2005 XC70 air/fuel issues

XCSwaggon97 · Post by **XCSwaggon97** » 08 Aug 2022, 07:00

Hey good morning. I'm new here and this is my first time using a forum site to post so sorry if I get some things wrong. My car is a 2005 xc70 2.5t and its been having a few big issues that I can't seem to figure out. One of the issues I'm having is when the car hits high rpm it will loose its acceleration and let out a huge backfire and other times it will be perfectly fine. Another issue I've been having is when I sometimes come to a stop at the lights or sitting in a drive through the car will just bog down and shut off, I do have a charging issue but I was able to keep starting the car after it shut off on me so power didn't cause that I don't think. The other issue I have which I think is related to the stalling at idle issue is that the car will also go into a fase for a minute or so where if I push the pedal too much it will try to stall itself which doesn't give the car enough power to keep the momentum going and throws misfire codes after that happens.
I did try replacing most of the main things that can cause fuel issues but most likely missing something. The parts I have replaced are the Fps (fuel pressure sensor) got it from a scrap car yard so its used but have tried multiple, I've replaced that cylinder thing that the gas lines run to underneath the manifold (forget what its called lol), fuel filter has been replaced twice cuz my plastic fuel tank has rusted metal pieces sitting in the bottom of it, I also just put a completely new fuel pump into her cuz I finally had enough of taking used parts off cars and then not working properly. The new fuel pump helped the backfire issue quite a bit cuz before I did that I literally couldn't go over 5000 rpm without backfiring and now most times I can push the rpms to where it should be able to. Once the cars been driving for a bit and gets to normal operating temp the issues become more persistent and annoying since I have to always boost the damn thing lol. Spark plugs were replaced, coil packs were tested, The MAF sensor has also been replaced along with a bigger sized boost pipe, replaced my downpipe with another used one cuz I was getting a code for the o2 sensor but thats gone now (car sounds amazing, its almost a straight pipe but it has a thrush glasspack).
Some of the codes I've been getting are P0089(fuel pressure sensor), P0087 (fuel pressure to low), P0442(small evap leak). One of the last owners had the car re-timed around 145km, currently there's about 230km on the car. I have also did the glove test for the pcv system but that was perfect. Going to check the car again for codes today but I don't have a vida/dice so I can only read the generic codes. I am planning on taking the car into the shop that works on these cars for them to scan it but there expensive.

Thank you for taking the time to help and read my bad writing skills.

ignatz · Post by **ignatz** » 08 Aug 2022, 07:43

I'd fix the charging issue first, even if its just replacing the battery. Not sure what your charging issue is.

XCSwaggon97 · Post by **XCSwaggon97** » 08 Aug 2022, 08:10

The alternator isn't quite putting out the power it should be. That was the next thing I'm planning on replacing new to make sure it works since I now have 3 other alternators off used cars that diddnt work. At least now I know how to remove the alternator without removing the power stearing and etc.
My step dad the other day suggested that one of the issues might be the throttle position sensor but im not too sure on that. I did notice that after I accelerate and then hold the gas pedal still, I can feel and hear the car get slightly more power after a second or two even though the pedal hasn't moved.

Post by **jonesg** » 10 Aug 2022, 17:33

how many volts do you get across the battery terminals at idle.?
14+v is decent.

you can either fire the parts canon at it or install vida on a laptop,
if you already have a laptop you can be up and running for $200 with vida.
I got the external USB drive version, it can be used on any laptop.
David gives excellent tech support.
https://diaglaptops.com/wp/dice-units/

XCSwaggon97 · Post by **XCSwaggon97** » 22 Aug 2022, 23:32

I just replaced my alternator the other day and now I'm getting about 14.8 volts but I think my battery has been dead for too long so its not holding the charge now, should be able to trickle charge it back up.

I only have a tower pc but there's a shop that can fully scan the car for about $100 so I'm going to try take it there soon cuz im still getting a lean idle. I'm thinking that the fuel lines going to the fuel level unit from the fuel pump is routed wrong. Right now they go up towards the back and is putting some stress on where it connects to the fuel level unit, since i had to loop the end of the line back up because of how it connects to the fuel level unit. I think it needs to go up to the front that way the connection to the fuel level unit doesn't have an extra loop.

Post by **abscate** » 23 Aug 2022, 04:09

You check fuel delivery by measuring pressure at. The rail with a gauge. It’s something like 55 psi spec. Loops in the hoses and stuff like that won’t matter.

Those codes are indicative of problems perhaps in the fuel pump module. That’s the device that converts the request from the motor for fuel to the actual drive signal on the pump. It’s a cheap used part, under $50

Commonly called PEM

You have to have a solid. 12.7 volt battery at rest , in these cars. They don’t run on the alternator with a bad battery

XCSwaggon97 · Post by **XCSwaggon97** » 23 Aug 2022, 22:30

I checked the fuel rail pressure a few weeks ago and it was about 50 to 55 psi. I did replace the pem last year and it says ford on it, I know ford has these engines too but maybe it was a little different causing issues.

Thanks for the reply ill have to charge up my battery maybe things are just not getting enough power I don't know, I don't have a battery light on anymore so thats good.

At the end of this month I am looking into getting a 2014d vxdiag nano j2534 scanner from aliexpress since its hard to get a vida dice unit or any good items for volvo in Canada unless I go to Hilton which im planning on getting a tune from them when I have the money and the car running properly lol

Post by **scot850** » 24 Aug 2022, 15:36

The Volvo part has FORD on the label. That is one of the causes of the codes you are getting. The other one is the fuel pump.

Do you know what brand of pump you used? Are you sure you got both the seals correctly fitted on the fuel pump and sender?

Other reasons for potential issues are air or vacuum leaks.

Neil.

XCSwaggon97 · Post by **XCSwaggon97** » 24 Aug 2022, 18:23

Yeah it says ford on it. My brother got the part from the scrap yard and thought it should work ,I don't know why he thought that.

My fuel pump i ordered from Amazon from an off brand but its been working perfectly fine except the plug on the top of the pump diddnt fit so I had to break off the shroud on the wire part but all the pins and everything else lined up right. Both seals are in proper, fuel pump also came with a new one, I also used the right tool for tightening the threaded gasket.

I'm just waiting on my step-dad to pick up my battery for charging and ill also go pick up a new/used pem from the scrap yard to see if those fix my problems. I also havnt scanned my car again for codes after I fixed a few things so ill try do that again soon.

Post by **br0dy519** » 24 Aug 2022, 18:34

I think scot is actually saying the Ford branding is OK. Buying any fuel pump brand other than Bosch is a no-no though.