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19 Not sure if this is Mechanical or Electrical Issue with my F7P engine

Reno 9

Active Member
Hi All,
Did not post anything since a long time, but i really do have a big issue for more than 2 month of work.
I was running F7R block with F7P head with some good modes and it was running perfect until i decided to go back to F7P and boost it.
My F7P was running healthy however i changed the Piston rings and full gasket and started the engine but it seems to run only 2 Cylinders 1 & 4:
Actions done to determine the issue:
1. Changed the whole Cylinder head everything attached to it with another one that i was using before.
2. Head gasket was new , however i changed it one more time.
3. Get a compression tester and found that all cylinders @ 130 PSI which is normal as i did not break in the engine yet.
4. For sure i do have a good spark on all Cylinders, however i changed the ignition Coil.
5. Tested the Injectors wiring and it is functioning well.
6. Changed the Injectors with another well known good injectors.
7. Did a injector flow test which shows that the 4 injectors having the same flow rate.
8. Checked the wiring and could not catch anything wrong on any of the sensors path, no short circuit , no resistance with any of the sensors and ECU wiring.
9. Changed the Piston rings again however the compression tester did not show any leak but i changed the piston rings again.
10. 3 new sets of sparks and every time they shows too black specially on the 2 working Cylinders 1 & 4
11. New Fuel Pump and filter.
12. Fuel pressure was tested.
13. Was using external Fuel pressure regulator which changed as well with new one and now tried the original Fuel pressure regulator which on the fuel rail.

I do have a Wide-band installed so i can see that the car is lean about 16 to 17 AFR however it makes Black smoke from the exhaust .
Once i disconnect the Spark plug of Cylinder 2 and 3 i feel no difference but the wide-band shows reach 13 AFR.
However if i disconnect the injector 2 or 3 and try to start the car it will no start.

Will be so happy i anyone has any suggestion for this problem.

Thanks,
 
Pretty sure you have checked but are the ignition leads in correct order
No1 flywheel end
Yes, i also checked the timing using the timing light and the reference on the gearbox and it shows ~ 11 degree before dead centre.

Right now i am going to extend the injector wiring .
As the F7P ECU uses batch fire.
I will swap the injector wiring 1 & 4 with 2 & 3 , to check if it will follow the wire.
However i already get the readings out of all the injectors wiring and all are the same:
5~6 volt on the ignition position and ~3 volt cranking.
 
It's one of those things I'd need to see in person
The afr,s aren't really relevant as you've probably got two cylinder pumping fresh air
Would your ecu be reading the afrs and trying to compensate?
 
It's one of those things I'd need to see in person
The afr,s aren't really relevant as you've probably got two cylinder pumping fresh air
Would your ecu be reading the afrs and trying to compensate?
Not sure if i get your point,i am not using the O2 sensor since a long time.
Also I tried another ECU as well which have the same readings and same symptoms.
I just want to confirm that this is a Electric issue and i am not going to resolve it as i will run after market ECU ( Megasquirt ).
But it is easier for me to connect the Megasquirt on the F7P wiring loom.
 
What's the difference between the f7rand F7p
As it's about the only thing you've not change
Flywheel trigger pattern?
Belt out a tooth?
All earths good on the loom / block?
Thank you so much for your help.
I finally found the problem, it was a short in the circuit which connects the 12v line to the injectors and idle middle terminal with a ground.
Now the car is running fine but very rich so i changed the injectors and reached 13 AFR instead of 11 at idle so it looks like the original fuel pressure regulator is bad.
I am going to use the after market fuel pressure regulator again as it was working fine.

Now i am break in the engine then i will start to install the megasquirt and have some fun with it.

Appreciate your help.
 
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