Dumb Question Thread - no flaming or sarcasm allowed
#7428
Registered
Failed??? Compression test
I recently started having slow hot starts with my rx8 and power loss going up hills. Because the engine is a rebuild I immediately knew to take it and have it tested for compression, however nobody in my area has the mazda tools and I am not a car person. The mechanic tested it with a standard cylinder compression tool and measured 3 readings between 40 and 50 psi, at 300rpms. The guy who sold me the engine is in a different state and had a 2 year warranty on the engine, but I have 2 weeks to get it sorted before the warranty expires. Obviously he doesnt want to pay for a new rebuild, and I dont want to pay to ship the engine to him and have a mechanic pull the engine for him to tell me something is wrong that was somehow my fault. (I.e. I did not premix)
i guess what my question is...is that I am SHOCKED that the car starts at all with such low compression numbers. My last engine was one that had 8 separate owners. Lord knows what it went through. It had numbers in the 60s to 70s range and refused to turn over, even warm. This engine has worse numbers and somehow performs better? What could mechanic be doing wrong with compression test? Is the analog method completely bogus?
i guess what my question is...is that I am SHOCKED that the car starts at all with such low compression numbers. My last engine was one that had 8 separate owners. Lord knows what it went through. It had numbers in the 60s to 70s range and refused to turn over, even warm. This engine has worse numbers and somehow performs better? What could mechanic be doing wrong with compression test? Is the analog method completely bogus?
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Cyryllys (06-07-2020)
#7430
Registered
OJ Imports. The car starts hot but is a slow start and has an uneven rev at idle. It JUST had difficulty going up a hill a few days ago.
the issue is that I may have to pay labor to pull engine again and ship it to have him give me trouble. Thanks for your fast reply
the issue is that I may have to pay labor to pull engine again and ship it to have him give me trouble. Thanks for your fast reply
#7431
Registered
I have contacted the owner at OJ imports and he has been very friendly with helping me troubleshoot, but it is difficult because closest dealer is 5 hours away and I was instructed not to put miles on car with engine acting up.
#7433
Registered
I'm really not mechanically inclined enough to do an engine swap. I'm mechanically inclined enough to change a CV joint and a starter. I'm thinking if it is an engine swap I am likely to sell the car. I'm in southern Colorado.
#7434
Registered
iTrader: (25)
to be fair it still remains to be seen whether there are other factors, but others didn’t do so well with this builder when it came to warranty.
https://www.rx8club.com/good-guy-bad...mports-265160/
The point to emphasize is that a proper Renesis engine build for long term durability is not cheap. Paying heavily is no guarantee either as there are details involved that make this engine unique over past rotary engines as well. Even the Mazda reman supplier doesn’t always do the best job. Unfortunately there are fewer and fewer people you can trust to do a good job for a Renesis rebuild.
Hopefully this might be a result of other mechanical issues; bad/clogged cat converter, fuel pump etc and the engine is ok once properly compression checked.
.
https://www.rx8club.com/good-guy-bad...mports-265160/
The point to emphasize is that a proper Renesis engine build for long term durability is not cheap. Paying heavily is no guarantee either as there are details involved that make this engine unique over past rotary engines as well. Even the Mazda reman supplier doesn’t always do the best job. Unfortunately there are fewer and fewer people you can trust to do a good job for a Renesis rebuild.
Hopefully this might be a result of other mechanical issues; bad/clogged cat converter, fuel pump etc and the engine is ok once properly compression checked.
.
Last edited by TeamRX8; 06-07-2020 at 01:07 PM.
The following users liked this post:
Cyryllys (06-07-2020)
#7435
Smoking turbo yay
You gotta be careful with warranties. I have seen warranties with fine prints that mention they exclude rotaries and diesels, so whatever paperwork they give you, I'd double check.
#7436
Registered
iTrader: (1)
One other thought: you could check the engine vacuum at idle. If the engine is really down to 50psi, you should be below spec in vacuum. That's an easy test any mechanic or you yourself can do.
Team is right, we can proceed by eliminating other causes: ignition coils, catalytic converter, fuel pump. Is this an auto or a manual?
Team is right, we can proceed by eliminating other causes: ignition coils, catalytic converter, fuel pump. Is this an auto or a manual?
#7438
Registered
Automatic. Mechanic got back today and said one coil wasnt sparking once car turned over. Hopefully replacing coils will improve performance and his compression check gauge was bad. Next would be cat. Car had mazda recalled fuel pump replacement and coils were done at the same time.
#7439
RX8 Fuel injection issues
Hello I'm new to this forum I've read it a lot but just started posting. I have no clue on how to create a post myself, but I'm having trouble with my rx8s I've been working on mine for some time its a 2004 manual 6 speed all stock with front air I think its called the VLAD. anyway I got this car about 4 months ago and I've fixed it all to the point that I've put 2000 miles on it and it fires right up, or it did.... now I'm having issue with it not firing up. it seems like the injectors are having issue priming. the pump is new, and primes just fine, but now it will not fire up until I turn the key on and off and prime the pump multiple times. I've cleaned the ssv and replaced the solenoid. I've de-carbed the motor and changed the plugs, coils, and wires. it really seems like an injector but I wanted a second opinion before I broke it down again. once it fires up it runs fire and there really isn't an difference in hot or cold start. let me know what yall need info wise. I am a mechanic just not a master so I need help sometimes
#7440
Are there any easy places to tap into the reverse switch in the front of the car especially near the head unit?
As an aside I really wish people didn't use imgur or photobucket on here. I have been looking for several hours for an answer and 90% of the posts are answered with "use the search" and the other 10% have links to images on imgur that don't exist anymore. If you read this, from now on PLEASE upload images instead of linking them...
As an aside I really wish people didn't use imgur or photobucket on here. I have been looking for several hours for an answer and 90% of the posts are answered with "use the search" and the other 10% have links to images on imgur that don't exist anymore. If you read this, from now on PLEASE upload images instead of linking them...
#7441
the reverse switch in the motor or the bolt on the bottom of the tranny? my wire got cut before I got mine and I had to practically bear hug the tranny to get to the wires then I just pulled off the bracket on the frame body and pulled the wire around far enough to reattach it.
#7442
Modulated Moderator
iTrader: (3)
Are there any easy places to tap into the reverse switch in the front of the car especially near the head unit?
As an aside I really wish people didn't use imgur or photobucket on here. I have been looking for several hours for an answer and 90% of the posts are answered with "use the search" and the other 10% have links to images on imgur that don't exist anymore. If you read this, from now on PLEASE upload images instead of linking them...
As an aside I really wish people didn't use imgur or photobucket on here. I have been looking for several hours for an answer and 90% of the posts are answered with "use the search" and the other 10% have links to images on imgur that don't exist anymore. If you read this, from now on PLEASE upload images instead of linking them...
The wires are in the engine harness and they run across the top of the engine and transmission... there is nothing inside the car. It wouldn't be too difficult to run the wire down the shifter boot area.
#7443
There must be then at the very least a wire going to the reverse bulbs on the tail lights? I'd rather keep it in the cabin if possible.
#7445
Registered
![Cool](https://www.rx8club.com/images/icons/icon6.gif)
I looked around for the answer to this question, because I'm sure it's been asked, but I couldn't find the answer.
I bought an '04 RX-8 SA that came with an extra motor and trans (because I can't say 'tranny' anymore)
One motor has been diagnosed with bad compression, The one in the car is, as yet, untested. (I been busy!)
Anyway, If I decide to do a rebuild and I tear apart the extra motor, only to find one rotor housing or one rotor is FUBAR, are the rotor housings interchangeable from front to rear? What about the rotors?
I'm asking if I can put a front housing or front rotor in the rear position - in the event I have 2 motors with 2 bad front housings, etc.
*Disclaimer* - never have I ever taken a rotary engine apart, busting my cherry on this one.
I bought an '04 RX-8 SA that came with an extra motor and trans (because I can't say 'tranny' anymore)
One motor has been diagnosed with bad compression, The one in the car is, as yet, untested. (I been busy!)
Anyway, If I decide to do a rebuild and I tear apart the extra motor, only to find one rotor housing or one rotor is FUBAR, are the rotor housings interchangeable from front to rear? What about the rotors?
I'm asking if I can put a front housing or front rotor in the rear position - in the event I have 2 motors with 2 bad front housings, etc.
*Disclaimer* - never have I ever taken a rotary engine apart, busting my cherry on this one.
#7449
![Newbie](https://www.rx8club.com/images/smilies/newbie.gif)