SleepR1

Just updating my thread. I ruled out turbo control issues and the turbos themselves as root causes. I'm chasing down either a boost leak or exhaust leak. I began snugging all the nuts on the turbo assembly (attachment to the exhaust manifold). A few of the nuts needed some snugging. The center bolt on the turbo assembly is backed all the way out. There are 5 bolts on the periphery, and a 14-mm nut/bolt in the middle between the precontrol and wastegate actuator rods. This is a very good place for exhaust gasses to leak out. I haven't figured out if this center bolt is broken or just backed out. I need to get a deep-well 14-mm socket and flex-head ratchet. Once I pull the bolt out and inspect it, I'll know. Hopefully I'll be able to just snug the center bolt back down, and my problem will be solved??!!

SleepR1

Following up on this thread. The boost pattern has dropped to 4-0-4. We've taken care of all the possible boost control issues. The '99 J-spec twins were inspected, and there doesn't appear to be any problems with the turbos themselves. New charge relief, charge control actuator, double throttle, and turbo control solenoids were installed (on the solenoid rack). CCA butterfly was checked. New o-ring in the CCA pipe installed. Intake system was pressureized, with no apparent leaks. Boost pattern remains 4-0-4.

It seems the lack of power/acceleration and subsequent lack of boost might be due to another system problem/failure.

Looking at fuel delivery, throttle sensor, ignition, exhaust restriction.

Herblenny

iTrader: (13)

Manny,

I'm going to suggest couple of things.. And I could be very wrong about this.. but I did have ton of boost issues in the past..

By my experience so far, when both turbos boost low, It always been leak in the IC.. I'm not sure if you are running aftermarket IC piping or stock.. but I would check your lines.. Also, check your IC itself.. I notice that its usually something simple.. when both turbos aren't making boost..

If that doesn't work.. it could be that your vac chamber is not holding enough vacuume.. maybe because of the oil, reducing space.. or your one way valves are bad.. which was my case when i had secondary boost issue..

but primary.. it might be the pre-control, turbo control, waste gate solenoid issue.. I recently had primary turbo problems.. where all my boost kicked on at 4000RPM.. And I think it was my AVC-R.. now it works fine.. The AVC-R replaces stock pre-control and waste gate..

SleepR1

checked all these. looking hard at an exhaust restriction or fuel delivery problem...

7racer

Manny,

are you still getting oil into the vacuum chamber despite the catch can???

what was the final consensus of the cause?

It seems like you started noticing turbo problems when this symptom first showed up.

SleepR1

Yes, I was, but not as much. My theory is that the GReddy 2-row FMIC is such a huge car that there's still residual oil in the core that makes its way into the intake. After the oil catch can install the intake piping is dry from the Efini Y-pipe to the inlet side of the FMIC. On the outlet side of the FMIC the piping has oil in it. Still don't understand why there is oil the vacuum chamber. I recently found out there was oil in the CCA actuator, which needed to be drained out. Still at 4-0-4.

PaulyDee

SleepR1

I was studying the 1993 Rx-7 Workshop Manual, Toubleshooting (Section F).

Basically my problem falls under "Poor Acceleration" and "Lack Of Power".

The manual defines "poor acceleration" as engine speed that increases but vehicle speed slowly increases during acceleration.

The manual suggests checking:

1. Fuel injectors (leakage or clog)
2. Pressure regulator
3. Fuel filter (clogged)
4. Spark plugs
5. Igniter (poor connection of connector)
6. Air leakage in intake
7. Pressure sensor (pressure sensor filter hose clogged, or poor connection of connector)
8. Crank angle sensor (poor conncection)
9. Metering oil pump (oil pump malfunction--fuel injection and ignition timing fixed)
10. Solenoid valves (Turbo control, charge control malfuction)
11. EGR control system (EGR control valve stuck open)
12. Water thermosensor (malfunction)
13. Double throttle control system

The manual defines "lack of power" as poor performance under load.

The manual suggests checking:

1. Pressure sensor (malfunction)
2. Secondary fuel injector (poor connection of injector or clogged nozzle)
3. Turbo boost leak
4. Spark plugs
5. Throttle sensor (full range)
6. Fuel filter (clogged)
7. Pressure regulator (malfunction)
8. Double throttle control system (double throttle valve not open)
9. Sequential twin turbo control system (secondary port not open)
10. EGR control system (EGR valve stuck open)
11. Air filter (clogged)
12. Catalytic converter (clogged)
13. Fuel low octane
14. Metering oil pump (poor connection of connector)

A few of the above items have been addressed on both lists.

For the good of the FD Rx7 community, I will follow-up once it's solved. Hopefully you all could learn from my solutions of problems and help others with answers instead of posting a "devil" smiley and relishing in someone's misfortune...

PaulyDee

You have no idea.

For the record, I contribute substantially to the FD community on and off this board. Had it been anyone else, the problem would have already been addressed and most likely alleviated. Good hunting.

Oh and one more thing.....

SleepR1

SleepR1

Updating this thread. The root cause for low boost was a clogged high-flow catalytic converter. The Bonez was installed in 1998. The cat had 74,000 miles. Currently deciding between midpipe and another high-flow cat replacement.

Herblenny

iTrader: (13)

That's awesome.. Good to hear that it was the cat..

SleepR1

Yeah, went with MP, air pump removal, and Power FC dyno-tuned to 1.05 kg/cm^2 (15 psi)

7racer

wow!

I thought those Bonez were suppose to last a lot longer?!?!?

SleepR1

7racer, I've had quite few track events on that cat. The extreme heat from open-tracking probably burned up the brick material and mesh screen that holds the honeycomb stuff together. I'll see if Rx7 Store can take pics of the Bonez high flow. As a precaution, I went with a MP, so I don't have to deal with that failure again I'm looking forward to what my car feels like with more top end juice, and perhaps flammage through the RB dual tip LOL

SleepR1

No pics, but I did peak inside the high flow cat. The bricks were in pieces. Shake the cat up and down, and you can hear the broken bricks (they sound like jigzaw puzzle pieces in a tin can). Replaced the high-flow cat with a straight-through MP and removed the air pump. What a difference?! Turbos spool much more quickly. Exhaust sound is ok at light throttle. Stomp on the go pedal, and the sound gets raw and angry. MP and leaned out AFRs yielded a 20 rwhp gain. 11ish AFRs is not rich enough to cause flammage out of the RB dual tip though.

7racer

wow congrats!! Now your making me seriously think about getting a MP....

I had my mind set on a high flow cat....I just don't think I can take the fumes

Mahjik

iTrader: (1)

Well, I'll bet the new tuning made the biggest difference. However, even going from a clogged cat to a new cat one would still feel like a huge power gain.

If fumes and smelling like exhaust are going to be a problem, stay away from a midpipe.

SleepR1

Actually the fumes weren't any worse than when my high-flow cat was failing (probably was clogged for awhile, and I didn't know it until the low boost pattern symptoms).

If you don't have to worry about SOs (significant others) riding with you, go midpipe, baby

I just read a post from 7 eleven on how to adjust my Power FC for flammage

Scroll toward the bottom of this thread https://www.rx7club.com/showthread.p...89#post2304489

7racer

Manny!

I thought you were one of the older more sensible forum members....

now your polluting the air and burning tail feathers!!!

What next......stickers?!?!?

just kidding

SleepR1

Older? Yes!

Indiana does not do emissions testing

Stickers? Yes, I'm running autocross numbers this weekend (3 SM2)

SleepR1

New boost pattern with straight-through (nonresonated) midpipe, Power FC tuned to 11 AFRs, and with recent 50 F ambient ATs yielding 18 to 20 C AITs:

0.85 kg/cm^2, pr/sc, 50% base duty cycle...12.1--14.1--12.1 psi

So much for that low boost pattern

Replacing the old clogged high-flow cat is like uncorking the Genie out of the bottle! Damn car is a beast, now. Still getting used to the new power Will autocross it this Sunday in SM2. Looking forward to drift practice hee hee

7racer

Damn!!! thats NICE!

Congrats Manny!

SleepR1

The 2 psi boost spike at the transition, is apparently common with a midpipe. I had Rx7 Store tune to 1.05 kg/cm^2 (15 psi), and at that level, I had a 1.15 kg/cm^2 (16.4 psi) spike, so a 0.99 kg/cm^2 (14.1 psi) spike is nothing to worry about even with the recent cool ambient air temps The car feels GREAT. Took my wife out in the car this evening...she doesn't like it. It's too stressful for her LOL

SleepR1

Although the transition from primary to secondary turbo is fine, I managed to vacuum pump 24 oz of oil from my vacuum chamber. I'm still puzzled by this. I can only guess that the FMIC (GReddy 2-row) has a very large internal volume. So the 7 months I ran "Speed Sauce" BEFORE re-routing the oil venting to a catch bottle, the intake oil had collected in the FMIC. AFTER the oil vent re-route job, the intake pipe BEFORE the FMIC is dry. There is some oil AFTER the FMIC, so this must be the oil source? Sooner or later the oil remaining in the FMIC core will be purged, and I won't have this problem (oil collecting in the vacuum chamber) anymore.