Hi All,

I am running a 5VZ_FE with M/T in a 1983 FJ40. The fuel consumption is pretty terrible around 10 MPG (4 KMPL) combined and I cannot figure out why. I expect at least 16 MPG.

The ECM does not support an OBD2 so all troubleshooting has to be done manually which is why I started this thread. Please share any ideas as to what I need to look into.

Here are the things checked already:

1. New OEM spark plugs installed
2. MAF sensor cleaned
3. Manually checked for any error codes but there were none
4. No exhaust leaks before (or after) O2 sensor
5. Engine seems to go in closed loop
6. No idle issues or misfires. Runs and drives great.

The previous spark plugs also seem fine and no signs that the vehicle is running rich. I belive they are flaky because the vehicle previously (months ago) had a MAF issue and was dumping fuel. Please see the attached picture:

The old plugs that were removed show no signs of running rich. Yes, they are the incorrect type and were replaced with OEM twin ground.

Looking forward to hearing your thoughts. Thank you.

 

Wondering why I am not getting any replies? Anyone?

 

Hi there, what you have is not something most members here would be familiar with.
Is there not a way to get codes out of that motor?
How about a JDM site?

 

Thanks for replying. Yes, you can manually pull codes but there aren't any as I mentioned above. I am not sure how to troubleshoot without seeing the sensor readings and maybe there is something else I might be missing.

 

You might get more responses if you gave more detail. For example you don't mention what you are using for an ecm, why you are assuming it is entering closed loop, or what sensor signals you have tested manually.

 

Following in these footsteps, the swaps I’ve worked on brought most of not all of the donor harness with them. So in essence you would be working on the newer vehicle but in an older vehicle shell. Or adding say a 350 to a hot rod or climbing rig which then is stripped down to either a stand alone efi or manual carbs. And in those cases, using something like Painless, they have trouble shooting guides knowing the capabilities and limitations of their systems.

The info you can give us, the help we can give you.