Power FC has power, but no CEL, car won't start
 

Hello, I posted in the Power FC forum a few days ago but perhaps this is the better place.

• Power FC has power (light on unit, handheld operational)
• CEL never illuminates on key turn
• Car cranks but doesn't start
• Newer coils, fuel pump does activate, EGI fuse looks good.
• Recent development, removed old FJO wideband controller but car ran ok immediately after removing controller.

Search on this site returns symptoms that would suggest ECU doesn't have power, yet it does in this case. I'm thinking something electrical given the recent changes but it could be coincidental. Other fuses I should check?

Thanks.

was it working before or is this a new install?

Thanks. I removed the FJO system, ran the car for 10 mins or so, came back a week later and it won't turn over. Car was running fine to this point. FJO wasn't tied into anything downstream. Someone just posted over on FB that the PFC disables the CEL on ignition start. I ** thought ** I had one before but maybe I didn't 🤔. Below is sensor check on ACC.

https://cimg7.ibsrv.net/gimg/www.rx7...fbf1519ba2.jpg

If you didn't change anything else, perhaps the engine is flooded? Check the plugs?
If memory serves, flooring the gas will shut off fuel and help unflood the engine.

If you have fuel, compression, and spark on at least one rotor, the car will at least *try* to start.

When I first got my FD, the reason it wouldn't run properly was because the ground wire on the block was loose (it was technically a parts car...hahaha). There's a million things that can go wrong on modified cars this old.

Check grounds and connectors.

CEL is not illuminated when running the PFC...

CEL doesn't work with PFC. The PFC doesn't have any of the factory fail safes when it comes to issues that would lead to LIMP mode on the stock ECU. I have had two PFCs die on me in two separate FDs in the last 3 years. Both worked perfectly fine one day, then the following the car would crank but wasnt getting fuel/spark. The tach was bouncing slightly so I knew the crank angle sensors were sending a signal. Find another good used one for $500.00 and be on your way.

I have been told that a weak battery can kill PFCs.

That is astonishing! Was there any indicator that led you to the PFC being the problem or did you just try swapping it out?

In my case, the car was presumably flooded and I had a bad fuse feeding the coils as well. I ended up having to remove the plugs to crank the fuel out. It hasn't been typically a problem but I did run it for about 2 minutes last time to validate the wiring changes and then left it sit cold for a week. I suppose the extra fuel being dumped in there during enrichment came back to haunt me.

Thanks everyone for the advice and confirming the absence of a CEL with the PFC.

so you got it started? a fuse generally shouldn’t just go bad all of the sudden unless you shorted it somehow.

I did! So I have the IGN1A coils and it has an in-line fuse. It connects on the negative terminal directly and seems to blow with some regularity (not every time) whenever I quick disconnect the battery and reconnect it. I'm not sure how normal it is for that system. In this case I removed the battery to put it on a tester. The primary issue was the flooding, but then I didn't have power to the coils secondarily. With both corrected, it ran like a champ.

The recent one was on my R2 with a very healthy lithium ion battery. I honestly can’t recall on the one before on battery condition. Both times I swapped in another ecu and the cars started immediately.

Yep, you just flooded it. Lesson learned there.

PFC's are relatively hardy, their failure rates are extremely low.

Read up on wiring for the IGN1a's, they have to be wired up VERY MUCH correctly or you are going to have continual problems.

Dale