Trying to solve a problem on an old project car of mine I dont want to give up on just yet.

The car is a clean 86 EGI, which had the air pump removed and since then refused to idle. It starts and runs fine on the throttle but on idle it just drops to nothing and stalls.

So far I have been through the ignition system with new wires,dizzy cap, rotor arm, cleaned up all the earthing points. I am certain its getting good spark from the fact it runs fine on throttle.

Ive also tried adjusting the screw atop the intake to see if that makes a difference - nope.

My suspicions lie with the air pump removal. 3 hose connections lie in question -

From the back of the airbox there is a hole where a pipe used to run, I think to the air pump. This is now open to atmosphere.

From the air pump location there is a large bore vacuum hose which runs around the back of the engine and then into a mess of stuff underneath the oil filler / injectors. This is now open to atmosphere

From the air pump location there is a small bore vacuum hose which runs around the back of the engine and appears to be connected to something round the back there, but I cant see what. This pipe has been blocked off.

Do these modifications sound right for running without an air pump?

 

The airpump has one large hose going to it from the air filter assy and one large hose going out of it to the ACV. No other hoses.

Most 86-87 airfilter boxes also have another nipple on its rear side and to the far right, that is blocked off with a rubber nipple. Goes nowhere, never has gone anywhere.

There is supposed to be a fairly large hose that runs from the bottom of the intake duct. Intake duct being the large duct b/t the throttle body and the afm.

This hose is on a rotating nipple about a half foot from the throttle body. It goes to a metal tube that is bolted to the rear of the dynamic chamber and goes to the left side of the engine to feed the bac and I think the air bypass valve.

There's no fuel injectors near the oil filler. Got me.

OOOPs. Euro car. I've not a clue then since it might be different than USA cars.

We need to give you a jpg of what a stock 86 USA version looks like. I'll see if I can find a thread like that with a picture. Later.

You might take a look at the BAC's plug and make sure the sockets in that PLUG are not pushed back. The BAC is supposed to help maintain a 750 rpm idle. But it also sounds like there are hose that are not routed right.

Did this engine idle right prior to the airpump being removed?

 

86 EGI

 

Go here: http://wombat.sevarg.net/RX7/RX-7_Training_Manuals/

Download FUEL AND EMISSIONS. Look at page 4-7. You can see the intake duct and the hose on the bottom of it. That hose comes up and to the rear of the dynamic chamber to a pipe that is bolted to the rear of the dynamic chamber. The pipe runs to the left side of the engine to the area around the fill pipe.

 

clearest pdfs ive seen yet on the car.. thanks

The engine idled correctly before the air pump removal.

Looking at the pdfs the port from the air cleaner to air pump is now just open, nothing there, the air pump is gone, the air control valve is gone and has been blanked off on the engine.

I suspect that the loose hose I have running around must be the one that comes off the intake duct and runs to the BAC. Would this cause the problem? if it is ill be kicking myself for not spotting it earlier

I will check this and the BAC connections on the car. Thanks for your help - and yep the car is a UK model, poor quality pic of it is here -

http://img378.imageshack.us/img378/5532/rx7he9.jpg

 

That hose on the bottom of the intake duct goes to the bolted down pipe on the rear of the dynamic chamber to feed both the BAC and the Air bypass solenoid clean filtered air. When the BAC is working it sends this air to a point after the throttle plates to help maintain an idle when the engine is under a load like having the headlights on, a/c on etc.

Tell you what, The BAC has a duty cycle and it should be sort of hummming or vibrating all the time the key is to ON. That would give you an idea if it's working any at all. Try listening after the engine is fully warm and maybe even before the engine is fully heated up. No hummm/vibration at all is not favorable. No duty cycle can mean the sockets in it's plug are pushed back or a worst case scenario of the transistor in the ECU being burnt out. It CAN be replaced for about a buck fifty or so. Hmmm. Let's see. In Euro's that'd probably be the equivalant of fifty cents the way the dollar is sliding.

Errr. Make that Pounds, not Euros.

I can't put up jpgs where I am now. Maybe in the next day or so. Maybe. Depends

 

Also, go to this site: http://www.rx7city.com/88manual.htm

Download the FUEL AND EMISSIONS for a non turbo. There are some views of how things are supposed to be concerning the BAC and Air Bypass Solenoid, but I have to admit they are easier for me to *SEE* because I've an idea on how things should be. For someone not sure of how things go, it might not be clear enough.

 

As suggested I turned the key and listened to the BAC, buzzing noise there so good good - traced back the hose and ah. solidly connected to the intake duct

but then i spotted another connector from the intake duct that looked like a likely candidate for my bit of loose hose. connected, started and it .. tried to idle but didnt quite make it! promising! so i put it on the hose more securely and tightened up the intake duct a bit more as it was a little loose at the top ... and

purrrrrrrrrrrrrrrrrrrrrrrr



idles perfectly now, from being so much scrap metal on my drive its a working car again!

of course last time i drove it it wanted to overheat as soon as you hit traffic, but thats going to be a lot easier to fix now it can idle!

 

EGI = Electronic Gas Injection. I believe that's how the Europeans referred to the 84+ injected 13B.

 

ahhhhhh

Is there a smilie for a lightbulb?