2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

so did a compression check and got ......

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Old Oct 18, 2005 | 01:50 PM
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so did a compression check and got ......

okay ... first of all ... i have no reason to think my motor is blown ... im just getting constant HORRIBLE flooding ... which since i have clean injectors ... the next thing to check would be compression ... so thats why i did the test ...

my battery is weak, (im pretty sure)
i didnt unplug my cas,
and the throttle wasnt held all the way open ....

when i held the valve in i got even pulses on all 3 faces ... each bounce was over approx 33PSI ... so that for the most part means that my apex seals are good ... correct?

when i let the valve go and do it ... it doesnt get more than 60 psi up on the guage ...

the car runs great once it actually starts, so surely the compression isnt that low ...

was it cause the throttle wasnt held open?
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Old Oct 18, 2005 | 02:09 PM
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try once again with the butterflys wide open cause good compresson is around 85 psi and plug the cas that helps and found yourself a fully charged battery
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Old Oct 18, 2005 | 02:12 PM
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and you're flooding all the time? , when you cleaned the injectors did you replace all the o-rings with new ones????
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Old Oct 18, 2005 | 02:27 PM
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Originally Posted by carzy driver
and you're flooding all the time? , when you cleaned the injectors did you replace all the o-rings with new ones????
they were sent off to witchhunter.com

they came back with all new orings and what not ...


it started flooding really bad about 2 weeks ago out of the blue ...


surely the injectors are good to go ... they were just cleaned about 2 months ago ..
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Old Oct 18, 2005 | 03:00 PM
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could be something going on with the fuel pressure regulator, maybe the vacuum hose going to came off
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Old Oct 18, 2005 | 03:02 PM
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how did your compression test do??
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Old Oct 18, 2005 | 03:10 PM
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It states that he got 3 even 33 psi bounces.

That is very low for a healthy motor.

You should be looking at around 3 even bounces around 85 - 110 .


I would try it again.

What compression tester are you using ? a common piston one ? and did you take out the checm valve.

If you did do the above and your still getting only 33 psi per face, Unfortunatly you have stuck seals or something worse.

Either way probably will need to open her up.
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Old Oct 18, 2005 | 05:21 PM
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from what i read .. first you just check for even pulses from the rotors ...
if you hold the check valve in , it will show you the pressure per face of the rotor ..

each rotor got even pulses in the 33 range ... which means NO seals are completley fucked ... or else i would have dead spots or uneven pulses ...
thats not the case ..

i did the test from reading landers website ..

it says to check for 3 even pulses first .. which should be around the 30PSI range ...
then to release the valve and try again ....

basically my question is ..

would not holding the throttle open cause a much lower reading?

and yes it was a normal piston compression tester that i used
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Old Oct 18, 2005 | 05:38 PM
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not holding the throttle open will give you a lower reading and I use a normal compression tester and found it no different in giving readings compared to the more fancier and expensive type
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Old Oct 18, 2005 | 06:26 PM
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cool ...

i mean like i said i got more than 30 psi per rotor face, so the seals should be good ...

i'll redo the test the correct way tomorrow if i can get around to it ... might also try to charge the battery for a while if i can
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Old Oct 18, 2005 | 06:28 PM
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Do both. 33psi, honestly, I don't even think the engine would run, let alone idle properly.
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Old Oct 18, 2005 | 07:09 PM
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man you guys arent listening ...

heres what it says on landers site

"Compression test using a piston engine tester:
1. note battery strength. A weak battery will yield low compression results.
2. Remove both lower plugs and wires.
3. remove EGI fuse from engine fusebox.
4. have a friend floor the accelerator pedal, opening the throttle for more airflow
5. insert your tester into the leading hole
6. hold the valve on the side of the tester open
7. have your friend crank the car over for 5+ seconds.
8. observe the needle bounces. You should see 3 in succession without skips, even bounces, in roughly the 30-35psi range.
9. let out on the valve now, and let the tester reach an overall compression value for all 3 faces(highest of 3 will be displayed). 115+ is like new, 100-115 is healthy, 90-100 is getting weak(1 year or less in most cases) below 90 could blow at any moment.
10. repeat for opposite rotor. Note difference in overall compression between rotors, which should be no more than 20psi max."


NOTICE WHERE IT SAYS THERE SHOULD BE 30 PSI BOUNCE???

thats what im talking about ...
the overall compression which i mentioned was 60 something, is flawed cause i didnt hold the throttle open, and have a weak battery ....

my main original question was would those two factors really yield that much lower of a result?
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Old Oct 18, 2005 | 08:09 PM
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weid my piston tester gets bounces up to 100 wiht the shrader valve removed
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Old Oct 18, 2005 | 10:10 PM
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Having good or crappy compression still doesn't explain for the constant flooding and since you said your injectors came back clean and with new o-rings then consider the fuel pressure regulator could have went bad, weird stuff can happen just overnight, or the vac hose could have come off or have a split in it. I mean after checking out landers site and reading your posts, I think your compression sould be fine, so start looking at your fuel delivery system starting with the FPR and vac lines. - Dave
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Old Oct 19, 2005 | 09:39 AM
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Holding the throttle open isn't going to change your reading much, if at all, on a standard piston tester.
Getting a better battery and cranking slighly faster will improve the readings, but that is why the FSM has a cranking speed correction factor.

Either way, your compression will not increase from 60 psi to 85 psi (min spec compression) just by changing those factors.

Some testers (like mine) work the way Landers describes. With others, the 'bounce test' will show the true compression as well.

Either way, IF you are getting three even bounces, but only 60 psi max reading, you have low compression. Could be a slighly chipped seal that wore the housing, tired housings, etc.

I would suggest trying another tester, just for a 2nd opinion.

Low compression engines will flood easily.

Last edited by eViLRotor; Oct 19, 2005 at 09:44 AM.
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Old Oct 19, 2005 | 09:57 AM
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I'm with the post above. Your compression is the reason the car *floods* easily. Your compression is sorry. As in bad/no good/bum compression. Buy some new rotor housings and rebuild the engine.
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Old Oct 19, 2005 | 10:50 AM
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Originally Posted by Fitness Stain
man you guys arent listening ...

8<

NOTICE WHERE IT SAYS THERE SHOULD BE 30 PSI BOUNCE???

thats what im talking about ...
the overall compression which i mentioned was 60 something, is flawed cause i didnt hold the throttle open, and have a weak battery ....

my main original question was would those two factors really yield that much lower of a result?
Does it give you 30psi both front and back?
Who did the rebuild?


-Ted
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Old Oct 19, 2005 | 12:33 PM
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Originally Posted by RETed
Does it give you 30psi both front and back?
Who did the rebuild?


-Ted

yes its even bounces all above 30 psi for both rotors ....

landers did the rebuild about a year ago now .....
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Old Oct 19, 2005 | 12:44 PM
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Landers does a great job rebuilding so I would doubt the motor went that fast. Have you leaned out or anything since you've had the car up and running? Hopefully it's just some obscure factor that you haven't found yet instead of low compression. Best of luck.

Zach
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Old Oct 19, 2005 | 12:48 PM
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Dude 30 is LOW.

I think Kevins site has a typo.

On my rebuild I did a test 500 miles in and I got 65-75psi per face and 75-80 cumulative per housing.

50-65psi pre face/housing is the idea of low compression.
80-100 is average
and 100-120 is perfect OMFG thank the rotary gods good.
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Old Oct 19, 2005 | 01:01 PM
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well its kinda wierd that a month or so after i add the new ECU (rtek 1.7) and bigger injectors it starts freaking out ....

surely its not a bad engine .... i mean ... i took it out like a week ago (after unflooding it) and it ran great ... idle was good ... and it felt pretty damn strong ...


im going to redo the compression test before i start freaking out ..

however if that freaking engine is toast, im parting the stupid car out ...and buying a mazda speed6
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Old Oct 19, 2005 | 01:15 PM
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No your not bitch!
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Old Oct 19, 2005 | 01:20 PM
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Originally Posted by djmtsu
No your not bitch!

lol


maybe DJ will save my soul...



seriously though if this engine is toast, were all having a build dustin a new engine party .... catered by me ..


it will involve alot of greasy food, and a keg of beer ....should be a nice learning experience
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Old Oct 19, 2005 | 01:38 PM
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I seriously doubt it needs an engine. Something else is awry.

Its not like you've been beating the dogshit out of that engine, you drive like a grandma!!

And I will be in for the build party!
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Old Oct 19, 2005 | 02:53 PM
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well i dont drive like grandma, but i do take care of the car and never push it when it cant handle it ..

surely its not the engine .....
the compression tester that i got made it real hard to secure the tester in the spark plug hole too ....
im not giving up yet ... hopefully
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