Anyway, my issue is this.

Back in the winter i bought a car sight unseen from Cleveland and had it delivered to me in KY. Turns out the guy failed to mention every coolant seal in the engine was shot to hell. All the irons and housings and rotors were trashed so i bought one with 0 miles to put in the car. All the original harness stayed in the car. The engine is street ported and has all emissions but the BAC removed properly. 75psi which is okay considering the engine might have a total of 10 minutes of run time. The problem shows itself when trying to start the car and im at a complete loss. Turn the key to the start position and it cranks and starts and will continue running on one rotor (because thats all the "start" circuit powers) until you let off the key then it runs for a few seconds and dies. Also if you hold the key and its running but you lift your foot the car dies as well. Anything that interrupts the "start" circuit kills the engine. Key in the on position and the pump runs with both the check connector jumpered and the AFM propped open. Power to the coils, injectors, all that fun stuff. HERES THE FUN PART... The PO installed a toggle switch on the black and white wire that feeds ignition voltage to the circuit opening relay, center pin on top on the harness side. with the switch in the on position supplying power to the relay the pump runs with the connector jumped, but the car will crank, stumble for a second and will just continue cranking. Toggle the switch off so that the pump doesnt run with the key "on" and you can crank it and it will start and run (with the key held in "start"). Ive taken the switch out and run the wires back together to double check with the same results. Connected, key on, pump on, no start. Disconnected, key on, pump off, starts right up and runs. If you connect the wire or toggle the switch on supplying voltage to said relay the car cuts off regardless of key position. SOMEONE HELP I NEED AN ADULT!!!!

 

Are you suggesting that the B/W wire powered by the engine fuse w/key to on has no power when "Disconnected, key on, pump off, starts right up and runs."

W/key to start the top row far left positioned wire receives voltage which causes the top row far right wire (Blue wire) to receive voltage and this wire powers the fuel pump. Top row center wire receives voltage w/key to on, and w/the engine running the same Blue wire is powered (just key to on and engine off does not power the Blue wire unless the fuel check connector is jumpered or AFM door opened but the jumpered check connector should not be used at all unless you're checking the function of the pump or there is something wrong w/the AFM.

 

Key on that B/W wire has voltage. I've been through all the fuses and whatnot. I see what you're saying there. Why is it that the car won't run with the B/W wire connected to the relay like it should be? Only with that wire out of the equation. On a side note. I did get the car to start and run before once for about 5 minutes but wouldn't idle and I had to keep it over 2k to stay running. Also ran very rough.

 

The car runs when top row center wire has no power? If so then there is a problem w/the relay. There two relays within the relay and one is for just starting and the other is to keep the engine running once it starts.

Secondly, a car which starts and you have to fight to keep it running by playing w/the throttle pedal can mean there is a vacuum leak.

Thirdly, you should not keep the key to start just to run the engine as you will damage the starter.

 

Yes that was the confusing part for me. Trying to make sense of these diagrams from the FSM is like translating hieroglyphics. I checked for vac leaks at my shop with the smoke machine and found nothing what so ever leaking anywhere. One of my friends suggested one or two clogged injectors or a fuel pump on its way out.

 

S4 or S5?

 

S4 sir

 

You could also have an issue w/the AFM. You could unplug it and w/the fuel check connector jumpered you could try to start the car. Now w/the sensor unplugged it will force the car to run rich so if the car starts up and idles okay do not run the car too long or the exhaust manifold will start to glow.

And w/the car idling it is imperative that the B/W wire (center position of circuit relay) has voltage.

 

Sorry for the delayed response. I swapped AFMs and got it to start and run! There's voltage to the B/W wire because the switch wired into it has a light that comes on. Im guessing the AFM was the problem the whole time. But now the issue is that it will start but wont stay running unless i give it gas constantly. Still no vacuum leaks showing themselves on the smoke test so maybe its fuel related.
Thanks for the guidance Satch

 

The injectors (primary ones) could be the issue. Also, make sure the plug wires are going to the right rotor housing position. Make sure the timing is correct.

 

Plug wires are all in order and Ive set and reset the timing a couple times according to the fsm so it should be right on. No real way to set it with a timing light since i cant get it to idle at all. As far as the injectors go, should i just take them out and test them with an ohm meter. I dont have a way to flow test them or anything like that.

 

You could ohm test them but if they are clogged you would have to have them professionaly cleaned. And all your injectors should be the same size so you could switch the secondaries for the primaries as an alternative.

 

I finally got around to checking out the injectors. I pulled off the intake, reconnected the fuel line to the secondary rail and zip tied all 4 injectors to the rails. Jumperd the fuel connector and turned the key on. I've got fuel pressure, no leaks from any of the injectors. Plugged in a spare CAS and spun it and the primaries fired like they should. Nice, even, consistent spray. Secondaries are the same. The injectors also all were within factory spec for the ohm test. Still having the problem.

 

1.) Are you still having to hold the key to the start position or is that now a thing of the past?

2.) Did you ever check the injector ohms? Should be a couple of ohms or so if 86 to 87.5 but changes to 12 ohms for the 87.5 to 88 S4's as they changed things up at Mazda during the middle of the S4 production.

3.) I've heard that smoke tests are not the most reliant way to check for vacuum leaks. And speaking of vacuum you might have a hose connected wrong.

4.) Have you eyed the timing? Can be done w/o the car running (there are many threads explaining how to do this by using the advanced search feature).

5.) Are you sure the components/sensors are compatible w/the engine you have?

6.) Sometimes new engines need to build compression to run better and perhaps you need to baby the car along to reach this point.

7). You might actually want to check the fuel pressure w/a pressure gauge as opposed to just a visual inspection.

 

They key issue has been solved. I swapped out the afm and now it stays running as long as I'm giving it gas.

The injectors are low imp. Orangish red tops with square plugs. They showed between 2-3 ohms on all 4 injectors.

I've only got a few vac hoses still on the engine. Just the essentials like the fpr, atmospheric pressure sensor and stuff like that. Everything else is capped off. I'd try the starting fluid around all the gaskets but I can't get it to run long enough to do that.

The timing was set up per the fsm instructions. Pulley set to tdc on the correct mark and the cas dropped in to where the dot lines up with the mark on the shaft.

Engine, sensors and harness are all from s4 cars before the 87.5 split.

 

As far as the spraying fluid is concerned, you should have one person start the car and apply the throttle to keep it running while the other sprays away.