Discovery I Fuel Pump Removal / Fix
#73
#74
Fuel pump / system issue and questions
Hi all - brand new here - just bought non-starting '98 Disco.
I appear to have a fuel delivery issue of some kind. I've researched a few things and discovered that I have an Advanced EVAP system (which most of you probably knew due to the model year). Previous owner said a shop's diagnosis was a 'fuel pressure issue'. Uh...yeah. Shops can be pretty frustrating. Anyway, with that info in hand and the fact that it wont start I decided to check for spark first. Got spark - good. Then I disconnected the MAF snorkel and sprayed a bit of ether in the plenum. Presto! Starts, then quickly dies. Now I moved on to a fuel pressure check. I have 39psi at the rail and a (continuously) running fuel pump (might the continuous running indicate a problem?). I depressurized the rail, and turned ignition to PII and fuel pressure moved up to 39psi again. It didn't 'snap' up to 39psi, but it only took about 1.5 seconds so it doesn't seem restricted by a clogged filter or sediment screen on the pump. That's more or less the end of the diagnostic work I've done.
So here are some questions: Is 39psi adequate? Do the injectors have some kind of minimum pressure 'gate' that will only allow fuel under a minimum amount of pressure to pass? Is the continually-running pump perhaps an indication of some other problem? IOW, should it come on for a few seconds after the ignition goes into PII, reach full pressure, then cut off? It is typical to have some epoxy around the fuel pump retaining ring, or is this a sign of an non-standard repair? How does one release the funky fittings on the pump outlet and return tubes?
My gut is telling me I need more than 39psi.
Thanks in advance for all the help.
I appear to have a fuel delivery issue of some kind. I've researched a few things and discovered that I have an Advanced EVAP system (which most of you probably knew due to the model year). Previous owner said a shop's diagnosis was a 'fuel pressure issue'. Uh...yeah. Shops can be pretty frustrating. Anyway, with that info in hand and the fact that it wont start I decided to check for spark first. Got spark - good. Then I disconnected the MAF snorkel and sprayed a bit of ether in the plenum. Presto! Starts, then quickly dies. Now I moved on to a fuel pressure check. I have 39psi at the rail and a (continuously) running fuel pump (might the continuous running indicate a problem?). I depressurized the rail, and turned ignition to PII and fuel pressure moved up to 39psi again. It didn't 'snap' up to 39psi, but it only took about 1.5 seconds so it doesn't seem restricted by a clogged filter or sediment screen on the pump. That's more or less the end of the diagnostic work I've done.
So here are some questions: Is 39psi adequate? Do the injectors have some kind of minimum pressure 'gate' that will only allow fuel under a minimum amount of pressure to pass? Is the continually-running pump perhaps an indication of some other problem? IOW, should it come on for a few seconds after the ignition goes into PII, reach full pressure, then cut off? It is typical to have some epoxy around the fuel pump retaining ring, or is this a sign of an non-standard repair? How does one release the funky fittings on the pump outlet and return tubes?
My gut is telling me I need more than 39psi.
Thanks in advance for all the help.
#75
#77
could be.... here is a link to the workshop manual (wmlj97e), electrical trouble shooting manual (etlj97x) and the owner's manual (hl0156n).
https://www.cubby.com/pl/LR3+worksho...0Discovery%20I (edit to insert the link....duh)
after fuses it is time to start looking at sensors... does it throw any codes? Is the "check engine" light on?
https://www.cubby.com/pl/LR3+worksho...0Discovery%20I (edit to insert the link....duh)
after fuses it is time to start looking at sensors... does it throw any codes? Is the "check engine" light on?
Last edited by WaltNYC; 12-11-2013 at 12:01 PM.
#78
Also, before we get too much further into this...is my key supposed to have some anti-theft circuitry in it?
Last edited by figgsbellevue; 12-10-2013 at 07:02 PM.
#79
#80
I have determined so far that my Disco has no pulse at the injectors but has 39psi at the rail and a running fuel pump and spark. I will test for +12V and for -12V pulse on the injectors and follow up.
Thanks for patience with my noob-ness.
Last edited by figgsbellevue; 12-11-2013 at 06:34 PM.