I drive a 2004 Ford Ranger, which I’ve had for the life of the truck. For a few years, I’ve had the CEL on more often than not, usually for codes related to oxygen sensors and cat converter.
I’ve taken the truck to a couple of shops and had O2 sensors replaced (repeatedly), but the CEL has come back on within a few days. I’m not at all experienced with auto-work, but I’ve been trying to pick up some new skills (in the interest of not going broke). So, aside from the shops doing their work, I’ve personally replaced a couple of O2 sensors, one catalytic converter, fuel filter, plugs, etc. Between going to the pros & doing work myself, I’ve spent a lot of money trying to keep my beloved Ranger running. Still, that CEL has persisted.
Somewhat recently, I’ve suspected (feared) that I need to replace the fuel pump, and I’ve been trying to work up the courage/knowledge to do that myself. HOWEVER, about a month ago the truck would not start; I replaced the fuel-pump relay just and got it to the shop where they replaced yet another O2 sensor (this one was under warranty from the last time they’d replaced it).
Now, a month later with a new fuel-pump relay, the CEL has stayed off. I’ve checked with my code-reader and I’m still getting a “pending p0430,” but otherwise this is the longest I’ve gone without that CEL coming on.
So, I’m wondering: could a faulty fuel-pump relay have caused multiple O2 sensors to fail? Was that the problem all along? AND, at this point, should I still plan on replacing the fuel pump itself?
Sorry for the lengthy post, and if these are dumb questions. Just hoping to get opinions from folks more experienced than I am.
Thanks!
No.
The fuel pump relay is just an electrical switch that controls when the fuel pump turns on and off.
Tester
Welcome to CarTalk…
How many miles are on the vehicle, what engine, given a P0430 code I assume either a 3.0L or a 4.0L??
Are you replacing the catalytic converter(s) with universal ones or direct fit ones?? Have you replaced the spark plugs and ignition wires…
Sounds like you are past what a code reader can do, you need a scanner that is able to read the Live Data to check things like your short/long term fuel trims…
It’s a 3.0L with just about 196,000 miles.
The one catalytic converter I replaced (the rear) was a direct fit. I replaced the plugs & ignition wires about a year ago.
I should also mention that, prior to replacing the relay, I’d have intermittent times where the CEL would actually start blinking; I’d stop the truck, shut it off & wait a minute before starting it again. I’d also have times, usually after a longer drive, when the engine wouldn’t start. The ignition sounded normal, but it acted like it wasn’t getting fuel. After waiting 20-30 minutes it would start. Maybe once a month or so I’d run into that.
Neither of those things has happened since changing the relay, but I realize that may be coincidence.
Thanks for the reply. If the relay was not working all of the time, affecting the pump, could that have caused codes for “running lean”? Or am I barking up the wrong tree?
Keep a can of starter fluid with you, if it doesn’t start, spray some starting fluid in the intake duct hose close to the throttle body, spray a little bit (follow directions on the can(?) towards the throttle body, if it start and runs a few seconds and then stalls out again, try it again, if same results then possible bad fuel pump…
Again, time for a scanner… Or just throw enough parts at it till hopefully one sticks…
You could have a failing crankshaft position sensor causing the crank no start and separate from the CEL issue…
This would be a good time for a scanner, don’t shut the truck off, check for history, current and pending codes, and check Live Data to see what is abnormal causing the CEL to flash…
An oxygen sensor-fuel system lean fault is a fuel supply problem, not an oxygen sensor problem.
I have seen malfunctioning fuel pump relays or ASD relays cause intermittent fuel pump operation but most of the time fuel pump failure is the cause of a no-start or system lean condition.
Hey, just wanted to say thanks to everyone for the replies; I very much appreciate the information.
Did you repair the issue??
No, I don’t have a resolution yet… but I haven’t had the blinking CEL or any issues starting since replacing the relay. I am looking into getting a more advanced scanner like you had mentioned; beyond that I’m kind of waiting for something to go wrong to give me a clue for my next step.
Maybe you got lucky and found the issue…
XTOOL D7 tablet for the DIYer needing a more advanced scanner has been getting pretty good reviews…
The Innova 5610 hand held does a decent job, but to me it is hard to navigate for some reason… lots of scrolling… I’ve only really messed around with my older (09ish) vehicles, haven’t looked to see what it is capable of on my 23 Toyota yet…
My next scanner though will probably be the XTOOL D8S… It is a high end DIY scanner without the Pro shop scanner price… Not the best for Euro’s…
Nothing beats the top Snap-on though for aftermarket scanners, but it is very pricey… lol
Of course dealership scanners are the best for manufacture specific systems, but out of reach for most mechanics…