I’ll try to be brief, I don’t want to bore anybody, I just want some outside opinions on a course of action.
I am not knowledgeable about cars, though I am wishing I were about now. My Suzuki has been in and out of maybe 5 shops in attempts to fix engine codes P0171 (system lean) and P0174 (bank 1 rich). None of them have successfully done so. I tried to take it into a dealer, but I was informed that diagnostic would take several hours (maybe $1000), and that the fix may be another ~$1500-2000, even though I have already replaced many parts related to these codes.
The dealer advised me to give up on the car, as the repairs could easily exceed the value of the car. I don’t really care about that, I just need a reliable car that works (and an end to this headache.) So- my options are these two:
Repair the car and hope it doesn’t have a major issue again (estimate $2500 to repair). My car has 103000 miles on it and otherwise runs well.
Buy another car and hope that it is a reliable one. (Estimate spending $5500.) Oh- and trading in my old car ears me about $0.00, unless I include a tax break and a $300 restaurant coupon.
I don’t know how car talk works, but I would appreciate some advice.
Do you have emission testing where you live? there are many possibilities, some simple some complex. Some states if you spend x amount of dollars you are off the hook. If you like the car and feel it is viable transportation I do not like the dealer estimate for analysis, so certainly go to a reputable local mechanic and get a second, or another reputable mechanic and 3rd opinion. It probably has to do with a manifold or vacuum, and the right guy can fix it for less than the dealer analysis I think, When you get the guy that says oh yeah I know what this is, go with it!
The two codes you are having are usually caused by an air leak between the air filter and the throttle body. It could also be the result of a defective intake manifold gasket. If you are getting both codes at the same time, then I’m leaning to the gasket as the unaccounted air would be getting to only one or two cylinders causing them to run lean (P0171) and the others to run rich (P0174).
A leaking intake manifold gasket usually causes the idle to be 950 or higher when the normal is 750.
Both are lean faults. The first step is to review the freeze frame data and the fuel trim values. You may not have the data or a scan tool to provide the information so you will just get wild guesses.
BTW the dealer is telling you your car is not welcome there, they don’t charge everybody $1000 for diagnoses. They probably have had bad experiences with Daewoo vehicles and too many abandon on the lot.
there are many things which can cause lean codes, besides obvious leaks such as that torn intake boot and leaking intake gaskets
Exhaust leaks ahead of the upstream oxygen sensor can and do cause lean codes
low fuel pressure can and does cause lean codes . . . and the engine often seems to run beautifully, but the fuel trims are essentially pegged
leaking intake gaskets do not always cause high idle. In fact, all of the flat intake gaskets I’ve replaced recently did lead to P0171 and P0174, but the idle was perfect
I think whoever’s been “diagnosing” this vehicle doesn’t know where to start, or they’re not going about it in a logical and systematic fashion. Maybe they don’t even have a fuel pressure test kit or an evap/smoke machine. If you don’t have the proper tools and/or knowledge, you shouldn’t be charging money to attempt to diagnose vehicles. That’s my opinion, FWIW
It’s even possible that whoever’s been taking money to diagnose this car has been blatantly guessing, and there never was any diagnosis of any kind
there are shops that specialize in “hard to fix” cars such as this. They even seek out that kind of work. I don’t know if there’s such a place in your area, but I’ll bet for such a guy, it wouldn’t be a hair-pulling experience. In many cases, those guys are not really smarter than the guys who unsucessfully tried to fix the car. But they have a more efficient and approach. That’s why they succeed, where the others failed
But my gut feeling is that there was incompetence, laziness, etc. at play when they took your money and didn’t fix anything
Thank you everybody for your helpful advice. It has given me a bit of stuff to think about.
@Barkydog I do have emission testing places nearby. My car will automatically fail, as I have been informed, due to my check engine light. Unfortunately for me, I moved to CA with this car and was about to get it registered with CA when the light came on. This mean I am not really eligible for their $650 repair check engine light waiver. I just wish I could find that ‘right guy’ without the $120 diagnosis each time.
@keith My car idles at about 1000 rpm, so maybe I could look into the manifold gasket.
@Nevada_545 You know, now that you mention it, you are probably right. The dealer probably did not want to deal with my car
@db4690 My car does run fine. It maybe accelerates a little more slowly than newer cars (unless I force it). The car has been to… 4 different places. 2 of them were definitely kind of guessing, and one of those two even returned a portion of the money I spent there. Do you have any additional information about those shops that specialize in “hard to fix” cars? I’d really like to give that a try. If not, I’ll try searching online.
Thanks again for the advice. If any of you are even vaguely interested, I’ll give a list of the parts that have been replaced/cleaned in attempts to fix the car.
To everybody who helped answer this question, thank you. The problem was fixed several days ago after I found the right mechanic. It was an air leak behind the engine. Why other mechanics could not spot it… I have no idea why. It was not exactly a quiet leak.
Sounds like you’ve found a shop that deserves your business… and your recommendations. A dozen doughnuts some morning for the mechanics to chow down on might be a nice touch too.
