KoukiS14 Posted June 7, 2013 Share Posted June 7, 2013 But it's not the FPR or the fuel pump, even though it exhibits classic bad FPR symptoms. Replaced the Walbro 255 with a DW300. Replaced first the FPR itself, then the entire FPR assembly. Attached a datalog. You can see it can run lean in boost and rich under idle. There's some accompanying knock under load, so it's not the 02 sensor malfunctioning. I'm at a loss for what to try next. Any input would be appreciated. Update: Answer in post 5: dirty MAF sensor. Link to comment Share on other sites More sharing options...
KoukiS14 Posted June 7, 2013 Author Share Posted June 7, 2013 Ah, cracked uppipe. Could that contribute here? Link to comment Share on other sites More sharing options...
bugblatterbeast Posted June 7, 2013 Share Posted June 7, 2013 is the FPR pressure reference line connected at the far end? you might want to pull the line off of the FPR and check that there's vacuum at idle. if there isn't the other end of the line might have come off Link to comment Share on other sites More sharing options...
SWP XT Posted June 7, 2013 Share Posted June 7, 2013 Mine is doing something similar. My learning view ad column a is -11, getting knock under load in two boxes, and car is losing power through high load pulls. It runs hard, and you can feel it back off about 15% for a half sec and the go back to 100%. Launching the car also exhibits a slight fueling hesitation recently. What's the classic fpr symptom and what's the test? Link to comment Share on other sites More sharing options...
KoukiS14 Posted June 7, 2013 Author Share Posted June 7, 2013 Okay, what does $550.50 buy you? New FPR New complete FPR assembly New DW300 fuel pump $.50 of brake cleaner Why brake cleaner? For that dirty @$$ MAF. Problem solved. Link to comment Share on other sites More sharing options...
KoukiS14 Posted June 7, 2013 Author Share Posted June 7, 2013 Mine is doing something similar. My learning view ad column a is -11, getting knock under load in two boxes, and car is losing power through high load pulls. It runs hard, and you can feel it back off about 15% for a half sec and the go back to 100%. Launching the car also exhibits a slight fueling hesitation recently. What's the classic fpr symptom and what's the test? Not too similar, really, but the classic FPR failure symptoms are rich idle and lean boost. The test is to plumb in a fuel pressure gauge and monitor pressure under those conditions. Base pressure should be 35ish at idle, 43ish at atmospheric pressure, and +1psi from there for each pound of boost, IIRC. is the FPR pressure reference line connected at the far end? you might want to pull the line off of the FPR and check that there's vacuum at idle. if there isn't the other end of the line might have come off Yeah, there was no problem with the signal line. It's super short and completely intact. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.