Is running 93 octane in my 96 z24 killing my mpg? The car has 310k and im slowly replacing everything that has wear(its my new daily driver) I installed a cool air intake ,2.2 style ignition, new plugs, new denso o2 sensor(not a damn bosch.. it died it one week) and OLD ass wires from an l98 corvette because I wanted to get my car running because the 2.4 ignition and modules were cracked.. Plug wires are on the way... it runs much much much better. I also cleaned the MAF/TB/IAC and replace the maf to intake vacuum line as well as some others. No check engines lights but car is getting around 16mpg average and my trans am is getting 22mpg average untuned with full boltons.. lol..
Another bit of info.. my motor/tranny mounts are shot. Could this be setting off knock sensors?
Goal for next spring is to have all of the brakes rebuilt, all of the hub assemblies replaced and balljoints /shocks/struts/steering rack and replace the cat.
I dont want this car to stand out at all and I just want it to be reliable as hell because Im getting ready to throw a crapton of money into the trans am this winter as well...
Octane is gasolines rating if resistance to detonation and knock. If your having problems with the knock sensor, switch to 87, which the engine was designed for. The higher the octane does mean it's a "cleaner" fuel. It means it takes a higher amount of compression to make the fuel self ignite. For example. Run 87 in your motor and it will run fine. It will run great with 87. Now, take a turbocharged porsche, and try to run 87. That motor is going to knock, and ping, and tick and it will run like @!#$. However, put 93 in that same turbo car, and it will run great.
Using the 93, and causing a knock sensor issue, it's a high likelihood that it's causing your mpg issues.
If you need further explanation about 93 verses 87, let me know, I get tired of making the same post about octane at least once a month.
Just wanted to know the best fuel(octane). I dont have a manual for this vehicle or have any experience with 4 cylinder car drivability factors and I know that this is a performance oriented 4 banger and im getting crappy mileage and everything has been replaced. Car runs like a bat out of hell though. My gfs mini required 93 and so does my car that ive drove/modded for many many years.. Ive also had no codes or no knock sensor issues. What is the C.R. of these cars and what does GM recommend?
My other car...
Compression ratio is 9.7:1 factory.
Calls for 87 octane.
EPA says 23 city, 33 highway. When I had the LD9, I had a 5 speed and saw 25 delivering pizza, and 32 highway no matter how I drove it. It had 150k when I sold it.
Thats a WS6 right? Looks real nice.
What are you doing for ignition if the ignitions modules are bad? Using coil packs from something else? Id say it probably has an ignition issue if its not burning fuel very efficiently.
How are you figuring fuel mileage?
Im using an ignition module setup from a 2.2 cavalier. The harness is a direct swapover and is supposed to give you better MPG and smoother idle/rev as posted as a thread on here.. here is an example pic from on here as well.
Figuring fuel mileage the same way as always... fill it up till it clicks and divide miles by gallons...and repeat
and yes it is Sunfiretun3r. thank you
Love the WS6. I need the find a license plate cover for mine.
I would just use 87 in your car. I used to run 93 all the time because I thought it was "better" Turns out I was just wasting money. I think I picked up a little MPG when I switched. Could you send me more info on your ignition swap?
Filled it up with 87 last night.
http://www.j-body.org/forums/read.php?f=2&i=404817&t=404817&p=4
there is the thread about the upgrade.
It all started doing this at random as well.. im about to take it to the dealership if it doesnt pop a code soon.....my dad got struck by lightning so he was forced into retirement(dealership ase mastertech/manager) Im sure theyll help me figure it out.. lol. I just need to go and buy a damn tech 2....
Ive got a tensioner/ pulley issue as well. Changed the belt and it got ten times worse. Could a harmonic balancer cause this? I pulled the relay on the ac so I know its not the clutch etc. Im going to change the tensioner hopefully by this weekend as well as all the engine/tranny mounts as well.
I hope its not a pcm problem.. lol.
It could still be the bearings in the A/C clutch. When they go bad they make a very distinct sound. Metallic sound.
yeah, I know I had to cut the belt off the trans am when It locked up and killed the engine... ill play the changing parts game.. remember. it has over 300k lol...
Well I finally got it to throw some codes... and after some googling I found this... this replicates the symptoms to a T..
http://www.jeepkings.ca/forums/showthread.php?87855-Please-Help!-99-Cavalier-Z24-P0507-amp-P0105-DTC-Codes
So.. im going to go digging for corrosion tomorrow morning, if i cant find any the first option is TPS/MAP/IAC replacement then onto the pcm.
I just have replace the PCM in my trans am for the same friggin issue, and being a 1998 trans am, it was the first year and last year it was used...
Opinions???
Before replacing the PCM, et a tech 2 on it and check for communication.
What codes did you get?
I am replacing the TPS/MAP/IAC in that order before I replace the PCM. I didnt see any frayed or other wires.
p0507 as stated above is the code.
I dont mind check engines lights as long as dont hinder the operation of the vehicle and its performance. Ive been running with a SES light in my trans am for three years.. but it has no emissions/cats/etc on it...
Sorry I didn't realize the code you are getting is the same code as stated in the link you posted.
Did any of the wires you looked at look "pregnant"? or were any of the connections loose at the plugs?
Plug wires are less than week old. All brand new. Cars runs great except when it goes into this spastic mod. I cleaned the map sensor with CRC MAF cleaner and the code is gone after clearing but its still getting RPM to high code. p0507. Gas is being absoutely destroyed and the fan kicks on all the time and the surging happens when that code is thrown. Reset the code and the surging is gone. Cleaned the IAC and no change either. Im leaning towards TPS sensor on this one. Ive replaced ALL of the vacuum lines with new goodyear hoses so Idk what i could be.
I didn't mean the plug wires, I meant the wires to the PCM, and the connectors.
I guess all that's left is the TPS. Try it and see what happens.
