#4

Post by 83_maxima » 14 years ago

asavage wrote:
83_maxima wrote:(which is a far cry from the engine management of the LD28).
I think that he's referring to the L28, not the LD28.

Kassim, a Q like that is probably better asked over at zcars.com or similar. Certainly, I don't know the answer.
Oops. I must have LD28 on the brain.

They might interchange. I've got 2 AFMs from 280zxs. 81 and 83. You are welcome to the 81, if you can't find one where you are. I don't need it now that I have the 83.

The only thing you would have to be sure of would be that all of the connectors at the AFM correspond to the correct pins on the ECU. That might be your sticking point. Z car and Max ECUs are markedly different - so I am told.

Unfortunately, people on the Z car forums are Maxima stupid and there are like 5 people on maxima.org with 1st gens. But the Z car guys ears do perk up when you mention the LD28.

You're welcome to try this AFM if you don't already have one.

Something that just crossed my mind: There is a guy in IL that has done a Z31 engine management conversion on the L28ET in his 84 (910). This may be something to think about (it is a bit of work though). There are quite a few writeups on the changeover on Hybridz.org, Zdriver, Zcar. The Z31 uses a MAF sensor which is less restrictive than our door-types. You can use the MAF, ECU and harness and convert the engine mgmt. system over for better tuneability.

I personally don't think that the 280zx AFM is going to make much of a difference becuase the principal behind the L24E and L28E units is the same. The ZX can flow a little more air than our cars, but I don't think you would notice much difference - IMHO.

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kassim503
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#5

Post by kassim503 » 14 years ago

83_maxima wrote: The only thing you would have to be sure of would be that all of the connectors at the AFM correspond to the correct pins on the ECU. That might be your sticking point. Z car and Max ECUs are markedly different - so I am told.
I do know that the maxima AFM are wired the same as the z car, the z cars AFM has a hose connection on both sides for the cold air intake, and the maximas have a square hole on one side to be hooked up to the air filter box




I think im going to just hook up the new throttle body to the old AFM, until I find something to rig up, the car really dosent look like it has alot of room for a cold air intake and im not a big fan of those cone air filters that you see on riced out hondas and stuff
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012

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asavage
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#6

Post by asavage » 14 years ago

kassim503 wrote:. . . and im not a big fan of those cone air filters that you see on riced out hondas and stuff
Your stock just went up a notch in my book.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

davehoos
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#7

Post by davehoos » 14 years ago

fuel injection gas[petrol].

maxima.L24E.
similar to our australian R30 skyline.[emission control,ADR 27[A,B,C] no catalist]
the L24E C32 laurel has an updated ECU.similar performance.
L28E early will be simmilar to a maxima but the later L28ET have the better management of used on japanese L20AE/L20EAT.

bigger thottle body/afm.simple test=fit vac gauge to intake manifold rev at wide open throttle.is it in vacuum.if so you need bigger intake.

very rare that the engine will desire more air unless you have series cam and exhauste changes..for this reason the engine/ecu is designed to run with the throttle open more than it needs with out excelleration.unlike older cars.over coming volumetric restrictions reducing emisions.so normaly you adjust the clock spring in the afm so it responds earlier.modify the intake to reduce bottle necks,sound mufflers.

pod filters reduce touque.increase ful consumption.

Problem.with a seporate fuel/ignition setup like i assume the maxima is this increases fuel,you also need to adjust timing and cam[air flow] at the same time.
combined fuel/ignition types.the ecu see the air flow change as extra load.it retards timing and adds fuel.

4 stages of tune with ecu.
1startup/warm up,limp home etc etc.
2 idle [warm up etc]
3 cruise-exceleration-decel in the normal driving mode.
with catalist[emision] engines the engine will hold set fuel mixture ratio's causing flat spots and rough running.o2 controlled cars osilate the mixture around 14.7.this has nothing to do with engine performance so it hard to modify this factory set programing.

4 above normal driving.most ecu will ignore afm and run rpm calculated fuel mixture.my R31 CA20E AFM is wide open at 2500 rpm R30 is litte more..mostly with rich mixtures with retarded timing to reduce engine damage.at a set point it shuts down to stop high speed running.it has to use rich mixtures as lean will do damage.

1985 on ecu can easy be modified with free software.
i would look at a 1990 on ecu and L28ET distributor modified to give a VG30 type signal.[L20AT system]

same deal aplies to emision LD28,my japanese LD20T imports originally lost power between after 3700 and full throttle under 4200.
the calibration book shows 5500+.
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.

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kassim503
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#8

Post by kassim503 » 14 years ago

davehoos wrote:f
bigger thottle body/afm.simple test=fit vac gauge to intake manifold rev at wide open throttle.is it in vacuum.if so you need bigger intake.

very rare that the engine will desire more air unless you have series cam and exhauste changes..for this reason the engine/ecu is designed to run with the throttle open more than it needs with out excelleration.unlike older cars.over coming volumetric restrictions reducing emisions.so normaly you adjust the clock spring in the afm so it responds earlier.modify the intake to reduce bottle necks,sound mufflers.
I do have a small vacuum, dont know how much but its something- ran without cold start valve attached at WOT and it sucked my finger over the hole and held it there with some force.


I do have a 2.5" exhaust, all smooth flowing so that might be giving me the extra flow thats causing the vaccuum.


Out of curiosity I ran this test with the breather hose disconnected and checked for vaccuum in the air hose that runs through the TB to the MAF and there was nearly none so I guess i dont need a bigger MAF
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012

davehoos
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Joined: 14 years ago
Location: Karuah Valley,NSW Australia
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#9

Post by davehoos » 14 years ago

some engines get power pulses in the air intake.my first LD20 conversions used japanese 910 intakes, had oil blowing into the air filter at highway speeds.i fitted a [cone shape]L24E intake rubber hose as a restriction.i guess this is like the muffler on the factory LD28.

most port fuel injection system have positive pressure near the intake vaves at certian rpm.long smooth intake runners give positive pressure at high rpm.the idea of the plenuim chamber is that air flows in at a steady rate collects then is feed into the engine.Im told that emmision manifolds are not great.My R30 L24E was no comparison to my latter stock RB30E and the RB20E had lots more top end.max tourque at 6500 RPM.
not talking DOHC or turbo as they blow you away nonstock..

have a look the carby manifolds.the 6cyl is twin carb feeding 1 into 3 so its might not be that good.i have stuffed around with some well worn hitachi on L28Z they run "OK" but not that drivable.

an aftermarket intake like the diesel might be worth looking at.wielding injector bosses and fitting a single t/body you find this is a good system using the original ecu.this is OK for a do it yourself nut that thinks it improved.

otherwise a tripple weber manifold with injector t/bodys.large box air chamber with trumpets inside.you find that it can be plumbed into the original air box.after all the big mods and still run quietly.i recomend an aftermarket ecu at this level.but an original ecu will run it.

I didnt add before that i used on the CA20E a larger AFM with a signal interceptor that modified the signal.this is when i found that in the programing the australian model has no egr but the ecu is calibrated to allow for the extra exhauste gas flow.this and other nasties are programmed into the ecu.my R30 skyline was an early model with a bosch type ecu.the latter models have more programing inside and just throw away as far as modifing.the 1985 ecu look like 200sx and 300z sold in USA late 80's these are full reprogramable.
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.

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