Last November I blew my engine. Details in this thread. https://www.rx7club.com/3rd-generation-specific-1993-2002-16/rough-idle-dies-running-hot-odd-smell-hard-starting-sound-byte-attached-480478/

I just got my engine back from Rob at Pineapple a few weeks ago and have been prepping everything for the install. All went fairly smoothly and 2 days ago I thought I would finally get to drive my 7 again. Well....... didnt exactly work out that way. There were a number of problems, most of which I resolved, but I am left with one more hurdle.

For the last couple of days, I have been scouring the forum for answers. Ive got a few ideas on things to check out, and I would appreciate any and all members throwing anything my way for things to check out, ideas, etc.

Overview of the problem:
- engine turns over but does not fire
- tonight I will do a spark and fuel test (I dont believe I am getting any spark and checking the plugs there was no sign of gasoline)
- got one error code #11 (long + short) - intake air thermosensor - open or short possible
- there are four wires on the harness on the drivers side that all have a female single spade type connector - black. I believe they go to the oil pressure, oil temp?, and starter. the 4th, Im not sure.
- switching the wires around, I find that 2 of them connected to the starter allows me to turn the engine over. The other 2 do nothing.
- the tachometer shows no activity on cranking.
- when i turn off the key the cooling fans come on and stay on.

thanks for the help and feedback, I will be taking regular breaks from the car this evening and checking the post for input.
chuck

 

The connector for the starter should be obvious b/c it is the only one of the 4 that will reach down there, and is paired up with the metal 90 degree bracket that bolts on to the starter with a 10mm nut. Also, the 4th connector may possibly be for the knock sensor.

There is a white connector down near the ecu that you may have accidentally unplugged when removing the engine, (it does not have to be unplugged to pull the engine wiring harness) make sure that it is plugged in.

Hope some of this helps

 

Thanks for input goodfella!

The knock sensor is already connected as is the power wire for the starter with its black plastic spade connector. I put one of the black spade connectors on the oil pressure sending unit and the other spade connector that originates from the rats nest goes to the small sending unit next to the oil pressure sending unit.

The remaining black plastic spade connector is part of the harness that is in the back of the engine by the fire wall, has a long lead which is protected with the corrugated tubing and is part of the harness that connects to some of the tranny connectors. This is one that I dont have a home for at present.

Still not getting any activity from fuel and ignition systems. Ideas on checks for these systems. Im working thru the shop manual but nothing definitive yet.

Im going under the dash again to see if I missed something when reconnecting the wiring harness back into the ECU.

chuck

 

Here are some more questions that have come to mind as I try to understand and resolve the problems Ive encountered - all feedback appreciated.

1. would the intake air thermosensor sending a code also trigger the cooling fans to come on?

2. to get the cooling fans to stop running, I had to disconnect all the relays. wondering if I got the relays connected wrong when I rebuilt the harnesses. if so, how do you determine which relay goes to which harness connector.

3. just thought of something. a while back I had removed the AWS. what kind of electrical connector is hooked to it. maybe that is the extra connection I have.

4. which device creates the tach signal.

5. the coils harness is connected. Im going to check where I connected the ground cable for that harness. I believe I cleaned paint off of all grounding points but that one harness I placed on the engine after the engine was put back in the car. do the coils rely on that ground being hooked directly to the coils mounting frame?

6. on the diagnostic connector I grounded the fuel pump connector to prime the new fuel pump but I didnt hear the pump running. if the fuel lines were reversed (inlet/return), would the pump run anyway.

7. I painted the crank angle sensor trigger ring. could this cause a problem?

8. if either the fuel or spark is not functioning, does the ecu shut the other function off automatically.

thanks for your input!
chuck

 

Nope

Have you checked your EGI relay? If that is having a problem, it will cause the fans to start running when you try to start the car as well as not allow the car to start.


Shouldn't matter where it's grounded as long as it's grounded well.

If the fuel lines are reversed, it will still run the pump.

That shouldn't cause a problem.

Nope. The ECU doesn't know if spark is happening or not.

 

NO

if you rewired the harness you should start trouble shooting there.

this is possible, these connectors can probably be swapped...I'm thinking they are key differently, but if the AWS was 3 key, and the AIT was two, then the 3 key can probably fit over the two key plug...but when you tried to fit the other it wouldn't work and you'd then realize they are swapped. Make sense???

ignitor/leading coil.

Later 93 cars, I believe Mazda did away with that ground...if its the one that grounds near the coil bracket.

yes, it would run, just not supply fuel of course.

Did you paint the back of it? If so, I'd sand it off...some run fine with paint or powdercoat, I refuse to plate something that is engine control. Too much paint could build up enough that the CAS magnets don't...pick up.

NO

no problem, GOOD LUCK!

 

^damn beat me too it.

 

Since I am at work and dont have the car or manuals here, can you tell me where I find that relay. What is EGI and what does the relay do?

My assumption is that since the car ran fine and all functions worked prior to blowing an apex seal, then all the functions should still be okay. The only difference is that the car has been up on blocks since last November, so all the components should still be okay.

Thanks Mahjik.

ps - Ive been following your thread - when engines break - great stuff - you must be getting pretty excited that your car is getting close to running again.

chuck

 

I'll have to look up again 'exactly' what it controls, but without it there (or a problem with it) it stops both fuel and spark (IIRC).


Thanks! Yep, it's getting closer. Just waiting for a few straggling parts.

 

My fans work too when I turn the key to on.
All the other electric work fine.
When I solve my problem I will inform you.
Check for the fun sensors it is 3 if I remember well.

 

EGI=electronic gasoline injection
The EGI relay is located in the main fuse box on next to the driver's side shock tower. There are two "main relays", one is the EGI, the other is the "circuit opening relay". The EGI controls power to both the injectors and the solenoids, and works in conjunction with the COR to basically control power flow to all vital engine functions.

You should hear an audible loud clicking sound when you turn the key.

 

Kento, thanks for the info. Will check it when I get home tonight. Hoping that it is just a bad or loose connection that needs to be resolved. Another point of interest - yesterday, when I disconnected the spade connector on the starter solenoid, that action also made the cooling fans stop running. I dont understand what the relationship is between the starter solenoid and the cooling fans.
chuck

 

Did the diagnostics on the EGI and tested the components with volt ohm meter and they checked okay. Had the key out of the ignition and hooked up the battery charger. Within a few minutes, the fans kicked on. hmmm. If I pull the starter solenoid wire, the fans stop. If I pull the fan control solenoid off the harness, the fans stop. If I reconnect the electrical, the fans start up again. Strange.

chuck

 

how much rework did you perform?

 

Sounds to me like you've got some connectors swapped (possibly caused by the "harness rebuilding" you did? what exactly did that entail?).

 

I peeled old wrapping off of the harness and rewrapped it with silicone tape. I had a couple of wires at the connectors break but fixed those right away, so there would be no mixup. I need to check connections on a wiring diagram to see what relationship these components may have to each other.

Did get the car started today. The problem was related to the new supra fuel pump I put in. Inside the tank are 2 connectors that plug in to the interconnecting piece in the cover. One connector is for the fuel level and the other is to power the pump. Both connectors are the same shape and size and I reversed these. Then the other problem was that I had switched the fuel inlet and return lines at the firewall going up to the engine, so I wasnt getting any fuel into the engine. Started right up once there was fuel.

Ive got an oil leak to deal with and need to make adjustments to the TPS.

kento and dubulup, thanks for your feedback.

chuck