Hangerbaby

Hey all, new member here, so I'm going to stick to the newbie question asking guidelines as strict as possible.

I'm trying to help my friend get his RX-7 road ready(needs a windshield but was running pretty nicely otherwise.) It is a series 4 turbo swap into an 87?? GXL body. So YES it is a swapped car, he bought the car already swapped and we're not sure on the mileage or anything like that ... anyways...
Everything is stock from what we can see, minus the radiator which is a nice aftermarket radiator, can't remember the brand now but that works fine


Checked out the manuals provided in the newbie FAQ. Didn't quite help me, as the diagram used showed an entirely different part altogether. The AFM in the manual had a bypass screw, it looked much different, and seemingly operated differently. Which is why I questioned my assumption that I have a AFM sitting next to me, rather than something else.

It was hard to start before(when cold), but always ran and idled. We were messing around and stuck a cone intake on it, then we realized it was barely idling. Next we put the stock intake on. I double checked everything, nothing was missing, no empty plugs etc. We messed with the idle speed screw and some starter fluid into the intake and we got it to start, but no idle. After taking the intake off(after quite some frustration), we were trying to start the car and the AFM was sitting there so I pressed the **** sticking out and viola... the car fires right up. Dies when I stop touching it, and repeat. Stays running when I hold it in also.

The problem is new, obviously, and I don't really have an explanation for it.


So TL;DR's look below this line for a less wordy, more direct question
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This is what I'm dealing with here. I think it is the AFM.
It connects to a big rubber intake tube going directly to the turbo, there is one electrical plug you cant see going into it. When I press on the right end of it while cranking the engine over, the car will start and run, the further I push it in, the higher the RPMs go. If I let go, it dies. There is a "clunking" noise after the cone is pressed into the housing at a certain point, it is coming from a small metal box full of electrical plugs located behind the passenger side light. I'm so confused I'm not sure what to ask here.

Do you think its the sensor? The AFM feels and looks fine. Also, why would the sensor just randomly **** out after trying a cone intake? I double checked all the plugins and nothing is missing. If anyone has any clues please let me know ASAP.

mzrx7man

iTrader: (9)

It sounds like you have an intake leak either between the turbo and afm or the turbo and throttlebody. The afm needs a certain amount of vacuum in order to open it. Either that or the afm is sticking.

2slow4stock

iTrader: (18)

Well you say the car is s4? That is a s5 afm. You say cone, so it makes me think s5.

So you have a s4 turbo motor "working" a s5 afm. Put in the stock s4 tii afm in. See if that helps.

RotaryRocket88

iTrader: (7)

Get a picture of the engine & the plug for the AFM. It may be an S5 engine & S5 wiring swapped in. Pray it isn't though, because who knows if the previous owner wired it correctly.

If it actually is an S4 engine, then as 2slow4stock said, you have the wrong series AFM. But the thing is, the S4 & S5 plugs are different, so what you have shouldn't even plug in. Something isn't adding up.

2slow4stock

iTrader: (18)

+1 ^^ On pictures and something's wrong.

Civerus

iTrader: (2)

Same AFM thats on my 1990 GTU S4 turbo swap, and mine works fine, what happends with mine is, if I even barely touch it to press it in, it stalls the engine out, almost immediately, if I press and let off in under a second it'll recover, but still try to die. So I would guess you're getting too much fuel, and the AFM isn't balancing the air due to an intake leak.

What I just said probably makes no sense to anyone but me, whel hey, its 4:24am, what can you expect?

HAILERS2

Like somebody said above, that is a series FIVE afm and it will not plug into a series FOUR harness. Even if one had a series FOUR car/harness and rewired the series FOUR afm plug to fit a series FIVE afm, the output signal will not be right for a series FOUR ECU.

You really NEED to clear up this issue as to whether this is a series four or series five chassis/electrical harness or if it's a series FIVE chassis/electrical harness. The build date of the car is on the plack (sp) inside the left hand door.

For what it's worth........the afm is not used for fuel during START. Only after 500 rpms has been achieved does the afm determine fuel to the engine.

Hangerbaby

Are there any visible differences between the S4/S5 motor??
I'm starting to wonder now if I was wrong to think its a S4. Keep in mind everything, including the AFM, worked less than a week ago. Are there any ways to tell if the unit is broken? Can I lube it? Bypass?

87 t-66

iTrader: (133)

s4's have a metal thermostat housing with 2 bolts. the s5 is plastic with 3 bolts.

in the pic it looks like its a n370 s5 t2 map sensor...

Hangerbaby

Hmm, that rings a bell. It might actually be a S5 then.

This is the metal "box" that makes a clunking noise when you push in the AFM past a certain pointl. It is located behind the passenger side light in the engine bay. In front of the airbox. Anyone know what it is? There are quite a few plugs going to it.

2slow4stock

iTrader: (18)

Civ, you are unrelated. You have a s5 chassis with s4 engine. You HAVE to use your s5 electronics. Yes, what you explained is how a normal afm works that is a flap type.

The easiest way to check, I mean easiest. Is where is your radiator fill cap? On the engine or radiator?

How about take a picture of your engine bay, and post it up. (that is if you can find out what engine you have.) But also the information on the car itself would help. Open the drivers door, and you'll see the date it was produced.




*edited*

That's the fuel pump resistor relay. Do a rewire on it, since your turbo'd now. Search "fuel pump rewire"

Hangerbaby

I just searched that and I found a lot of topics on what its about, but nothing about how to do it. Are you telling me to do it because its specific to the problem I'm having (Turns over, chokes but won't idle without pressing on the AFM)
Or because it is a necessary mod for the turbo engined Rx7? If it's the latter, I'm going to leave it up to the kid who owns this car. I just want to see this thing running

P.S. It is a s5 engine now I'm fairly certain.

rx7fitz

iTrader: (1)

Dahts muh car!

is there anyway to bypass that airflow meter/ sensor

2slow4stock

iTrader: (18)

The fuel pump resistor relay controls fuel. You say, you push in the cone and it idles/starts better? I would replaced the afm first, and if that doesn't fix the problem then go ahead an do the fuel pump rewire.

87 t-66

iTrader: (133)

get a standalone EMS.

Civerus

iTrader: (2)

http://www.1300cc.com/howto/how2/rewire.htm

This, it fixed all of my idle and fuel problems, also you would be amazed how responsive the throttle on the car will become if this is the problem. Mine, I can actually confidently start from a stop now without the car trying to die, or having to rev to 3-4k.

Yeah I would go with 2slow on this one and try replacing the AFM, the fuel pump resistor/relay is designed to switch between 9v and 12v, 9 obviously at idle and cruise, and 12 when on the gas. I switched from NA to turbo, and was able to keep mine functioning 100% and still on the rich side.

HAILERS2

The engine idles if he pushes the cone in the afm aft. Sounds not at all like a fuel pressure problem. Make sure you have the right afm for a Turbo car and not a non turbo car. Should have a number on it like N370 etc.

Or just put a fuel pressure gauge on the fuel line and then put the key to ON with the yellow fuel pump check connector jumpered. Fuel pressure should be approx 37-39 psi with key ON, engine OFF. Hell, 30psi would be more than enough fuel pressure for idle and light driving.

Chassis seems to be a series FIVE for sure, what with the fuel pump/resistor relay. Engine? Who cares. Matters not if series four or five.

AFM and pressure/boost sensor plus ECU should all match. AS in all those items being TURBO or all non turbo. They should match the type engine.

Hangerbaby

Thanks. Keep in mind all worked last week 100%, performance was great. My belief is that it hard idled cold because previous owner removed the cold start feature.. (why?)

either way, I'm starting to get a sinking feeling about the vacuum tube hooked into the turbo not being snug enough.. means the car is not getting enough vacuum to start/idle..