FC3Sreaver

putting a link showing what its doing and explaining whats been done need some help.

AGreen

iTrader: (11)

Get a can of carb spray, spray all around the intake manifold while it's running. When you find the vacuum leak, fix it.

I'll be willing to bet it's a piece of old intake gasket stuck on the manifold that didn't get properly scraped off when you replaced it.

K-Tune

iTrader: (26)

Try adjusting the cold start linkage so that it doesn't idle at 5krpm on startup....there should be an adjustment where it rides on the thermal pellet.

beefhole

iTrader: (29)

Don't mess with the thermowax cams. Once you mess with those, you will suffer for a while until you figure out the stock positions. It sounds like it's doing the AWS high RPM start up (3K) except obviously a bit too much. You can hear/see it's dropping off after a few seconds. Vacuum leak, yes... Throttle cable, maybe... Disconnect it. Also, set the timing on your own. the builder probably screwed that up.

-RotorDemon-

Sounds like it's only running on one rotor....

K-Tune

iTrader: (26)

Maybe at first, you hear it wake up when it evens out at 4,000rpm. Too smooth to be on just one rotor.

Sounds like decent compression when you are cranking it also.



And who says the shop didn't already dick around with the fast idle adjustment in the 3 months they had it?


But yes...verify the Cas is stabbed correctly.

88 SE

All signs point to a pretty large vacuum leak, the engine sounds pretty healthy so I wouldn't suspect the rebuild.

Your cold start idle is way too high which is a sure indicator of a leak. Do me a favor and get some high res pictures of your engine bay at as many angles as you can so we can see if there's anything obvious we can spot that's missing/loose.

It is possible that the timing is off by a tooth as well, as this would cause the car to die when you hit the gas. But, we need to focus on one variable at a time. Since this is a free fix, I would start out by taking the CAS out (after setting engine to TDC of course) and re-inserting it properly. It is very easy to jam the thing in one tooth off which would cause these problems.

FC3Sreaver

i found a vacuum leak between the upper and lower intake manifold going to take the whole thing off tomorrow and fix that and see if it fixes everything. now that i look into it a little more i see the "work" that i payed for. lol thats sarcasm but will update and see if that fixes it all and i will also upload some pics to of the engine bay too

88 SE

Also check the lower intake to engine for a leak. Mazda superceded the gasket with a new multi-layer metal gasket that has different torque pattern and installation method then what is indicated in most mauals. If your engine builder installed this gasket and didn't do it correctly, it WILL be leaking (I know from experience lol)

AGreen

iTrader: (11)

FC3Sreaver

its a little bit better but still sound like its missing. its also surging now that i can get it to hold a high idle.

AGreen

iTrader: (11)

I assume it's an S4 NA by looking at the dash. First, there's a screw on the very top of the throttle body. It may have a little black cap over it. Screw it all the way down. Next, there is a throttle stop screw that may be turned too far. I don't remember where it is, but I'll bet you can find it. I know that on the S5 NA it's on the top right in the front, and on the TII models it's on the top at the back. Either way, it's probably on top, and has an 8mm nut holding a tiny little flat head screw.

Also check the fast idle adjustment as some people have stated. Pg. 4A-56 :
http://www.rotaryheads.com/PDF/2nd_g...systems_na.pdf

As for the misfiring, check Pg. 4A-52 of that link for how to properly install the crank angle sensor. If that guy's misaligned, it will definitely misfire.

How high of an idle is it now?

FC3Sreaver

ok we messed with the screws a little bit and got it to idle pretty smooth but if i barely step on the gas it will sputter but slowly rev up but if i push it even a little more the car sputters alot and tries to cut off. if i get it to after the aux ports open up i can floor it and it will only sputter a little. i will try and post a video tomorrow as it is too dark now. the intake vacuum leak was due to the shop trying to get the gasket off. i can feel a depression in the upper intake manifold where they used some sort of grinding tool to take off the old gasket. i fixed it with a new gasket and a little rtv. no vacuum leaks but im starting to think it might be fuel but not too sure i was going to check to see how the filters look and what fuel pressure im getting if i can find someone with that tool. we also got the car timed right too using a timing light. ill post if i remember anything else that can give any clues and a video

AGreen

iTrader: (11)

How high was the idle when you set the timing? It has to be below 1100 rpm.

SpikeDerailed

iTrader: (7)

What he said. How fresh is this rebuild? I would suspect it was just done in which case i would just get the car to idle and drive for the first 500 miles till is more broken in and then set the idle and tps, but do make sure the CAS is stabbed properly.

GoodfellaFD3S

iTrader: (213)

Lots of good advice here.

I have to ask, who did the work?

rx7_FREAKKK

iTrader: (1)

get a timing light on the cas with the top open see if the timing is jumping around... Mine did the same thing cause it had a huge vac leak.. when it settles down then you can adjust the idle.

ghost1000

iTrader: (1)

My guess is more than one problem.
I would start by checking the engine codes
U have fuel and spark. Sounds like the problem is in closed loop mode.
Double check wiring and grounds.
MAF, MAPS, TPS, water temp and 02 all have to be wired correctly.
It's really to tough of a problem to write a post about. U have some work to do.

w0ppe

+1 to the vacuum leak. You can get a lot of back firing by overloading the amount of air going into the vehicle (Since it's open throttle + extra vacuum leak air).

shocker003

check sensors,
pressure sensor for voltage, not sure about s4 but on the s5 its a 3 wire plug not the 4.
the 4 wire plug is for the auto adjusting suspension. 3 wires, ground signal and 5 volt. signal will change depending on vacuum.
afm for resistance, moves up and down smoothly
tps for resistance, or voltage, moves up and down smoothly
check injectors, make sure they have the right plugs on them, i think secondary's are plugs at the end of the harness.
and like they said check dizy and if you have pressure gauge, fuel pressure.
hope that helps

FC3Sreaver

the engine has not even been driven yet down the street. impossible at this point because it was cutting off when i give it gas. so no miles.

FC3Sreaver

three face racing.

FC3Sreaver

found a vacuum leak and fixed it already. but still stutters a lot when i give it gas but doesnt cut off

FC3Sreaver

i set the idle at 750 rpm when it was warmed up

FC3Sreaver

i will try that i got it in timing but didnt have the top open.