Hi all, if I am still running stock fuel system, when I do the seq. simplification mod, do I keep the pressure regulator solenoid in place? The seq. simplification diagram do not show the pressure regulator solenoid, does that mean an aftermarket fuel regulator is replaced in lieu of the stock one? TIA

 

I retained my solenoid for the regulator, but you may be able to hook it to another solenoid.

 

You can eliminate the FPR Solenoid ((A), orange connector, IIRC) by connecting the stock FPR's vacuum hose directly to the diagonal nipple at the inside base of the LIM (by the primary injectors housing).



Also, I noticed you have a high-flow cat in your mods list. The sequential turbo simplification (which does not alter anything involved with the stock sequential system) eliminates the factory emissions control systems among other things. Removing either the airpump, the ACV, or the cats, renders the other two useless and they should be eliminated or disabled as well. If you want to keep airpump pulley for increased tension on the waterpump, then simply disconnect the airpump's two-prong grey connector and it will free-wheel. If you eliminated the airpump and are still running stock pulleys, then a 300K4 belt will fit nicely. Make sure belt wraps around the driver's side of the water pump pulley, as it is designed to spin counter-clockwise.

 

Thanks, I notice there are 2 vacuum hoses connects to the FPR solenoid, one of them connects to the LIM near the primary injectors, the other one kinda goes into the FPR, if I eliminate the solenoid, and connect the line directly from the FPR nipple to the nipple inside the LIM, will I cause any irregular fuel pressure in my stock system? Keep in mind I am runnin stock fuel setup still. Also another question I have is that I notice the seq. simplification diagram shows the vacuum line off the Y-pipe which normally goes into the pressure chamber with a check valve now goes to nowhere according to the diagram, do I plug the nipple off with a cap and be done with? or do I "Tee it with another vacuum line and tie it into the pressure chamber? I did the seq simp mod last night, and instantly got secondary boost, but after a few pulls on the highway, I notice a high pitch whistle whenever the boost is building up, and my boost pattern is slowly dropping from 12 psi to like 8-6 psi, maybe a leak in the system? TIA guys

 

Page F-111 of the service manual:
"This system cancels the vacuum applied to the pressure regulator and increases the fuel pressure during hot start-up and for a period immediately following engine start-up. This improves hot stanting as well as providing smooth idle.
To prevent vapor-lock during hot restart idle, vacuum to the pressure regulator is momentarily cut, and fuel injection pressure is increased."
A few people have eliminated this without any problems.

 

thanks JONSKI,
Can someone who has done the seq. simplification mod tells me where is the vacuum line from the Y-pipe to the pressure chamber goes after the seq. simplify mod? TIA

 

Connect the y-pipe to the top nipple on the LIM. Those 4 pairs of nipples on the front of the LIM go straight through and do not connect with the intake runners or anything else.

 

Thanks, this is one step I over-looked. I will make this change the next time I tear into mine.

 

Simplified Sequential is the way to go. You should feel great after doing this mod

Jonski nice to see you're still around helping out! My cousin moved to marco island where I think you used to live

RotaryPolo try your sig like this. I think it looks better and doesn't take up half the page...well some still do haha

1994 RX-7 53k Miles
New Ported Engine 2mm 2 piece Mazda Seals - 62-1 Turbo 1.00 Divided- HKS SS Divided Manifold - HKS 50mm Racing Wastegate - TIAL 50mm BOV - Modified Greddy 3 Row FMIC - Apexi PFC + Commander + Datalogit - New # GM 3 Bar Map Sensor + Connector - 50/50 Water/Alcohol Injection - Custom Spec Clutch with M2 Lightened Flywheel - 1680cc Secondary Injectors - 850cc Primary Injectors - Aeromotive Fpr with VDO FP gauge - Dual Twin Supra TT Fuel Pumps - Custom LIM - Crane Cams HI-6 Ignition - Magnecore 10mm Plug Wires - Greddy Racing Spark Plugs - Custom Air Intake - Custom Downpipe With Cutout - Midpipe With Borla XR-1 Muffler - Greddy SP Catback Exhaust - Greddy Pulley Kit - Greddy Profec B Spec II - PFS Boost Gauge - Modified Pettit Aluminum AST - Relocated Battery - M2 Trailing Links - Gotham Racing SS Braided OMP lines - Koyo Radiator - Engine Tq Brace - Little bit of Polishing ; )

 

Thanks guy, I think I overlooked this step too since I printed the seq. diagram in black and white and was confused. I think this will definitely solve the problem since my EGR vacuum line is still connected to the EGR ( I was too lazy to remove the EGR), however, the EGR line is plugged into the pressure chamber, meaning my pressure chamber is not charged at all....

 

UPDATE:
I connected the mysterious vacummn line to the pressure chamber, and went for a spin, the car immediately came alive, I got full primary & secondary boost. The weirdest thing happened this morning, everything works great until I did one pull, and after that, my car would not go into boost until 4500 rmp, then the second one came on full. I did a few pulls with the same result, no boost tilll 4500, then full boost to redline....can anyone explain what causes that? I thought in order for the 2nd turbo to come on, the primary needs to come on at least 8 psi? But I got no boost up to 4000, then 4500, full boost to redline...anyone can explain this?

 

how did you do that second pull? Did you come to a complete stop and run again or did you just slow down? If you just slowed down, did you drop your revs below 3k to unlock the turbos from parallel?

 

I've seen that on my car. I wouldn't "feel" any boost but my gauge would go to 5psi drop to 3psi and when I hit 4.5k rpms the secondary would come on and then I'd get the real boosted pushed into my chair feeling. Everywhere you read that the secondary turbo will not come online unless you've got at least 8psi on the primary, but not in my case.

Anyway I took off a bunch of the hoses to look for a boost leak. I found that the ribbing on the lower elbow that connects to the IC(stock) had 4 splits. I hot glued and duct taped it(temp fix, I'm buying another). Now I can REALLY feel the boost before 4.5k rpms.

So I think you might have a leak, or maybe one of the vac lines popped off when you did that last good pull.

 

well felt like the turbos are wired together parallel when I did the last pull, big lag till 4K transition, then a huge boost and felt like both turbo came on...I am puzzled. Also it was stop and go traffic, so the car definitly been below 3 K and stopped. The exhaust tone also sounded a little louder as well, like an NA car....Maybe a hose popped lose....

 

Sounds like your TCA solenoid may be stuck or bad or a popped hose...

 

Ok, just took the car out during lunch, remember the car was behaving like it was a parallel setup, both come on @ 4500 rmp? Well, I did a few pulls again, and all 4 times, the system worked flawlessly. Primary came on, then secondary. After the 4th pull, the car acted the same again, no boost till transition, exhaust note changed, then both came on......probably a stuck solenoid, I replaced both turbo control solenoids a few weeks back, so the only solenoids remain are the CCR and CC solenoids. what would you all think?

 

guys, I swapped out the CC and CR solenoids, and now the car is working fine. However, I do notice w/ the new seq. turbo simplification setup, there is one weird problem though. When I boost over 12 psi, the car would always go into parallel mode until after 10-20 second of recovery, then everything goes back to normal boost pattern, anybody experience this? Seems like the pressure chamber needs to be recharged after each hard pulls, any ideas?

 

Stock solenoids work well up to about 10 psi (sometimes lower)... anything above that and it's "iffy"

 

What a great thread.

Considering my current boosting problems are greatly resembling this one, I think I'll give this mod a shot.

What exactly is the idea though? Defeating some of the numerous vacuum lines? Making the seq. system itself more...predictable?

I like the idea of defeating emissions devices. I don't really care about that stuff myself. I'll prolly leave the air pump free-spinning though...

Oh, ya know what though? I get this damn squeak sound almost every time I start off from a stop in 1st gear, and even alot when I shift. All my belts are tight. Any ideas?