Lost compression for no apparent reason!! HELP!!
12-16-12, 12:37 PM
#1
Lost compression for no apparent reason!! HELP!!
Hey guys,
so I have no idea what happened to my car!
When I had it idling at my house, compression was great 100-103 on both rotors...then we get to the shop, hadnt changed anything on the car, started it up and it ran like crap
check compression...and the rear rotor was down at 40 psi max
i really dont understand it...
I have another motor to swap in, but is there anything i can try to see if this motor will respond before i swap it out?
heres videos of what it sounded like running well at my house and then like crap at the shop...
HELP!!
BEFORE:
AFTER:
so I have no idea what happened to my car!
When I had it idling at my house, compression was great 100-103 on both rotors...then we get to the shop, hadnt changed anything on the car, started it up and it ran like crap
check compression...and the rear rotor was down at 40 psi max
i really dont understand it...
I have another motor to swap in, but is there anything i can try to see if this motor will respond before i swap it out?
heres videos of what it sounded like running well at my house and then like crap at the shop...
HELP!!
BEFORE:
AFTER:
12-16-12, 05:21 PM
#4
damn so its something that was building up to this then...i thought it sounded fine...it had just been flooded from the first time i tried to start it so it fouled the plugs, then with new plugs is what it sounded like in the first video
some people have told me that the seals might just be stuck and to try the ATF trick...gona give it a shot, hopefully its just that as the car had been sitting for a year before this start up
some people have told me that the seals might just be stuck and to try the ATF trick...gona give it a shot, hopefully its just that as the car had been sitting for a year before this start up
12-16-12, 05:43 PM
#5
Rotary Enthusiast
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Have you thought about doing a water treatment session which basically steam cleans the engine?
https://www.rx7club.com/general-rota...ngines-416908/
Not sure if this was a newly rebuilt engine or not. If it's an older one, perhaps the water treatment might work....if it was newly rebuilt, and the carbon remove, I don't think I would do it.
https://www.rx7club.com/general-rota...ngines-416908/
Not sure if this was a newly rebuilt engine or not. If it's an older one, perhaps the water treatment might work....if it was newly rebuilt, and the carbon remove, I don't think I would do it.
12-16-12, 05:48 PM
#6
Something sounds wrong in the first video already. If compression was fine before and went down after, you broke it driving it with whatever was wrong before. Not to trying to be a downer but apex seals being stuck is extremely unlikely.
Also, randomly reving the car serves no purpose in diagnosing a problem.
thewird
Also, randomly reving the car serves no purpose in diagnosing a problem.
thewird
12-16-12, 05:50 PM
#7
How do you check compression while the car is idling ?
I would try the ATF trick since the motor sat for a year. You still have your OMP and it injects used/dirty motor oil which causes carbon buildup.... It's worth a shot..
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12-16-12, 08:11 PM
#12
Original Gangster/Rotary!
iTrader: (213)
What are the details on history of the engine?
Also, 100 psi compression on a stone cold engine isn't what I'd call 'great,' although it's a helluva lot better than 40. Sorry to hear
Also, 100 psi compression on a stone cold engine isn't what I'd call 'great,' although it's a helluva lot better than 40. Sorry to hear
12-16-12, 08:21 PM
#13
"Something went wrong and they checked the compression", aka engine blew and there is your reason. What is to blame now, good luck with that. The blame will be tossed around and end result it won't be found. Good luck with your new setup.
thewird
thewird
12-16-12, 08:59 PM
#14
Sounds like multiple people with questionable knowledge and experience had their hands on it. They either grenaded it on the dyno (possibly from something stupid like an overboost), or they left insufficient safety margin and it blew on the street soon after.
As thewird was saying, fingers will be pointed but ultimately you will end up with a bill and very few answers.
Pardon my ignorance, but I'm not sure who VJ is. I don't know what being "basemapped" consists of. I don't know what "fully dyno'd and tuned" means in this context--what kind of pulls did they do, and what did they change?
As thewird was saying, fingers will be pointed but ultimately you will end up with a bill and very few answers.
Pardon my ignorance, but I'm not sure who VJ is. I don't know what being "basemapped" consists of. I don't know what "fully dyno'd and tuned" means in this context--what kind of pulls did they do, and what did they change?
12-16-12, 09:56 PM
#15
Motor was rebuilt about a year and a half ago and he was driving the car with no issues for 6k miles. He started his twin setup and body work on the car and it hasn't been run or driven in about 11 to 12 months. The injectors & rails were replaced with a new setup, new fuel pump and the twin setup installed. He finally got the car restarted last week and that's were we are today.
According to VJ, the owner of this FD, it was started up a few times to let idle and come up to temp last week prior to trailering it to the Tuner...
According to VJ, the owner of this FD, it was started up a few times to let idle and come up to temp last week prior to trailering it to the Tuner...
12-16-12, 10:00 PM
#16
Something like an overboost or ignition knock (maybe they set the ignition numbers too extreme) during boost under load on the dyno could have done it.
Best to just strip it down and have a look. Even then you wont get the full story, only the resultant damage. Rebuild or use other engine, and when you go through the tuning process again, be very picky with who you let touch the car..
Best to just strip it down and have a look. Even then you wont get the full story, only the resultant damage. Rebuild or use other engine, and when you go through the tuning process again, be very picky with who you let touch the car..
12-16-12, 10:02 PM
#17
It would be extremely difficult to damage the motor at idle unless it was overheated (air pocket for example) or some oil issue. The tune would have to be massively off and even then I'm not sure if it would hurt it at idle. However, I do notice that your group of car guys likes to rev the motor for no reason so it just wasn't at idle. You can pretty much throw out the fact that it sat for a year, that means nothing.
The setup was changed and a retune was attempted, somewhere along the line something was messed up. Tuner error/negligence or setup failure are the culprits. Whoever was touching the car when it happened, would be able to give you the most insight, however it sounds like it was being tuned when it happened and he's giving you the "I don't know what happened" speech instead of I was doing (or had just done) X when I noticed Y.
thewird
The setup was changed and a retune was attempted, somewhere along the line something was messed up. Tuner error/negligence or setup failure are the culprits. Whoever was touching the car when it happened, would be able to give you the most insight, however it sounds like it was being tuned when it happened and he's giving you the "I don't know what happened" speech instead of I was doing (or had just done) X when I noticed Y.
thewird
12-16-12, 11:57 PM
#21
Ok so heres the run down on the motor for better understanding, i forgot you guys have no idea whats been going on.
So the motor was rebuild in 2010 due to a bad water seal and street ported, also i replaced the stock seals with RA Super Seals and an Atkins complete rebuild kit was used
as Joe said, i put about 6k miles on it, and never ran the car hard in that time because i didnt know what kind of tune was on the Apexi that i have in the car (i bought it used)
the motor was working and running perfectly when i put it down for the build
Then the car went down to do the twin turbo setup and rebuild of the car...it took about a year
the motor was never pulled from the car in any of that time
Things i changed on the motor (excluding turbo setup):
stock injectors --> ID850 primaries with FFE rail, ID2200 secondaries with FFE rail
Walbro 255 --> Walbro 400
TurboSmart FPR800 pressure regulator
stock wiring harness --> single turbo harness
So after the build, the first start is the first video
I started and let her run for about 20 min. for 3 days before i took the car to the tuners shop.
When i got there i off loaded the car, and cranked her up...and thats what it sounded like...
The only difference from when i started the car at my house, to when i started at the tuners shop was that at my house it was running with an open throttle body, and at the tuners shop the intake piping was put on the car
The car was never put on the dyno because we couldnt get it to run right...the only changes made to the ECU was the injector sizes and lag times were changed for the new injectors and the duty cycles on the primaries were lowered to accomodate the 850 primaries
A couple of people have mentioned to me to try the ATF trick as the seals might just be stuck from sitting for so long, i will be trying this tomorrow
hopefully this solves the issue
oh and with the exception of my engine builder, i'm the only person thats ever touched this car, it was never taken to random shops to be worked on and everything that i've done has been done as per "How-Tos" and "DIYs" on this forum. It only went to this shop to get tuned by a very reputable tuner in our area that has tuned a friend of mines car which ran hard and never had any issues, also there hasnt been any bad raps or stories about him which is a good thing.
I know he also does alot of tuning in Puerto Rico on some of the rotaries down there.
is it possible that the seals are so stuck at opening the motor will be required to fix this?
is there another explanation as to what happened?
any other insight will be very greatly appreciated
So the motor was rebuild in 2010 due to a bad water seal and street ported, also i replaced the stock seals with RA Super Seals and an Atkins complete rebuild kit was used
as Joe said, i put about 6k miles on it, and never ran the car hard in that time because i didnt know what kind of tune was on the Apexi that i have in the car (i bought it used)
the motor was working and running perfectly when i put it down for the build
Then the car went down to do the twin turbo setup and rebuild of the car...it took about a year
the motor was never pulled from the car in any of that time
Things i changed on the motor (excluding turbo setup):
stock injectors --> ID850 primaries with FFE rail, ID2200 secondaries with FFE rail
Walbro 255 --> Walbro 400
TurboSmart FPR800 pressure regulator
stock wiring harness --> single turbo harness
So after the build, the first start is the first video
I started and let her run for about 20 min. for 3 days before i took the car to the tuners shop.
When i got there i off loaded the car, and cranked her up...and thats what it sounded like...
The only difference from when i started the car at my house, to when i started at the tuners shop was that at my house it was running with an open throttle body, and at the tuners shop the intake piping was put on the car
The car was never put on the dyno because we couldnt get it to run right...the only changes made to the ECU was the injector sizes and lag times were changed for the new injectors and the duty cycles on the primaries were lowered to accomodate the 850 primaries
A couple of people have mentioned to me to try the ATF trick as the seals might just be stuck from sitting for so long, i will be trying this tomorrow
hopefully this solves the issue
oh and with the exception of my engine builder, i'm the only person thats ever touched this car, it was never taken to random shops to be worked on and everything that i've done has been done as per "How-Tos" and "DIYs" on this forum. It only went to this shop to get tuned by a very reputable tuner in our area that has tuned a friend of mines car which ran hard and never had any issues, also there hasnt been any bad raps or stories about him which is a good thing.
I know he also does alot of tuning in Puerto Rico on some of the rotaries down there.
is it possible that the seals are so stuck at opening the motor will be required to fix this?
is there another explanation as to what happened?
any other insight will be very greatly appreciated
12-17-12, 06:59 AM
#22
Like I mentioned in your build thread, the "first start" video and the after video sound very similar (the second video the car is running a slightly higher idle). It sounds like it is running on one rotor. In my experience if you are able to get a flooded engine started it will typically clear up after the first rev or two, so the hard start was more than just a flooded engine from the beginning.
That tells me that the motor was damaged either during the build or somehow while you attempted to start it for the first time seeing as how it was running perfectly when you started the project.
^ Maybe this is the problem. This forum has alot of good information in it, however it also has alot more garbage in it.
Also you mentioned you installed a "single turbo harness"? But I thought you just installed twin turbos as part of this project? (j/k). Where did this single turbo harness come from, maybe injectors or crank angle sensors were hooked up wrong...
That tells me that the motor was damaged either during the build or somehow while you attempted to start it for the first time seeing as how it was running perfectly when you started the project.
oh and with the exception of my engine builder, i'm the only person thats ever touched this car, it was never taken to random shops to be worked on and everything that i've done has been done as per "How-Tos" and "DIYs" on this forum. It only went to this shop to get tuned by a very reputable tuner in our area that has tuned a friend of mines car which ran hard and never had any issues, also there hasnt been any bad raps or stories about him which is a good thing.
^ Maybe this is the problem. This forum has alot of good information in it, however it also has alot more garbage in it.
Also you mentioned you installed a "single turbo harness"? But I thought you just installed twin turbos as part of this project?
(j/k). Where did this single turbo harness come from, maybe injectors or crank angle sensors were hooked up wrong...
12-17-12, 07:16 AM
#23
Racing Rotary Since 1983
iTrader: (6)
there are a lot of things that could have caused the problem but i am not comfortable running the engine w an open throttle body. going from decent compression to 40 takes something major. perhaps the motor ingested something other than air.
good luck
howard
good luck
howard
