Ok, I've been chasing problems left and right. I finally figure one out, thinking it will fix my major problems, only to find it cured one and added another. My main, persistent problem is a highly rich fuel mixture. I must also add that my idle is high and my vacuum is low (12-15in. @ 1100-1500rpm), but I have written this off to a failing motor; I think my apex seals are going since I only have about 95psi compression in both rotors.
Well I was looking for a vac leak since someone suggested that might be my problem. I was spraying around with starting fluid. I did not find anything unusual; no surge in rpms. After I shut off the car I smelled a strong, raw fuel smell. To make a long story short, I found a puddle of fuel around the primary injector distributor assy. I recently sent all the injectors to RC so my first thought was that I had installed one wrong, but I could not see any wetness around the top of the injectors. So my conclusion is that my air bleed sockets and insulators are leaking.
This brings me to my question: I thought I read somewhere that this kind of leak will cause a vac leak into the motor itself, is this true? Could this cause my fuel mixture to be ultra rich?
Sorry for the long post but I wanted to be thorough. Thanx in advance for any help.

 

Check your boost map sensor on the upper right side of the fire wall. You probably bumped it.

 

There are two o-rings on the injectors. The top one prevents fuel from leaking externally, the bottom one prevents fuel from leaking into the intake. You may have damaged the o-rings installing the injectors.

Too much fuel will actually wash the lubrication away and reduce your compression (lower your vacuum). I experienced this when my FPR went out and was dumping fuel into the intake. My idle was at about 1200 rpm with only 13-14" of vacuum.

 

95 psi is good if i'm not mistaken. I recently tested my compression and got about 90psi on all 6 faces. My engine runs strong. I doubt your apex seals are failing. I recently had extremely low vacuum after frying my computer and thought I had toasted the motor. It turns out that the fried computer was running the car really rich and fouled out my spark plugs really badly. I replaced the computer and plugs and the car ran perfect, with vacuum going back to normal. I think I was only running on one rotor with those bad plugs, I could have sworn I blew that engine since It felt like it had like 50hp at full throttle. Checked my compression twice to be sure and got around 90psi holding down the air bleeder on my generic autozone compression tester.

 

FormerPorscheGuy: Sorry, that was one thing I forgot to mention; I just replaced my boost/press. sensor this week thinking that was my problem. It changed nothing.

rynberg: Wow, thanx, I didn't think that the extra fuel would do that but it makes sense. I'll check those o-rings first.

twinturboy: Really, 90psi is good? I'm a mechanic and on a piston engine, anything under 100psi is failing. Guess I should look up the specs in the maual before I just assume I know what I'm doing. That is another thing I left out; I replaced the computer about 3 weeks ago. It solved a lot of my problems but not the richness. I also changed the plugs recently and the main wiring harness too (between ECU & engine).
Thanx again to you guys for the help, it has given me something to try.

 

I just checked the manual and here are the minimum values it gives for compression:
590kPa(8.0kgf/cm^2, 85psi)-250 rpm

Also has the differential limit as the following:
150kPa(1.5kgf/cm^2, 21psi)-250 rpm

 

If you can see fuel around the primary fuel rail and the top of the injector is not leaking then it may be the fuel pulsation dampner. Its the thing on the end of the fuel rail towards the firewall. 95psi is not great but its fair. Its also important that all 6 chambers be similar.

 

Go right to the o-rings and check these. With this kind of activity I would just replace the o-rings flat-out, even if you're not sure the cause.

Do not drive the car until this is fixed. Serious fire hazard and I wouldn't want to see your FD burning.

 

twinturboy: That's actually great news because that means that my engine might not be as far gone as I thought!

rx7will: I pulled the primary fuel distributor assy. this weekend and the insulators and air bleed sockets were toasty. The insulators were shredded but surprisingly pliable. The seals on top of the sockets were cracked but the socket itself is not bad (for 10 yrs. old). The pulsation dampner was dry but the inlet to the assy. (opposite end) was wet around the surface. I think I will order the o-rings for these end pieces and the insulators and sockets. I'll call Ray @ Malloy first thing in the morning.

clayne: I pulled the injectors out of the assy. first thing because I thought I possibly screwed up an o-ring putting them in; but they looked perfectly fine, so I think I will leave them alone. Plus there was no wetness around the tops of the injectors.
Believe me, I will NOT drive it until I fix this fuel leak. This poor car has already been through one engine fire; that's how I bought it. I have been working very hard to bring her back to life.
Thanx guys, keep the suggestions comin', I enjoy reading them!

 

I called Ray @ Malloy yesterday to make my order and found something that could have caused the leak. I was telling him what I needed and asked about the piece under the fuel distributor. He said it was a spacer made of plastic. Well mine was melted from the fire and was pretty much non-existent. He said that was the most probable cause of the leak, along with the bad insulators.
I would still like to know if this would cause the rich fuel mixture. I'm still not exactly sure what the computer does to compensate for a vac. leak downstream from the MAP/boost sensor. I'm pretty sure that the fuel leak was causing a vac. leak into the intake. Anyone have anymore suggestions or info?

 

Really, you need to fix the problem you know first - sounds like the bad air bleed sockets and the like aren't helping things.

Another common intake leak is the lower intake manifold to engine gasket - the early cars had a paper gasket, and later cars had a metal gasket. The metal one is sturdy, but the paper one will fail. Unfortunately, you have to pull the turbos and all kinda crap to get the lower intake manifold off -not a fun chore.

With the upper intake manifold and injectors out, you might be able to tell what gasket you have. The metal gasket is actually mutiple thin layers of metal stuck together.

Dale

Dale

 

dcfc3s: I do still have the old paper gasket. That could be my problem but I don't have time right now to pull the turbos and manifold to change it. Maybe next spring?

Well I got my parts today (got them in 2 days! thanx Ray!). I cleaned all the old pieces with some carb cleaner put everyting back together. When I got all the fuel syst. ready, I wanted to check for leaks so I ran the fuel pump up to pressurize the syst. As soon as press. came up, I see fuel dribbling out the top of the damper WTF! So I shut it off and wipe the fuel off and try it again but same result. I don't think this was where my leak was originally since the damper seemed to be the only thing that was dry before I took it all apart. I replaced the o-ring that seals it to the distributor and cleaned it with carb cleaner and that's it. I guess I'll have to get another one.
BTW, does any one know excatly what the fuel damper does? I have an idea; I think it is similar to the regulator but is uncontrolled/passive. Am I wrong?