My first post here. I hope there isn't a better sub-forum than this one on this site, for my question.
2003 Protege5 with about 132k miles. Daughter called the other day, saying her CEL came on and her engine died. I told her to try to start it and get it home. She got it home ok.
CEL codes were P0090 and P0171. From a bunch of research, it seems it may be the fuel pressure regulator solenoid. Vacuum hoses to that part are in good shape, so I don't suspect a vacuum leak. I cleared the codes and ran it about 7 miles, and everything seemed fine. Then she then ran it a few more miles and the CEL came on again. Same codes.
Before buying a new FPR solenoid (about $65-75 new, or $22 for a fleabay used one), I will try to bypass it and see what happens. I simply bypassed the solenoid with a new vacuum line, leaving the solenoid electrical connector on it, but its 2 vacuum lines now go to the atmosphere.
If the CEL doesn't come back on, then that tells me that the solenoid is bad. But what if the CEL comes back on with the solenoid being bypassed? Possibly a bad electrical connection causing the CEL? Or something else?
The next thing I gather might be defective is the O2 sensor. Am I correct in that? My daughter is moving 2 hours away to med school in 1.5 weeks, and I really want to get this squared away before she leaves. I don't want to go needlessly "shotgunning" parts that won't fix the problem.
I have done a ton of research on this over the last few days, but most of it says the same thing - that a P0090 and P0171 indicate a bad FPR solenoid. What I don't understand is how an improper variation in fuel pressure (from a device intended to aid hot or cold starting) would cause both of these error codes. So that is why I am posting here. Has anyone ever dealt with this, or have a real understanding of the role the solenoid plays? If I take out the variance in fuel pressure by bypassing the solenoid, I don't see how it will affect how the engine runs, once it has started, seeing as how the purpose of the solenoid is to improve hot (or cold - my old memory fails me) restarting. How could a defective solenoid cause a running engine to die (which is what originally happened)?
I am a mechanical engineer (a real one - not a "theoretical one"), meaning I have over 30 years of zero mechanics but me touching my cars (including timing belt replacements, clutch replacements and manual transmission rebuilds). I know how cars work and I know my way around a garage and tools, but I have never run across this problem before, and I need to get it fixed quickly.
I hope what I wrote makes sense. I would greatly appreciate any helpful advice.
2003 Protege5 with about 132k miles. Daughter called the other day, saying her CEL came on and her engine died. I told her to try to start it and get it home. She got it home ok.
CEL codes were P0090 and P0171. From a bunch of research, it seems it may be the fuel pressure regulator solenoid. Vacuum hoses to that part are in good shape, so I don't suspect a vacuum leak. I cleared the codes and ran it about 7 miles, and everything seemed fine. Then she then ran it a few more miles and the CEL came on again. Same codes.
Before buying a new FPR solenoid (about $65-75 new, or $22 for a fleabay used one), I will try to bypass it and see what happens. I simply bypassed the solenoid with a new vacuum line, leaving the solenoid electrical connector on it, but its 2 vacuum lines now go to the atmosphere.
If the CEL doesn't come back on, then that tells me that the solenoid is bad. But what if the CEL comes back on with the solenoid being bypassed? Possibly a bad electrical connection causing the CEL? Or something else?
The next thing I gather might be defective is the O2 sensor. Am I correct in that? My daughter is moving 2 hours away to med school in 1.5 weeks, and I really want to get this squared away before she leaves. I don't want to go needlessly "shotgunning" parts that won't fix the problem.
I have done a ton of research on this over the last few days, but most of it says the same thing - that a P0090 and P0171 indicate a bad FPR solenoid. What I don't understand is how an improper variation in fuel pressure (from a device intended to aid hot or cold starting) would cause both of these error codes. So that is why I am posting here. Has anyone ever dealt with this, or have a real understanding of the role the solenoid plays? If I take out the variance in fuel pressure by bypassing the solenoid, I don't see how it will affect how the engine runs, once it has started, seeing as how the purpose of the solenoid is to improve hot (or cold - my old memory fails me) restarting. How could a defective solenoid cause a running engine to die (which is what originally happened)?
I am a mechanical engineer (a real one - not a "theoretical one"), meaning I have over 30 years of zero mechanics but me touching my cars (including timing belt replacements, clutch replacements and manual transmission rebuilds). I know how cars work and I know my way around a garage and tools, but I have never run across this problem before, and I need to get it fixed quickly.
I hope what I wrote makes sense. I would greatly appreciate any helpful advice.
