Hey guys, not sure if anyone has ever had this issue but the search wasn’t helping. I’ve had my s2000 for over 20 years and the last 2-3 years; it’s been a weekend driver. I during this time, I noticed a sporadic issue that seems to only occur when the car is warm/hot. Example driving the car, Turing it off to get gas and then trying to turn it back on. This issue never occurs while driving.

The issue is when you try and start the car, the fuel pump doesn’t prime and the dashboard temp gauge shows full/max bars, as if there was a short or something. When you try and start it, nothing happens.

If I continue to try, within a minute or two, I would see the dash to back to 3 bars, fuel pump prime and it starts with no issue. While driving, the car never experiences this.

Any idea on what this can be? No engine codes appear and I’m not sure where to start diagnosing.

 

Start with a wiring diagram of the ignition and coolant temp sensor see where they have common grounds and check them.

I'm guessing the ground on the back of the head.

 

How old is the battery? Are all the ground connections under the hood in good shape?

Thanks!

 

Thanks for the info, I’ll check the wiring to verify.

I do have a rad temp gauge mod, which allows you to adjust the temp bars setting. Even if this was an issue, why would it prevent the car from starting if the temp bar mod is failing or has a ground issue? Can there be an ecu lock that if it sees the car pegging all bars, that it doesn’t allow the car to start?

 

Does the car have a good battery?

 

What kind of fuel pump are you running and is it rewired?
If you're still on stock wiring and aftermarket pump with higher current draw then you main relay is most likely on it's way out.

 

If it's interfering with the back of head ground the car won't start.

Like another person stated, it could also be a fuel pump relay.

 

The Engine Coolant Temperature sensor is an input to the ECM so it's reasonable that the ECM is preventing the car from starting with a high coolant temperature.

It seems too coincidental that you installed a radiator temperature gauge mod and when it won't start the temperature is pegged.

 

Battery is old but still works. I have a cut off since I use the car now every other weekend.

The temp mod I’ve had one for 10 years. This issue has been present the last 2-3 years but it’s rare since I normally let the car cool down when I park it.

Fuel pump is also 10 years old. It’s a walboro 255. Had this setup when I was running my turbo but converted back to stock.

I also have a vafc, with a plug and play harness, but don’t think that would cause the peg. I can replace the replay since it’s a cheap replacement but find it strange it only seems to happen when the car is hot, shut it off and try to turn it back on. While driving, the car doesn’t peg or shut off, works perfectly fine. I’ll try and get a video.

 

The bars on the cluster does not necessary show the same temp as what the ecu reads.
If you connect an obd reader you should be able to read what the ecu actually think.
You should follow the no prime lead first though since this for sure will not make it start.