Is this loss of conpression
 

hello there i bought a 04 rx8 bout a month and half a go after spending a good bit a time reseaching them. just recently it got hard to start hot and cold so i figured it was the starter cuz it still had the origial weak starter on it and it was fine for a day or 2 then the same issue started happing again i belive its loss of conpression i would like to see what the community has to say

the car is 2004 mazda rx8 auto winning blue with 50800 miles
after buying the car i change the oil and put in a bhr ignition coil set with new wires and plugs and new starter
heres the links to videos of a cold and hot start
cold -https://www.youtube.com/watch?v=etS2fZoclms&nohtml5=False
hot - on the hot start i did get it started it it took a another cycle my phone happed to die right as i was doing the video
any help would be great

Best way to tell is a compression test, but cold start should still be ok. Check thst there isn't a vacuum leak from when you had the intake apart to do the coils. Do you have away to read the OBD data? Stft and ltft would help.

How does it drive otherwise?

when i start it cold it takes any ware from 2 to 8 ish seconds depending on the temperature. ive pulled it all back out to make sure it was all put back to geather corrcetly and it was. i have a obd 2 craftsmen scaner and it doesnt pull up any engine codes at all. pardon my ignorance what do you mean by stft and ltft

The OBD reader can pull codes, but it can also display live data from the various sensors when the car is running. I suggest you get it to idle and post up the values for: airflow (lb/min or g/sec), short term fuel trim (stft), long-ter fuel trim (ltft), coolant temp"(ect), rpm, afr(air fuel ratio) . If possible try to capture everything it can give you.

i will do that tomarro as soon as i figure out how to get mine to do that im going to have to find the book lol

I own the same exact car mine had it's fourth engine put in at 59k. It has a Banzai Racing rebuild now and compression is @ 109 on both rotors Mine starts in about a second hot or cold with stock coils.
We own the bastard child of all Rx8's!

You need one of these!

https://cimg5.ibsrv.net/gimg/www.rx8...5b1cc0d576.jpg

My car

https://cimg0.ibsrv.net/gimg/www.rx8...a779d08638.jpg

This car is the reason I ended up owning this company!
RotaryCompressionTester.com

Good luck! Winning blue is the best color.......

This what I came up with. And for how it drives once it on it drive great feels like lots of power no issues and I was out starting it yesterday and it didn't get me any trouble at all hot or cold i just don't know maybe it's something silly
https://cimg6.ibsrv.net/gimg/www.rx8...f66a1a81b4.png


https://cimg0.ibsrv.net/gimg/www.rx8...9c5065fbb5.png

the car runs great once its on it feels like it has lots of power. yesterday i went out and started it and took it for a drive and after i was done i tryed to hot start it and it started right up muti times maybe its something silly im missing but heres the numbers i was able to come up with

i did it twice once as soon as it got warmed up and a little bit later

ect was 180 and 201 the stft was 1.6 and .8 ltft was 13.3 and 14.8 rpm was 819 and 820 intake temp was 52 and 57 degrees mass air flow was 5.01 g/s, 0.7lb/min and 5.15 g/s, .0.7lb/min
the cat temp was 667.2 and 1460.7

i couldnt find the afr

That's a good start! The ltft is on the high side, it effectively means your car is ingesting 13-15% more air and fuel than the original programming expects. Your MAF airflow is about right at 5g/sec, so that extra air could be coming through a vacuum leak in the intake tubing. Alternatively, you have an injector or injectors that aren't putting out the expected amount of fuel per shot, so it's compensating by asking for more fuel.

In your video the audio is really bad, so it's hard to tell if it's spinning but not catching or spinning and trying to start. Ehat does it sound like?

I don't think this is compression loss, you wouldn't be able to restart it quite so easily hot or have cold start problems.

Check that there isn't a loose or cracked vacuum hose under the hood and that all connections are snug. Long shot but easy to verify.

How fast is your starter turning? You could check with the same OBD tool while cranking. If it's down under 200 you may need a new starter.

P. S. 201 coolant temp seems high. You shouldn't see temps like that in 57 degree weather. How is your coolant level? Is there any white smoke from the exhaust on cold start or bubbles in the radiator overflow while running? (DO NOT OPEN the overflow when the car is not cold!!)

So I had a compression test done Jerk haha so rotor 1 is6.0 6.1 and 6.1 rotor 2 is 4.4 4.4 4.5

Toasted.


Travis

Ya I know not the best feeling

I've been through it many times, and will many more times im sure.

It's part of the reason people think Rotary people are CRAZY!... Because we love cars that every so often you have to rebuild the motor lol.

It's all part of Rotary Love.


Travis

just picked up a new job to fund my rebuild , Looking forward to having a new bill of life for me 8. Know the feeling bud, sorry to hear about the engine.

Yupp thats the way mine was,harder to start when hot.

I've been following this thread, and, to the OP, i'm really sorry for how it turned out to be. But here's a question for all the experts out there...

So he's saying that it started right up, when hot, MULTIPLE times. If it's really low compression, shouldn't the hot start issue be consistent? Shouldn't it always be hard to start when hot?

What gives?