Need high level techie

[2003dodgeman]

03 Caravan sport (3.3), getting 11 MPG city/16 HGWY (EPA=19/24). Figures hand calculated (no overhead console) over month. Calced with AC on/off, cruise on/off, maintained optimum speeds, no jump starts, no crazy driving, no loads except people (1 - 4). Issue first identified in Feb 04 by previous owner. NO codes, NO problems then. Just had state inspection/emissions, by dealer - NO codes, NO problems. Did a 'FLASH' of PCM. STILL GETTING 11 MPG. Tire pressure monitored, plugs, wires, O2 sensor, air filter, injectors, fuel leaks, brakes checked. Use 87 fuel. NO power loss, quick startup, smooth running, no smoke, no sputtering.
HELP!!!! Answer or point me to place to post question inside or outside this site. Thax

[shelbydodgeimp]

Hmm, you said the plugs were ok- but did they show any signs of running rich?

Could still be a faulty O2 sensor since they dont usually show codes until they're dead (and can be "out of range" and randomly stop working for months before they finally go...)

Since its running ok, we could prolly rule out the crank, cam and map sensors...

How's your TBPS sensor? coolant temp sender? thermostat?

[2003dodgeman]

Thanks for info. Can't do much work/checking myself, but trying to get direction to guide dealer. Van still under 3/36 warrenty, so can get them to test and swap out items.

Van was previously owned by employee of dealership and problem identified in Feb/04. I purchased in 9/05. In that span, problem was not identified or corrected and assume???? some of your specified items were checked, but I'll give everything a fresh look.

Van has been running very good. How does TBPS sensor, coolent temp sensor, thermostat effect MPG??

[shelbydodgeimp]

TBPS is used in the calculations the PCM does to determine how much fuel to use in your fuel curve. Its used with the MAP and RPM to determine, amoung other things- how much load is on the engine (more load means more fuel requirements).

Coolent temp sensor also gets tied into those calculations but I forget exactly how, dont believe its used in figuring out engine load...

'course I am assuming the 2003 PCM caculates fuel requirements the same way as a 1990-1993 era PCM would.

I dont suppose your in a state that does emission testing? Sometimes that can show if you're running really rich.

Alternatively I would be tempted to throw an A/F and EGT gauge on there but, that prolly wouldnt be allowed on a car still under warrenty (or would it?). A/F uses the O2 sensor's signal and displays what the O2 is reading and can help vissualize an extreme rich or lean condition, EGT uses the temp of the exhaust gases immediately leaving the engine to determine lean/rich conditions (lean = hotter), between the two you can figure out if its running rich. If it is- then you just have to figure out why. But if it isnt running rich, you're fuel use is going up for a different reason.

[shelbydodgeimp]

Stupid question: have they checked the engines internals yet? Like with a compression check?

How's the head gasket, valves, etc?

[2003dodgeman]

Live in PA, which has pretty extensive Emissions testing. Requires a seperate sticker on windshield. Even special gas formulas depending on time of year. Testing was done just last week and passed with flying colors. They are required to give written report, so have data if needed. As to engine internals, emissions test usually picks up problems. Had a bad cylinder in 97 van, Red flags all over the place. But will put on list to review. Main goal is to create a check list and then rule out each item one by one. The dealer will love me, but doesn't cost me anything except time and energy.

[shelbydodgeimp]

Wow, this is getting strange- with all the sensors good & passing emissions tests I am starting to wonder whats left that could be wrong.

If you passed the emissions your seals and valves are prolly good and your prolly not running rich.

Are the brakes sticking and making the engine work harder? How's the transmission and how it shifts?

[2003dodgeman]

Yes, is strange. At least when something wrong, can focus there and correct. Why it surprised me previous owner could not resolve anything, working at dealership. I know the possability exists that sensor(s) or something is bad and somehow not showing up on tests or codes. Thats why trying to get a list up of issue areas. At the same time emission test done, had PA state inspection. Any sticking brakes should have been picked up. I was thinking ABS system. Transmission seems find. There seems to be a few 'quirks' when going very slow, ready to stop. Sort of a lurch. And under some quick manuvers, seems rough shifting, but still trying to define that, because does not happen all the time.

[gas28man]

Aha! The infamous lurch from the tranny. I'd say you ought to have the tranny checked. Have them reflash the solenoid pack, or determine if the solenoid pack should be replaced. I'd also have the brakes looked at. If the vehicle sat for any length of time, rear brakes could have seized and will cause a drag on the vehicle. You wouldn't necessarily notice it because ABS masks the effect. But your front brakes will only last about 8,000 miles and will always be leaving copious amounts of dust on the wheels.

Good luck.

Rick

[2003dodgeman]

Thanks for the tips. trans and brakes definately at top of look at things. From reading responses, getting things in a 'pecking' order. Trans, brakes, O2 sensor and PCM are the biggies. Dealer did a flash of the PCM last week (no MPG change), but not focused towards any mechincal issue, just complaint of poor Mileage. In my mind with its limited knowledge, was leaning towards trans and PCM. Hope to get it back to dealer next week for second go around. Keep ideas coming. Will follow up with results

[2003dodgeman]

UPDATE (Still unresolved). Going back and forth with Dealer(s) on milage issue (11MPG city). Won't or can't define problem - NO CODES. They can not justify
swapping' out parts to resolve problem. Faulty O2 sensor?, TBPS sensor?, bad PCM? (Previously flashed in Sept), Etc. Can do it at cost to me, but car still under warranty. As previously stated NO emission issues or performance issues. Are there specific tests (other than PCM) that can be run on specific sensors/ equipment, in line , to determine if faulty??

[05es]

once i had a older gm truck that had simmilar issues with milage much lower than it should be,well to make a long story short it was a restricted exhaust flow... it showed every thing normal till there was a load placed on it... my opinion i would check the air inlet tract for restrictions and also exhaust... seen people back into parking spots and bend tail pipes,actually kinking them only to reach down and pull it back,slap there hands together thinking they just fixed it when actually just adding another kink to the pipe... good luck ...

[Chet42]

Sometimes a weak torque convertor will cause this problem, the engine has to work harder to keep the vehicle rolling, all the while the convertor is slipping, you don't feel anything different but the problem is present. You may have to press on the acclerator just a bit harder to compensate for the slippage. A good tech can detect this problem with a good test run. Find yourself and old timer not a button pusher and have them look at it.

Chet.

[CBP ENGINEER]

What about speedometer calibration? You can check this by traveling several miles on an interstate and checking the mile marker posts against your odometer. This is a long shot because your mpg is about half of what it should be, that would mean your odometer would be ticking off miles at about twice the actual rate. Actually, make sure your odometer isn't recording kilometers, that would definately throw off your mpg calculations. If that is the case, you bought a van with a heck of a lot less miles than you thought.

I just checked the conversion. 1 mi = 1.61 km.

If your odometer is showing kilometers, then your mpg of 11/16 mpg would actually be 17.7/25.8 mpg, which is on par with the EPA ratings.

[MYCVIL]

I think you need to reverse that - If it were registering Kilometers, his odometer would read high each go - which would mean more "Miles" per gallon than actual miles travelled.

If it read KM instead of miles, his actual would go down to more like... 7/9 mpg... - Ouch...

Overall, I like the exhaust restriction suggestion, Leadfooting it could bring it down - My Highway drops down to 16ish if I have it out of overdrive running 75-80MPH.

It is shifting through all the gears, correct? - What RPMS when crusing around 55 - should be around 1500-1700 - If it's up in the 2000's it's either slipping, or the OD/3 selector is in the wrong place...

Extreme cold drops it all down pretty well - It is a 2WD correct? - Does it have a trip computer - what does that read for MPG - is it way off as well, or does it read the same as your manual method (Plus or minus 10-15%)...

Any accessories on it - Luggage carrier (box) on the top, added weight inside, etc.

Correct tires for it correct (OEM?)

Alignment is good?

Good luck!
Billy

[CBP ENGINEER]

I think you need to reverse that - If it were registering Kilometers, his odometer would read high each go - which would mean more "Miles" per gallon than actual miles travelled.


:whackit: Yes, I flipped my units around. I've been in a fog today due to a cold. I would still check the odometer calibration against mile markers on an interstate. A change in tire size as MYCIVIL noted would affect the calibration. As a comparison, I get 19 - 24 mpg in my 97 Caravan with the 3.3L. Let us know if you get this worked out.

[2003dodgeman]

Thanks All. Alot of good ideas which I will check out. Main issue (with dealers) has been NO CODE -- NO PROBLEM. Can't get anyone to dig into it, unless they are punching a computer. I can get non-dealer guys (some old timers) to look at, but will be out of pocket expense for me. Feel I have identified a warrenty problem, and should be looked at beyond a computer. Live in PA with extensive emissions requirements. I meet all with flying colors. Not sure if restricted exhaust flow would effect? Will check torque converter. Anyway to test, beyond 'feel'? Think speedometer calibration ok. PA Inspection requires calibrated correctly (but will test tonight on way home). Don't lead foot and Trans seems to shift ok and though all gears (see previous comments). Can't monitor Rpm's. Van is 2WD. Problem occurring in Sept (70-80's) so temp does not appear to be issure. Van still has factory tires. Alot of stuff I tested originally. Tire pressure, a/c on/off. weight. Just had it to dealer Mon for 24,000 maintenance - great shape

[gas28man]

Do you live in an area where another dealer is not too far away? You know any Chrysler or Dodge dealer will service any Chrysler or Dodge vehicle. In fact, some real enterprising dealership service departments have begun servicing cars from ALL manufacturers (not that that helps you with your warranty issue). If you have been having problems getting satisfaction from one dealer, I strongly advise taking it to another one. And be vocal about it too. Send a correspondence to the place you gave up on, as well as higher up the corporate food chain, letting them know of your dissatisfaction.

You definitely do have a problem somewhere. That mileage is just wrong. My 96 3.8 T&C has gotten 19 city/24 hiway/21 combined throughout its 316,000 miles.

Good luck, and keep us posted on your progress.

Rick

[2003dodgeman]

Live in area with alot of dealers. On my second '5 star' dealership, which I thought would make a difference - NOT, plus original owner worked at dealership. So far three 'expert' orginizations can't resolve problem. Getting ready to start on 4th - calling - interviewing. Taking approach to have them check a specific item, which they don't like to do without a specific problem, instead of defining general MPG problem. Just need to find a guru. Gets me back to original question. If I wanted, lets say to test O2 sensor, is there a specific test to do that, even with no code. They will not just swap out an item. If any dealers in Phila PA area reading this and can resolve, I'll be at your door

[CBP ENGINEER]

If you go to a mechanic with a good quality code scanner, he can check individual components while operating the vehicle. For example, he can look at the voltage output by the O2 sensor. If he knows the correct range of the voltage for the sensor, he can tell if it is working properly. Even some "shade tree, old timer" mechanics have these scanners. You might be able to get one to spend some time testing your van.

Are you still checking your fuel mileage? You noted that the poor mileage occured in September, but is it still so low?

[2003dodgeman]

I would have firgured the dealer(s) would have a quality code scanner and when don't find any computer codes take 'the next step', which they have not. I'm looking. In Sept dealer did a 'flash' on PCM. MPG went to a little over 13 for about two weeks then dropped back to 11. I check at every fill up. MPG has consistently been 11.x every week, since late sept. Weather does not seem to be a factor. December was very cold here and January was very warm, but no changes in MPG

[CBP ENGINEER]

How about the air filter? Has it been replaced recently? Check to make sure the inlet is not plugged and that there are not restrictions in any of the tubing. If the van seems to be running correctly, it may be some type of mechanincal problem rather than an electronic part.

At 11 mpg, if it takes 18 gallons to fill a nearly empty tank, you should only be getting about 200 miles out of each tankful. Just a check to make sure your mpg calculations are correct.

[2003dodgeman]

Air Filter was just changed Mon, at 24,000 mile maint service. Filled up yesterday, approx 16 gallons and total milage between fill ups was less than 200. Did calculation and MPG came in at 11.743 MPG. There may be some restrictions or mechnical issures, but car runs and performs very well

[CBP ENGINEER]

You may have already seen this thread, but I found this to be interesting reading: http://www.dodgetalk.com/forums/showthread.php?t=25317&highlight=mileage

Where do you drive? You mentioned being near Philly, so is most of your driving inner city with a lot of stop and go traffic? Also wondering if you've checked mileage on long trips, several hundred miles at sustained highway speeds. Your fuel mileage does seem low, but if you don't have performance problems and it is passing the emissions tests, there may not be a problem with the vehicle. It could be long periods of idling, such as warming up the vehicle when it is cold or letting it run when you go into the store.

[gas28man]

In answer to your question about testing individual components/sensors, I have seen the Chrysler factory manual for my van, and yes, there are specific instructions in it on how to test each individual sensor and component on the vehicle, right down to the accepted ranges of voltage, impedence, or whatever the component needs to operate.

Your problem is finding someone willing to test these components. It is time-consuming, and the dealership's service department is under time pressure from the bosses to keep margins up and costs down, so they're more inclined to replace the part than pull it and bench-test it, or whatever.

I'd say a phone call or some other correspondence to regional service management is in order here. Tell them your story and see if they can't put pressure on one of the dealers in your area to spend some time with your vehicle and get it right. I would also ask them what their policies are if you take your vehicle to a Certified, but non-Chrysler repair shop (i.e. your local mechanic). Will they reimburse you if you have to put out money for someone else to diagnose what their guys can't.

What you have here is what mechanics call a "driveability" issue, and short of the engine control module itself, I can't think of a single component in the driveability system that would cause your poor mileage, not throw a code, and cost over $200 to replace. You might just want to bite the bullet to have done with the whole issue.

Good luck, and keep us posted on your progress.

Rick

[2003dodgeman]

As said earlier, tested most 'driving issues' up front. Turned off when not in use, etc. Do city driving, but still should be in 14-16 range. On long trip, with cruise control getting 17MPG.

Rick - I can see your point. I will try checking into regional management and see what they say and may end up biting the bullet. Just irks me. Would think with the GM issues would want to keep customers happy, before I drive my Dodge to the Toyota dealer

[ade]

unless i missed it,,,,what is your rpm`s at 55mph??? and also going at that speed when you lightly touch the gas pedal, does your torque converter temporaily dissengage and then quickly lock back up???11mpgs are way to low, even if all city driving.

[CBP ENGINEER]

). Don't lead foot and Trans seems to shift ok and though all gears (see previous comments). Can't monitor Rpm's. Unfortunately I don't think he has a tach. If he can get someone with a good code scanner to take it for a test drive, they should be able to monitor rpm's, transmission, and emissions components. My bet is on the O2 sensor(s) not working correctly, even though it/they aren't throwing a code. At 11 mpg, that is a lot of excess money going towards gas.

[2003dodgeman]

Car is not equipped with RPM guage. Car seems to run smoothly, What would torque converter slipping/disengaging feel like. In process of trying to work things out with dealer, for extensive testing.

[CBP ENGINEER]

Torque converter disengaging/engaging would basically feel like it is shifting gears. If it is slipping, it would seem like the engine is revving without accelerating quickly. Without being able to monitor your rpm's, it is difficult to check this out on your vehicle, especially since you indicate it is running fairly well. You may have some slippage, but probably not that you can tell with the "seat of the pants". Hope you can work things out to get it tested by the dealer. That will be your best solution. Keep us posted, especially if you get it fixed.