RB25 refuses to start

[maximajim]

Hello,

I have an RB25DET here that refuses to start. I just finished installing the engine. Before engine removal, it ran perfectly.

What I know:

1) Timing was set correctly

2) It will run on Starting fluid for ~5seconds

3) Cas does work, I rotated it and I can hear injectors clicking

4) As stated above injectors work, Also pulled first 3 coil packs, they all work

5) Fuel pump is working, I can hear it prime and I also pulled the fuel line to make sure fuel is coming out

6) I have a nismo FPR, at this point fuel pressure is unknown

7) Getting error codes for TPS and AFM

8) the Fuel in the Tank is ~1 1/2yrs old

When I go back to troubleshooting, first two things I will check is fuel pressure and compression.

The two main things I'm concerned about are the TPS and AFM. Per JPNZ R33 FSM, there is no reference to the TPS or AFM for starting. However per Z32 Nissan FSM, a AFM will cause a hard start/no start.

Anyone have experience with a bad AFM causing a no start?

I am focusing on fuel pressure but I have a feeling it's fine.

Thank you.

[beario]

gees i would definately put NEW fuel in,thats way to old,it might not be the problem but i am sure it will help...

[BigDatto]

Hi Jim,

Are you using a stock ECU or aftermarket ?

Are you using a stock AFM or Z32 ?

Have you performed an ECU diagnostic test for error codes ?

I have a Z32 AFM on the RB25 & it won't start with stock ECU due to it's lower voltage output. So i run an A'pexi PowerFC, which allows the user to select different AFM's in the "airflow" menu.

Also are you running a stock fuel pump ? I need to prime my GTR pump (without anti-drain valve) 3 times before I have enough pressure to turn it over. Otherwise it just won't play the game.

As stated above, I would definitely drain the tank & refill. You can buy 100 octane gasoline Stateside, right ?

If everything else is OK, it should at least turn over.

Good luck with it.

[maximajim]

Hi Jim,

Are you using a stock ECU or aftermarket ?

Are you using a stock AFM or Z32 ?

Have you performed an ECU diagnostic test for error codes ?

I have a Z32 AFM on the RB25 & it won't start with stock ECU due to it's lower voltage output. So i run an A'pexi PowerFC, which allows the user to select different AFM's in the "airflow" menu.

Also are you running a stock fuel pump ? I need to prime my GTR pump (without anti-drain valve) 3 times before I have enough pressure to turn it over. Otherwise it just won't play the game.

As stated above, I would definitely drain the tank & refill. You can buy 100 octane gasoline Stateside, right ?

If everything else is OK, it should at least turn over.

Good luck with it.

Hello Datto,

Thank you for your reply. The ECU and AFM are factory items. I have performed the ECU diagnostic and it shows codes for AFM and TPS.

I find it interesting your car didn't start with the Z32 AFM. I always thought Any nissan could start without an AFM plugged in, maybe a false signal would cause a no start?. I will look into that.

The pump is a Walbro 255lph, I've tried to start the car multiple times in succession so I don't think priming is the problem.

I will drain the tank and replenish with new fuel.

Thanks

[sweetr33]

make sure u have connect the supply and return fuel lines to the right section of the rail.. We made this simple error on a mates r33 and that was the only drama, doesnt matter if timings out really unless ur talking teeth on the timing belt, we had the engine cam adjuster things out of whack by along way and it started first kick once the fuel lines were coreected.

[blind_elk]

I wouldn't expect the age of the gasoline to be a problem - after all, it's still basically gasoline.

The other thing to check is the battery voltage while cranking. The ECU requires a minimum of around 7V to spark it into life. If the cranking voltage falls below this level, then there's no ECU to make anything work.

Also, reset the ECU to clear the errors before deciding if there really is an error.

[h8t_copsr32]

i have had problems with mine but my was more ecu probs then any because the ecu was telling the engine that there was no fuel the ecu was reading it as an error and even cold cranking amps did nothing mine was reading 8.5 v so i fixs thatproblem by taking it to an auto electrician an they fixed it within 4 hrs the computer had to be reset though

[maximajim]

Ding! Ding!

Datto pretty much got it!

Turns out the AFM voltage is off. It reads -0.26V instead of +0.30V. While cranking it reads -1v. So I pulled the AFM plug and it starts. Now I need to figure out why it reads negative..

[BigDatto]

Jim do yourself a favour, check my thread in the DIY section with pinouts etc for the AFM.

You will know straight up whether it's the meter or loom/ecu.

Must have been music to your ears to at least hear it turn over !

[Craved]

nice work, have similar issues with my car atm, where did you get the AFM voltages from? direct from the plug? nice work with removing the afm will definately try that in the morning