Poor Fuel Economy

[baloneyhomie]

Hi everyone, I've had an account here since I purchased my Marauder back in January.(I'm not much of a message forum guy, I usually stick to the /r/Crownvictoria subreddit), I have a question that I feel y'all would be more qualified in helping me out with. To start, this is a 2003 Marauder that I purchased with only 35k miles, and have put about 2.5k on, it is now at 38,7xx miles. As far as aftermarket parts goes, I have not put anything on since I purchased it although it does have a Reinhart performance chip, an electric water pump, and underdrive pulleys. Now, I always get 10MPG in my town no matter how I drive it, whether or not I have the performance chip "on" or off (in my specific car the previous owner had set up a rotary dial that allows me to switch to and from the performance mode to what I assume is the stock tune, and a valet mode. The blank selections act as a kill switch of sorts, but I digress). The only time I get even above 12MPG is when some of my driving is on the highway, but I rarely ever get on a controlled access road like that. I have checked the tire pressure and all four are at the recommended PSI, I have changed the oil as of 2 days ago (not sure if that could affect it but worth listing I figure), the transmission fluid is in good shape, but I routinely get 200 miles or so out of every tank (I usually fill up when the fuel light comes on because I hate taking chances with gas, even if I'm in a pretty urban area) even if I have the performance tune selected the entire time, or the stock grandma tune selected. I really cannot think of any way that the only other thing that might affect the fuel economy (the underdrive pulleys) could affect it so much so as to bring it down to barely double digits. For context, I live in Georgia and my area is basically a pancake besides some very soft/rolling hills. It's not really stop and go hence my usage of town instead of city. If anyone has any suggestions, please put em down below. I can survive with 10 MPG since I don't drive often but if there's an anomaly on this car then I'd like to get that fixed or looked at if it's out of my area of expertise. I can provide pictures of stuff if needed, please just give me the word. Thanks.

[gdmjoe]

Given that the advertised fuel mileage is 17/23 (city/highway) IMO you have a DEFINITE ANOMALY. *Especially with the minimal mod's that you have.
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[baloneyhomie]

Given that the advertised fuel mileage is 17/23 (city/highway) IMO you have a DEFINITE ANOMALY. *Especially with the minimal mod's that you have.
.
Indeed. I can send the link to the BaT auction if that'd help.

[RubberCtyRauder]

Get rid of the Rheinhart crap. You live in GA. See Marty Ochs, Mo's Speed Shop, Dallas, GA for a real tune.

[baloneyhomie]

Get rid of the Rheinhart crap. You live in GA. See Marty Ochs, Mo's Speed Shop, Dallas, GA for a real tune.
About an hour drive from where I live. I'll try and put some time aside to give them a visit this weekend. That being said, what's the issue with the Reinhart tune, or is it more of the fact that Mo's Speed Shop is just better?

[blazen71]

Get rid of the Rheinhart crap. You live in GA. See Marty Ochs, Mo's Speed Shop, Dallas, GA for a real tune.

I agree. Marty will get your car straightened out.

[blazen71]

About an hour drive from where I live. I'll try and put some time aside to give them a visit this weekend. That being said, what's the issue with the Reinhart tune, or is it more of the fact that Mo's Speed Shop is just better?
Reinhart was known to many as a hack and a crook. I personally never dealt with him.

[baloneyhomie]

Reinhart was known to many as a hack and a crook. I personally never dealt with him.
Too bad. Either way, I’ll head over there ASAP and see if Marty can fix me up.

[baloneyhomie]

I agree. Marty will get your car straightened out.
Thanks for the help. Will do. I’ll still keep an eye on this thread in case anyone else has any ideas though.

[RubberCtyRauder]

Send me a pm, I'll give you Marty's phone..best to call him, it's a busy shop

[baloneyhomie]

Send me a pm, I'll give you Marty's phone..best to call him, it's a busy shop

I sent you a PM although I am unsure it went through - thanks for the help.

[RubberCtyRauder]

Pm received and replied..You have to change your message sent preferences for them to be saved.

[Ken]

Let us know what he finds. My mileage generally suffers due to my heavy foot, but my MPG is still generally double your results.

[baloneyhomie]

I'm pretty positive it was actually the damn tune. Although the fuel gauge isn't really accurate, I've driven her enough to know that I usually get to 50 miles every quarter tank. I took off the tune (It was a weird one that connected to the serial port inside the EEC rather than programmed through the OBDII port. I forget this thing is 17 years old so the computers inside are ancient!) and topped of my tank. I've driven 20 miles already which normally the fuel gauge would be about between the 3/4 tank and full tank, but it's still on the full tank marker. I'm not totally sure, but honestly given how well taken care of this car was I couldn't find or think of any other reason why I got such *****y fuel economy. I'll try and attach an image of the chip and switch so y'all can see what I mean.
51121
51122

Going to get that Marty tune, methinks. The stock tune is so anemic. It appears the MPG issue was solved, from what I can tell based off the fuel gauge compared to my normal experience. Kinda pissed off I went through more fuel than I could have, but oh well. Thanks for all the help, guys.

[WhatsUpDOHC]

Love my MartyO tune with 410s. 4250 lb. car chirps 2nd.

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[Peace2Peep]

when you get that tune...lookout! the "Partay" will begin...it's a better experience in EVERY manner!

[baloneyhomie]

when you get that tune...lookout! the "Partay" will begin...it's a better experience in EVERY manner!
How difference is the fuel economy with the tune or is it basically negligible? I assume I'll lose out on maybe 1 or 2 MPG but it's a far cry from the 10 MPG I was getting with that godawful Reinhart tune.

[MyBlackBeasts]

How difference is the fuel economy with the tune or is it basically negligible? I assume I'll lose out on maybe 1 or 2 MPG but it's a far cry from the 10 MPG I was getting with that godawful Reinhart tune.

It will go up from what you currently have.

OEM with Lidio tune = 22mpg
Add 410s = 20.5mpg (and well worth it!!)
Add Trilogy with canned Trilogy tune at 350 RWHP = 24mpg
Add Martyo dyno tune, 17* timing, 409 RWHP = 17mpg
Add my custom designed exhaust fabbed by Red at Martyo's with new dyno tune, 14* timing, 436 RWHP = 20mpg (16* timing shot it to 463 RWHP so Jeff had to dial it back as still OEM block internals)

So, ya, you can do better.

Good luck!

[Peace2Peep]

Not totally sure in your specific case, but with the 4.10's and the tune you should be even or just 1-2 loss from normal. Normal for me was 21mpg

[Mebot]

Complaining about mpg with a Marauder is silly. We all know what we were getting into when we purchased this vehicle. We made our bed, we'll sleep in it.

However... complaining about mpg with a valid reason is completely different. As GDMJOE said.. It's an anomaly.

Even with a crappy supercharger or elite amp/sound system, No Marauder should be under 17 mpg. Are the fuel lines clear? Tank empty of debris? Saw another thread (not here on this forum and not a Marauder) that some guy got a leaf or something stuck in the tank and covered the flow from the fuel pump to the engine.

Now, how likely is that on your Marauder? I would venture slim to none. But can't rule out the outliers. One thing I've learned with ownership of this car is that SHE'LL fool you. I hope you figure out your gremlin

Also yes go to Marty for all things modification.

[Joe Walsh]

10 MPG average is horrible unless you drive WOT a majority of the time.
If not, the exhaust fumes would be awful at idle.

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[justbob]

Even with a crappy supercharger or elite amp/sound system, No Marauder should be under 17 mpg.

Step up to 80# injectors..!

This biotch can DRINK!


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[baloneyhomie]

Hey y'all, sorry it's been so long. I totally forget about this thread, but it's been several months that I've had my Marty tune and I absolutely love it. I manage 15 mpg in my area in most of my tanks, although I still get as low as 10 sometimes, but I suspect that's just from the geography.

All is good, and thank y'all for your suggestion of getting a Marty tune. He does good work, and my car feels so much faster.

Thinking of maybe sticking some 4.10s in it if the fuel eco wouldn't suffer too much. Thoughts?

[fastblackmerc]

Hey y'all, sorry it's been so long. I totally forget about this thread, but it's been several months that I've had my Marty tune and I absolutely love it. I manage 15 mpg in my area in most of my tanks, although I still get as low as 10 sometimes, but I suspect that's just from the geography.

All is good, and thank y'all for your suggestion of getting a Marty tune. He does good work, and my car feels so much faster.

Thinking of maybe sticking some 4.10s in it if the fuel eco wouldn't suffer too much. Thoughts?

You'll lose maybe 1 or 2 MPG. Well worth the 4.10's.

[Mr. Man]

If you are really getting 15 mpg's or lower in regular driving you still have a problem. Your profile says your MM is NA. I'd take the car to Mo's and have them go over it to find out why your mpg's are so bad. You should be getting low to mid 20mpg's.

[baloneyhomie]

If you are really getting 15 mpg's or lower in regular driving you still have a problem. Your profile says your MM is NA. I'd take the car to Mo's and have them go over it to find out why your mpg's are so bad. You should be getting low to mid 20mpg's.

It's effectively stock. I assumed 15 was normal for NA but I guess not. My old '09 SAP CVPI with 3.27s managed a solid 20-25 in my town.

Luckily I live about an hour away from Mo's; I assume I just gotta give his shop the call and let him know what's up?

Now I'm getting a bit worried, considering how good of shape this particular car is in :P

[baloneyhomie]

You'll lose maybe 1 or 2 MPG. Well worth the 4.10's.

I'll put them on the list, in that case.

[blazen71]

My first Marauder was stock when I bought it. My first mod was 4.10's and a tune. Best bang for the buck!

[RubberCtyRauder]

How are you calculating fuel mileage? Are your rear tires factory size?

[baloneyhomie]

How are you calculating fuel mileage? Are your rear tires factory size?

Dividing the miles driven on the trip odometer (reset it every tank) by the gas pumped into the car next time I fill up. I got 12ish MPG on my last tank. Tires are factory size.

[Mr. Man]

It's effectively stock. I assumed 15 was normal for NA but I guess not. My old '09 SAP CVPI with 3.27s managed a solid 20-25 in my town.

Luckily I live about an hour away from Mo's; I assume I just gotta give his shop the call and let him know what's up?

Now I'm getting a bit worried, considering how good of shape this particular car is in :PMake the call to Mo's. I'm getting 24-5mpg on the freeway and 19-21mpg putting around town. Be interested to hear why your mileage is so bad. I'm making an assumption you are not wide open everywhere you go.

[baloneyhomie]

Make the call to Mo's. I'm getting 24-5mpg on the freeway and 19-21mpg putting around town. Be interested to hear why your mileage is so bad. I'm making an assumption you are not wide open everywhere you go.

Nope. I went a full tank going full grandpa-light-on-the-pedal once or twice and still only managed 15. I drive it mildly spirited and I still (sometimes) get as low as 10. Usually 12-15 though.

Who would have thought this thing managed the same fuel economy of my three ton hightop Chevy conversion van with the 350.

No worries though, I’ll shoot Marty a call once I’m free this afternoon.

[burt ragio]

No way should you be getting such poor gas mileage. I would be very curious to hear what Marty finds. I am guessing if you are calculating your mileage correctly I would check: brakes possible bad calipers. Pull all spark plugs they will give you a world of info. Maybe your injectors are leaking, bad or wrong stall speed converter or maybe cams have been advanced either way your car will be in the best of hands.

[baloneyhomie]

No way should you be getting such poor gas mileage. I would be very curious to hear what Marty finds. I am guessing if you are calculating your mileage correctly I would check: brakes possible bad calipers. Pull all spark plugs they will give you a world of info. Maybe your injectors are leaking, bad or wrong stall speed converter or maybe cams have been advanced either way your car will be in the best of hands.

Just checked the plugs in fact. They look good, ditto for the coils. I have yet to service the brakes or calipers since my purchase of it last year although it doesn’t feel like anything is wrong on the brake side of things.

I gave him a call and left a voice message and let him know what’s up. Will update y’all accordingly.

[justbob]

Probably just some lazy oxygen sensors.

But don’t believe every claim you here. When mine was first purchased the best I could get was 21.5. This was zero traffic, speed limit 45 for five miles, then expressway for fifteen, and finally another fifteen or so of country roads at 55 with maybe four stop signs so definitely not city but a mixture nonetheless.

Then I put on the Trilogy I used to have and mileage actually went up one from tuning I suppose.

Finally a best ever of 23.5 once I had a dyno session and custom tune.

It’s been a long road down to single digits since. [emoji16]


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[baloneyhomie]

It's entirely possible you are right - I'm also a stubborn fella and I would really like to think I could squeeze more MPGs out of this 2 ton hunk of steel.


At worst, I'll be tuning up the crap outta this car, so maybe not a complete fool's errand. :P

[baloneyhomie]

I spoke to Marty a week ago and he suggested some stuff. I've already done the first two suggestions, and the third was swap the fuel filter. (The filter on my car is 5 years old)

The filter only has 5kish miles on it, but it's an 8 dollar part from Rockauto and OEM so worth a shot. I hope to replace it and maybe even crack open the old one and see how it looks. Will update more, thanks y'all.

[Curless]

About an hour drive from where I live. I'll try and put some time aside to give them a visit this weekend. That being said, what's the issue with the Reinhart tune, or is it more of the fact that Mo's Speed Shop is just better?

Be sure to call first, don't just show up. Busy as hell shop, it's based on appointments not walk ins... it's not Autozone...

[baloneyhomie]

Yes I had figured after I sent my message that it's probably not a wise idea to show up without an appointment :P

No worries though