Hey Guys,

Just got my first RX7, its a JDM that I imported and I just got it on Saturday. From what I can tell its bone stock with a massive exhaust. I pretty much immediately changed oil and spark plugs before even driving it.

So car starts fine, cold or hot no issues. Turns over within 1-2 seconds. It will free-rev no problem all the way to redline.

The issue im having is that the idle seems a bit lumpy (sits around 1000-1100 rpm) and it sounds like it chugs more than it should. Not a nice consistant buzz..

It drives fine, out of boost. As soon as I put my foot in it and it boosts past 0.3 bar or so it seems to sputter (almost feels like fuel cut). Itll keep boosting and it will hold boost but will sputter the whole way.

It is a JDM and has been sitting for god knows how long, so Ive been driving it careful.

The problem seems to get a bit better the warmer it gets but never quite goes away. Sometimes it will boost no problem, but most of the time it gives me these sputtering issues.

Any help with where to start would be greatly appreciated.

 

Its a 1995, sorry forgot to mention that

 

My theories are: 02 Sensor, water temp sensor, TPS, fuel filter, clogged injectors or good old bad fuel...

 

OK team....

Update!!

I noticed that the hose that goes from the intake box to the back of the engine (just under the UIM) had a broken connector at the airbox, and the previous owner just sort of shoved it in. I had an A'Pexi intake I picked up a while ago so I figured I would toss it on and hopefully that would correct any issues that could have been caused by the busted OEM intake.


So I fired the car up, started fine as usual, started smoking a bit (as per usual, just smells like super richy rich, not like coolant or anything). I revved it up and realized that it was blowing exhaust out of the upper intake filter... I noticed a bit of smoke when the OEM intake was on, but I thought it could have been some **** falling onto the manifold and burning up when it gets hot.

I undid hoses and found that its the same hose, the one that goes to the back of the engine under the UIM thats blowing exhaust out. SOOOOOOO im thinking a few things.... PCV or clogged cat from all the stop and start from bringing it over seas. Maybe the EGR as well. Ill check compression as well but I dont think that is the issue, it dosent have all the symptoms of a blown seal.

TPS is bueno, ignition is good and I cant hear any other leaks or whatnot.

Thoughts??? I want to avoid bringing it into RX7 specialties as Ive heard some mixed reviews (dont want to start an RXSP flame war)

 

Anyone?

I noticed today that the bottom hose of the pressure chamber is not connected to anything, just cut off at the bottom of the box

 

Sounds like a boost leak, that would give you high idle and mess your boost. Check all your vacuum lines.
You could also check your tps, might be out of tolerance.

 

Awesome thanks!

Could that also cause the exhaust blow-by out of the PCV hose?

Cam

 

That Hose is for the ACV ,

the ACV which is on the LIM works in conjunction with teh air pump to help pass emissions , if your state does not require emissions I'd eliminate BOTH of these things as they are kind of just dead weight .

IF YOU DO NEED THEM , You Either have a bad ACV , OR a bad check at the ACV

I had a bad check and my car was doing the exact same thing .

 

Do you Have any detailed pictures?

I know it helps me alot to see someone's system when I'm trying to help, cause the previous owner could have done something really stupid...


J.

 

download the factory service manual and look up the acv .

I dont have any diagrams , besides my head .

If you take off the upper intake manifold which is very easy to remove you will see the ACV on the lower intake facing the solenoids You would need block off plates if you deleted it , or just take it out to inspect .

If you do a search for ACV or air control Valve , YOU MAY find some results with diagrams , but I'm at work and my hooky time is limited LOL

 

Hey guys thanks!

Could my other symptoms be attributed to this ACV issue?

I dont have any detailed photos but from what I can see everything is as it came stock. With the exception of one hose missing from the pressure chamber to a nipple on the turbo.

 

Would you just replace both the check and the ACV then? Or is there a way to test them?

Its smoking from the upper right hose on the OEM intake box, which goes to the back of the block and from what i understand the PCV. I also noticed there was some oil in the airbox which i attributed to a bad PCV

 

Ive sourced an ACV check valve locally. Should I replace the check valve or just elminiate the ACV and Air Pump altogether?

I was thinking that would be easiest but since I have yet to have it working properly I would rather figure out what the problem is, then repair it before I start modifying it any.

 

Update:

So Ive just booked it in with RX7 Specialties here in Calgary to have a look at it. I dont have the time to keep dicking around...

I did notice though, that the upper right hose on the factory airbox (which was blowing exhaust out) is releasing a steady stream of exhaust. Not just at WOT as I had suspected..

Any ideas?

 

I noticed that nobody has said this yet (probably because it is so common that people don't think about it) but your "lumpy idle" could simply be evidence that the previous owner had the engine street ported. When I bought my FD I tried to figure out why my idle was so lumpy and after some research into my car i found that the previous owner had done a medium street port. It wouldn't be the cause of the sputter when you're driving I don't think because mine evens out once I get on the throttle. it's something to look into anyway.

 

Thanks for the input! Yes I was thinking the same thing, that it may have been streetported. Compression is good so im not stressing about that too much.

UPDATE!!

Smoke coming from the hose on the air intake was infact a screwed ACV, so we went ahead and did ACV and airpump delete. Also found the cat was hugely clogged so we popped a megan mid pipe in there...

After doing that took it for a rip and the miss was still there. Decided to swap the plug wires (as they looked old as fuark), it seemed to help a bit (or maybe just in my brain) but the misfire comes on as soon as i get past about 1/2 throttle. Regardless of if im in boost or not.

Anyone have any ideas? What typically causes stuttering/missing past 1/2 throttle.

 

Another update:

Noticed that my buddy who did the plugs put all the plugs in the wrong spots.

He had 7's in the leading and 9's in the trailing. I havent had a chance to go for a drive since i put them back right but could this have caused it? Ill update once I go for a rip, ill just be away from it for a few days... also noticed that there was no knock sensor (above T2 sparkplug hole), would this cause any of these issues?

Cam

 

Anyone?

The new plug wires helped out a lot but didnt get rid of the problem 100%.

Idle is magically back to normal. go figure

Shes driving great 90% of the time but as soon as it sees heavy load (WOT or going uphill etc) it will stutter/miss/bog down. I took it for a drive yesterday and I was able to push it through the stuttering and get it all the way to redline. It just gets stuck between 4500 and 5500 or so RPM

Cam

 

Apexi power FC fixed the problem for me...

 

Ya ive got one on order hopefully that does it

 

Pulled codes with the LED method, came up with code 11-intake air temp sensor.

Ive got a new one coming in so lets see if that does it.

Also have a PFC and OEM replacement coils coming so shell be running right again soon!

Cam

 

2 questions....#1 I had a shop do my emissions delete, they left the hose that goes from the ACV to the cat in place but I have a mid pipe so its not actually connected to anything... should I remove it or is it fine? #2 I found a large "nipple" (best way to describe it) below the crank wheel that feels like its meant to have something threaded into it. Anyone have any idea

 

Intake air temperature sensor has arrived, ill throw it in tonight and see what happens. PFC and OEM coils should be here next week

 

IAT sensor didnt help one bit.... PFC and Coils are next, 99% positive that will fix it

 

Not related to your questions, but you're running stock ECU/untuned PFC with a catless midpipe? Do you have anything in place to ensure your boost is under control?