Backfire, Lean Rev, Fuel Drips
 

Hey,

So I took my car on its first big trip this weekend. 1600kms round trip, made it down there with no problems. On the way back I got about 1km from my home town and the car began to sputter, A/F gauge ran the entire trip at about 11:1 - 12:1 which I know is rich but its scheduled for the dyno on the 15th of November and I wanted to make sure it could survive more than 50kms of driving.

So about 1km away the A/F gauge jumped to anywhere between 13 - 17 so I had to keep it at about 2400rpm to get 14.7 which meant I was slowly coming to a stop. Everytime I gave it gas over 2400 it would shoot up to around 16:1 and sputter.

I started thinking maybe I am running out of fuel and that's causing reduced fuel pressure and the turbo kicks in and leans me out. Car came to a stop about 5 blocks away from the finish line.

Flooded, took spark plugs out and followed deflooding procedure, started it up and had it running when I took the video. Also noticed that there was gas dripping out of my muffler. Which confuses me how I can be running Lean and have fuel dripping out of my muffler.

The Rev-Backfire situation has happened to me once before. We had the wires from my Microtech x4 to trailing coils mixed up and it did the same thing. Obviously I didn't switch the coils mid trip.

My thoughts are - Can I foul a plug from running 800kms at 11:1 A/F ratio? Did the plug just suddenly foul and that's resulting in the same effect that no trailing had?

- Rotary Facebook Group said Injectors but the injectors have less than 10,000kms on them.

Car will start with a lot of effort but doesn't like to keep running and definitely wont move until I get it figured. My plan is to buy new plugs tomorrow. Any suggestions on what else it could be?

Video -

Replace the plugs, check the coils, check the plug wires. If the issues still persists I'd get to troubleshooting deeper. Did you put together your Microtech harness, did you do a good job of it?

Had the local RX7 Specialty shop do the microtech install and harness build. I checked the plug for the x4 and microtech just to see and they seem secure.

Plugs were dry White/Light Brown colour when I pulled them but I'll replace anyways.

Pulled bottom plugs and turned over to see how compression is. Appears to be fine which is good news.
Next step plugs and wires then send injectors away? I didn't think it was possible to foul a plug while driving on the highway but I guess at low air:fuel rations for a long time maybe?

Pulled plugs and they were nice and wet.

Attachment 546627

the video where it was rolling over, it may of been the camera, but I only heard 4 good wooshes, not six

The video where your car is running it sounds really weird, but I'm gonna guess thats the gilmer kit your running, cause I know they are noisy.

Being how you flooded out driving, and gas coming out've the exhaust, I would actually start off with compression #'s, not sounds. Also, what do you have for a FPR? Stock? Aftermarket? Known good?

The rev backfire situation, could be because of a dead rotor, or a FPR letting to much fuel go by and heat of exhaust making it fire. Those things are fairly easy to check

More than likely it's the phone making it sound weird, the wooshes sound more like a chunk chunk on the video. I'll order the electronic compression tester and get an actual reading.

FPR is aftermarket aerometer which is working as far as I can tell. I took a clip of it when the car was running in the first video.

Going to test coils today and have an order made for the compression reader.

You don't need to spend the big bucks on the digital compression tester, regular one will work fine to give you an idea

So I didn't have a compression tester, but assuming from the sound that all was well I decided to test the plugs by keeping them connected and watching for spark. No spark. Then I put a volt meter to the +- of the coil and turned the key, no volts. From looking at a simple diagram of the Microtech x4 ignition control it appears that it controls the - , which apparently it has no ground.

The computer is working and providing details on the handset so my thoughts are its the ignition box, but tomorrow I will check the ground to the box to make sure its good.