white520

I have an 87 Turbo II and I just rebuilt the engine. I all new seals and bearings. When I bought the car it had a blown apex seal and was hard to start. You would have to play with the gas pedal to get it to start. Now that I have the motor back in the car it won't start all the time. I have gone through 3 sets of plugs. When it does start running it will run for about 30 min then it will cut itself off and won't start. If you try and start it the plugs get fouled out. When I start the car I can smell fuel. I have good spark and the compression is good on both rotors. These were check by the mazda dealer. The codes he pulled up were a 07 and a 09. These go to the intake pressure sensor and the atmosphiric sensor. It idles Ok when it is running, around 700-900 rpms. I can't find a vacuum leak. The dealer does not want to work on it anymore because of the age of the car and I just don't know what to check any more.

Here is what I have tried so far:

New vacuum lines
New coolant temp sensor
Two used intake pressure sensors
3 sets of plugs
Fuel pump switch installed
Injectors cleaned and flow tested



Here is what I have checked so far:

Mass airflow meter
Coolant temp sensor
Coils
Crank angle sensor
Timing (Dealer)
Fuel pressure (Dealer)
Compression (Dealer)

I was told that I could have a bad wire harness or computer. I just got another computer today, but I have no clue where I can get a engine wire harness.
If it is one of these things what could be causing the problem and why does the fuel pump always have twelve volts to it, even when the key is in the on position? Why is it loading up with fuel when it runs and why do these cars flood all the time?


Help!!!!!!

HAILERS

1. About the 12v on the pump all the time......you sure the fuel pump check connector is not jumpered? Are you sure the fuel pump switch you installed has an OFF position? Is is the 12v still there at the pump if you disconnect the afm plug?

2. Have you tried to lean the Variable Resistor for the idling? Maybe it's too rich? Just for idle.

3. How many miles on the rebuild? After 500 it should have gotten where it has been broken in so to speak.

4. It's odd that the car floods out if you have a fuel cut switch. Next time you go buy plugs......just buy a couple of Lead plugs. No sense wasting money on trail plugs.

5. I can't really help. I notice that the dealer says the fuel pump pressure is good and the timing is ok. Coils are good, cas is ok(never seen a bad one), compression is good. Got me. The only thing about the harness would be if it had bare spots in the area around the fuel injector plug and they/it was shorting out and causing the injector to go full open. Not likely.

6. The 07 and 09 could indeed be caused by a bad connection a those sensors. I don't think either would cause a car to die though. I've run without the boost/pressure sensor connected (experimenting around, not boosting with it disconnected) and I can asssure you the car will run like that.

7. I ain't got a clue why it dies. Got me. Have you driven it for any distance????

white520

I have zero miles on it. I am afraid it will leave me on the side of the road. The voltage that I was talking about was before I put the switch in. The pump has power when the key is in the on position. Thats why I put the switch in.

HAILERS

So.......take the switch out of the circuit....turn the key to ON....check for 12v at the pumps plugs Blue wire...if there.....take the plug off the afm....if its still there.....make sure the jumper is not in the fuel pump check connector.....if its still there......then the circuit opening relay under the dash might be bad....so check to make sure there is not a ground being put on the Circuit Opening Relay's BROWN wire......if there's no ground there to hold the relay in.....the relay is bad internaly (possible).

My personal opinion is.....This car NEEDS to be driven on the road for many miles. There's nothing as much fun as driving a new engine in a car, when the car has no plates/inspection sticker/ insurance. Best done in the middle of the night on the interstate. Makes one ...well ... anxious while driving.

HAILERS

Or how about this.......the car idles as you say. But lets say that the fast idle cam/thermowax stays on its cam because for some unknown reason its not getting hot enough until thirty minutes later when it expands because of heat soak from the engine/throttle body. So now it falls off the cam. Walla, the car dies because by falling off the cam it closes the throttle plates to much for this rebuilt engine??? Yeah.

white520

Ok first thing is I had the switch on the red wire as I thought this was the power wire for the pump. Where is the fuel pump jumper wire and circuit open relay located? What is the cam/thermowax and where is it located? How would I check it?

When the car does die it does fall off slowly and does not restart. Yesterday I pulled the plugs after it died and the plugs were not wet with fuel, but the car did not restart. All it did was flood with fuel. BTW this was at operating temp.

Thanks for your help. I'll check those things when I get to wor tomorrow.

HAILERS

The fuel pump check connector is *near*the right front strut tower. It's a two socket connnector. Yellow in color. Maybe a piece of black rubber surrounding it(maybe). It is just hanging there off the harness. One wire is black, the other brown. Jumper a piece of wire from one socket to the other with the key to ON. You should hear a click of a relay, and with good hearing, hear the fuel running thru the fuel rail. 12v should show up a the blue wire at the fuel pumps plug when you do that. That fuel pump plug is under the carpet on the back of the left rear strut tower.

The circuit opening relay is in the car. It's above the steering wheel shaft. Maybe a foot from the firewall??? It should have five wires in a six socket relay base. One is blue that goes to the pump, one is brown that goes to the afm, one is black that goes to ground, one is black/red that goes to the starter system and one is black/white that is a source of 12v from the ENGINE fuse which gets that 12v from the ignition switch.

A normal car will idle a bit high, say about 1500 rpm and gradually come down in rpms in about three to five minutes (never timed it myself) depending on how cold the outside air temperature is. Since your car is doing something similar to what I described, then that show the thermowax is working to some degree. The thermowax is located on the aft side of the throttle body and you have to use a mirror to see it and even then you have to know what to look for.

I KNOW what I would do if I were you. I'd buy me some PVC pipe at HomeDepot that is the same size as the diameter of the hose that feeds the intercooler and the same size as exits the intercooler. Also buy a ninety degress pvc elbow to connect the pvc to the hose that exits the intercooler. Now remove the intercooler and set it to the side. Put the pvc piping in its place to connect b/t the two hose that fed/exited the turbo. Plus cap off the two small hose that went to the intercooler. What you gain by doing this is...........room to work and access to the throttle linkage. Now you can see the thermowax with a mirror and even more exciting is you can see a very small screw on the aft side of the throttle bodys linkage that has a very small nut on it (8mm, I think). It's a throttle stop screw. Guess what you can do with a throttle stop screw?????? Screw it in a touch to keep the throttle open and the engine idling at a higher speed . I'd do that and not mess with the thermowax until you get some MILES on the engine to break it in a bit.

You NEED to access the online factory service manual at http://www.iluvmyrx7.com and download the FUEL SECTION. There you will find how to adjust the thermowax, set the timing, set the idle etc. It's quite possible the thermowax is ok but the engine needs some serious run time put on it even if you have to sit there and keep the engine running with your foot (screw the throttle stop screw in some and you won't have to do that).

Some if not most rebuilds might/will have flooding problems until they get some run time on them. Not all rebuilds though. I rebuilt two 12A engines with brand new rotor housings and they both were trouble free in that respect.

Get more engine run time on the engine. Preferably driving it, even if just in the neighborhood.

HAILERS

About the fuel pump check connector and jumpering that connector. All you are doing when you jumper it is put a ground on the Circuit Opening Relay to pull it's contacts in and make a circuit to the fuel pump to turn it on. The very same thing is done to the Circuit Opening Relay when the engine starts, but is done by the flapper door in the afm making a ground circuit for the same relay.....as long as air is passing thru the afm.

white520

OK. I drove the car for about 30 minutes. The car has more power than I thought it should have for such a small engine.
I checked the items you said but on my car the fuel pump wire is getting power from the black wire w/ the white stripe. I checked the wire diagram and the blue one is suppose to be the power wire for the fuel pump. Is this normal or do I need to check something else. I raised the idle speed to 1000 rpm buy moving the stop bolt. This made it not die on its own after getting warm. I also noticed that the plug for the idle control motor was not in good shape. If I move the wire bck and forth iI can hear the idle motor run. Is it suppose to run with the key on? What would happen is the two wires on the plug where switched? The reason I ask this is when I was putting the engine back it I remember the wires coming out of the socket. I think I may have put them in the wrong way.

After I drove it I let it run for an hour. It never cut off and it never coughed or smoked, but when I cut it off and tried to restart it the car would not start. Does the idle speed motor have anything to do with the restarting the car. I know it is part of my cutting off problem, but I don't know about the no start problem.

And what about the power signal for the fuel pump? I cut the power off by cutting the blue wire and the cr still ran, but the black wire w/ the white stripe was still powered up.

Hey man thanks for all your help. This car is very quick, but it is no good if I can't get it started without flooding or if I can't start after it gets warm. This car surprised me.

HAILERS

Idle Control Motor........I'll guess and say you mean the BAC located on the right side of the motor, just above the air control valve..NO, it does not matter which wire goes in which socket.

Read this: http://www.teamfc3s.org/info/articles/idle.html

We're miscommunicating. The fuel pump does get fed from the Blue wire on the Fuel Pump Relay and Resistor located just infront and below the air filter. That relay gets fed by the LR or blue/red wire from the Circuit Opening Relay.

The Circuit Opening Relay gets 12v from the ignition switch and the ENGINE fuse that's inbetween them. That relay supplies power to the Fuel Pump Relay and Resistor then to the fuel pump.

The Circuit Opening Relay has to have a ground for it to work. That ground comes from the afm when the engine is running. Or if you look at the picture, it also can be pulled in by turning the key to START, but that relay will relax if the key is put to any other position.

The BAC is a part of the starting procedure. The BAC goes wide open when you start the car, and once the car is started will drop to about a 45 percent duty cycle. Be sure to read http://www.teamfc3s.org/info/articles/idle.html

If you drove the car.....then you have no fuel pump probvlem that I can see. If the car is dieing at idle ....then that's a idle problem, not fuel related.

HAILERS

In case I did not mention it......the key to ON does not make the pump run. It takes more than that. The pump is not supposed to run if the engine is not running.

white520

IS the pump suppose to be on when starting or just when the car has started running on its own.

On most car I have repaired the pump has one long pulse when you turn on the key and the injectors open for a split second. Then the pump has no power until the car is running. True or not true?

Again thanks for all the help.

HAILERS

NO. You turn the key to ON. The pump does not pump. You turn the key to START, the pump runs as long as you can hold the key to START. You let go of the key and let it return to ON. The pump stops if the engine does not start. If the engine starts then when you return the key to ON......the fuel pump keeps running until your engine stops running.

HAILERS

HAILERS

white520

I got it to idle pretty good without the help of the throttle stop bolt. I adjusted the throttle postion sensor by stretching the holes to make it adjustable instead of a fixed sensor. The sensor adjuster bolt just was not enough. After I did that the BAC started to read and I could adjust the idle from there. Is 950- 1000 rmp to high. I can't get it to go any lower. When I tried setting it to 750 rpm it would die until the car got warm.
I still can't start it with out turning the fue pump off.
I notice you said the pump runs when you are in the start position. Do the injectors pulse when you are in the start position. I'm just trying to solve the flooding problem now. Unless you tell me that 950 rpm is too fast an idle speed.

One more thing. That rich-lean resistor on th rf strut tower does not seem to do anything. How do you know it is bad, and is it supposed to spin in either direction and not stop in any position?

Thanks Man. All advise was good advise. I don't think I could hve gotten this far without your help.

91DropTop

Nice work!!
Good paint

HAILERS

1. When you are in START the engine is cranking which means the crank angle sensor is rotating. The injectors work off the cas signal. So yes, the injectors are injecting when you are cranking.

2.The idle should not be set until the engine gets fully warm.

3. The variable resistor probably won't show much in the way of any noticable change until you get the idle speed down to around 750. On both of my cars the output of that device is around 1.65 volts.

4. There should be a stop on full R and a stop on full L. I'd check with a voltmeter to see what the output is and if it's varying when the screw is turned.

5. Having to wallow out the holes for the tps is.....well, different. You should not have had to do that. Got me. The bottom line is that the tps on a series four should have a output of approx 1 volt when properly adjusted (fully hot car). You can see this output at pin 2G of the ECU or by looking at the green/red wires output at the tps connector.

I think that car needs to be driven or a lot of idle time put on it. Preferably driven. Around the neighbor hood if nothing else.

white520

Could the Variable Resistor cause a car to flood if it does not work properly or is it just for idle adjustment?

HAILERS

I *think* it's just for idle. I don't know for sure but I'd put my money on just for idle. Sometime this weekend I'll just unplug mine and see what if anything happens to my afr at idle. I *think* if it fails or is unplugged it goes to a default value in the ECU. I don't *know* that for sure. But it'd be interesting to see if my afr changes when it's unplugged.

white520

Hailers,

I checked the Variable Resistor and it has no ohm reading at all. There is no signal at any position and the dial just spins. I also put a fuel pressure gauge on the enigne for about 20 min. The pressure started at 35 psi and after 20 min the pressure droped to 22 psi. Does this mean that the injectors are leaking. (BTW) The fuel and return lines where pinched off.

Do you know where I cn find another Resistor!

HAILERS

At idle, with a fully warmed up engine, the fuel pressure should be around 28psi.

The manual says to jumper the FPR solenoid and when you do that the pressure should go to 34-39 psi. When you do that all your doing is shutting off vacuum to the fpr and allowing it to see atmospheric pressure...that's why it goes to 39psi.

The 22 seems just a touch low, but that could be the calibration of the fuel pressure gauge. In other words it's a normal thing to see lower pressure in the fuel rails as more vacuum is applied to the fpr. It sounds like your engine is pretty tight or put another way, the seals are doing a good job.

You might pull the fuel pumps strainer off the end of the pump and clean it in acetone or buy a new one and while your at it replace the fuel filter. Then you know those items are good. I'm not sure if I'd be all that worried about 22psi at idle.

You see the higher pressure at the begining for a reason. On start up, the fpr solenoid closes and ports atmospheric pressure to the fpr for 50 seconds. During that period you should expect to see b/t 35-40 psi. Then after 50 seconds, the fpr solenoid passes intake manifold pressure to the fpr and the fpr regulates fuel pressure to approx 28psi. So 28psi fuel rail pressue is normal. 22psi? Well it might be worth taking a look a the fuel filter and sock on the end of the pump.

Did you check the output of the pump itself? Should be 71-92 psi coming out of the pump, nothing else connected to the output of the pump.

Have you tried to warm the engine up, then turn it off. Then turn the key to ON. Then jumper the fuel pump check connector. Now observe the fuel rail pressure. Now turn the key to off. The pressure in the fuel rail should stay constant for several minutes(I forgot how long). If the pressure drops dramatically in a few seconds...then the injectors are probably leaking.

OOOps. I just re-read your words. You pinched the hoses off. You should not have to do that. Jumper the fuel pump check connector with the key to ON, not Start. The fuel rail pressure should build up to apporx 35-40 psi. Now turn the key to OFF. The pressure will drop off, but not dramatically. 22psi after a few minutes does not sound bad to me.

HAILERS

By the way. On my car, the variable resistor is set to approx 1.65 volts. When set like that the car idles just fine and the afr is 13.0. IF I unplugg the variable resistor, the ECU defaults to some value and the afr is now 13.5. The idle is still acceptable like this....just even better when the afr is 13.0

HAILERS

I noticed something that I should have noticed before when you mentioned wallowing out the tps holes.

The engine needs to be fully HOT before setting the tps. When the car is cold, the throttle is being held open a touch by the THERMOWAX and the fast idle cam. Let the car get fully warm before setting the tps. When fully warmed up, the fast idle cam is off its roll pin and not effecting any thing to do with the tps.

So fully heat the engine up. Then go out and reset the tps.

The tps output will not read the same when the car becomes cold later. That's because the thermowax's piston has the throttle position as the car got cold. That is a normal thing. Only check/set the tps when the engine is fully warmed up.