Some Poor Acceleration and crappy gas mileage

Mojomonkey · 02-15-2006, 05:41 PM

Alright, so up until this sunday, my 1987 MR2 was runnin fine, just had a tune up, blah blah blah, then come monday i fill the tank up, and today (wed.) the gas is GONE, i mean GONE GONE. And its REAL slow to accelerate, so when i let off the clutch in 1st, it lags until it hits 2.5k RPMs and then it accelerates fine. What could the problem be? Dirty fuel filter, bad fuel pump? Any help would be cool

seven_mgte · 02-15-2006, 09:26 PM

is it throwing any codes?

mr2greasemonkey · 02-15-2006, 09:27 PM

blind guess......maybe yr maf.

Mojomonkey · 02-16-2006, 01:19 AM

No, the ECU isnt throwing any codes. I just had it smogged 4 days ago, so anything with the ECU or timing would have been picked up then. I seriously want to know what it is though, im blowing through at least $50 in gas a week and i need it to stop. COuld it be Clogged fuel filter? Maybe a vacume leak? Bad fuel pump? What gives?

Enthalpy · 02-16-2006, 01:32 AM

Check the codes anyway. The ECU will store them even when the light doesn't come on.

One smog test itself doesn't necessarily pick up on ECU faults. Differences year-to-year in smog tests pick up on ECU faults much better.

Did this behavior coincide at all with the tuneup? If so, that's where I would start. If a mechanic did it, take it back to them with these symptoms.

Mojomonkey · 02-16-2006, 02:09 AM

Yeah, im going to a mechanic tomorrow. Now one of my headlights keeps popping up and down when i have my headlights on, what could THIS be.

Mojomonkey · 02-16-2006, 03:50 PM

Ok, i just put in $10 this morning and its GONE, i mean GONE! Im going to try and use some fuel system cleaner today when i fully fill up, but if that fails what else should i do? Engine Runs smooth, but is slow to accelerate, and there is this hissing noise under load i can hear from the cabin. Any help would be nice, sugestions and what not

Enthalpy · 02-16-2006, 07:35 PM

Why haven't you done what was already suggested? Did the mechanic do the tuneup? Did you check the codes? Did you visit the shop where it was worked on?

V6'er · 02-16-2006, 10:44 PM

Hissing noise? Must be the sound of raw gasoline spraying on the road.

Mojomonkey · 02-17-2006, 01:09 AM

I solved the gas problem, added some fuel system cleaner to a tank of 103 octain (cuz im cool like that

) but the slow acceleration still persists. NOW what gives?

TomsMR2 · 02-17-2006, 01:17 AM

its the 103 octane gas. your car was designed to run on 87 octane gas.

Mojomonkey · 02-17-2006, 04:42 AM

The higher octain doesnt do ANYTHING besides keep the engine cleaner and burn more efficiently. I always use 103 when i take it to the track.

Enthalpy · 02-17-2006, 02:04 PM

Quote:

Originally Posted by Mojomonkey

The higher octain doesnt do ANYTHING besides keep the engine cleaner and burn more efficiently. I always use 103 when i take it to the track.

That's not true.

Higher octane burns slower, which means you have to feed your engine more ignition timing across the whole operating range. As a result, a healthy engine will lose mileage.

Higher octane also uses certain octane boosting agents that are cancer-causing by the metric ton in lab rats.

Higher octane leaves a brownish coating on the spark plugs.

Higher octane does NOT burn cleaner. It has a harder time evaporating, which means you get higher HC emissions.

Luni · 02-17-2006, 02:11 PM

Have you checked for vacuum leaks?

Mojomonkey · 02-17-2006, 02:15 PM

To make things clear, i have the ignition system modified, it puts out enough voltage to run primarily off of 91 octain. I think the hissing is a vacum leak, the gas wouldnt cause it hiss.

Enthalpy · 02-17-2006, 03:19 PM

Of course not. A vacuum leak has the potential of crapping on your mileage, though.

If you have a vacuum leak in one of the injector seals or one of the runners, that cylinder runs lean. The O2 system picks up on that and corrects it, but it applies that corrected fueling to EVERY cylinder. Now, you have one that runs a little lean and 3 that run REALLY rich.

MR.twooooo · 03-18-2006, 02:10 PM

did u check that there is no water around the sparkpulgs? this could be the problem with it not accelerating and kicking in at 2500

MR.twooooo · 03-18-2006, 06:55 PM

When i had water around my spark plugs i could feel it when the last cylinder would go in and out. I could see where it would cause you to use more gas because you are only running on 3 cylinders

lilred · 10-05-2006, 12:15 AM

Replace your distributer cap and rotor button

Mojomonkey · 10-05-2006, 03:24 AM

Ok, well thanks to all who tried to help me with this problem, issue has been solved. But just do add, Enthalpy YOU ARE WRONG, high octane DOES BURN CLEANER, with my timing advanced to suit the 103 it burns MUCH cleaner, and who told you it was cancer causing? Its not like im drinking it, im burning it. And as far as it making my smog emissons come out low, your DEAD WRONG!!!! And what makes you think i DIDNT BRING IT TO THE MECHANIC? Your a douch bag, you dont know EVERYTHING....so piss off mate.

02-15-2006, 05:41 PM	#1 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Some Poor Acceleration and crappy gas mileage Alright, so up until this sunday, my 1987 MR2 was runnin fine, just had a tune up, blah blah blah, then come monday i fill the tank up, and today (wed.) the gas is GONE, i mean GONE GONE. And its REAL slow to accelerate, so when i let off the clutch in 1st, it lags until it hits 2.5k RPMs and then it accelerates fine. What could the problem be? Dirty fuel filter, bad fuel pump? Any help would be cool

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02-15-2006, 09:26 PM	#2 (permalink)
seven_mgte Cage Fighter Join Date: Aug 2005 Location: Coquitlam, BC.ca Posts: 327 Thanks: 0 Thanked 7 Times in 7 Posts My Google Map iTrader Rating: (0/0% )	is it throwing any codes?

02-15-2006, 09:27 PM	#3 (permalink)
mr2greasemonkey Once again....yups Join Date: Sep 2005 Location: Portland, OR Posts: 1,658 Thanks: 4 Thanked 63 Times in 42 Posts iTrader Rating: (0/0% )	blind guess......maybe yr maf.

02-16-2006, 01:19 AM	#4 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	No, the ECU isnt throwing any codes. I just had it smogged 4 days ago, so anything with the ECU or timing would have been picked up then. I seriously want to know what it is though, im blowing through at least $50 in gas a week and i need it to stop. COuld it be Clogged fuel filter? Maybe a vacume leak? Bad fuel pump? What gives?

02-16-2006, 01:32 AM	#5 (permalink)
Enthalpy EMS Harmonizer Join Date: Feb 2006 Location: Denver, CO Posts: 1,226 Thanks: 8 Thanked 55 Times in 43 Posts My Google Map iTrader Rating: (2/100% )	Check the codes anyway. The ECU will store them even when the light doesn't come on. One smog test itself doesn't necessarily pick up on ECU faults. Differences year-to-year in smog tests pick up on ECU faults much better. Did this behavior coincide at all with the tuneup? If so, that's where I would start. If a mechanic did it, take it back to them with these symptoms.

02-16-2006, 02:09 AM	#6 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Yeah, im going to a mechanic tomorrow. Now one of my headlights keeps popping up and down when i have my headlights on, what could THIS be.

02-16-2006, 03:50 PM	#7 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Ok, i just put in $10 this morning and its GONE, i mean GONE! Im going to try and use some fuel system cleaner today when i fully fill up, but if that fails what else should i do? Engine Runs smooth, but is slow to accelerate, and there is this hissing noise under load i can hear from the cabin. Any help would be nice, sugestions and what not

02-16-2006, 07:35 PM	#8 (permalink)
Enthalpy EMS Harmonizer Join Date: Feb 2006 Location: Denver, CO Posts: 1,226 Thanks: 8 Thanked 55 Times in 43 Posts My Google Map iTrader Rating: (2/100% )	Why haven't you done what was already suggested? Did the mechanic do the tuneup? Did you check the codes? Did you visit the shop where it was worked on?

02-16-2006, 10:44 PM	#9 (permalink)
V6'er All Torque, All the Time Join Date: Apr 2005 Location: Charlotte, NC Posts: 899 Thanks: 0 Thanked 26 Times in 19 Posts iTrader Rating: (1/100% )	Hissing noise? Must be the sound of raw gasoline spraying on the road.

02-17-2006, 01:09 AM	#10 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	I solved the gas problem, added some fuel system cleaner to a tank of 103 octain (cuz im cool like that ) but the slow acceleration still persists. NOW what gives?

02-17-2006, 01:17 AM	#11 (permalink)
TomsMR2 Still not heraldo. Join Date: Feb 2005 Location: Pineapple under the sea Posts: 4,912 Thanks: 18 Thanked 406 Times in 303 Posts Blog Entries: 1 iTrader Rating: (4/100% )	its the 103 octane gas. your car was designed to run on 87 octane gas.

02-17-2006, 04:42 AM	#12 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	The higher octain doesnt do ANYTHING besides keep the engine cleaner and burn more efficiently. I always use 103 when i take it to the track.

02-17-2006, 02:11 PM	#14 (permalink)
Luni Cage Fighter Join Date: Oct 2005 Location: Salt Lake City Utah Posts: 3,213 Thanks: 10 Thanked 130 Times in 110 Posts My Google Map iTrader Rating: (8/100% )	Have you checked for vacuum leaks?

02-17-2006, 02:15 PM	#15 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	To make things clear, i have the ignition system modified, it puts out enough voltage to run primarily off of 91 octain. I think the hissing is a vacum leak, the gas wouldnt cause it hiss.

02-17-2006, 03:19 PM	#16 (permalink)
Enthalpy EMS Harmonizer Join Date: Feb 2006 Location: Denver, CO Posts: 1,226 Thanks: 8 Thanked 55 Times in 43 Posts My Google Map iTrader Rating: (2/100% )	Of course not. A vacuum leak has the potential of crapping on your mileage, though. If you have a vacuum leak in one of the injector seals or one of the runners, that cylinder runs lean. The O2 system picks up on that and corrects it, but it applies that corrected fueling to EVERY cylinder. Now, you have one that runs a little lean and 3 that run REALLY rich.

03-18-2006, 02:10 PM	#17 (permalink)
MR.twooooo Some Skills Join Date: Mar 2006 Location: Alabama Posts: 55 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	did u check that there is no water around the sparkpulgs? this could be the problem with it not accelerating and kicking in at 2500

03-18-2006, 06:55 PM	#18 (permalink)
MR.twooooo Some Skills Join Date: Mar 2006 Location: Alabama Posts: 55 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	When i had water around my spark plugs i could feel it when the last cylinder would go in and out. I could see where it would cause you to use more gas because you are only running on 3 cylinders

10-05-2006, 12:15 AM	#19 (permalink)
lilred No Skills Join Date: Oct 2006 Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Replace your distributer cap and rotor button

10-05-2006, 03:24 AM	#20 (permalink)
Mojomonkey Host brotha Join Date: Feb 2006 Location: San Jose, CA Posts: 109 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Ok, well thanks to all who tried to help me with this problem, issue has been solved. But just do add, Enthalpy YOU ARE WRONG, high octane DOES BURN CLEANER, with my timing advanced to suit the 103 it burns MUCH cleaner, and who told you it was cancer causing? Its not like im drinking it, im burning it. And as far as it making my smog emissons come out low, your DEAD WRONG!!!! And what makes you think i DIDNT BRING IT TO THE MECHANIC? Your a douch bag, you dont know EVERYTHING....so piss off mate.