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Gas milage


zoltanb

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I am amazed at the gas milage I got on a 25 yr. old car, better than a boat load of new cars. This was my Reattas first really long trip since I've owned it.

post-78046-143142036641_thumb.jpg The first pic is going the second is back in the garage. I ran into traffic outside of Fredrick Md.

post-78046-143142036635_thumb.jpg

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Guest my3buicks

I agree, I did 31 on the way home, I drove though the night with no traffic, top up, and didn't need the a/c - I was extremely pleased with the mileage. It was pushing 29 mpg going out. As I was streaking across the dark interstates like a white hot arrow on the way home, enjoying the new 16 way seat, I thought to myself, traveling doesn't get much better than this. LOL

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What do you guys get in the city? I drive like an old lady and coast when I can. I still can't break more than 15-16mpg :/

Think ill try a new air filter and fuel filter.

Also, does the delco ignition add more hp or torque to the standard specs?

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when was the last time you changed your O2 sensor/

What do you guys get in the city? I drive like an old lady and coast when I can. I still can't break more than 15-16mpg :/

Think ill try a new air filter and fuel filter.

Also, does the delco ignition add more hp or torque to the standard specs?

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You both must be very gentle on the throttle and have long open roads. When I cruise along at 50-55mpg the engine barely uses any fuel. The reading shows an average of 38mpg+ at that speed. If only my wretched city wouldnt have put 100 stop lights along that road..........

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You both must be very gentle on the throttle and have long open roads. When I cruise along at 50-55mpg the engine barely uses any fuel. The reading shows an average of 38mpg+ at that speed. If only my wretched city wouldnt have put 100 stop lights along that road..........

You kidding? I drive like freakin Speed Racer in that thing. Not many long open roads for me. I only use the cruise on the belt way for 6 miles at most.

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  • 2 weeks later...

With the delco coils you should go with ac 14 rapid fire plugs as well. Improving gas mileage as a few other factors as well IE engine condition, plug wires, air filter, oil viscosity, egr, oxygen sensor, and other electronics. That aside the ac 45 plugs are weak if you are still using them or something comparable.

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Guest Furman83

My 88 gets around 31 on highway at 65 MPH with cruise on and 21.9 mixed, per the Computer. If I do it manually HWY is around 31.4 and Mixed around 23.8. I have replaced Plugs (high end), Plug wires (high end), Harmonic Balancer, Oil Pressure sensor, Fuel filter, IAC, O2 Sensor, New Tires, and Lots of High end Wax (helps with wind co-effecent just kidding!, but have waxed it alot). I have NOT replaced Fuel pump or screen. I have 124,000K plus miles. Just an FYI

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The only things I could replace maybe are the fuel filter and air filter. Ill give that a go and see what I come back with.

I mentioned earlier my MPG was 16 or so, I reset a couple weeks before I changed out the ignition. It showed me averaging 21MPG. With my same driving habits its seem to be slowly getting worse and worse. It is now at 18. Doing 65 shows me 28-32 MPG changes as I drive. The difference is doing 45MPH, It used to show nearly 40MPG at a cruising speed, now it shows me barely 30MPG. Ill know soon for sure once I use up this tank of gas.

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That was the first thing I checked and works fine. Its ever since my installation of the delco ignition. Even the slightest acceleration seems to use excess amounts of fuel.. I think I might go back to Magnavox and see if it makes a difference..

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That was the first thing I checked and works fine. Its ever since my installation of the delco ignition. Even the slightest acceleration seems to use excess amounts of fuel.. I think I might go back to Magnavox and see if it makes a difference..
You seem to be looking at the instantaneous gas mileage reading to determine fuel usage. That will run you crazy. Ignore the computer and check the average mpg the old fashion way. Fill the tank and take note of the miles driven before you fill it back up again. Then divide the miles driven by the gallons used.
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Guest Mc_Reatta

Yes, looking at the instantaneous MPG readout can be misleading. It shows a low number when you're on the gas, and a fantastic number when you coast downhill, and everything in between.

Best way to get a feel for how your car is performing at speed is to find a level stretch of road that you can maintain a steady speed between 45 and 55 MPH so that your in 4th with TCC lockup and then look at the readout. If your over 30 MPG then things are OK. (Do it with headlights down obviously)

If you can't trust your foot, use the cruise to hold speed steady.

Since you've got the CRT, start a log showing values for TPS, MAF, O2 cross counts, MAT etc so you have a reference for down the road when you are having a problem. You can use snapshot or just log the readings manually.

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Guest Mc_Reatta
So my fuel mileage is dropping even more apparently. According to the computer im doing 13MPG. Regular driving habbits (soft acceleration).

How smooth is your warm idle?

Was that Delco swap out new or used?

Were plugs, wires, O2 sensor changed out at the same time as the Delco switch, or later?

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How smooth is your warm idle?

Was that Delco swap out new or used?

Were plugs, wires, O2 sensor changed out at the same time as the Delco switch, or later?

My warm idle has never been all that smooth I thought. But to answer your question, it isnt the greatest, my power steering pump is quite loud and needs to be replaced.

Delco unit was swapped out from a 93 bonneville with 100k miles.

02 Sensor was replaced before unit. But I changed plugs, wire, and ignition all together.

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Guest Mc_Reatta

I'd recommend triple checking that the wires weren't crossed when installed.

Clean the MAF and IAC.

If still no change, reinstall the Magnavox ICM and see if that helps any.

Think the consensus is there's a 1 in 3 chance that a used untested Delco might be bad.

Certainly check that the mounting plate and bottom of the ICM is clean so that it is well grounded.

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Guest Mc_Reatta

Anything from slight misfire to no spark condition.

The ICM is best tested at a FLAPS that has the ability to test it. I think most Autozones and O'Rileys can do so.

Here's a you tube video that has some testing info:

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Guest Corvanti
Is it the same range for the delco unit?

idk, Brendan. you might want to google "3.8 series II delco coil pack diagnostic", if others don't respond.

in any case, if one of the packs is way off on the multimeter numbers, logic dictates that would be the problem pack.;)

EDIT: sorry i couldn't help more, but the wax on the Reatta is drying, gotta get back to it.

Edited by Corvanti (see edit history)
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Haha, I understand.

I tried using autoglym super resin polish. Gives a good shine if your paint is decent.

So I changed out the delco pack and went for a drive. Gave me 20 mpg like usual, even with the .60 gap plugs still in. (Didn't feel like burning my hand to change them)

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Guest Mc_Reatta

Delco coils should read no higher than 11K ohms from tip to tip, while Maggies can be up to 12.5K

If the coils check out, I think another ICM is in your future.

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so after puttin in the magnavox system, I went for another drive. Ended up getting the same crappy gas mileage. I noticed at coasting speeds it would do better, but any kind of acceleration just RUINED it. Like I mean, even the SLIGHTEST acceleration at already cruising speeds would end up sucking the mileage down. I did 28-32mph, taking at least 10 seconds or so just to slowly accelerate to and it shoots up to 10mpg or less. Is there anything that can cause massive fuel consumption upon acceleration? (I know this sounds stupid since accelerating is a fuel suck anyway but when I first got the car, I could not even get it to read what it says now)

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Are you resetting the gas mileage and then going for a drive? That is the only way you are going to get that fluxuation in gas mileage. I would fill up the car drive it, fill it again and check the mileage that way. Taking it off the CRT is not always accurate. Also go to the screen that gets you the average speed will kind of give you an average as well. If the car reads a low average speed it computes a low MPG

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I can tell its sucking fuel and the CRT must be somewhat correct. Every time I go for a drive a bar comes off. Before I would get 25-30 km per bar now I get aprox 15km maybe 20 if I push it. As much as I know CRT readings are usually inaccurate, everything seems to add up

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