Hi all,

Like the title states, here's another "car wont start" thread after installing a PFC on my 93. I searched around and tried most of the mentioned methods but still no dice.

I bought the Power FC used from a member here who "stated" it was in working condition. I installed it following the FAQ by DaleClark. The commander came on fine. I did a factory reset and tried starting the car. The car cranks but wont start (PFC read ~200rpm while cranking if I remember correctly). I checked the grounds and they "look" good. I uninstall the Power FC and re-installed the stock ECU and the car fires right up.

I read something about disabling the boost controller. Is this not turned off after a factory reset? (I'll try to find that setting tonight and verify once I get home from work just to be sure)

Is there somewhere where I can compare the sensor values ?

Any ideas what else might be wrong ?

Any advice would be much appreciated.

Thanks in advanced!

 

Check for fuel pressure and spark, lowering the boost will not effect the starting of the car.

When you turn the key forward do you hear the fuel pump prime?

 

I just tired it and it does seem like the fuel pump doesn't prime. (I hope it's not my ears playing tricks on me) That's odd, what would cause it not to prime? Especially since it's fine when the stock EDU is on.

 

Here are the readings on the commander (Car off/Key in ON position):





While cranking:
InjDuty: 15.7%
IgnT Ld: 7 deg
IgnT Tr: 1 deg
Eng. Rev: 217 rpm
Speed: 0 km/h
Boost: -37 mmHg
WtrTemp: 13˚C

 

I noticed that the FPD (Fuel Pump Operation) switch switches on when I crank. I'm guessing that means the Fuel pump IS working?

Any thoughts or advice would be greatly appreciated!

 

Pull the fuel supply line and see if there is pressure. Just because the PFC is grounding a switch does not mean that your pump is priming. Jumper the FP at the diagnostic box , this should turn on the pump, you will be able to hear the fuel flowing, then try to start the car.

 

Thanks. I'll give that a try tonight.

What can cause the FP not to prime w/ the Power FC but does w/ the stock ECU? Can something be defective w/ the Power FC?

 

Wowzers! I jumpered the FP and the heard the fuel pump prime. I tried to start it and the car started right up! Now I'm almost at a lost why the fuel pump would work w/ the stock ECU and not the Power FC... any ideas?

 

You bought used electronics, potentially the fuel pump circuit is fried.

You cut the 4 wires at the PFC? Are you sure you cut the correct ones? ECU wire 1T triggers the pump, This is the same circuit that you just grounded at the diagnostic box, so the relay itself works, just not from the PFC. So verify that 1T is seated properly.

 

Thanks for all the help! I'm quite sure I cut the right wires. I triple-checked them before cutting and it looks like 1T is pretty far from the wires that needed to be cut. But I'll go make sure 1T is properly seated.

I guess if the wiring looks good, I'll have to send the Power FC in for diagnostics and repair

Anything else I should try before I send it in?

Any recommended place that deals w/ Power FCs other than APEXi USA? (I heard their turn around time is quite long)

Thanks!

 

Checked the wires and 1T and 1K are seated properly. Busted Power FC?

 

Test it in someone else's car.

 

I know this thread is suuuuper old. BUT. I found it via Google while diagnosing the same exact symptoms on a brand new PFC. I sent the OP a PM asking if he found a solution and he replied tonight (thanks!)

Since there wasn’t a resolution posted previously, I wanted to post and say that we both had to send our PFC back to Apexi, both were found defective. They replaced the board in mine and likely the same for the OP’s ECU. Once we got them back, the car started up immediately.

Correct wires were depinned per the Dale Clark guide, but the PFC wasn’t sending ground to the fuel pump I believe. I could jumper the FP and GND in the Diag box and get the car started on the PFC. If I switched back to the stock ecu, the car would start fine without the jumper.

In the event someone in the future stumbles upon this thread, I wanted to post the resolution we both found success in. I did email Chris at Banzai (who I got mine from, new late 2021) just to let him know. It’s highly unlikely to be defective right out of the box, but it is possible. Luckily they had parts here in California and didn’t have to send it off to Japan… i can’t exactly recall but I think it was about 6 weeks from shipping it out to Apex to get it back in the car.

But boy, she’s happy these days! Good luck if you’re diagnosing a similar issue.

 

I think the Apexi guys do test the ecus one way or another and probaly fix the non passing ones by hand. I had a brand new one from Banzai and one of the 74HC chips had been reworked/replaced by hand. (was pretty easy to tell as it still had flux around it and was soldered on not entrily striaght). nonetheless the ecu works just fine.. =)