Ok, i took my car for a ride for the first time, since i got it about 4 days ago. So i drove it around to warm up and took in the freeway, tried to red line it, it take forever to get there. I could feel the power for the car below 3500 rpms but after that it completeley dies out...

Anybody had the same problem or know what to do plz helpl!!!

 

secondary injectors are probably not firing or/and your auxilary ports are not functioning properly

 

hey buggy-fc3s, i was a newbie like you and asked literally the exact same question... do a search on "3800 rpm hesitation" and you will find a gajillion answers to your question, as well as some things you can do to at least HELP fix it

 

so can i fix that 3800 rpm hesitation ??

 

search button--it is your friend. Yes it can be fixed but its probably your 5th and 6th ports not opening.

 

5th and 6th ports would not kill the car alltogether... it is probably ur secondary injectors as said befor.. i have a feeling that they aren't getting any power at all...

 

cool thanx, now i know what to look for...

 

Ok i found out that i could take out the intake manifold and soak it with degreaser or WD40, that should clean it.

To tell you the truth is i never done this kind of thing before can someone who cleaned the 5th and 6th ports before walk me through the process some how??

And the injectors how do i clean them?? I think this is the reason why i bought this FC. I bought it to fix it's problem to get the experience to deal with some real problems with a car.

If any one can tell the process of doing this would be great, in the mean time i'll read the Haynes manual and see what i could scoup out it.

Thanks for you help...i appreciate it.

 

Ok i found out that i could take out the intake manifold and soak it with degreaser or WD40, that should clean it.

To tell you the truth is i never done this kind of thing before can someone who cleaned the 5th and 6th ports before walk me through the process some how??

And the injectors how do i clean them?? I think this is the reason why i bought this FC. I bought it to fix it's problem to get the experience to deal with some real problems with a car.

If any one can tell the process of doing this would be great, in the mean time i'll read the Haynes manual and see what i could scoup out it.

Thanks for you help...i appreciate it.

So far i'm really loving my car....it's sweet!!!
Once i get it running right...i could image now the my planned out suspension tunning i'm gonna do to her.

 

Check if the secondaries are firing by:

- unplugging boost sensor line
- revving to 4,000 rpm

Do you hear the secondaries clicking ?

If no, then you have a problem but it is probably in the wiring.

Please, do yourself a big favor and donload the FSM at www.fc3s.org under how-to->manual->86-88 section about "fuel and emissions"

the procedure is actually explained there

Try not to take everything apart until you have properly diagnosed the problem.

Hugues -

 

I forgot to mention:

Do you get the same symptoms (no power past 3,500)
when you gently push on the gas pedal ?

You see, the secondaries come on at 3,800 under load, so if you accelerate slowly and you get the same thing, the secondaries can be put out of the picture.

If you get same symptoms even when you depress the gas pedal slowly, then problem is probably something else, maybe a fuel delivery problem or a clogged exhaust.

Hugues -

 

I found out something, i heard the my 87 FC only have 4 ports, meaning i don't have the 5th and 6th ports malfunction. So correct me if i'm wrong.

Another thing. Which ones are the secondary injectors?? are those the one in the back nearest to the fire wall??

 

Do you mean the secondary injectors or secondary spark plugs??

Oh thanks for the site, i'm gonna check it out when i get home, i'm just gonna gather all the info. i can get then i'll work on the car next week. check it one by one and narrow out the problem.

 

Isn't the boost sensor only for T-II??

If not, where is it locate??

 

You guys say that it might be the secondary injectors rite??

Well when i bought my '87 RX-7 it seemed like the lady who drove it didn't drive it in high rpms. Is it possible that the secondary injectors could be just dirty or carboned up since it doesn't turn on offen??

I don't know much about rotary, but i'm learning little by little. So assuming that the secondary injectors only turns on in a certain high rpm, if that's true that means that if the car was not driven in high rpms often enough it could be dirty or clogged up with carbon right??

If all that is true, could a simple fuel injector cleaner might possibly clean up or fix the problem??

Anybody every tried it this way?? If anybody did, did it work or even help a little??

 

I found out something else last nite, when i press the gas slowly it's fine, but the problem it once i flow it, then it feels like it doesn't have any power.

YOu said before that it might be something with the fuel delivery you mean it might be the fuel filter, fuel pump or the injectors?? or maybe even the exhaust is clogged??

But it seems like i have an exhaust like somewhere close to the engine i'm trying to find some time to find out exactly where it is. Could that be the problem an exhaust leak??

Tomorrow i don't have class i'm gonna do some visual check on the components you guys mention.

-boost sensor
-pressure sensor
-bad ground on the sensor
-clogged and leak exhaust

 

Look at my posts above and do the checks I describe
which are also in FSM

When I say 'secondaries', I mean 'secondary injectors'

Do you hit a wall at 3,500 or is it just an hesitation. IF you hit a wall, the secondary injectors are not firing. If it's just an hesitation, then it is a grounding problem at the ECU or boost sensor (if grounding at boost sensor does not solve the hesitation, you have to ground the ECU properly).

you could also have a clogged fuel filter. If you don't remember the last time it was changed, it's probably time to change it.

Hugues -

 

where is the boost sensor located?? isn't that for Turbo II only??

 

Isn't boost senser only for Turbo II and not for N/A?? if i'm wrong, then where is the boost sensor located??

 

Boost sensor (aka pressure sensor) is located on the passenger side strut tower, its a little black box, that has a vacuum hose on the botton running to a nipple on the side of the lower intake manifold. It sounds to me like your auxillary ports (5th and 6th ports..) arent opening. If the secondary injectors werent firing, you wouldnt be able to redline it under full throttle at all. The 3800 rpm hesitation is just that, a hesitation. If that was the problem it would pick back up in a second or so. 3800 RPM hesitation is usually due to bad grounds (especially ECU ground) All N/A FCs were 6-port, and turbo FCs are 4-port. To clean the auxillary ports you need to take off the intake manifolds and clean them basically. Lots of wd-40, pb blaster, whatever. Just keep turning them until it is almost effortless. Hope I answered most of your questions.

 

Cool Thanks.

One more thing, there is another extra throttle plate connected to the main throttle linkage, it opens when at a certain rpm. I don't know what rpm it opens on coz i was under the hood when i notice it. It's rite one top of the main throttle. What is that it seems that, that it opens and lets in more air...i just wanted to know cuz i i thought that was the 5th and 6th ports.

Back to the main problem, if the injectors are not working, i won't be able to redline, which i can but it just take forever to get there.

Narrowing down the problem to the 5th and 6th ports which are the auxillary ports or bad ground of the ECU or the boost sensor.

Ok it makes better sense now thanx a lot!!! I think that should fix, now i just need to find time to fix it.

 

The "5th and 6 ports" are located on the lower intake manifold. If you stand by the passenger fender and look at the engine from the side (removing the air intake tube would be helpful) you will see a large valve in the center of the lower intake, with a hose going to the airpump, and a hose coming straight out and bending toward the front of the car, and a hose going back to the split air pipe toward the cat. This is your ACV valve.. On either side of that , there are 2 diaphragms. These are your auxillary port activators. YOu will see that they are attached to a metal rod, that you should be able to push down on, and open the ports by hand. If you cant even push down on them, or it is difficult, then they are stuck. You will need to take the intake manifolds off and clean teh inside of it out. You will see that on the lower intake, 2 rods come out from the side of the intake, where the actuators are, and these rods extend into the side of the engine, and turn metal sleeves that open and close the port. Make sure that 1) the sleeves can turn freely, and 2) the rods can turn freely, and 3) the actuators themselves work (just push them and make sure they spring back and go "whoosh") Hope this helps.

 

I finally fixed it!!! it was one of the secondary injectors it wasn't firing. It was clogged for for some reason. but i got it and i can finally feel the true power of the car. Thanks for all your help.

Now i just need to get my sunroof working correctly, rite now it's a auto/manual sunroof...meaning it needs some pushing to open and close it.

Thanks for you patience!!!