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Tune-up on 3.8L

71K views 108 replies 38 participants last post by  fatalalbert 
#1 ·
I just did a tune-up on my 2003 and while the van only has 42k on it and was still running original plugs and wires, there's a noticeable difference in how the engine runs now compared to before. It's much smoother and I definitely feel more power. Also surprisingly it does not ping anymore. I though it was a bad egr valve or something. I guess not.
In any case. After failing to find a decent set of aftermarket ignition wire set, I decided to make my own. I ordered some Taylor Spiral Pro 8mm ignition wire in bulk, spark plug terminals, boots and wire separators. For spark plugs I decided to try out new Bosch +4 Fusion. I've had good results with the original +4, I figured why not, the price was the same for me either way. The original plugs were in pretty bad shape. Giant gaps and missing platinum on most of them.
The rear plugs were a bit of a pain to get to but I've got long skinny hands, so it only took me a few minutes to get them out.
Here are are a couple shots of the finished product. Hopefully this will cure my horrible gas mileage. Oxygen sensor is next, just have to get a good scan of it to make sure whether it's working properly or not and if not, it's still under the factory warranty ( whatever it's good for now).





Alex...
 
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#3 ·
Very wrong plugs. Chrysler and Champion developed a dual plat plug for this application and I highly recommend that specific plug in this application. The Bosch plugs are only plat on one side of the spark. Remember, the 3.8 fires from center electrode to ground in one plug and then from ground to center electrode on the consecutive firing plug.
 
#5 ·
Actually...

I just put in new plugs and wires in my own Chrysler Corporation 3.8L EGH V6 that's sitting in my Town & Country and I did NOT put in Champion Dual-Platinum plugs. Squawk as everyone might, I did NOT just put in the Bosch Platinum +4™ plugs that are really popular... I put a set of Bosch Platinum Iridium Fusion™ plugs along with Bosch Ultra-Premium 7mm Opti-Layer Mag Core wires. I've since put several thousand miles on that engine and it has run beautifully. I've gotten great fuel economy... runs smoother than it did before.

About a month ago, I took a look at the plugs and they look absolutely fine.

I agree that the OEM equipment is CHAMPION... and that you really should go with OEM in most cases, but that doesn't mean ALL cases.
 
#4 ·
amelnik, GREAT Wiring Job :thumb:

Looks like you've found your nich
:lol:

Seriously, though. Wiring is GREAT. :headbange

Other side of the coin, As was mentioned by Richard Certain plugs actually detract from engine performance, with these engines. Don't have any recommendations, myself, except to "search" the threads on the forum and you'll find several dedicated to plugs and which ones work well, etc.

Best wishes.
 
#6 ·
I though it was a bad egr valve or something. I guess not.
Looking at the photos, I can see that your engine does not have an EGR valve.
 
#7 ·
amelnik, Looks like you've opened up one of those proverbial "Can o' Worms". Another one is "OIL" preference, but most seem to agree on a small number of oil filters. Just avoid the discussion of air filters, though.
:lol:
 
#8 ·
LOL, thanks guys. Yes, I went with +4 fusion because I had reservations about the waste spark on these engines. I guess we'll see how it turns out. So far, the engine is running much, much smoother. I guess I will also not mention that I also put a drop in K&N filter. :eek:
It's funny but I've been on turbo dodge forums, subaru wrx forums and now this forum and there's always "fights" over the same exact issues, oil filter, air filter, spark plugs and oil.
I know that a properly matched Bosch +4 worked great on my old 2.2L turbo engines making over 350hp, and those have waste spark as well, though not as advanced as the new generation ignition Chrysler is using on our cars.
I've been driving around town for the past 2 weeks and my overhead console was showing 13.9 mpg average. Also I've not seen my average go over 15.5mpg on highway as well. I really hope that new plugs and wires fix that.

Alex...
 
#10 ·
I'll also not mention that I put in K&N filters in all my vehciles............anyhow, I've been getting low number milage myself. After reading your post, Im contemplating doing a plug change, even though its only at 33300. We're goin to NC in a month and I would really like to get my max milage up past 18 by then.
 
#16 ·
Not really considering I get considerably better economy than he is getting... actually MUCH better economy... and I am running Bosch plugs/wires and have a K&N filter in both Town & Country's.

If I was getting economy like what he's getting on that 2003... I'd be driving around an older 4-cyl Dodge Avenger.
 
#18 ·
SEARCH the threads on spark plugs (plugs), and consider the fact many here on the Forum (by trial and error - others by dumb luck) have found some plugs that actually get poor gas mileage in these engines. Not sure why, but they do, in contrast, some have been found to get very good gas mileage. :blink:
 
#59 ·
I was wondering if perhaps someone could point more specifically where to look to find the threads discussing this. A simple search of plugs yields upwards of 500 results. I'm very happy taking the answer of just sticking with the stock Champion plugs, and that's what I did when I changed mine. But I would like to read more on it.
 
#21 ·
of course you all should know this, but another tip for highway driving is to draft the person in front of you. Bigger vehicle out front, better for you. Although, I stay far away from semi's, feels like Im gettn beat around with a rag doll being behind one and Ive been nearly ran off the road multiple times being beside them. I usually try to draft as much as possible, but doin so can be hard to use cruise.
 
#23 ·
Getting another 1/2 MPG is useless if somebody dies in the process. Being close enough to get a draft is being too close to allow for reaction time in case of an accident ahead. Be careful out there.
 
#26 ·
Actually, I think there are a few people who posted above you, including me who would agree with your "I'm not riding the persons ass!!!" comment" quite strongly!
 
#27 ·
Is this the mileage you report with the new wheels? If so are you adjusting your mileage for incorrect wheel diameter? for example, you are driving more miles than your odometer reports because of the larger wheels.

The AWD will get you every time. In our 04 Pacifica, we really had to work hard to get 15 mpg driving in town w/ the 3.5 L and AWD. Our 05 T&C gets 15+ easy and its a 3.8 and 2WD.
 
#30 ·
Nothing wrong with non-dual plat plugs, I just would be surprised if they lasted as long.
 
#31 ·
Update

Well I went for a 200 mile round trip today and I reset my trip compute to see what I get. I got up to 17.8 by the time I was heading back but I got stuck in an hour long stand still traffic and that was all she said.
Before my best was 15.5 on the highway. Looks like tune-up really did make a good difference. Now to see what my city driving looks like.
Also made a small aerodynamic mod today. I'm thinking it's good for may be 1/2 to 1 mpg. What do you guys think? (Sorry for crappy pics, only had my Blackberry with my and it was getting dark)











Alex...
 
#34 ·
I'm curious though, with that flare modification he made... at what point does it actually make a difference when the weight of the modification is considered? What I mean is... adding the flares might make the vehicle more aerodynamic, thus increasing fuel economy by "X" amount... but at the same time, the weight of the flares adds to the weight of the vehicle thus decreasing fuel economy by "Y" amount....

I'm just thinking about how you'd go about figuring out how such a modification would really be worth it or not....
 
#38 ·
funny how this thread went from tune ups to head light adjustment1
 
#41 ·
Alex....strange the mileage stayed the same.. but you did do a tune up too right?
Had an 86 Toyota 4x4. I put larger wheels on it so my overall diameter was larger. When I would take trips and see the mileage markers (the odometer checks) I came up a 10th of a mile short every mile. This was 10% off so I took 10% of my total miles for the tank and added that back to the total tank miles to do my calcs. Similar when I had a 64 VW bug in college. I lowered the front and put smaller tires on. On these same mileage checks, I would turn 1.1 miles when I traveled 1 mile, so I had to subtract out 10% of my miles for each tank.

Fixit
 
#42 ·
Well, it was hard to tell because it kept going down with old wheels and continued going down with new wheels and tires. I even smelled raw gas from exhaust after long trips.
It looks like the tune-up took care of all issues as I'm getting much better mileage now and I've not smelled gas from exhaust since the tune-up.

Alex...
 
#48 ·
I like your after burners.:blink:
 
#49 ·
2005 Grand Caravan XLT - 3.8 92,000 miles

Hello, I'm new to the forum and need some help. Not sure if this is the right forum but here goes.:hi2:

:help_wsig

As stated above, my Caravan has 92,000 miles and spark knocks like crazy. I haven't tuned the vehicle since it was new. I took it to a Goodyear service center and to a Dodge dealer for tune up pricing. Both places quoted over $400 to replace plugs and wires. Holy s**t; why so much?

What's involved in doing a tune up on a 05 V6? Do you have to change the plug wires? You can offer help here or PM me with suggestions and info.

I live in the Phoenix area and if there are any members here close by and can recommend someone to me would be most appreciated.

I use to be able to do things like this myself but now at 64 with so so eyes, I don't think I want to try this myself.
 
#50 ·
Does it set any codes. Personally I have not done it on the Vans, the Pacifica was a little tough but do able. The rear plugs may be a little tough to reach.

BTW.. the Volkswagen dealer wanted $495 to change a thermostat and temp sensor on my Jetta. Repairs can be very pricey these days.
 
#51 ·
That's a rip-off! I think they quote that much because the procedure calls for intake plenum removal and they quote it as a 3-4hr job. In reality you do not need to remove the intake, I didn't, though you will have to reach for the rear plugs. I think it took me about an hour to do my tune-up but that included cutting the wires to length, crimping the terminals and putting on the boots on and making it all look pretty.
I would recommend that you buy the plugs and wires yourself and have a local mechanic install it. If they charge you more than 1hr labor, then it's a rip-off. Also I would highly recommend that you run some injector cleaner through a couple of gas tanks. Chevron Techtron is the best out of all that I've tried over the years. Also change your air filter as well. The spark plugs will run you about $3 each and the ignition wire set will run you between $20 and $50 depending on the brand.

Alex...
 
#53 ·
A number of different factors have been mentioned such as: AWD (usually lose 1-2mpg), larger diameter tires/wheels (which would rotate less over a given distance as show up as mileage decrease). A couple of things really make the most difference, speed at which you drive, how you accelerate. The old adage that to drive like there is an egg between your foot and the accelerator is a good saying. Keeping good air pressure can be as or more important than anything else mentioned. I run 35psi. Tire composition, tread design make small difference also due to rolling resistance. You can also jack up your van and make sure you don't have a brake dragging a little too much. I have an 01 TC LXI with the 3.8 and I get an average of anywhere between 22-25 mpg on the Hwy on a tank of gas. That's consistent. Sure I can drive 100 miles and get 27-28 mpg but the average on a full tank won't be that. I have 190K on my van and am satisfied with my mileage.. I drive pretty easy though.
BTW nice job on the wiring, I know it's not easy reaching those rear plugs. I've had four different spark plugs over the years with not appreciable difference in mileage or driveablity. I will say that one set of Bosch plugs make the engine idle a bit smoother but that was it. Good luck in your quest for higher MPG. Tom
 
#54 ·
MPG Update

Well, I've driven about 500 miles or so with the new setup and I've come to the conclusion that NYC sucks for fuel economy. Damn Mike Bloomberg and his quest to banish cars from Manhattan... Most roads have lanes closed and converted to bike/pedestrian lanes and all cars get squeezed into one or two lanes where as before they had 3 or 4 lanes. I work 15 minute walking distance from West Side highway and it takes me 45 minutes do drive from parking lot to the West Side! And this is with less cars on the road! :mad: I remember it used to take 5-10 minutes with a lot more cars only 4-5 years ago.
Well my mileage in the city driving is around 13 and on the highway I get around 24. Combined I get 16 and that's from doing calculations from fill-up gallons and miles driven. The computer is showing 15.7 mpg average. I still have not put in the speedometer re-calibrator, so the computer is still showing less that real life miles. I'm looking into exhaust upgrade to both improve sound/power and to see if I can get another 2-3 mpg out of it.

Alex...
 
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