Engine wont rev more than 4000
 

Just bought a fd about a week ago knowing it didnt work hoping to fix it. The car will start and idle but it will not rev over 4000 rpms. i also have to pump accelerator for like 2 minutes to get it up there. if i press in the accelerator all the way the rpms will just drop and stall. Can anyone help me or maybe give me some ideas of what it could possibly be? all responses are very appreciated

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well since no one else has got to this thread yet.. i'll try to brew something up.

It would help to know though, milage? mods? other problems? (leaks, etc..)

I would check compression first. Search poor mans compression for rotary or something like that on google. Also check vacuum lines..
hmm.. injectors? could be spark plugs maybe?

I'm just rifling off things to get you started while other members are getting to it.
I would start by checking those things.. why not just change the plugs? it'll need it soon probably anyways.

By the time you've done that, you'll have alot of posts and help in here :nod:

Thanks for helping out. the mileage is unknown and the car is completely stock. i dont know how to check vacuum lines and ive already changed the spark plugs, sea foamed car, and changed fuel filter. do you think it would have to do anything with the fuel pump?

i don't think fuel pump.. however, I think right around 4k rpm is when the car switches over to the secondary injectors. I would look into that. Does it go past 4k on light throttle?

There could also be something happening with the ECU that rev limits it? Doubt it though if it's stock.

Checking vacuum lines can be tedious. I would say just hook up a boost gauge and if it boosts normally thats a pretty good sign but with this problem, you might have a tough time with that aha.

the only time i can get it up to 4k is on light throttle. but if i gas it all the way anytime im reving the rpms will just drop and sometimes stall. And if i would be the ecu what could i do about it?

How the hell did you just buy a car and NOT know the mileage???

I purposely set my rev limiter to about 3k whenever I put it into storage or let a stranger drive it (for shipping and stuff like that).

Are you sure this vehicle was aquired legally and honestly?

From what i understand the guy told me that he took an engine out of a jdm rx7 and dropped it in instead of rebuilding it. the car was only 5k and i thought was gunna be an easy fix thats why i thought it was a great opportunity to get an fd. how can i set the rev limiter

boost cut, fuel cut could be the only answer

Check the easy things first
If the car has the stock ECU and the boost sensor hose gets disconnected the ECU goes to "limp home" mode... Sounds like that might be your problem.

If it is only running on one rotor then the sound of the engine should be distinctly mess up.

where is the boost sensor hose located?

Its a little black sensor on the driver side firewall at the top

check your TPS sensor and check the vacuum line on te MAP sensor.

Where are all these sensors located? sorry im really new to all this

I just read a thread relating to the fc, the fd might be the same but the fact the it revs past 4k rpm on light throttle almost certainly (assuming it's set up the same way) indicated a problem with secondary injectors.. :scratch:

dude, honestly I would take it to a shop that can quickly diagnose the problem. If you don't know what your doing, you can cause other issues that will just put you in a bigger mess(if its not a big one already. Not saying that it isnt as simple as a vacuum line, but you need to at least understand or some what know where what goes where and is located or you'll be lost.

I had an issue with the first fd I ever had, the second turbo would never come on, 8 months later, it was a wrongly swapped vacuum line that I never would have realized if I never sat down and studied the vacuum line diagram.

Just saying...

well I had a similiar problem with my fd but my would only start up to idle and as soon as i touch the gas it would stal. I wana say i tryed it over 20 times on different days. One mechanic told me he thought my sencondaries werent coming on, one day i just kept messing with the gas trying to accelerate and it finally went through, so im assuming the secondaries were dirty or something.

and as for checking for vaccum leaks I know spraying carb cleaner to check for leaks you spray it around the hoses and it will stal it out or change the idle when it is sitting on idle if you spray a leak. BUT PLEASE BE CAREFULL CARB CLEANER CAN MESS UP YOU PAINT!!!!!!!!!!

the only thing I can think of , are the plug wires were swapped. Some one changed the plugs in his fd and it had the same problems, they apparently swapped around plug wires.. I cant remember if they swapped the leading front and rear are the trailing from and rear but when I checked it that was the problem... Check that.

so do you mean my leading and trailing might be mixed up?

Find the service highlights manual. It will show where stuff is and how some of the systems work, its good stuff and should help you out. Also take a look at the workshop manual.

Here is the link to the manuals

http://foxed.ca/foxed/index.php?page=rx7manual#thirdgen

If the lead and trailing was mixed up it wouldn't idle much more start I think.. I saying your leading and leading might be mixed up, or your trailing and trailing might be mixed up.

i thought both trailing plugs where the same?

supposedly, but i think it has something to do with charge time at the second burn of the rotor face??i could be talking rubbish here... not sure in that department but I remember switching either front or rear and the car was perfectly fine afterwards.

or it could have been to the wrong spark plug on the correct housing... Just check and make sure the trailing and leading go to the right housings and spark plugs.. you know which is lead and trailing right?

http://foxed.ca/rx7manual/manuals/19...al_systems.pdf

g20 & 21

but if the leading and trailing were all mixed up would the car even start at all? and i dont really understand how to check the vacuum hoses

it can start, even idle sometimes.. just check and make sure they are correct. It takes you a whole of 2 minutes to check.
Not to sound harsh but, we're trying to tell you things that can affect your car without knowing much about the car itself... take the information while you can...If your trying to actually learn how a rotary works, then I advise you to buy a book and read.

alright. well i appreciate you helping me out. ill check them

I got one for you that no one has mention,,, I fixed a VW golf for a friend other day 100% same symptoms as you, would idle fine could rev with light throttle, wouldnt go over about 4200rpm. If i gassed medium to hard car would try to die straight away.. Blocked cat it was in the end, i dropped cat off and fired up car. Started right up 100% perfect! Installed new cat and car is perfect (i know its not an RX7 but when i was scratching my head at beggining it was like it was been starved, never thought a blocked exaust !)

yea i tried to take out my whole exhaust and that wasnt it either

I have one more suggestion for you. When i first got my rx7 someone had put the crank angle sensors on back to front. Car wouldnt rev and run rough. But did still run. Worth a look!

How many different sensors are on the whole car?

There are two crank angle sensors on the front cover. The connectors to the harness will go on either sensor, but because of their position, getting them mixed up will cause the car to not run properly.

Since you didn't install the engine, you need to basically start from scratch. Check the following:

* CAS connectors on proper order
* Water & fuel thermosensor connectors on correct sensor
* Ignition harness connected in proper order
* Fuel injectors are switching on/off and have proper power
* Ground connections are clean and grounded

If you don't know where these things are, download the Factory Service Manual (FSM):

http://www.wrex-racing.com/web/fd/info.htm#Docs

http://www.youtube.com/watch?v=P9wWy...layer_embedded

This is a video explaining the symptoms

That car sounds bad.

Start with audible compression check, if that passes use a compression tester to see actual compression values. If that pases, double check spark plug wires to make sure they aren't crossed. You may have to check the coil pack hardness as well to make sure those plugs aren't crossed.

What ECU are you using?

Sounds like you need a mechanic....what part of houston are you at...

compression sounds fine according to the cranking in the video so i don't think it is engine related.

first pull codes from the ECU to see if it spits anything out
then start by inspecting the leading coil pack, it's known to melt down due to heat. possibly replace wires anyways.
next have the injectors sent out to be serviced/cleaned while your checking the coils
inspect the wiring harness for the injectors and ignition coils thoroughly
if none of that fixes the issue then check fuel pressure, if fuel pressure is within spec- replace the ECU.

the car sounds like that because i took out the cat to see if that was the problem. ive tried to taken of every bolt to the intake manifold and still cant take it off to get to the injectors and to check for vacuum leaks

im in league city. near galveston

Eh, a bit far for me to go check it out. Gas is too pricey. haha. Good luck. Some pics of engine bay probably help

thats what im trying to do but dont know how ha

http://1993rx7enginebay.shutterfly.com/pictures

this is the only way i know how to upload pics

if yall know can yall tell me where all that unhooked stuff is suppose to go?

there is nothing unhooked that is of importance.

the blue connector is for the EGR which your car probably doesn't have a sensor for.
the hose end on the airbox is just for a muffler hose to hang down under the airbox.
the connector by the brake MC is for the cruise control, which was deleted.
the cap on the UIM is normal.
the broken bolt in the center of the UIM should be repaired.
the wiring by the diagnostic connector has me a little worried though, make sure the wire colors all match up at the joints and they don't pull out easily if you tug on them lightly.

would i just put a bolt into the intake manifold?

another question can yall tell me what the size of the secondary injector and is the secondary injector located the closest to you from the top of the engine?

the secondary injectors sizes (if oem) is 850cc. It is the (look from the fron of the car, the two left injectors, that are set in the LIM.

You should fix the intercooler hose, seems loose.

Also, check the map sensor (pic DSCN1002- black switch right behind the Throttle body elbow..attached to the bracket on the firewall) Disconnect it after the car is started to see if the car changes idle tone..

Have you taken a look at the plug wires yet? If your still unsure, take pictures of the wires from coil to plug. Also, check if your coils are firing from the end of the plug that clips to the spark plug..

So you took the upper intake off? I'm not trying to be mean...but do you have a mechanic experience? Like, ever work on a car besides maybe an oil change? I think ideally , you might really wanna get/pay someone to look at the car less your really adamant about learning about this car.

yea i had someone come by and mess with the map sensor and it didnt change a thing. and i also looked at the plugs again and they were correct. so we started taking apart the intake manifold and one of the secondary injectors was disconnected. when i plug it in it didnt start up or anything. but if i plugged it in when the car was in idle it would run rich. when it was plugged in i could full throttle it and it wouldnt stall unlike before if it was unplugged and i full throttled it it would try to stall

and he also checked volts on one of the secondary injectors