jman6226

I just installed my SE engine after a rebuild (totally stock). It won’t start unless I give it a shot of starting fluid. Runs great until the fluid is exhausted. But, plugs are bone dry after repeated cranking. I’m convinced that my injectors are not spraying. I’ve checked the following:

1) Trailing coil – terminal continuity is good all the way back to the U terminal of the ECU.
2) Both coils and ignitors test out fine.
3) Fusible links are fine.
4) Both main relay sides click when key is turned (tested separately).
5) Timing is dead on (+5, +20 ATDC)
6) Good compression in both housings.
7) The tachometer registers when I crank it. I think the timing signal is getting to the ECU
8) The gas tank was pulled and flushed. New premium gas in the tank. New fuel filter.
9) Fuel Pump: I tested it with both Fuel Pump Short Connector jumped, and with the flapper of the AFM propped open (separate tests). I can hear fuel going through the fuel rail in both cases.
10) I checked all grounds.
11) Installed new NGK BR9EQ-14s.
12) I checked voltage at the two injector terminals (F, H) of the ECU, +12V on each with switch ON.
13) I tried the Vicegrips on the Return Line trick. No impact.
14) I checked the Pressure Regulator Solenoid Valve function per the FSM. Seems OK.
15) I pulled the DC off, and rechecked the installation of the rail and injectors.

Is there any way to test whether the fire signal is making it from the ECU to the injectors ? Would low fuel pump pressure cause no fuel, or just make it run poorly ?

Obviously, I've read through a lot of posts by knowledgable folks in this forum. I just haven't found the problem yet. Any advice would be appreciated.

Thanks. jman

mazdaverx713b

iTrader: (91)

i had the SAME ******* problem!!! there is a ground wire that has a ring terminal on it that needs to be grounded. its close to the intake. i cant remember the wire color, most likely black. but i grounded it to a bolt on the rats nest if that helps. it was like two years ago.... please report back and let us know what you find.

Siraniko

iTrader: (13)

ring terminal with 2 ground wires

jman6226

hey..thanks for the reply. I checked that ground again, and it looks solid. Still no luck.

JIMMY54

iTrader: (2)

Re-check your #1 option, continuity is fine but phyiscally check for spark out of the spark plug.

There are adaptors that you plug in between your sparkplug wire and the spark plug and you'll see spark during the cranking of the motor.



Reason being is that the:

********INJECTORS WON'T OPEN UNLESS THE SPARK PLUGS FIRE.*******

That took me a month to figure out.


Other causes can be bad ignitors..... double check that cheesy wiring around the coils aswell.

jman6226

Jimmy,

All plugs fire. I tested each one grounded to a strut tower bolt. All have good spark. #1 (continuity) is a check in the FSM to make sure the fire signal is getting to the ECU. Thanks for the input.

NewRXr

I would think that if he can check timing he's getting spark. Jman, low fuel pressure would still eventually start or run, besides clamping the return line would have at least flooded it. I don't think you're getting any injector pulse at all. The ECU grounds the injector circuit to turn them on. Take the dynamic chamber back off and rig a test light or small LED across the injector plug wires. With the engine cranking you will see flashing if the ECU is grounding the circut. The ECU grounds them through that ring terminal the guys are telling you about. Check that the ECU has continuity to that terminal. If you have continuity you could have a bad injector driver on the ECU board.

What do you know about the injectors? Are they the old ones that were working fine or did you replace them? Check them with an Ohm meter, they should be 1.5-3 Ohms. If they are high impendence they won't fire with the stock ECU.

Vernon

jman6226

Vernon,

The injectors are the originals. Resistance is in range. I will check the continuity from the ring terminals to the ECU. The wiring diagrams show them going to terminals B, D, and S on the ECU.

Thanks

linexrandy

I had a similiar problem, but was varnish buildup. I cleaned all fuel lines i could see, new fuel pump, filter, had tank proffessionaly flushed, everything imaginable and the damn bitch would not start. Then i noticed the valve up on the underside, forward of the spare well, and took it off, blew air back though to the tank and the damn thing started! My symptoms were identical to yours. Dry plugs, starter fluid, i even squirted gas into the sparkplug holes and she would start for a second. But turned out to be crude in that valve or just the valve itself gone to ****. Just something else to check.

jman6226

I haven't checked that valve. Will do it tomorrow. Before you blew the valve out, were you able to hear fuel running through the fuel rail. Just seems like if the fuel is circulating, it's not a problem in the flow path.

Thanks

mazdaverx713b

iTrader: (91)

also, have you checked the condition of your fusible links?

mazdaverx713b

iTrader: (91)

also, check to see if your pressure regulator solenoid valve is hooked up. its near the vaccume solenoid valve and next to the vent solenoid valve. its the thrid connector to the front from the purge valve. check that connector to make sure its plugged in and not loose.

mazdaverx713b

iTrader: (91)

another thing that can you can check is the air flow meter. you will want to press open the throttle plate and measure the resistance between pins E2 and Fc and the resistance between E2 and Vs. open you should get 20 to 1000 ohms. closed you will get 20 to 400 ohms.

NewRXr

That's the "Check and Cut" valve. I found mine was sticking and causing the vapor pressure in the tank to build up beyond what the ECU could deal with. The car would go from one extreme to the other on fuel ratio depending on thottle positon and vapor pressure. I took mine apart and cleaned it up. That made for smoother running and a bunch more power. Since then it's stuck again and Mazda wants $125 for a new one. Until then I just leave the gas cap slightly loose.

Vernon

jman6226

All,

Just read your excellent posts since my last entry.

1) Fusible links are all good.
2) Pressure Regulator SV tested good and hooked up correctly.
3) Will test the AFM pinouts.
4) Will test the Check and Cut Valve, or loosen gas cap.

My main problem right now is, with all the cranking, cranking, cranking, I think I smoked my starter motor. Until I get that fixed, active troubleshooting is on hold. This is frustrating. I bought the car new in 84, and love it like a baby. My son is 15 now (learner's permit, ouch !!), and we've spent a couple of years (off-and-on) rebuilding it. My dad taught me the ins-and-outs of car maintenance and rebuilding, and I have to pass it on. Anyway, I digress...... I'll let you know how these tests work out (I'm getting real suspicious about that gas cap)...Thanks everybody.

mazdaverx713b

iTrader: (91)

keep us updated and let usknow what you find. i'll bet its just a loose wire. something very simple.

jman6226

It's running !!!

I want to thank everybody for your inputs.

I put on a new starter motor (2nd one, the primary terminal snapped off of the first one and set me back two days til another could come in. Of course the defective one was the last in stock).

I pulled the DC and checked and air-cleaned the injectors. I don't think that was the culprit.
While I had the DC off I really cleaned everything related to those two ring terminal ground wires under the rat's nest. I then did a flow test on the injectors. Put them in a big ziplock and cranked the engine over (no ignition active). Got flow, I didn't care how much.

I put everything back together and cranked it. It fire right away !

Spent the rest of the day bleeding brakes and clutch, checking fluid levels, etc. Nothing seems to be leaking. I actually backed it out of the garage up into the street. That's the first time that car has moved under its own power in 9 or 10 years. Smoke a big cigar and had several Coronas to celebrate.

If I had to guess (because I made several checks at once), I'd have to give the prize to mazdaverx7 for figuring it out. I'm pretty sure it was a bad ground. Muchas gracias !! Something for the "No Start' thread?

Still have a lot to do, but made significant progress today. I'm getting a surge at idle. Guess it's time to set the TPS.

Later