on my 91 ls, i'm noticing the car gets really poor mileage. i've changed EVERYTHING on it to improve it and nothing is working.

plugs, wires, o2 sensor, fuel filter, oil change, fuel injector cleaner, PCV valve, Distributor cap, seafoam all have been done recently.

i rarely step on it, but when i do i can tell it goes down even quicker..also friends told me i'm blowing a lot of dark smoke out the back when i floor it.

I dont even know what it could be at this point.

 

is the car bogging? is it hestiant? from what u told me i would run fuel injector cleaner through it.

 

no bogging, no hesitation at all. car driver 100% normal.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DAcraze &raquo;</TD></TR><TR><TD CLASS="quote">from what u told me i would run fuel injector cleaner through it.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stacked &raquo;</TD></TR><TR><TD CLASS="quote">
plugs, wires, o2 sensor, fuel filter, oil change, fuel injector cleaner, PCV valve, Distributor cap, seafoam all have been done recently.</TD></TR></TABLE>

i did it already.

 

i js had tah same prob that you have and it turned out to be my MAP sensor...switched it out and now everything is runnin fine

 

i'm almost sure that you got bad piston rings.. stop guessing and get new rings and everything will be perfect..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dc2_boi &raquo;</TD></TR><TR><TD CLASS="quote">i'm almost sure that you got bad piston rings.. stop guessing and get new rings and everything will be perfect..</TD></TR></TABLE>

uhhh. he didnt say he was burning oil.
are you burning oil?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by D 2da A9 &raquo;</TD></TR><TR><TD CLASS="quote">

uhhh. he didnt say he was burning oil.
are you burning oil?</TD></TR></TABLE>

i do believe so actually.

 

 

is the smoke out of the exhaust black? or grayish blue?

 

dont know. probably both since i'm running rich and burning oil

 

 

Like the guy said before, MAP Sensor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sturat77 &raquo;</TD></TR><TR><TD CLASS="quote">Like the guy said before, MAP Sensor.</TD></TR></TABLE>

Would a defective Map sensor throw the Check Engine Light? If so, is your CEL on?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tornadom &raquo;</TD></TR><TR><TD CLASS="quote">

Would a defective Map sensor throw the Check Engine Light? If so, is your CEL on?</TD></TR></TABLE>

it depends on what you mean by defective. defective could mean its sending out the wrong signals, therefore its still working, just not as it should. have you checked your coolant temp. sensor? there are tolerances that you can find online to see if its ok. It might be that your car isnt going into closed loop mode and is staying in open loop. have someone check it for you. anotehr thing you can do is apply vacuum to your map sensor and see what voltage it is sending and compare it to what it should be sending. those are my 2 cents.

dont change **** anymore, diagnose, you are throwing **** away that way. with the moeny you spend on just buying new ****, you can pay a mechanic to find the correct part thats bad.

 

Don't mean to thread jack, this kinda goes along with his question. Just bought a 90 dA, the guy said it usually gets 25 mpg and I thought that was kindof low but am not sure. Then I drove in front of a buddy and he said it looked like some smoke came out when I romped on it. I had followed the previous owner though and never saw smoking exhaust.
I'm really hoping it's not the piston rings, but apparantly it doesn't burn oil.
I've only had it for a few days though, so I'll check my gas mileage and oil at the next fillup.

 

check the MAP but also check the coolant sensor . If the car thinks its cold all the time it will run rich.

 

I recently had this problem as well, first off have a mechanic check your car before you replace the rings. On my car it turns out that the previous owner had turned the fuel pressure up to an astronomical height. You might want to check that first. It should be around 36-38psi. Mine was MUCH higher than that, and my car also drive fine for the most part however when I would get on it I would blow a ton of black smoke out the back.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tornadom &raquo;</TD></TR><TR><TD CLASS="quote">

Would a defective Map sensor throw the Check Engine Light? If so, is your CEL on?</TD></TR></TABLE>

no CEL, no codes.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Diego Dangers. &raquo;</TD></TR><TR><TD CLASS="quote">

it depends on what you mean by defective. defective could mean its sending out the wrong signals, therefore its still working, just not as it should. have you checked your coolant temp. sensor? there are tolerances that you can find online to see if its ok. It might be that your car isnt going into closed loop mode and is staying in open loop. have someone check it for you. anotehr thing you can do is apply vacuum to your map sensor and see what voltage it is sending and compare it to what it should be sending. those are my 2 cents.</TD></TR></TABLE>

i havent checked either of those. i'll look into it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Diego Dangers. &raquo;</TD></TR><TR><TD CLASS="quote">
dont change **** anymore, diagnose, you are throwing **** away that way. with the moeny you spend on just buying new ****, you can pay a mechanic to find the correct part thats bad. </TD></TR></TABLE>

well i wanted to change most of that stuff on my car anyways to get optimal gas mileage.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 53JDMDC2 &raquo;</TD></TR><TR><TD CLASS="quote">check the MAP but also check the coolant sensor . If the car thinks its cold all the time it will run rich.</TD></TR></TABLE>

would that have anything to do with the temp gauge? i had a temp gauge problem last week here.. https://honda-tech.com/zerothread?id=1534153

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlackDC2_05 &raquo;</TD></TR><TR><TD CLASS="quote">I recently had this problem as well, first off have a mechanic check your car before you replace the rings. On my car it turns out that the previous owner had turned the fuel pressure up to an astronomical height. You might want to check that first. It should be around 36-38psi. Mine was MUCH higher than that, and my car also drive fine for the most part however when I would get on it I would blow a ton of black smoke out the back. </TD></TR></TABLE>

was it a stock fpr?

 

I have always used a stant thermostat. so aftermarket is not always bad.

yes it could have something to do with the temp gauge, but not sure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stacked &raquo;</TD></TR><TR><TD CLASS="quote">

was it a stock fpr?</TD></TR></TABLE>
No it is an AEM FPR. The previous owner unhooked the MAP sensor from the ECU. Pulled and capped the O2 sensors, and turned the fuel pressure up. When I checked it, it was at 95psi. ******* moron. I have had to fix alot of his **** since I got it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 53JDMDC2 &raquo;</TD></TR><TR><TD CLASS="quote">check the MAP but also check the coolant sensor . If the car thinks its cold all the time it will run rich.</TD></TR></TABLE>


where is this locatedby the way?


I have the same problem, my ECU trows an O2 sensor code, but ive already changed the O2 sensor 3 times already, and i get the worst MPG...

 

rings? no way, when you have bad rings the smoke is white not black, black smoke is cause it has too much gas but if he has a fuel regulator that is totally normal if he doesn't best guess THE MAP SENSOR

 

02 Sensor maybe? 95 psi is crazy high.