Fuel rail pressure sensor reading 0 volts at all times.

Set your multimeter lower. When you set it high to 400 ohms that's trying to read a lot. Did you check the voltage at the spill valve by connecting positive lead to one terminal and the negative to the other termimal at the spill valve or did you connect the negative to ground?

 

400 is the lowest value i have on my multimeter unfortunatly i think i have another one somewhere that may have a lower value setting ill check. I checked by putting the negative to ground and positive to the positive wire from the harness. But now you say that i realize i need to check between the two wires in the plug.

 

Okay I’ve confirmed that cyl 3 is absolutely dead and its not just a fuel pressure issue causing some anomaly. I ran the car and unplugged each coil with the car running and when i unplug 1,2,and 4 the idle dropps. When i unplug 3 absolutely nothing happens. Im going to do a leak-down test on the engine tomorrow and see if its leaking and if so from where and if not i guess i need to check the wiring for the injector and ignition coil.

 

Hey Matt,

I just checked...my AP doesn't have a monitor gauge for HPFP Sens Voltage, but it does have one for DI Fuel Press. Voltage.

Mine does not register 0 volts at all times. It fluctuates from 0 - 5 V while driving.

 

You have a gen 2 right? Probably why its different. Okay cool thanks for checking bro

 

Okay sooooo interesting development here.

I took the manifold off put the old fuel rail pressure sensor back in

took all the injectors out and tested them to see if they “click” when i put power to them and put them back in the car in a random order.

I put everything back together and it seems to idle better and now my fuel trims are slightly negative ,like negative 2-4, at idle instead of +20-25 and now cyl 1 flagged a misfire.

 

So I wonder if the injector is bad and is now in cylinder 1. Should have marked where they moved to

 

I would pull the injectors and send them out for cleaning and testing Matt. If they've never been done at 180,000 miles, it's way past due.

Usually, the outfits that do this process have a couple of extra cores laying around that you can buy off of them for not too much money. Allows you to replace the bad injectors and have them all flow matched.

 

As a matter of fact i found a shop near me who actually refurbishes injectors/ replaces the “filters” and all seals in them, ultrasonic cleans them and flow tests them after and they come with a 6 month warranty and he charges $215 a set if you turn in your cores. And he has some sets already done ready to sell. Now my only question is are my $300 injector seals worthless now or can they be reused?

 

Are they able to do direct injectors? There is a difference between port injectors and direct injectors in terms of equipment to clean/service them.

 

This is the add posted. He specializes in mazdaspeeds

 

Isn't Overspeed located in California now? Does he still do injector cleaning?

 

As long as they come with flow test sheets I'd just do it especially if you're trying to reduce down time. I would however ask if he's using own seals or not it only matters IF you're going to use the bottom seals between the injector and the block the top seals for the rail doesn't matter. You "can" re-use the CS injector seals 2-3 times

 

Injectorrx.com did mine for 1/2 that. Get em cleaned and new o rings and seals will eliminate any guessing.

 

Yeah he has his own equipment and owns a shop. He does them in batches of 10 Or so at a time. It was the injector. The car is running like a champ. It has never felt this good in the 2 years i have owned it. It feels incredible now. I think im going to need a retune however because its pulling like 27-28% fuel at idle now. And it spiked to 24psi in 4th and my tune is for 22psi ive never had it spike to 24 in 4th. It would barely hit 22 in 4th for a second or 2

 

Wait for fuel trims to settle, glad it's running well

 

So when the fuel trims “settle” isnt LTFT supposed to be less than +\- 10%? Cuz right now my LTFT IS 20.88% and STFT IS 7.44%. And thanks I appreciate it. Im very elated after all the work it took to figure this out and I really appreciate everyone who has helped me figure it out.

 

I may have missed it...did you already replace the injectors? If your trims are positive, it's adding fuel.

How many miles since you reset the ECU?

Might want to do another check for a boost leak or something, given how much stuff you removed and re-assembled.

 

Reset that ECU will take about 20miles after ECU reset to start to settle if it's not then you've got yourself a leak somewhere

 

How many miles were on these injectors? My tuner told me if you have over 80k and haven't had them serviced you are asking for a really bad time. Edit I see now over 180k Jesus