KenH

anybody know a good compression for cold engine. Engine can't started.

1st test 16 26 33
2nd test 19 27 35
3rd test 18 27 35

Thanks rx7 member I am looking to buy this 93 fd, I needed for feed back on this first time with rx7

I asked again because My post deleted twice by site admin??

lduley

iTrader: (1)

Is that PSI? If so the engine is shot and i'm amazed you even got that reading

KenH

yes its psi. the fd started a month ago. Last week I checked it out thinking to get it. We tried clear the flood and still can not get it to start. I also bypassed the relay too. power fc unit. do you know what's the min for cold compression?
Thanks

KenH

This vid took last month still running fine.

diabolical1

iTrader: (3)

welcome to the board.

well, i have no idea if you performed the test correctly or not, but assuming you did, those numbers spell doom anyway you choose to slice it (hot, cold, flooded, etc.). describe your procedure.

check this thread: https://www.rx7club.com/general-rota...-motor-858218/

i didn't watch the video so this may or may not be relevant depending on how the car was starting and running before. however, if the car has just been sitting for the past month doing nothing, then something is amiss. also, you indicated 3 tests, but presumably only one rotor.

KenH

Thanks for the feed back. The only compression I can do are cold. Engine current not starting. the reading above from front rotor leading hole. (Anybody know what's the min reading for cold engine?) I know hot engine would be 85 psi + with even drop to (0) and bounce back.

I test with both analog gauge and digital gauge compressor with the stem removed.

I also test the rear the number very close to the front.


and the vid above how the engine ran 1 month ago.

satch

iTrader: (1)

Use starter fluid to clear the engine housings of excessive fuel and then try the compression test again.

lduley

iTrader: (1)

You really think fuel would wash it out that much to give that low of readings?

Another way is put oil into each housing and try and start it, if it runs for a bit than quits, check compression again before trying to restart

diabolical1

iTrader: (3)

are you sure the battery and starter are up to the task? also, are you holding the throttle open?

the majority of references that i've read say that cold engines give lower readings, but i have read in one or two places where it said cold engines are higher. i tend to believe the former, but i figured i should mention the ambiguity i found in case my belief is incorrect.

i would agree with checking the compression again after clearing the chambers. i might even go a step further and say put some oil in the chambers and turn it a bit before testing. honestly, unless the compression was **** poor beforehand, i don't think even a flooded condition should give you the numbers you got, but i'm surely not an expert.


as far as your previous thread goes (and the post i edited above), i deleted it because when you mentioned the specifics, you're basically turning your thread into an ad and that's a big no-no in this section of the forum. i neglected to PM you and explain that when i deleted the thread, so that was my bad.

KenH

Thank You, for your help, I have been in many forums before. 1st time with rx7club, now I got it, and will post better next time. I'm very Sorry for the inconvenience.

Ok we tried to start it again this evening. I prayed some carb cleaner, removed all 4 spark plugs cranks the engine for about 30 sec twice. Installed new ngk spark plugs. tried to start again it click click click then almost start. We tried a few more times no go.
I removed the spark plugs it very wet with gas. I spray some carb cleaner into the throttle body it almost started for sec then died. I got some motor oil in the front and rear rotors. TWO, jumper box connected to the battery. same result 20, 33 36 psi. My friend he gave up on this. I will tow it to my shop next week and will report back . From my experienced with pistons engine it almost like old gas .


I just do some researched and this Compression Check

very close to my test.

.

lduley

iTrader: (1)

if your still getting those readings, I'm sure the motor is shot, and you keep trying to start it could be doing more damage to the internals than whats already done

if you have one of those nifty worm inspection cameras, shove it in the plug holes and peek around in there