L24/28e Fuel Injection Special Tool MST4802

[asavage]

On a whim, I picked this up at the Portland Auto Swap Meet earlier this month.

By Miller Tools, Nissan Electronic Fuel Injection Analyser, MST4802. It can be used to test the fuel injection wiring harness and most of the sensors, as well as the electrical operation of the Ign. switch and fuel pump. It won't test the ECU, and it also won't work for the turbo versions of the 280Z(X), so the manual says. It won't run the car without the OEM ECU like Kassim's apparently will; this unit just checks the sensors and harness. The price was right though.

(click on any image for larger)



I've scanned the 20-page manual and have it online here.

Don't know what the heck I'll do with this thing, I don't think I'm in the market for a gasser Gen1 Maxima or 280Z.

[kassim503]

After blowing thru the manual, I noticed it has something to read air temperature. I does the L-jetronic measure air temperature? I didnt think they had a air temp sensor, if it does I have reason to believe mine is broken, or disconnected.

[asavage]

Yup, 1982 FSM page EF-14 shows an air temperature input.

Page EF-17 says the idle bypass port in the AFM contains an air temp sensor. In the picture, physically it looks like it's contained as part of the back of the flapper position sensor.

Page EF-18 has two paragraphs describing its operation.

Page EF-29 has Air Temperature Sensor tests on a full page. Instead of a temperature/resistance graph, they give a mere two test condition chart.

My guess is that this iteration of the L-Jetronic system does not lean too heavily on the air charge temperature input.

[kassim503]

Yep, it most certianly does, but when I connected my efi tester onto the harness, it has no reading for the air temperature. Ill look into it next week, it appears to be running fine without it- its been like this for years

[davehoos]

air temp is part of the AFM.ive often seen it replaced seporatly as with the bosch afm.

not working it would be rich or lean depending on ECU default setting.
cant help with spec but i guess it is rich.

common thing now is to fit a set resistance value to give cold air setting.
this gives you 100HP extra while improoving fuel economy.

[asavage]

common thing now is to fit a set resistance value to give cold air setting.
this gives you 100HP extra while improoving fuel economy.

That must be a typo. Changing a A/F ratio setting on a 150 HP engine is not going to make a 75% difference to the better, not a chance.

[kassim503]

Yeah, running a bit richer than stock may pick up a few hp, like 5, 10 tops.

My efi tester also has a manual control over the feedback sensors, so I could just set it to the appropriate temp, see if it makes a difference