Parked my car for two weeks, drove my car about a block away from my house and it died in the middle of the street. Was able to get it running long enough to get back to my house but after that it would start and immediately die.

Since then I’ve replaced the fuel pump(verified that it works by jumping the f/p in the diagnostics box), fuel filter, plug wires, and spark plugs. Car still died immediately after starting, even tried all the deflooding methods... Was wondering if I could get some insight as to what this is. It’s been 2 months since this

car has been actually driven and I’m depressed.

 

If it was me, my first order of business would be checking compression. If you have bad compression and don't know it you'll be chasing rabbits trying to troubleshoot the problem.

Once you have that baseline (if it's good), you can start narrowing down other culprits. The other major functions that an engine needs to run are fuel and spark (at the right time). Spark is easier to check than fuel, but if it starts and then dies, it's probably more of a fuel issue than spark. Also, you generally won't flood a car if it's been running, you will flood it when cranking if it doesn't start though

Seeing you have no undertray, i'm guessing the engine may have been heat stressed. That could be a contributing factor. You may want to pressure check your coolant system as well

Good luck

 

Sorry if this is a stupid question, but wouldn't they have a lot of trouble starting the car up if it was dying due to low compression?

Is this happening with the stock ECU, or is it on an aftermarket one?

 

I’ve never had cooling issues ever, but I guess it’d be smart of me to do a compression test on the motor. I’m just stumped and want this thing to run like it used to

Thats what I’d assume too, it starts up just fine but dies immediately. I feel like the fuel is being cut, I’ll hear the pump turn on when I turn off the car but it never primes when I have the key set to ON.

I have a stock ECU connected to a HKS FCON

 

If it's hot yes. If it cools down, it may start fine

What other mods do you have? Injectors?

If your're running the stock ECU, you should run everything stock IMO. Better would be to change out to a PFC and get a proper tune (assuming you have good compression)

And get an undertray

 

That’s really really hard to believe. How do you monitor temps?

 

I’ll be ordering one as soon as I can confirm my motor isn’t toast, which I really hope it isn’t. It’s single turbo swapped and I don’t really know the history behind it as it was imported from Japan recently it only has 40,000 miles. I’ve been reading that maybe a faulty temp sensor could cause the car to not run?

https://www.rx7club.com/new-member-r...on-fd-1109148/

Literally the same problem.

Stock temp gauge... I’m a new Rotary owner so I’m assuming it would work fine. It never spiked up while driving.

 

For what its worth, I had cold start issues on the stock ECU when I was still using it. Only the first start, after that it would start fine cold or hot. It never died though once it was started.

Since I swapped the PFC in it starts immediately every time, but occasionally will die at idle (but starts back up immediately similar to OPs issue).

The cold start issue could have just been because the engine had been sitting for a while, while I did numerous repairs on the car without being run. I haven't put the stock ECU back on to check since then. If I sprayed a bit of oil or carb cleaner in one of the vacuum lines it fired right up even then.

I have not zeroed in on the idle issue with my PFC yet. If/when I figure it out I will post it up on this thread in case its helpful to you. I think it might just be a tuning issue though.

I wasn't even aware a single turbo would run well on the stock ECU. I guess that's neat.

 

Interesting, I tried the WD40 method into the UIM nipple to see if that would make the motor stay on longer but apparently that trick is to only help with a flooded motor. I think I’m gonna see if putting atf in the chambers helps when I pull the plugs to check for compression.

Thanks! I really hope you get down to the bottom of your problem. I’m still on the fence about keeping the car so I haven’t pulled the trigger on a stand-alone ECU, I think I’m going to go with AEM infinity or Haltech if I do keep it.

Its currently running the HKS FPCON tuned by FEED hooked up to the stock ECU, I haven’t changed anything other than maintenance items since this car has come from Japan.

 

Do not rely on that. The stock temperature gauge isn’t linear. That means it goes to just before half-way almost as soon as the car is running and stays there until just before it overheats. When it moves higher it’s likely too late. Search for reliability mods. An aftermarket temperature gauge is one of the first suggested. My bet is you’re running hot.
Hopefully you can find an under tray to fit that bumper. If you can’t, get rid of it and find a stock bumper.

 

Yea I’m gonna order some new gauges, the car has aftermarket gauges but they’re all shot. Thanks for the heads up tho I didn’t realize the importance of the undertrays! I’ll probably order the one from LRB speed.

 

i tried one of their trays and seemed to have fitment issues with a 99 spec bumper. You may want to contact them on fitment with your aftermarket bumper. Alternative would be to have one fabricated if stock wont fit.

 

Figured it out I think! My car starts, runs, and drives now. Relocated my battery to the back seat using 0 gauge wiring, also rewired my fuel pump. Pretty excited

 

What was the problem? Relocating your battery and rewiring the pump shouldn't have fixed anything. The rewiring of the pump equating to your car running again could be an indication of low fuel pressure. With the rewire, the pump is seeing 12v always which could be the small boost it needs to overcome the lack of pressure. Next opportunity you get, you may want to check your fuel pressure. You can rent the garage from auto zone or somewhere similar.

If you are having fuel pressure issues, you may want to be careful