Monkeynuts85

Hi Before I get jumped on, I will explain. I have just bought an RX8 and it won't start, now I know all about the flooding side of things and I don't think this is the issue! I am in need of some technical advise as although I am an automotive engineer of over 10 years I need some answers to some unknowns as what I know about rotary engines leaves a fair bit to be desired.

My discoveries:

1. Car wouldn't start, hence why I got it cheap.
2. The. Engine was extremely low on oil, this has now been topped up.
3. Engine will fire when a touch of intake air cleaner is sprayed up the intake, but stops straight away, a bit of a dodgy thing to do but confirms to me that there is a lack of fuel, that the ignition side (spark) is working and that it has reasonable compression?!
4. Fuel pump does not prime on ignition or crank, I have confirmed this by removing the two fuel lines under the bonnet and put them into a jug whilst turning on the ignition and also under cranking.
5. I have bridged the fuel pump relay to force the pump to run, which it does! Still won't start with the pump running constant. This says to me that it is not injecting fuel?

After all these discoveries I think and I am open to being proved wrong that for some reason, for the life of me I don't know why, the Ecu is not grounding the fuel pump relay on ignition or crank, but is also not firing the injectors!

Question:
1. What could cause the ECU not to prime the fuel pump and injectors? Inertia switch (does it have one)? Is it a passive anti theft system fault/immobiliser type thing?
2. Obviously there are sensors on the engine that know the position of the rotors and crank etc. what are these and where are they?


I don't honestly think this can be a flooding problem as until I have bridged the relay there was no fuel. I would really love some insight into this fault.

Thanks in advance.

Kev

RIWWP

iTrader: (2)

Make sure you check the simple stuff.

For example: the ESS (e-shaft sensor, same thing as a crankshaft sensor on other cars) needs to be within spec distance from the trigger wheel and clean of any fouling debris, or it easily could be simply not telling the ECU WHEN to fire ignition and injectors, so they never get fired.

Still, it sounds like you have some sort of electrical problem on your hands, likely wiring and not electronic in nature. Perhaps grounding points damaged/corroded, perhaps fuses shorted out?

I believe that there is a post-crash start inhibitor on the RX-8, but I also think it will clear itself after some time has past, and I don't recall specifically how the inhibition is implemented.

Monkeynuts85

I fully agree with what you say, it is clearly something stopping the fuelling circuit and on a normal engine I would head for the crank or cam sensor. Where is this ess located?

RIWWP

iTrader: (2)

Same spot as a crank sensor on a piston engine. It is immediately next to the trigger wheel that rides behind the front crank nose pulley. In the case of the RX-8, it is about 4 o'clock looking at the pulley head on.

Monkeynuts85

Ok thanks, I have had enough for tonight so will have a look tomorrow. Just to confirm it is on the FEAD belt end. I'll check the wiring isn't damaged and pop the sensor out to have a look. Thanks for your help.

RIWWP

iTrader: (2)

Not sure what you mean by 'FEAD', but here:

Monkeynuts85

Ahhh perfect. It's all jacked up on stands now so that should be fairly easy to get to. Something else to try at least. Thanks

Monkeynuts85

I have a RUNNING RX8!!

Just to let everybody know what I found.
I managed to get hold if an ids and VCM with the Mazda software which let's you's carry out a KOEO test for non starting (key on engine off). This have me a whole host of fault codes for the inlet in bank 1. I had a look at the inlet valves believe it's called a tuning valve and one was seized open or closed. This had in turn blown fuse 32 which is engine management something or other which was the culprit behind why my fuel pump wouldn't prime and why I had no fuel. Freed the air valve and replaced the fuse and my fuel pump began to prime again on ignition. Still a tall pain and wouldn't start. Decided to take the plugs out (which were seized) got them out and they were saturated. Cleaned them off and dried them out with a blow lamp, ended up doing this procedure twice and FINALLY with a huge cloud of smoke, she fired up. Currently sat running sweet as a nut now! I hope someday this might help someone else.

Thanks for the replies

Monkeynuts85

Update:

The car still starts and runs, but it has quite a bad misfire that appears once it has warmed up.

I still have a code for HO2S post cat high voltage but that shouldnt induce a mis-fire!

Any ideas??

Williard

iTrader: (18)

How old are the ignition parts? I.E. Coils plugs wires. Have you cleaned your MAF? Is the CEL flashing?

RIWWP

iTrader: (2)

Is there anything left in the "Suffering from a Misfire?" thread that you haven't covered?

Monkeynuts85

Hi ya, the igniton stuff all looks pretty original to me so that was my next port of call. Was thinking of changing the plugs, leads and coils. Have seen you can get an NGK set consiting of all 3 parts for £149.99 on ebay, seemed quite reasonable?! I haven't cleaned the MAF no so I shall do that, I have had the battery off recently and reading some of the other threads it seems this can cause some strange behaviour, not a horrific misfire but.......

RIWWP

iTrader: (2)

That's ~$252 USD, which is within the acceptable range. Ebay is something to be wary of though, as there are counterfeit coils out there. Be sure you know what brand of coils you are getting. Don't take "Mazda" branded coils at face value either, since that is what the counterfeits claim to be.

Monkeynuts85

Sorry didn't realise there was such a thread, where is this?

RIWWP

iTrader: (2)

https://www.rx8club.com/series-i-tec...t-here-222280/

Monkeynuts85

Thanks for that, that is a really, really helpful thread. I will work my way through that lot and see where i get. Re the eBay ignition set it is all NGK stuff and comes with a 2 year warranty apparently?!

RIWWP

iTrader: (2)

NGK doesn't make coils for the RX-8, so while the plugs and wires may be NGK, the coils won't be.

If there are clear pics of the coils in the listing, compare to these: https://www.rx8club.com/series-i-tec...-247265/page2/

jcrane81

mazda rotary parts is a good place to get coils and plugs, mazda parts at a good price when it comes to rx8 parts stay clear of ebay not worth taking the risk


Posted from Rx8club.com App for Android

MSgtHops

Hey! Thanks for all the info as I am having the same issue. Which is fuse 32? I have a 2006 that I have bought for my son and I have replaced all ignition components but still no fire to the fuel pump. I can however run a jumper wire to the pump and the car will fire right up. Any help would be greatly appreciated!

Stefan Wolf

Fuse 32 is "Tail" for rear tail lights. Nothing to do with ECU unless he's talking about something else. I'm having the same problem. The fuel pump will not prime put in the on position. Relay is good, fuel pump fuse is good. New few pump and still zero fuel pressure. No current to fuel up in the on position. What else is there?

TeamRX8

iTrader: (25)

If the immobilizer security is engaged you’re not going to be getting any response per the other thread discussion

MSgtHops

Stefan Wolf it seems we might have an immobilizer issue. Hopefully there is an easy and inexpensive way to fix/bypass it. I'll let you know if I find anything useful.
I did find a way to bypass the pump and it drives fine with no CEL. I still would rather find the problem honestly because it's bugging me 😅
Thanks Team RX8 for the advice!

Stefan Wolf

@MSgtHops I don't have an immobilizer issue I was just inquiring about how the system works in another tread since we are running a stock ECU and wiring harness in a race car which isn't a common practice. It ended up being the ground to the pump, I was in a scramble because our race was two days away. Long story short I just ran another ground to the pump since I didn't have time to chase it down. But you should share how you bypassed it on an immobilizer thread I'm very curious what you did and could save some people a lot of money.

Oscar Martiinez

i would like to know, where Post-crash inhibitor is located in 2005 Mazda RX8. Thank you.