My cars stored a couple of hours drive away but the last time i drove it, it stumbelled and spluttered when i floored the car but was ok when i gently pushed the accelerator. This only happens above 3500rpm, so after research i thought i might be the fifth and six port actuators but when i checked my car it doesn't have actuators. Its an 86 N/A second gen does this mean its a four port or a six port.



Cheers for any help.



I'v read a couple of times now that all 84-92 13b's are six ports so are the ports always open. I'v been looking for any other posts about this for a long time.

having your ports stuck closed will cause the car to peak in power around 5000 rpm, so basicly u will still rev but have seemed to run outa steam above 5500ish

it will not cause stumbles, this sounds like possibly a tps issue or maybe a secondary injector not working correctly

All N/A 2nd gens came with the 13B that is a 6-port. It is possible someone took the actuators off but that wouldn't cause the stuttering.



Got any pics of the manifold side of the motor?

Sorry i haven't got any good pictures with the inlet pipe removed. But just to make things more clear the actuators are not jammed open or blanked off there is no sign of them ever being on the lower intake manifold.

I'v attached a picture the item circled in red is not on the manifold but there is a blanking plate, so it could have been removed.(what is it?)



The actuators (one circled in green) are missing all together and there is no holes or blanking plates on the manifold for it so it hasn't just been removed. https://www.nopistons.com/forums/pub...1047683561.gif

In your diagram, the green are the actuators and the red is the ACV. Sounds like you have the ACV removed and blocked off with a plate. That should be OK. I think I see a header there so I'm assuming you don't need it anyway. There should be little arms where the actuators connect to that move clockwise/counterclockwise the actuator rods that move the port sleeves. See if you can turn these by hand. If not, your aux sleeves are stuck in place.

why does this engine have a distributor? the vin plate on the fire wall says "FC", but wasnt the dizzy removed in place of a crank angle sensor, and 3 coil packs (2 singles and one double).



dont mean to jack the thread, but does this help in answering his question at all?

sorry, just thought of something!



RWD: someones been in your engine before you, there are headers installed, and your smog pump is gone, which leads me to believe there's a full (cat-less) exhaust. (note: the cat is where the backpressure line origionates to actuate the ports) if it wasnt you that put the exhaust in or removed the air pump, then previous owner may have removed the big bulky "actuators" you're looking for, but underneath what you have circled in green is actually a small arm, not much longer than your fingernail (should be two of those) thats the actuator, the big bulky thing is a just spring housing, to close it when you let off the gas. in my car the spring housings are removed but the actuators are still in and wired (tied) about 1/2-3/4 way open, I found that to be a pretty good medium.



ok, now the stumble: I second kompressorlogic: sounds like a secondary fuel injector issue.

-get a multi-meter or one of those test lights

-disconnect one of the secondary fuel injectors and hook up the light (or the meter when set to VDC)

-start your car and rev it to about 4000rpm's (just real quick, you dont have to hold it)



the test light should fire up like the dickens, or read about 12.something VDC on the meter. do it for both.

this'll atleast tell you if they're getting the signal to fire. I have no idea what to do if they arent, or how to check the injector itself...



hope this helps bud.

Looks like maybe somone put a FB motor in it. Which is 4-port. Which would explain the lack of port actuators. Look by the oil fill tube on the top of the rotor housing(the aluminum part). Does it say 12A or 13B?



EDIT:

Aslo you said in your orginal post "...84-92 are 13b's..." FC/13B started in 86.

The winsheild wiper motor is on the wrong side. The brake booster is on the wrong side....

Where are you from RWD-POG?

wait a tick... lets say it is a FB motor:

if it was a 13-b out of a GSL-SE then it would be a 6 port right?

if it was a 12-a then that intake manifold wouldnt fit right? that is a six port 13-b manifold there.



hope we can get this worked out so we can help him with his stumbeling problem.

thats cuz his drivers seat is on the "other side" we're the only wierd ones that drive on the left side. I'm thinking... australian?

I imagine the topic starter is from Europe or Aus. The European FC didnt have rotating sleeves for the 6 port, it had plates like a throttle instead.



It also came with the distributor in place of the CAS. And yes it is a 6 port

Learn someting new everyday!!

Thanks for all the help everyone i'ts been very useful.



To answer a few questions the car is english, thats why the brake master cylinder and wiper motor are swapped round.



It says 13B on the two rotor housings.



There does not appear to be any small arms sticking out of the lower inkake manifold so i don't think the actuators have just been removed.



As for modifying the engine, a previous owner has removed the air conditioning pump and fitted a new dual exhaust system.

That is a European model. They do not have actuators. What they do have is butterflies installed in the lower intake manifold. I am pretty sure the actuator is located in between the 2 intake manifold halves. This is the best possible 6 port engine for a streetport or bridgeport since the end of the auxiliary ports are not squared off. I have been hunting for a couple of these plates for a project but they are hard to find.

hey do u have any more pictures of the intake manifold on the pass side?? im interested too see how different looking it is than the us spec ones.

I haven't really got any great pictures and like i said the cars a few hours drive away but i'll post the ones i do have for you



[attachment=41287:attachment]

[attachment=41288:attachment]

[attachment=41289:attachment]

thats ok, ive never actually seen pics of what hte european intake manifold looks like, ive allways been curious

Do the Euro LIM have the ACV and stuff on it?

Because those manifolds would make it easier when turboing an N/A block. You wouldn't have to make a spacer for the turbo.

yeah i wonder.... i just went and port matched some t2 manifolds wen i did a 6 port turbo setup...

Same here....

The 3500 rpm hesitation is usually caused by a ground issue...



The following is from ICEMARK from the RX7 Club:

I have this hesitation whenever I accelerate right around 3500-4000 RPM

The dreaded 3800 RPM hesitation is cause 90% of the time by poor ground connections between the engine, the battery, and the car. Clean or replace all the under hood ground connections. On 86 model year cars , replacing/regrounding the pressure sensor's ground wire has helped (do not re-ground a 87 or later model year). If there is still a problem after that, look at cleaning the fuel injectors and (on a N/A) that your 5th/6th ports are operating correctly.



Hope this helps...

cant believe no one thought of this, the 3,800 hesitation

I'd say the 3800RPM grounding issue is very likely; don't rule out a clogged cat as well (If you running one).

Sorry i haven't replied to you guys a bit sooner. The car hasn't got a cat so i think the problem is likely to be either earths or fuel injectors. Has anyone ever used these fuel injector/engine cleaners that you pour in the fuel tank and do they have any effect. I am tempted to try that before removing the injectors but i don't want to course any damage to the engine.



Cheers to the members who have helped out, you guys are legends and i can't wait to have the old rx running at full power as i'v never experienced this yet.

https://www.nopistons.com/forums/pub...IR#>/bigok.gif



When i get some better pics of the LIM i will post them as well.

Fix your grounds first man. Pick up a generic grounding kit and go to town with FAQ in hand. Chances are this is your problem.



Also... Injector cleaners work SOME of the time, but for the most part, they are worth their weight in tapeworms. Just run some MMO (Marvel Mystery Oil) in your gas from now on. Its a pretty gentle solvent that won't ruin anything. Over some time it might fix your problem (if its not grounding).



Ultimately, if grounding doesn't help, send your injectors in to get ultrasonically cleaned and flow tested. Thats where you will notice a difference.

The cleaners aren't going to hurt anything but, they're more for preventative maintenance than harcore cleaning.



What you might try though is do a double does of the cleaner. If the bottle treats a full tank of gas, do 2 bottles. I did thiss once and it cleaned a butt load of carbon out. So much so, it clogged my cats!

I use a product called SeaFoam to clean injectors. Good stuff.

Did this form of 6th port actuation make any more hp or torque than the rotating sleeves did? It seems like a cleaner, more consistant method of controlling the extra ports, and would have the benefits that you would get from running the sleeve inserts. Whats the reason that europe got a different form of actuation?

Some of you guys were asking for pictures of the lower inlet manifold so heres a few i'v just taken. As i suspected the butterflies where rusted solid so a bit of WD40 and and a push and there moving again. The butterflies where jammed open so, so far all i have driven is an rx-7 that produces poor bottom end power because of the actuators and no top end power because of the spluttering around 4000 rpm https://www.nopistons.com/forums/pub...1047683664.gif .



http://img100.imageshack.us/img100/5922/dscf3966dq6.jpg



http://img176.imageshack.us/img176/7536/dscf3968gf8.jpg



http://img100.imageshack.us/img100/6755/dscf3976ed3.jpg

Well, thats pretty damn cool.

Re: No port actuators
 

Anyone have anything else on this 5 years later