As the title says I have a bad case of leaky primary injectors (so I think). It is so bad that I had to install a fuel pump kill switch to band-aid the issue, it does work. Today, I took the top manifold out and left the fuel line intact strapped the injectors to the fuel rail and placed a bucket under the primary injectors. Then, I had another person crank the engine while I was watching the fuel injectors. For the fuel injectors being cold and all they were holding pressure and the spray pattern was consistent. I did the same for the secondaries by wiring them with primary clips.

I strongly believe there is a alternate behavior of these once they become hot (correct me if I'm wrong)?
I did have them removed once before and sent for cleaning and they were holding pressure and everything was good so I'm told. I hate to be doing this for the third time so I'm looking for suggestions.

Are there alternative Injectors that I can use that are multi-hole type(not needle type)?

 

Is the issue starting after driving?

 

Check compression with the motor hot as well.

 

This happens only after I try to re-start the car with the engine hot, it starts cold every time.
I've checked compression and its fine.

 

I'd be looking at your water thermo sensor at the back of the Waterpump.

 

Try jumping the Fuel pump at the pass side shock tower. Then watch the injectors. Cranking with all that loose stuff can lead to bedlam. If you have an extra CAS, which most 7 owners seem to do you can unplug the existing CAS, plug in the spare, then give it a spin with the ignition on....again, can lead to bedlam but your injectors will fire. Once I had a huge flame pop out of the LIM doing this, hit my head on the hood, and then the hood slammed shut. So....be careful

Note: I dont think you have an issue with your injectors since you had them cleaned. Ive had more sets cleaned than I can remember and had only good results. These were some old *** injectors so I have always thought of them as more than good engineering.

Assuming you have good compression: Use the factory shop manual to check the thermo sensor and install a fresh set of plugs.

Check the MAF, TPS, Air temp and look for leaks from the maf to the manifold.

Good luck.

 

I did, the ohms were good. I also did the wiring for it and ended up installing a interrupter switch. But that didn't help.

I have some semi good plugs and on top of that I have an MSD box on the trailing coil.
But I may just get a brand new set of plugs.

The only thing that I don't have is those injector sieves on the primaries as they broke off when taking injectors out the first time. Luckily they broke while being out of harms way.

 

Did you check the voltage at the ECU? Backprobe the ecu harness connector at that wire and check the voltage to ground. I thought my wiring was good because I tested continuity numerous times, but it turns out that the wires were pulling out of the back of the connector. So when I'd disconnect it, it would somehow make contact again, but then I'd plug it back in and it would break the connection again. That's when I learned to check voltage at the ECU, which takes less time to check it there than it does trying to cram a voltmeter lead behind the alternator.

If your injectors are not leaky, they're not leaky. There's usually a priming pulse when the key is turned on. If the ecu thinks the engine is colder than it is, the priming pulse is usually longer. That and cranking pulses are longer when the engine is cold, which will wash your compression away when the engine is actually warm.

 

Am I the only one who thinks that the hot start problem is normal?

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Maybe.
Mine doesn't have any hot start issues.

 

Probably not the only one, but it's not normal. Get rid of the stock ECU and controls and you'll find out how certain things are not normal. I have not flooded the engine in about 2 years now after swapping to a standalone. Even on short starts.

 

Getting stranded is normal? Wow thanks Mazda

Could anyone help me out? Ive been wondering what the spec in ohms is for the sensor behind the waterpump. also what is this things actual name? thermo? temp? sensor? switch?

 

 

Yea I'm going megasquirt next month. The rtek is just not the same...

...

 

I went through all the troubleshooting before, testing all the ECU pin outs and what not. I also read that the S4 wiring is piece of junk. Last year I did rewire injectors and the thermosensor wiring as they were crummy and falling apart. I also installed a interrupter switch to trigger a hot start mode which I tested at the injector clips with a volt meter to assure it worked.
I think for now I'll swap primaries with secondaries and go back to square one with diagnosing the hot start issue.

 

You mean on the leading I hope? You can't have a single MSD box on the trailing...

 

awesome thanks

 

Thanks for the correction.


I was contemplating in buying SAFC Apexi unit to be able to somewhat control the air fuel ratio. I am wondering if that would potentially help reduce the injector pulse even further by leaning out the very first rpm setting. I understand this is not the same as having all fancy standalone features but it might aid a bit.