Here I go. About 3 weeks ago, just bought her, Daphne, 1990 FC3C vert, na, 145,000 miles, smoking and highest idle known to man. Asked advice, rudely, and was told to READ< READ<READ, and get "smart". I did. Have read more in 3 weeks, than I previously did in 40 years of Life. Long and short, she purrs like a kitten. Thanks all, for the past threads, current *** chewing, and great knowledge. ACW, TPS, O2 sensor, etc, etc, etc, either changed out, or adjusted as per YOUR knowledge. Today, new AFM, from junk yard, 20 bucks, TPS, same junk yard, 30 bucks, and wala. 750 rpms dead nuts, no smoke, no runs , no drips, no errors. I am thrilled. Compression test, numbers like a new engine, I think, 89, 90, 88, 89. Three equal bounces on all 4, Im in love. Thanks again, all of you. Will send pictures soon, have to take her out and make love to her first. Im hooked for life. SWEEEEEEEEET!!!

 

thats sweet, I have been moving a little slow on mine but hope to have it running just right in the near future. I have it holding an idle of about 1200 rpm and it burns a **** load of gas but i plan on getting it right.

 

Ill tell you what xero, the more I read, the easier it was. Im not patient, but this car has taught me to be just that. Stick with it, and it will come. If I can have success, anyone can.
these people really know their stuff, dam glad I found them

 

heh, its nice to see all the "SEARCH NEWB!" yelling does pay off sometimes......now about those damn "can i turbo my n/a threads" lol

 

hmm... I don't want to completely rain on your parade, but good compression #'s for a s5 N/A would have to be 100+psi, a new s5 motor would have around 120psi...

Either way, Daphne's still got some life in her... Treat her right and hopefully she'll return the favor.

I assume when you're talking about the "three equal bounces on all 4", you're referring to the compression on the rotor faces by testing through all 4 spark plug holes? No biggie, but you only need to test the front and rear rotors via the lower spark plug holes.

 

And don't forget, if you test with the throttle closed, you'll lose some PSI..

Have someone hold it WOT while you do the compression test on the lower plugs..
and make sure both lower plugs are out when you do it.. it lets the engine turn over easier.

 

I guess thats why they call me newbie. WOT, had son do that, will check again tomorrow, and I was referring to the rotor faces. One thing, why is it so important to make sure engine is up to temp when doing this?, and for an engine with so many miles, what would a really good compression be? Thanks, As I was expecting to put a new engine in, this is a nicely needed brake. By the time, knock on wood, that comes around, I should have this site memorized. hehehehehehhe. Thanks again.

 

ive got 110psi across the board on my 91 vert with 92K original

 

but ive seen rotaries run with alot worse compression than that

 

oh and you just in vallejo, im just across the bridge in pinole, if you need some help let me know. be glad to help a fellow RX'er. tournapart@yahoo.com

 

Sorry it took so long, but I just redid my compression test , this time with son pushing throttle to wide open, and big difference. Readings with WOT 112 , 109, 112, 110. Makes feel even better about Daphne and her 150 thou miles. Thanks again for knowledge. Ill hook up with you soon Tournapart. Thanks.

 

thats great compression, glad to hear it man

 

You do the compression test when the engine is warm becuase thats when you'll have the lowest numbers. When the engine is cold compression will be high, but thats not what counts since it gets hot when running, and its when the engine is running that you want to know what kind of shape its in, thus test when hot.

 

Hijacking your thread a little here, how much does the numbers go down over time? Obviously it would depend on how it is driven/maintained, how many miles etc.... but as a rough guide, how much does the compression generally deteriorate over a year? and when does it all start going to hell?

Just asking since I'm out looking for a 1990 S5 as we speak.. my S3 got stolen, and I'm wanting a guide for compression when I'm testing.

 

For an FC3S 13B 6-port non-turbo, hitting 150k to 200k miles is just about it's "golden years".
Due to it's power output, I wouldn't be surprised that compression doesn't go down till after 200k miles.
Those numbers are what I would expect from a 150k miles engine that's been well-maintained.


-Ted

 

Thanks for that comment Ted. After the way I started out on this site, and the way the car ran, I thought we'd both be dead by now. Ill take pictures and post them. For 15 year old car, this vehicle is CLEAN.

 

Oh, I can name a few that want me dead...

Congrads and good luck with the car!


-Ted

 

Sweet man, were all in it toghether.