raenner

I need some help here on tracking down a problem...here's the deal...

For a long time after installing my new motor, I had a vacuum leak I didn't know about. After I finally found it and fixed it, my car had sooo much more power, it was incredible. However, three days later it was back to it's old power level. Since then, I've been trying to find the source of the problem. I've tried:

1. Hunting down more vac leaks...can't find any
2. Replaced water thermo sensor
3. Replaced intake air sensor
4. Run fuel injector cleaner thru a few times
5. Swapped ECUs
6. I'm pretty sure my 6-ports are opening. I have them hooked up to the air pump and they open when I'm just revving it in neutral. I assume they're opening under load (maybe not all the way?)

Still the same thing. I guess something that might be a clue is that my A/F gauge never really gets past the first or second green bar when WOT. Shouldn't it read full-rich? I'm not sure if this is related or not, but my car has a hot-start problem that goes away whenever I run injector-cleaner thru, but then comes back again a few tanks later.

Aaaanyways, if you have any ideas, let me know. Sorry for the long post.

-Jonathan
88 RX-7 SE
(streetported, hi-comp rotors, balanced, etc., etc.)

HAILERS

The one thing that caught my eye was the sixports opening while reving in neutral. I'm at a disadvantage in that I've only worked on 86, 87 and 87 turbo's, but on my cars I have never seen the port open just sitting in the driveway with a stock exaust much less a RBeat. I thought that the 88 was the same way, they open with back pressure from the exaust. So if that if so, why are yours opening. Lots of back pressure that should not be there??? Just a thought. Sounds like a wicked engine withe the porting and high compression rotors.

raenner

About the 6-ports...I should have explained. My exhaust is basically completely open, so I didn't have enough backpressure to activate the actuators. I tapped the relief hose coming off the ACV, so when it starts dumping air at 3700, the 6 ports open.

Thanks for the reply.
-Jonathan

HAILERS

Sorry about the earlier post. Your step 6 missed my eye in your first post. Yeah, I think you should read richer at wot. I do not have a air fuel meter but I have a digital volt meter tapped into the oxygen sensor at the ecu that I've been monitoring for a couple of weeks on my n/a and turboii both. At wot the meter will read like .7 or .9 on both cars. Sounds llike your secondaries might not be opening. Then again I'm not using the A/F meter so I do not really know. The firsts n/a I owned and rebuilt irritated me cause its power was not as good as my 82 with RB header. I monkeyed around and found that whenever I plugged and unplugged the engine harness in the upper right passenger compartment the car acted much better. Long story made a bit shorter is the boost sensor black and brown wire needs a good ground in the engine bay. This blaack and brown wire is the ground for air flow meter, tps, boost sensor, atmopheric pressure sensor, water thermo sensor well you get the point. The gnd was not getting back to the ecu under the passenger feet because the connectors b/t the eng and ecu were corrupt. Try gnding the brown and black wire on the pressure sensor plug. Its possible the ecu is not getting proper info back from those sensors.

HAILERS

Talk about functional illiterate. I noticed finaly that yours is ported and balanced. Seems like you need an upgrade in the secondaries like a pair of 680's from a 84gsl. But then again it acted real strong for a day or so then wents **** up. Still seems like the 680's might help someday in the future. The line to the boost or pressure sensor on the right strut , is it hooked up ok and does it have a pill or orfice in it that slightly restricts flow? Try a vaccum line there with and without the orfice(pill) in it.

raenner

Hailers, dude, thanks for that post. Finally someone with the same problem (kind of)! That's a great suggestion -- I cleaned up the other engine grounds and added two new ones, but I overlooked the boost sensor. I'll do that one tonite.

Thanks again! I didn't know it was the ground point for those critical sensors. Maybe this will even help my hot-start problem (didn't Mazda's TSB mention re-grounding the boost sensor to fix that? Or the 3800 hesitation...I forget). I'll let you know what happens.

Thanks!
-Jonathan