Loss of fuel pressure

Ok, before we get to the main issue, let me list out what I've got.

2007 speed3:

• Cpe short ram intake
• Street unit dual port blow off valve
• Cpe top mount intercooler
• Corksport HPFP internals
• Cpe injector seals
• ATP 3" catted downpipe
• Borla cat-back
• Cobb AP
• Tune

Let me say that all mods are from a previous owner, not me. Now onto the shit show.

Back in February the car started running real rough, a lot of misfires, and getting some smoke from the tailpipe when shifting. I replaced the spark plugs thinking that would help. It didn't. It got bad enough that I parked it and stopped driving it. About two weeks later I was gonna drive it over to a shop and have them look at it, but the car wouldn't stay running for more than 30 seconds. I started tearing it down a bit and found my spark plugs were coated in oil, and you could see gunk all over the piston through the spark plug hole.



So I got worried, and kept tearing down some more. Took the throttle body off and looked into the intake manifold.



I wondered where this all could be coming from so I looked around and found a little oil around/under the turbo. I also found oil leaking out of the intercooler. Well that basically sold me on the fact that the turbo was bad. Not going to confirm or deny that... I have a bad habit of convincing myself of things and running with them full force lol.

So a friend of mine and I swapped the turbo out with another ko4 that I had from a different speed3 that I had that flooded. We cleaned everything up a bit, and threw another set of plugs in and hoped we could burn out the excess oil since, hopefully, there wouldn't be oil getting in through the intake anymore. So the car started up, but same thing, it wouldn't stay running very long before it would die. It also had a lot of blow-by from the line that connects to the intake pipe near the MAF sensor. So we started watching the AP and noticed that right before the car would die, the fuel pressure dropped insanely quickly.

And that leads us to today. After a lot of reading I thought that I was losing fuel pressure because of either:

1. Bad itfp
2. Bad hpfp
3. Relief valve on the fuel rail
4. Or something electrical

Admittedly im not great with electrical, but I tried. I checked fuses and relays with a multi-meter for continuity and everything came back good. Then I checked the relief valve with an air compressor and it was fine. So I swapped out the itfp with one from my old car, and tried running it again. It was still dying after about 30 seconds or so due to fuel pressure loss. So I ordered some hpfp internals from corksport and replaced that. After I replaced the hpfp internals the car did run a lot better. It actually ran for about 10 min before it died.

I had it running on jumper cables because the battery that was in it was super old and hadn't been charged. Well the car died after those 10 minutes because I took off the jumper cables. I tried to start it again, but nothing on the dash came on. I hooked up the jumper cables and checked battery voltage with the cables connected and it was around 12.7 V I think. After I took the cables off it dropped to 12.1 v. So I knew the alternator was bad.

So I replaced the alternator, got a new battery, and got my ever so hopeful self ready to drive my beloved car again after one more repair.

It didn't work.

Car only ran for about 5 minutes after that, and then died again. It would crank and run fine for about a minute. Checked fuel pressure and there was still a mysterious drop in pressure right before the car died. After replacing the alternator and battery, it threw a p2004 code, and a U code. I have had the u code for a little bit without any other codes, but the p2004 code was new. After several tries to get the car to stay running, it wouldn't start anymore. Fuel pressure on the AP was sitting in the 16-19 range and wouldn't build back up. So I let it sit.

After work today i jumped the connector for the fuel pump resistor, and I replaced the fuel pump and circuit relays. Car started right up and ran for about 6 minutes before it died again. I was able to start it a few times, but each time I started it, it ran for shorter periods. Then it wouldn't start at all again, with fuel pressure sitting in the 16-19 psi range.

The car is also smoking pretty bad out of the tail pipe while running. Very white smoke. Forgot to throw that in there somewhere.

Does anyone else have experience with anything like this? Any help would be appreciated. I just want my damn car back, I havent driven it since February.

 

16psi with the car just sitting there?

 

Yep. KOEO pressure was between 16 and 19 psi when it wouldn't start

 

beats me, unless you put in another bad ITFP. I'd start looking from your tank. to your HPFP. Only thing I would think that would start dying the longer you run the car.

https://corksport.com/blog/hpfp-troubleshooting/
With the key on and engine off (KOEO), you should have 55–71 psi registering on your Accessport. This pressure should hold steady for a few minutes until the EVAP system slowly drops the pressure and everything leaks back down. If you don’t have any pressure reading at all, or a value much lower than that, expect a fuel delivery issue in the tank. This can be caused by any of the following:
◦ A bad in-tank fuel pump.
◦ A bad fuel pump relay.
◦ A clogged fuel pump filter.
◦ Faulty wiring and connections.

 

Im going to check koeo pressure in the morning. It's been starting fine after sitting for a bit, so im betting that pressure will be alright tomorrow until it runs for a bit. Guess I have a lot of wiring to start checking lol. Might see what testing i can do with the itfp to rule it out or not

 

This was KOEO pressure as of this morning. Ran for a few minutes then died, same as usual.



This is a video of whats it's doing. Ive checked more fuses, and replaced the fuel pump relay this morning, and nothing has changed. Haven't found any fuses that were bad.

 

Have you read through this thread??

https://www.mazdaspeeds.org/index.php?threads/fuel-pressure-drops-then-stalls.5606/page-3

 

Yah I did, thats what made me think I've got something electrical going on.

This morning I jumped the fuel pump resistor, the circuit relay, and the F/pump 2 relay and the car ran fine. Didnt stall once. I took the f/pump2 jumper out and put a relay back there and the car started dying again. The car will stay running if I plug back in the fuel pump resistor and the circuit relay and only jump the f/pump2 relay. But, I went and bought a new relay for f/pump2 and it still died with the new relay in

 

Hey man, I'm having a very similar issue to you and I was wondering if you ever resolved it. Thanks!

 

i was reading the one guy post about having fuel pressure issue and you asked if its resolved are you having same issue as him or whats up cause i was having a similar issue recently and fixed it with a high pressure relief valve cause at w.o.t i would drop to under 1500 psi so what i did was the hprv test with the k.o.e.o and watch the pressure build to 1525 psi when factory there suppose to go to 1850/1890 if i member correctly