I’ve tried to reply via my email, but I get this message:
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Does anyone know what is going wrong? I didn’t inlude any “embedded media item” !
I am going to try posting directly here, the messages that “didn’t work”:
Sorry I have been so long in responding. I wrote this entry a couple weeks ago, but it got rejected for some reason and never posted. So I am posting it again. Van is running the same. Same P0171 code, same 9.3 miles to the gallon driving in town (! – it should get perhaps 15 or 16 in town; it used to get about 13 before these problems cropped up):
I did a little more reading, this time about vapor lock. Found this on some random car site:
"
Since vapor lock has to do with high heat impacting the fuel system, one of the quickest tips that you can use to eliminate the vapor lock immediately is cooling down the fuel system.
What you can do is you can turn off the ignition switch and pour some cold water over the fuel pump and around the fuel lines. This way, the temperature will drop significantly, and the vaporized fuel will convert into the liquid back, illuminating the vapor lock.
"
Is there a good way to test for vapor lock by cooling down the fuel system? Suppose the next time the van won’t start at the grocery store parking lot, I go in and buy some ice and somehow use it to cool the fuel line? Anybody ever done this? Where would I put the ice and how to keep it there?
Also, if this were to be the problem, why would vapor lock not occur while the van is running? When testing the car after replacing the Crank Positon Sensor, I ran the car at idle, going nowhere, for maybe 20 minutes. So there was none of the “air cooling when running” going on, but the engine did not quit. So it is not a problem of heat gradually reaching ?the fuel line? or some other part when the car is stopped, it would seem? Or is vapor lock something that happens easier when the car has been off for 10 minutes, not due to extra heat building up, but due to a lack of flow or something? That might make sense; when running the fuel can’t overheat in the line or other fuel processes, because it is flowing, whereas when the car is stopped the fuel is not moving… But it still seems strange that it would take10 minutes for the fuel to lock up… or does that also make sense?
Thanks again.
Success! it seems to have posted! I don’t know what was wrong (maybe something hidden in the quoted part, above?). Here is another post that failed to post:
As I noted in my post a moment ago, the van only gets about 9.5 miles to gallon in town. WAY lower than it should. On the freeway it seems to do pretty well; a 4 hour freeway trip will raise the average up to about 16, and might raise it further if I had occasion to do more solid freeway driving…
I wonder if this might be a major clue? Is the computer failing to make the proper adjustments so that the van can get good mileage in town? Perhaps it is “stuck” at some adjustment all the time that happens to be good for highway driving and not good for stop and go city driving?
Appreciate any thoughtful thoughts.
A new sympton; the Brake Light comes on and turns off, somewhat randomly. It may come on when I make a right hand turn, more often than otherwise, and may turn off when I make a left hand turn, more often than otherwise. It made me wonder whether the TIPM was bad, but when I look up the symptoms of a bad TIPM, this does not seem to be among them.
Those symptoms indicate you are low on brake fluid, check and fill the brake fluid reservoir.
This is another of those threads that I just do not understand . As long as this vehicle has had problems and no solution in sight why not have a good independent fix it . I just would not want to go this long and run the risk of it failing to start in a not so safe area.
Vapor lock does not happen on fuel injected engines.
Residual Fuel Pressure Test
When the pump is turned off or stops running, the system should hold residual pressure for several minutes (look up the specs to see how much pressure drop is allowed over a given period of time). If pressure drops quickly, the vehicle may have a leaky fuel line, a leaky fuel pump check valve, a leaky fuel pressure regulator or one or more leaky fuel injectors. Low residual fuel pressure can cause hard starting and vapor lock during hot weather.
Tester
Hard starting, a fuel system lean fault and fuel economy display miscalculation, the fuel pump is failing.
I stand by my statement. Fuel injected cars don’t vapor lock.
If the residual pressure was low, the in tank or near tank high pressure fuel pump’s 40 to 60 psi will push the vapor right out the pressure regulator and back to the tank and through the injectors to purge the vapor with nice cool fuel. On returnless systems cranking will purge it through the injectors.
If anyone can describe how a modern injection system can vapor lock, I’d be interested to read how.
Tester
My sense, from reading and thinking about this, is I think the fuel pump (or regulator, which is part of the fuel pump in this vehicle) is most likely the culprit. I should clarify, though, that the fuel economy display is not “miscalculating”; the vehicle is REALLY getting very poor mileage.
I wonder if anyone can say whether a weak fuel pump would cause this poor-fuel-economy-in-city-driving effect, with a concurrent condition of still-pretty-good-or-maybe-even-just-dandy-fuel-economy-effect-in-highway-driving effect? Does good city fuel economy require higher fuel pressure, while highway does not?
I was researching this very question for an hour or two last night; I found the middle reference you offer. I concur that vapor lock CAN occur in a fuel-injected vehicle.
I do think it is interesting to note that the problem is still occurring now that the daytime temperatures here in Portland, OR are in the fifties… it happened yesterday at the Grocery Store, and it was already dark; the temperature was probably in the forties Fahrenheit.
Does this negate the possibility of vapor lock? I think not, because if the fuel pressure is low, then (??) this (?) means (?) that the fuel is more likely to vaporize (?).
What do you think?
I bought a pressure test kit at Harbor Freight weeks ago, but this vehicle does not have a schraeder valve, so one would need to get in and remove a section of the fuel line and put in a hose with a “T” in it to accomodate the tester. Looking at the engine, this is not even as semi-easy as it sounds. To get at both ends of the final section of fuel line will entail removing some other things. And it is cold out, I don’t have a garage, and I am intimidated by cold. Perhaps I will do it anyhow, but I am trying to do all the narrowing down I can via logic and research before spending several hours testing the fuel pressure.
I don’t have extra money for someone else to play around with. As for “failing to start in a not so safe area.” –
Last night I was listening to both the radio and the CD player (integrated in the original radio unit that came with the van). Listened to the CD even for 20 seconds after I stopped the van upon arriving home.
Today, the radio unit lit up and displayed radio stations, and displayed CD tracks that were “playing” and ejected and re-accepted the same CD. But there was NO SOUND.
After I spent 90 minutes at the gym, though, it worked fine.
I don’t know what this means, but it makes me again wonder (along with the Brake Light coming on unexpectedly a lot of the time lately), whether there might be a problem with the TIPM.
Any thoughts about this line of inquiry are most welcome.
I thought it was fine a few weeks ago, so I just assumed it still was… not a good assumption. I just looked and it is just barely below the MIN fill line.
So that should take care of the Brake light issue…
Thank you!
Do you refill the tank after city and highway driving, then calculate the fuel economy?
Yes. I go whole tanks that are 95% city. And I need to refill 20 gallons after about 200 to 220 miles. So, yes, it is getting terrible mileage. It was better a year to a year-and-a-half ago, when I had first bought the van, used. It has about 150,000 miles now, bought at about 129,000.
Even when it got “better” city mileage, it was about 13 mpg. So it has never got the city mileage that it is claimed to get.
The highway mileage was also better awhile ago, but since I only do the Portland to Seattle trip occassionally, it is not clear what the actual mileage is. It raises up to about 15 or 16 mpg in that trip, NOW. BEFORE, it would raise up to about 18.5 during that trip. So is it getting poorer highway miles now, or is it just that the average is dragged down by the bad city mpg? I get the impression that the mpg calculation is referential to some recent period of driving, but I don’t know exactly how it is calculated… if I did know that, I could better estimate that a c t u a l highway mpg.
This vehicle has a 20-gallon fuel tank, refilling when “empty” would be 15 to 18 gallons.
If you have proven your fuel economy matches the vehicles display, you either understand basic mathematics or entered the miles/gallons into a calculator. How did you calculate the fuel economy?