P0090 fuel pressure code

[localkineguy]

Hi all,
My car has started having some real problems on accelerating and it recently flashed a cylinder #1 misfire and a P0090 code, I can't remember the exact wording of what a P0090 code is but it's something like fuel pressure regulator circuit. Anyway, the engine stutters when I try to accelerate hard and it happens in all gears.
Is this a clogged fuel filter, dying fuel pump, or something like that?
Thanks

edit: I forgot to mention that the car idles decently but does hiccup about once per 10-20 seconds. Also, if I'm in neutral and rev to ~2000 RPM there it's smooth and no stuttering or hiccuping.

 

[localkineguy]

Update:
Pulled the coilpacks and cylinder #1 (passenger side right?) is definitely giving spark, the plug itself is oil-fouled. I changed out all spark plugs. Compression test gave 180-180-180-160 PSI. Cleared the cylinder #1 misfire and fuel pressure regulator circuit 1 codes. Ran the car around the apartment complex and got the same CELs within a minute. Engine still runs fairly rough. Any thoughts: injector, fuel pump, leaks?

 

[Red Demon]

The coil pack could still be giving spark but be bad under load at the same time. I just replaced my coilpacks and they were only 80 bucks for the pair at autozone. I doubt the FPR would be expensive either so I'd replace that as well. There's an awesome thread not too far down the line on this site about the fuel pump that gives a diagram of all the parts you would need and part #'s as well as instructions on how to change it. If you're cylinder specific, I'd start with the coil pack and injector though. It also sounds like you might be losing a ring in that cylinder if the spark plug is oil fouled and you've got lower compression in that cylinder.

 

[localkineguy]

Actually compression in that cylinder is 180 along with the others. The lower compression is on the opposite side (on the driver's side). I'm going to switch out the injector between cylinder #1 and #2 and see if I get a CEL on #2 instead. I've replaced the coil packs almost right after I bought the car back in 2009.
I just went to Pep Boys and injectors were $260/ea!!! Is that normal? I can just clean my old ones right? I'm hoping somebody has a cheap reliable idea/fix on this.

 

[localkineguy]

I still want somebody to confirm that cylinder #1 is the one closest to the passenger side.
I swapped what I think is #1 and #3 fuel injector and am still receiving the same CELs saying cylinder #1 misfire and fuel pressure regulator 1 circuit errors.

 

[Red Demon]

Looks like you can buy a refurbished fuel injector from Rock Auto for $27.79, just to get you going anyway. I'm not sure which cylinder is #1, but it seems like a huge coincidence that 1 cylinder is having less compression and 1 cylinder also has an oil soaked spark plug. The FPR is not expensive either, so replace that for sure. It is possible that the wiring to the injector has a fray or some shorting problem causing the error, but unlikely. Change the FPR and see what happens. At least the injectors aren't expensive, eh?! The price you were quoting sounds like what I pay for diesel injectors!

 

[localkineguy]

Thanks Red Demon. The lowered compression was in the opposite cylinder though. I reported 180-180-180-160 in what I think is 1-2-3-4 cylinders. So the lowered compression was in cylinder #4 and did not have an oil-fouled spark plug. I just ordered a FPR from Amazon for $50 and I'll swap that in to see what's up.

 

[Red Demon]

I'll keep an eye out. Glad you've got a start on it anyhow. Once you're started, it always feels better and you know you'll end up fixing it in the end. While you're waiting for the FPR, see if you can check the wiring very carefully to that cylinder's fuel injector that is giving you fits to see if there is some issue with it. Does the car run the same regardless of if that injector is plugged in to the wire harness or not? Another possibility, although less likely, is that as rough as the car is running the timing belt may have possibly skipped a tooth on the cam gears. not sure how to test for it, and it's probably the least likely thing, but it is possible.

 

[localkineguy]

No dice. I replaced the fuel pressure regulator to no success. Installed the new FPR, cleared the codes, drove the car around the block and I'm still getting the same error codes: cylinder #1 misfire and fuel pressure regulator 1 control circuit. I didn't open up the wire molding but the wiring that I can see going to the fuel injectors doesn't look frayed.

Opinions? Nobody's received this combination of CELs?

I'm mainly confused because the error code mentions a control circuit but based on the fuel pressure regulator that I put in, there doesn't appear to be anything electrical connected to it: http://images.carparts.com/product_images/thumbs200/standard/sipr337.jpg

So my new questions are:
1. is the picture indeed a fuel pressure regulator?
2. what is the "control circuit" for the fuel pressure regulator 1
3. is there an individual "control circuit" for each of the 4 cylinders (i.e. are there similar codes for fuel pressure regulator 2 control circuit, fuel pressure regulator 3 control circuit, and fuel pressure regulator 4 control circuit)?

 

[Red Demon]

I'm still wondering if the cyl #1 misfire changes how the engine runs if you unplug that fuel injector from the harness or not. If it runs on 3 cylinders all the time and shakes, but it doesn't change if you swap injectors, then there must be an issue with the wires controlling that cylinder fuel injector.

 

[localkineguy]

Good point and it's a quick test. Lemme do that now.

edit: YOU'RE RIGHT. Unplugged the wiring harness to fuel injector #1 and the car runs the same and no new codes are popping up. So....this sounds considerably more difficult to troubleshoot and subsequently fix. Is it normal to just throw in the towel and buy a new wiring harness and put that in or should I take a multimeter to the tons of wires and look for a short/open?

 

[Red Demon]

Hey bud,
Just for the hell of it, test the injector itself first. It's supposed to be appx 13.8 ohms. If that is not it, then most likely it will be either a short or an open on 1 of the 2 wires in the cylinder #1 fuel injector harness. There is this huge test you can perform on alldatapro that involves the SST 104 pin breakout box, but I think if it's possible for you to follow those 2 wires through the harness you'll eventually find a problem with them somewhere down the line that you can fix. More than likely it would be somewhere near the firewall and it would most likely be an outside wire. It could also have rested against the motor somewhere and melted. Check that injector first though. Also check the vacuum going to the FPR to make sure it's proper.

I just did some more searching on alldatapro and I have something new that I think you should check. It's called the fuel pressure control solenoid. It's located on the back of the intake manifold and apparently can cause the exact issues you're having. I hope this pic comes through for you:

EDIT: 1ressure regulator
2:Quick release connector
3RC solenoid valve
4ulsation damper
5:Fuel injector
6:Fuel pump relay

 

[localkineguy]

Well, remember I swapped injector #1 and #3 and that didn't do anything. I can still test resistance across the injector though. edit: checked resistances of 1, 2, and 4. All were ~ 18 ohms. Where'd you get that 13.8 ohm spec?
Regarding the PRC solenoid...what am I checking? Is there a resistance I should get? I was actually eying that part out this afternoon when I was working in the hood. However, if that went bad, wouldn't it affect all of my cylinders, not just cylinder #1?

 

[Red Demon]

Here's the test for it: The next picture will be of the parts of the solenoid.

 

[Red Demon]

Here's a pic of the solenoid to go with the above:

 

[cantin03]

Hi,
I have the exact same problem!! How did you solve it?
THanks!