I finally got the car to fire after being badly flooded..however it runs very rough and dies after a few seconds. I also have to keep working the gas pedal or it will die. My guess is HUGE vacuum leak? I THINK both rotors are firing.

Since the engine ran last, the emissions were removed and block-off plates installed with RTV. The intake was removed and swapped for an S5 intake. I followed a write up to the best of my ability.

I removed the brake booster hose and all but one of the other vacuum hoses and just capped them off in an attempt to get this to start.

I believe the intake is installed correctly. I'm using a new LIM>block gasket and sealant on all the other ones. Airpump and ACV removed and blocked off. Other things that I have capped off: Nipple on inside of LIM, two nipples on backside of LIM, injector air bleeds, two nipples on lower back of UIM, three nipples on back of throttle body. One large nipple on left side of LIM, one nipple on left side of UIM, and the large nipple on the snorkle.

I unplugged the fuel pump and then sprayed starting fluid on various locations of the engine and then tried to start it. I couldn't even get one pop out of it which would seem like I don't have any leaks, much less a HUGE leak.

Any guesses on where to start looking?

 

I hooked up an autometer boost/vac gauge to the throttle body and it didn't even move when I cranked it...

 

where's the damn prize????

 

http://www.boostpro.net/prodtester.html scroll down for universal boost leak/vacuum leak tester. you can also fabricate your own.

This is a good way to check for leaks (especially if you spray a little soapy water around as well) and you don't have to start the car. I've never used it on an n/a but you should be able to remove your cone filter and attach it with a coupler. I'm not sure what size though.

 

Interesting...like a radiator pressure tester....I suppose that would work if you could prevent it from blowing right out the exhaust...

 

it doesn't blow right out the exhaust. Don't ask me why. It just works... i've found multiple stupid little vacuum leaks on my car with it. That type of tester is commonly used on 3000GT's which are absolutely horrible for boost/vacuum leaks with all the plumbing and emissions crap they have.

 

Going on your recommendation I'm going to pick one up, I have a feeling it will definitely see it's fair share of use.


I would think my leak is a pretty serious one...but I don't know where it could be.

 

On a series four non turbo, there is a black duct b/t the afm and the throttle body. Just before the throttle body, on the black duct, there is a half inch line teeing off that black duct. Is that tee still there? Or left open.

It fed fresh air from that black intake duct to a metal tube on the aft side of the dynamic chamber on to the Air Bypass Valve and the BAC if memory serves. Is that plumbing still there on the aft, left side of the engine? I mean the air bypass valve/bac etc?

 

Or the brake booster line isn't connected up.

 

Or the electrical plug on the afm is ....off. Result, the car will start but not run worth a darn.

 

Thanks for the things to check. The tee is still there, and I had it connected to the air bleeds on the fuel injectors. However, when I started having problems, I blocked it off with a piece of heater hose plugged with JBweld. I wasn't sure where to hook the brake booster line up, so I left it off, but plugged all the engine-side holes.

BAC and bypass valve have been removed. I don't really see any plumbing on the left side of the engine. AFM is plugged in.

Here are some pictures for your viewing pleasure.

 

Re-connect the BAC valve! Our cars (stock) really need it to run well.

 

I'd need the one from the s5 intake though, right? That's the one "emissions" item I wanted to keep.

 

Check out NZConvertible's posts...
Great info for fabricating your own!
https://www.rx7club.com/forum/showthread.php?t=590288
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/water-sensors-water-pump-diff-models-583211/
http://www.stealth316.com/2-pressuretester.htm

 

Yeah, I figured that out right after I ordered it. Oh well. This one will work and has a gauge.

Also picking up an N/A S5 BAC...

 

In your second picture, there is a hose. This hose is connected to another hose using a brass coupling that has flats on the brass coupling. It is resting against the dipstick. What does that line do in life on your car?

Same picture: There is another line similar to the one described. Its end is open and there is a clamp on the end of the hose. What does that line do in life on your car? That line is off to the far right of that second picture.

In the fourth picture, is seems there is a fuel line going to the secondary fuel rails aft end, but there is no clamp on the hose. How does that work in life?

I don't know enough about fuel injector air bleeds on a series five, so I won't question the hoses going to them. There. I didn't say anything about air bleed hoses.

 

The first hose is a coolant hose...it connects the hose from the back of the block to the hose coming off the back of the coolant neck.

I'm not sure where that second hose goes. The other end goes to the purge canister (which hasn't been installed either)

as for the lack of clamp...I put the fuel rail on, realized I didn't have a clamp on it, and could NOT remove it to add the clamp, so I figured it was tight enough...haha. I'll add one anyways if it will make my car start.

I don't know anything about the air bleed hoses either...I read they were supposed to be hooked up to metered air but after I was having problems I hooked them up to vacuum.

 

if its a huge vacuum leak check for unplugged hoses, personally I had the same problem and found out that it was the intake hose. it wasn't clamped properly and came loose, cause a huge leak allowing air to go in. from the picture it does look like you should check the intake.

 

Air bleeds connected to vacuum will make a engine run CRUMMY. That's the technical word for what happens.

 

What intake hose? The one teed off from the bottom of the intake? That's not a vacuum leak...it's the hose going to that point that's a vacuum leak. Either way, it's plugged.



Hmm. I'll just plug them for now, I guess. Those are the secondary injectors anyways...they shouldn't be firing at all, I just want this thing to idle right now

 

Arghx wins the cookie...I love this little unit!

Reasonably priced, super fast shipping, and I found a HUGE leak where the TB spacer is. I had sealer on it, but the spacer is warped.

More on this as the story develops...

 

Throttle body spacer was installed backwards. this explains the MASSIVE vaccum leak and the reason why the vacuum gauge I hooked to the top vac port showed zero

 

Good job. I have been reading your progress and I saved this under "technical" for the vaccuum tester.

 

I just ordered this device as well for my T2. I am definately having a problem with a leak somewhere because of the insanely high idle I'm getting. Plus, I'm only seeing about 17 in/hg of vaccum even at 1600 to 1800 rpms.

 

Lol that sucks dude, easy problem that you proabably wouldn't have checked...oh well. Good luck, hows the s5 intake swap? I'm gonna do it to my s4 motor ive got 2 s5 motors