please leave info on any ideas or answers

Just purchased 1993 RX7 129,300 odo, the car has histroy of ported engine single turbo and a long list of mods that i can provide if necessary. The car was in a since stripped and put back to factory. Rebuilt motor, 20k on the twins, OEM intake, OEM IC, OEM CAT, and OEM CAT-Back.

Aftermarket:
Alarm
Down Pipe
Short Shifter
Supra Fuel Pump
Fluidyne Rad.
AST delete
A/C delete
Batt relocate

So far i've:
Rewired Radio (bad ground)
Cleared/painted/sealed the turn/running lights
Rewired the aftermarket alram (poor job/mult. wires zip-tied to the steering)
Sealed the IC duct (missing the cover/Batt. relocate)
Installed Boost Gauge
Fresh Rubber x4 (Nitto 255/50/16)

Info/Questions:
-At random (any gear, any load) the fuel chokes at 2500+- rpm (not good)
-Normal driving under 4000-4500 rpm boost is at 5-7 psi (is that norm)
-WOT 5-7 up to 4500 rpm (is that norm)
-WOT over 4500 rpm 10 psi (good)
-@ 6000 rpm the car feels like it (chokes/tachs out/fuel cut) (not good)
-Add Coolant Alarm has been going off on every start (last 4 times) i add a small amout of water to the resivior and or rad. cap and it cuts off. going to purchase a new rad cap, check for leaks, and closely monitor coolant levels.

To Do:-fix the boost/choking issues
-fix Add Coolant Alarm problem
-clean/replace grounds
-clean/replace oil pressure sending unit
-Install center triple guage (water temp./oil temp./????)
-Buy PowerFC
-Racing Beat Cat Back
-ect.

 

I would go with oil pressure or wideband AFR for the third gauge.

 

Definitely a Wideband.You will need it later on with the PFC anyways.
I would check the TPS.Although I am not an FD owner,when bogging occurs that is one of the things to check.
Check into an AST delete system.The FD's have a sub-par cooling system.

 

*Deleting the AST won't improve cooling.
*Get a copy of the Factory Service Manual if you haven't already. No... 5 to7 psi isn't normal. If the previous owner switched back from a single turbo to stock twins, who knows what's going on. You'll have to trouble-shoot. Go to the stickys in the 3rd Gen. section and scroll down for appropriate links and threads.
*Same suggestion for bogging/lack of power/fuel cut...whatever. I suspect that there were fuel mods when the car was single turbo. They may have been left on the car after switching back and negatively influencing things.
*Apparently consuming coolant concerns me. Check for coolant leaks REALLY closely. Pressure test the system. And get an aftermarket coolant temperature gauge on it ASAP. DO NOT rely on the stock gauge.
*Do you have any CEL's? If the previous owner went single he would have had to remove emissions. Unless he carefull re-installed emissions equipment with the sequential system you should have check engine lights with the stock ECU. If this is the case that might explain at least some of the poor performance/running.

 

No CEL.

Coolant fixed
Problem with the cut feeling at high rpm was boost cut.
Ordered boost controller

 

What was the coolant issue?
Do you have emissions?....airpump, split-air bypass, egr, etc? If not and your on the stock ECU you should have multiple codes.

While the pills may have been removed from the lines and cause low boost, a boost contoller won't cure the higher rpm issues. The PFC isn't likely to cure it either. I still recommend you do some searching in the 3rd Gen. stickys and get that FSM.

BTW, the oil pressure sender/signal is a known issue with these cars. But in my experience it's usually the spade connector at the sender...it's right under the oil filter pedestal and get's dirty. You'll typically get very low or no reading at idle, which is just the weaker signal not being able to get through the grime. Cleaning is alot cheaper fix than a new sender.

 

Radiator cap bad. Have all factory emissions. My problem was boost cut as far as I know.

 

It sounds like fuel cut, not boost cut at 6k rpm. With the MAP system and on the stock ECU, fuel is cut at ~ 12 or 13 psi. Actually that can happen at any rpm if the ECU sees too much boost. I'll correct my earlier post, a BC might help that.

 

Greddy BC on its way. Will update..

 

Got the Greddy 2 EBC in!!! Need to find some silicone hose or a substitute then grab some "T" fittings and I can get started.

 

Install worked out well. Boost is under control. It was boost cut. EBC is holding the boost at a perfect 10 psi. Now to install the the water temp gauge. I don't want to drill and tap. I know it's the best method but itd rather T into the hose before the throttle body. What do you guys think?

 

Actually drilling and tapping the T-stat housing is not the best method IMO and I agree with you. The throttle-body coolant line gives accurate temps real time and you're not waiting for the t-stat to open. Here's an older thread explaining why. Depending on your gauge sensor, post #36 gives a list of needed fittings. ---> https://www.rx7club.com/3rd-generati...d-idea-392910/

I installed mine there years ago. Even though I now have a PFC and can monitor temps on the Commander, I still like the gauge for quick glances.....I'm old and it just seems easier. A few years ago during a rebuild I also did away with AWS and removed the line going to the throttle-body (I don't drive the car in the winter), but kept the line and just looped it from front to back. Still works like a charm......

 

Thanks for the help!!! Here is what I e come up with so far.

 

Can some one tell me what this is. Notice the hole in the bottom.

 

That is normal trust me.I can't explain what it is but it is normal! ( I have an FD upper on my FC.)

 

It does not look factory at all. I've not seen this hole in other pictures. Why would someone do this.

 

It's stock. The small hole on the right is the air-bleed. I've never had to mess with my t-body, so I'm not up on it intimately, but I think that larger hole might be related to the PCV. IIRC there's a bulge in the casting corresponding to it. At any rate, your's doesn't appear to be modded in any way. My t-body looks the same.

 

Thank again. Water temp gauge installed!!! Highway temp is 170ish.

 

This makes me wish I was more ambitious in doing things myself back when I first bought my FD.
I have no knowledge, but wish you the best in your adventure.

Looking at the pictures makes me think, "so that's what it would look like if I took that apart".

 

Agreeded

 

The car can be a little intimidating to a new owner. It was to me too. But I also got a hard-copy of the Factory Service Manual with it. Every time I saw something in the engine bay that I couldn't identify, I opened the manual and found out what it was. I'd also search on this forum for additional info, tips and understanding. If I felt it was still complicated, I'd keep a cheap camera handy as I took things apart and click away, using the pictures later as a reference to make sure of vacuum line routing, electrical hook-ups etc. for re-assembly.

 

Good point. I make sure I use my cell to take pics while I take things off.

 

What's the oil neck gasket called? I think I'm leaking from this area.

 

IIRC it's actually an 'O' ring. I'd clean the area up well and see if it's really leaking or it's just from spillage. If it's leaking, search in the 3rd Gen. section for Malloy Mazda. They have an 800 number. Call 'Ray' in the parts department. He's an FD owner and reliable source for OEM. You also probably won't get it any cheaper, even with shipping/postage.

 

Thanks. I'll pull the parts off today and check. I'll update with pics if I remember