LBManiac

I have read through a lot of info and did a lot of tinkering around with the car to see what I can work out myself but just wanted to post here for any final tips.

Problem: Car does not start when hot (after town driving or sitting idle), will start after a number of minutes cooling down. When it is left running the car gets noticeably hot and even the centre console and gearstick gaiter become quite warm.

Recent changes: Upgraded coils to LS2, Upgraded starter motor

I have took the Fan 1 relay out and shorted the left contacts, this makes the fan come on, right contacts do not appear to do anything. I have also confirmed the fan does come on after the car sits idle for a period of time and reaches temperature although to me this seems to be excessive.

Current Solution/Idea: mod the relay so the fan comes on earlier using a kit like this: https://www.rx8performance.com/produ...an-control-kit
The other potential problem could be a faulty thermostat meaning the radiator isn't doing its job at all.

OBD shows coolant temp at 100c when car is hot and will not start, this can take 10 minutes before it cools down and starts again. On long drives the car is nice and cool when parked up, short drives and traffic = hot hot.

I am not sure if I have diagnosed this correctly or there is something else I should be looking at. I know the fan works and comes on and the next step is to check the radiator temperature when the car is hot and that may point towards the thermostat...

Have had some great advice already on here, hopefully someone can steer me in the right direction.

PS. The hot start problem is likely due to poor compression which I am well aware of and will be sorting at a later date with a recondition. In the meantime if I can get the car cooler it will start. It always starts from cold with no issues and eventually starts after cooling for a while. A lot of the things I have done so far are improvements which will carry over once I look at getting the engine recondition done.

Loki

iTrader: (1)

If the cabin floor is getting hot, you may want to take down your catalytic converter and checking it for clogging. Once your coils start to go, the cat is often next.

As for the fans, you refer to 1 fan. Do you mean only 1 turns or both the primary and auxiliary turn on?

By all means, the fans on low kit will help, as long as both fans are operational.

And finally, what's the ambient temperature when your car idles at 100C?

LBManiac

Found this along the way which is useful info.
Cooling will be a sticky plaster till the engine is sorted but there definitely seems to be a problem somewhere that is causing it to get hot

LBManiac

I only took out fan relay 1 and placed wire across the 2 left terminals, this made a fan come on, I am not sure which, the right terminals do not bring anything on. I could only tell by listening at the front of the car

Catalytic converter was degrading and has been emptied when I first got the car.

Ambient temps are between 10-20c

Loki

iTrader: (1)

Yikes! There's no good reason for the car to idle at 100C when it's 10-20C outside. If it's nice and cool at speed, but not standing still, it sounds like a fan problem. If the thermostat was jammed, it would be hot all the time because no coolant is going to the radiator.

I'd see exactly what's happening with those fans.

LBManiac

The fans do come on but its almost as if they are coming on way too late.

When shorting the relay is it only the left terminals that should bring on the fan/s, Is it worth checking the other relays and which fans do these power?

steveo540

iTrader: (1)

I had similar temperature issues when sitting at idle in traffic and slow stop and go. As long as both your fans are working properly, I recommend the cooling control kit you previously linked. It really does work to bring temps down quickly and is very simple to install.

Your hot start issue sounds like a failing fuel pump or low compression to me.

LBManiac

I've already ordered the kit :D

Yes low compression is the culprit, these things are bandaids until I am in a position to get the engine recon done.

NotAPreppie

My center console also gets pretty hot. This is normal.

Get an OBD-II bluetooth adapter and verify what temp the fans turn on. They should turn on full blast at ~207˚F/97˚C.

Here's info for troubleshooting the fan circuits:
https://www.rx8club.com/series-i-tro...7/#post4312789

LBManiac

OBD reader is just over 100c before fans come on.

According to this 105c is when fans should come on, at least the kit will drop that down a bit

LBManiac

Video of issue:

steveo540

iTrader: (1)

+1 on the OBDII adapter with Bluetooth. You'll notice with the control kit that the fans come on high much lower (around 195°) and will stay on until it drops below 185°. They will also continue to run for about 15 seconds when you shut off the car.

9krpmrx8

iTrader: (46)

WTF are people recommending fan control kits (useless and un needed). You need to verify fuel pressure when this hot hard start happens and if fuel pressure is good then you need a compression test.

LBManiac

Compression test is done and has shown low compression. Not sure about the fuel pressure but given that the low compression is already a known issue I havent looked into it.

Engine recondition is next on shopping list

steveo540

iTrader: (1)

I am recommending a fan control kit based on my personal success after installing one. In regards to controlling high temps at idle and slow traffic it has worked perfectly for me with little drawback. The OP mentioned he is also having temperature control issues in addition to a hot start problem, which has already been diagnosed as low compression.

LBManiac

And I was very appreciative of your feedback on the kit, it will be a good thing no matter what. Even when the engine is sorted. Cooler the better

9krpmrx8

iTrader: (46)

208F is not, that is well below normal operating range. The OEM fan control programming is just fine if the cooling system is in proper working order and temps should never go beyond the acceptable range.

If compression is low the dicking around with the rest of it is pointless.

NotAPreppie

Agreed.

That coolant temperature doesn't concern me.

Thinking about it, 10 minutes of cooling before it will start again seems short for a heat-soaked engine block but sounds more reasonable for a failing fuel pump.

Get a fuel pressure gauge and verify your fuel pressure.

LBManiac

Dicking around? Since I have got the car it has got an upgraded starter, LS2 Coil conversion, Exhaust decat(out of necessity more than want)

When I am in a position to get the engine sorted it will be done and these upgrades will still be there and benefit the new engine will they not?

So no its not dicking around, as I have mentioned these are small things which will help in the short term but will last long term.

LBManiac

No worries, I will get that checked out too, I did have an issue with the connector coming off the fuel lifter pump under the back seat and it seems to have a broken clip so there could well be an issue there.

LBManiac

Although being honest this thing has no problem getting fuel through it lol

Loki

iTrader: (1)

See post #3 in this thread for testing procedure.
https://www.rx8club.com/series-i-tec...g-fans-166524/

If your fans don't turn on at all until 103, that sounds like the auxiliary is turning on but not the primary. Sometimes they get jammed by things falling into the fan.

LBManiac

I did this earlier and the fan came on even with the key out of the ignition,

Is it possible to get a view of both fans with the car on the ground?

Loki

iTrader: (1)

Yes, just look down between the battery and intake box, or those and the engine. May need a flashlight.

Worst case, remove the intake box, though it's a bit of a pain.

If they turn on with a wire, but not with a relay, then the relay might be the problem.

LBManiac

Had the airbox out recently when upgrading the coils so not too bad a job, thanks for the tip. They are turning on with the relay, think the mod to turn them on a bit earlier is worth doing bad engine or not.