New DSM owner.. Major problems with gas mileage

[TAndrus]

Hello everyone.

I'm proud to say I just purchased a '95 Eagle Talon TSi AWD. I don't know too much about the car besides the following:

• HKS blow off valve
• Cold air intake system (brand unknown)
• Coil over lowering kit (lowered 1.5")
• Strut tower brace
• 18" Chrome Motegi wheels
• Aftermarket exhaust (brand unknown)
• Whiteface gauges

Im new to driving a manual so I haven't really tried too much with it, but when I floor it, I get up to 16psi on my boost gauge. I really know nothing else about this car. It's got about 119,000 miles on it and the "intercooler gasket" was replaced 1000 miles ago supposedly.

I have found a few issues though that I'd like to ask about. I've found I'm only getting 12mpg which seems EXTREMELY low to what I should be getting. What could be causing this?

Also, I need to buy new headlamps but I can't really find any nice aftermarket ones. Where could I look to find some?

Thanks a ton. I hope to be a long term member of the board and stay active around here.

-Taylor

 

[MountainDew]

You could be boost spiking 15psi. If you're on the stock T-25 with no MBC it would be kind of hard to believe you're running a steady 15psi, even with the BCS removed.

I guess anything is possible though. As far as the first gear thing, not really sure if that's normal. It definitely wouldn't hurt to get a tranny flush and some new fluid in it. Search around on here for what kind of fluid to use.

Your plug wires do look pretty new, and aftermarket, so they should be fine. Definitely pick up those NGKs. Whatever you do, don't buy autolite or bosch or anything. I did and the stupid things are still in my car.

 

[TAndrus]

Are these the same spark plugs?? If so, I could pick them up at the local O'Reilly's store..

 

[MountainDew]

The NGKs? You'd have to call and ask. It'd be cheaper to order online.

 

[kenamond]

I'm trying to keep all the posts in this thread straight. Anyway, here goes:

You can get the NGK BPR6ES spark plugs (yes, that's what you want) from NAPA for $2.50 each, and you need 4 (same price as ExtremePSI but no shipping cost and you don't have to wait). Pick up a spark plug gapping tool while you're there and ask them how to use it (don't be too proud and you'll learn a lot more). The gap is actually 0.028" not 0.28". If the NAPA guy is nice, he might actually gap one of the spark plugs right there for you. Also, pick up some anti-seize compound. They come in packets like ketchup or in big bottles, but one packet is enough. You smear that into the threads of the spark plug so that it will not get stuck when you next change your spark plugs (and if it gets stuck, it could damage the engine head which is VERY expensive to replace). You can also get the spark plug socket while you're there and test fit it to one of the plugs. If you don't have a socket set, go get a Craftsman set from Sears or similar at a hardware or auto parts store. If you plan on doing much to your car, you're going to accumulate tools...but most guys I know don't need much of an excuse to buy a new tool.

After you remove the spark plug cover (black plastic plate on the top of the motor), be careful pulling the spark plug wires off the plugs. Pull straight up and wiggle it a bit side to side. Mine are always a pain to get off, and I've busted them before pulling them off.

You should also pick up a torque wrench. This is a big "honkin'" ratchet that can be set to specific torque levels (twisting force) and will "tell you" via a "click" sound when you've applied that level of torque to a bolt. Many bolts and nuts on the car need to be tightened to a specific torque level or it'll come loose or you'll strip out threads or break bolts. The torque wrench is required when doing any of this. And you need the torque wrench to properly tighten the spark plugs.

Another thing you should get is a Haynes or Chilton manual for your model of car. It will tell you how to do most things on your stock setup (but not the mods...come here for that). They're like $20 or so at Autozone.

The adapter you need for your HKS BOV also needs a hose. The stock hose will not reach. I'd ask/search around to find out what you need. Or you could put the stock BOV back on.

It looks like you have the stock intercooler piping. A brief explanation: The turbo compresses the air, and spits it out the bottom of the passenger side of the turbo (that's the compressor side of the turbo). Compressing air makes it hotter which would be a bad thing to send to your motor. So it runs through a pipe (lower intercooler pipe or LICP) to an "intercooler". If you look into the front bumper cover on the passenger side (left-most opening in the plastic bumper cover), you'll see the intercooler. It's right in front of the passenger-front wheel. It looks like a radiator. The air flows through the port in the bumper cover and through the intercooler and out through the slots in the fender well (take a look in your fender well and you'll see the louvered vents). The hot air from the turbo is on the inside of that intercooler and is cooled down by that external air flow. The air from the turbo then exits the top of the intercooler through the upper intercooler pipe (UICP). That pipe passes through a hole in the sheet metal of your engine bay right next to your air filter element (you can see it in several of the pictures you posted). It's molded plastic with some words/numbers molded into the surface. It runs under your fuse box. At the end, it has a flange on it where your BOV attaches. Just after the BOV the plastic part ends and is coupled to a flexible silicone pipe with braided "skin" that goes to your throttle body (TB) and into the intake manifold (IM). Since youre UICP is the plastic part, you've still got the stock UICP. This makes me wonder about that "intercooler gasket" the previous owner mentioned.

If you don't have an aftermarket boost gauge, you might want to pick one up. That'll burn a few hours one day to get it installed. You'd also need something to mount the boost gauge to. Most folks get an "a-pillar gauge pod". You can get one with one, two, or three pods for other gauges. They bolt right onto the A-pillar (separates the windshield and side windows). That will tell you - with numbers - what boost you're running. It will also help with boost leak testing, as you need to know how fast/slow the air is leaking down from boost leaks, and it will tell you when you've added sufficient pressure during the test. You don't want to put too much pressure into your intake or you can blow seals.

I didn't like many of the designs of boost leak testers I found. I had to adapt the very common design a bit to get the valve to seal to the PVC end cap. But it's not rocket science. You'll also need a source of compressed air. If you have an air compressor, you need to be sure you're limiting the pressure you add either via a regulator on the compressor or by being VERY careful. I use a portable air tank ($30 for 10 gallon model) that I fill at a gas station. As many have mentioned, this is an important test. Leaks will develop over time, and I'd bet a dollar that you have several. This is worth a bit more elaboration:

Many of the plastic parts deteriorate over time. They used to hold pressure, but they don't any more. The ECU (engine control unit) gets its information about how much air is entering the engine at the MAS (clamped to your air filter element). That's waaaaay upwind of the engine, so there are many places for air to leak between the MAS and the engine. The ECU computes how much fuel to inject based on the airflow reading it gets from the MAS. So if you're boosting and have leaks in your intake tract between the MAS and the engine, the ECU doesn't know about it. It thinks it's getting more air than it actually is, so it injects too much fuel. This robs power and makes you push the gas pedal more than you would normally need to. That robs fuel efficiency.

BOV recirculation: When you're going through the gears "getting on it", the following happens. You tromp the gas. The turbo spools (speeds up) and increaslingly compresses the intake air (boosts). Then you get to redline and want to shift. When you lift the gas pedal, the throttle plate closes. This blocks the flow of air into the engine. The air that was being forced through the intake by the turbo now has no place to go. The BOV is also called the "turbo bypass valve". When you let off the gas, the motor is still at redline and is trying to suck air, but the throttle plate isn't letting that happen. As a result, the intake manifold (between the throttle plate and the engine) pressure drops to vaccuum. This vaccuum is used to trigger the BOV to bypass air (trace that vaccuum line on your BOV, and you'll find that it runs to the intake manifold). The BOV takes air that is hauling ass through the UICP and redirects it so that it recirculates back into the intake pipe upwind of the turbo. So the turbo can continue to spin like the dickens and basically push air in a big loop until you open the throttle again and the vaccuum in the IM goes back to positive pressure. However, your BOV is not quite doing this. Instead of sending the air back to the intake pipe for a 2nd "go" through the turbo, it is just dumping the air to the engine bay under the hood (called venting). But remember that MAS and the ECU and the fact that the ECU is expecting every bit of air the MAS detects to go into the engine. When you vent, all that air is not going into the engine. So whenever you let off the gas and the IM goes into vaccuum, the BOV is dumping air that the engine is expecting to burn. So you run pig rich just after lifting off the gas pedal. When you recirculate, all the air measured by the MAS stays in the system; during a shift, the engine all of the sudden starts to "rebreathe" a fair fraction of the air - sort of as it doesn't actually get to the engine. When you vent, the turbo keeps pulling air through the MAS and then dumping it under the hood, so the ECU sees much more air flow than it should.

Do the boost leak test on a warm motor. A cold motor will leak lots of air past the piston rings, and this may appear to be a mysterious boost leak. When the engine is warm, the piston rings expand and seal much better.

That should do it for now.

 

[a_flint87]

You mentioned it was hard to get into first gear, is this when you are down shifting? Or when you are stopped and getting ready to get moving?

 

[TAndrus]

You mentioned it was hard to get into first gear, is this when you are down shifting? Or when you are stopped and getting ready to get moving?

It seems a little of both.

 

[Boostin91TSi]

I have the same problem with first gear, and I have the shifter plate bushings and shifter cable stiffners.
As for the gas mileage, I have that problem too, and I have almost no boost leak.

 

[TAndrus]

Also, is there chronic problems with the gas gauge on the talons?

 

[kenamond]

I've never heard of gas gauge problems, but that doesn't mean there isn't one.

Perhaps you know this already, but here's how I compute mpg:

Next time you fill up your tank, reset the trip odometer. This gets you started for regular mileage checks.

Every time you fill up after that, do the following:
Fill up until the pump kicks off automatically.
Make a note of the gallons on the pump.
Check the miles on the trip odometer.
Divide miles by gallons.
Reset the trip odometer.

Do this several times. City driving will get lower mpg than highway (duh), but if you don't keep that in mind, you might confuse yourself. I have a short commute and rarely put highway miles on my car. This gets me around 22mpg. But if I cruise through a tank of gas on the highway, I get 27mpg. Obviously, if you're a major lead-foot, your numbers will go down. Also, I'm not sure if there's much difference between manual and auto trannys. I have a manual transmission. I imagine that the AWDs may get worse mileage than FWD cars, but that's just an educated guess.

Make sure your tire pressure and aligment are correct. That can drop mileage as well.

Finally, I hope I'm not dumbing stuff down too much. If so, please just take what you don't know (if anything) from what I say and forgive me. I'm just trying to make sure I'm clear.

 

[TAndrus]

Haha. Well, you're making it quite simple for me and I thank you. But I know how to compute mpg. I'm hoping I can do the simple division at least. The other stuff you explained was good though. I didn't know anything about the recirculation stuff. By the way, I found it ironic that you mentioned getting a chilton repair manual because when I got home, my dad had bought one.

I actually took my car in to Midas today to get a maintenance check done. Everything checked out well besides needing to get my oil changed, a latch on my exhaust, and then the glaring problem, my rear alignment is out. It's so bad that you can stand back from the rear of the car and notice about a 85ish degree, instead of 90, slope to the tire from the ground. The inner treads on both rear tires are worn all the way down. I have 225/40ZR18's on there now and each tire is about $200 from what I've seen and you've have to buy two. Then I have to find some place that does custom alignment because I have a lowering kit on my car. Any ideas how much that'll cost me?

 

[MountainDew]

You could try Big O tires in Gardner. They have had the best price on alignments I have seen. $49.95

Everyone in the metro wants like 79.95 to 99.95.

 

[TAndrus]

Anyone know where to get aftermarket headlamps for the talon?

 

[dsmulla]

Best place to get aftermarket headlamps would be ebay. Cheap and also functional.

 

[MountainDew]

Anyone know where to get aftermarket headlamps for the talon?

There are some Halos for sale locally that I'm probably picking up. I have painted my stock headlights black (the inside housing) and cleared the corners. I'd sell them if you're interested. They look great on black Talons.

 

[TAndrus]

Just a little update.. I've ordered these things

Okay. So far I've gathered that I should do the following:

• Spark plugs
• Recirculating part

The spark plugs I'm going to get help with at the local O'Reillys, but the guy who is helping me with that doesn't know what to do with the recirculating part for the bov. I have no idea how to install it either.

I also got my oil changed. I'm getting about 16mpg now, but that still seems low. My gas gauge is all messed up too because it stays at max for about 60 miles, then drops to half tank over the next 20 miles, then just doesn't move. Not sure why.

I'm also going to purchase some headlights on ebay I think.. I've found one made for the talon here (I think they look okay), and then one for the eclipse here (but not sure they will fit). I personally like the second ones better. Any other opinions? And will the second ones fit my 95 Talon?

Lastly I saw the thread on making your own mesh grill. I'm going to try and do that tomorrow with some gutter guard from home depot. I'll put some pictures up later.

 

[MountainDew]

The second ones will fit. And I still think you should buy my headlights.

Either that or I can mod yours for you. Mine were really fogged but they cleaned up real nice. All you do is buff them with plastic wax for about 30 minutes then wetsand if needed. Also bake them in the oven to melt the glue then pull them apart, unscrew the amber corners and paint the chrome housing black.

That's all I did and they look terrific. Just like the 2gbs but with clear corners.

 

[Turbo Talon DL]

Have you tried looking at your spark plugs recently to see what color they are? When you do look at them, compare them to the spark plug 'reading' pictures provided in the Haynes/or whatever manual you have. If the plugs are black and your engine compression is good, then try changing your stock fuel pressure regulator with a new one. Check the fuel injector o-rings and throttle body shaft seals too. any leak after the MAS will kill gas mileage. Dont worry about an aftermarket upgrade until you get the car running right. Is your airflow sensor hacked? Change your fuel filter? Just do a full tune up and see what happens. I doubt the guys at Midas or whereever you went did a full extensive look-through on your car like you would do yourself. Just take your time with it. Its not impossible and can be fixed.

 

[bwild97]

Reguarding your MPG, funky fuel gauge reading. Sounds to me like a previous owner replaced the OEM fuel pump with the high flowing 255lph Pump and screwed up the fuel level sending unit in the process. The high flowing pump will over-run the stock "fuel pressure Regulator"(FPR)
and cause the pressure to exceed 60psi at idle and it only gets worse with boost. As for the sending unit you should take the car to a trust worthy auto shop (if you know one) and ask to have a tech look at it to see if it is functioning properly, while he is at it he could check your static fuel pressure, should be 43 psi.

 

[Defiant]

TAndrus, I've yet to see a question asked here that isn't covered either in the FAQ, or simply answering by a quick search. Moving from "bad mileage" to "which headlights" is too much a stretch.
Search first, ask second. In a new thread when the topic changes.

 

[hubz91talontsi]

Is there any gauges i can buy that tell me how many miles per gallon i am getting? Me and this gas mileage battle is never ending. 15 MPG isn't very satifying...Any pointers or tips? I started my car up before school today, it was cold out so i gave it 10min and when i get it i used about 1/5 of gas up. I don't have any problems with smoke coming out. Checked my sparkplugs although my cables look nasty i was planning on new ones. What do you think?

 

[red97tib]

http://www.dsmtuners.com/forums/showthread.php?t=271621&highlight=better+gas This thread has alot of tips on stuff you can do to improve gas mileage.

 

[snowborder714]

You don't need a gauge. Just Excel. Start a gas mileage sheet and keep track. In mine I have these columns: date, mileage of car at fill-up, price of gas, how much I paid, how many gallons it took to fill it up, and how many miles I traveled on the last tank (trip number on the cluster). Then I have a calculated field for miles per gallon. You just take miles traveled/how many gallons. Easy as that. This way you can watch your driving trends and also see if longer trips yield better gas mileage.

Also, don't leave your car idling for 10 minutes even if it's cold outside. Anything longer than 30 seconds or a minute (I believe...) is just wasting gas. Just start it, let it warm up a bit, then drive it. This will get your operating temps up faster than just letting it idle. Just don't boost it at first.

If you're planning on getting new cables, I'd get new NGK BPR6ES plugs at the same time.

 

[Defiant]

it was cold out so i gave it 10min

Don't do stationary warm-ups, just go easy the first two miles- less than half throttle, and less than half-load.