|
|
Joined: Aug 2002
Posts: 23
New CEG\'er
|
OP
New CEG\'er
Joined: Aug 2002
Posts: 23 |
I have a 95 Mercury Mystique. 2.5L My car has the following symptoms. While driving, power seems to come on sluggishly. If I depress the gas peddle as normal, it hesitates. Seems to idle OK. It's as if I go to take off from a light, and I have hardly any power. I have to get into it 3/4 peddle or more to get it to move. If I don't get into it further, it will eventually start gaining power. The same way that a turbo lags and then kicks in. It's been doing it for about a week now. I will occasionally get a CEL. I checked it out and got the following codes:
172 - Oxygen Sensor - mixture too weak
176 - Oxygen Sensor - mixture too weak
543 - Fuel Pump Circut
I remember reading a post about the same codes, but I can't seem to find the post. FYI, I have cleaned the MAF wire using the procedure outlined in the forum ( carb cleaner, followed by brake cleaner) and change the gas filter and looked at the fuel.
The car also get's a sulfer exhaust smell once in a while.
The intake has been cleaned once. About 10K ago. The car now has 56K.
I'm thinking the fuel pump my be going bad. But I don't want to go replacing good parts.
Any Ideas?
Thanks,
Cranky
|
|
|
|
|
Joined: Jun 2001
Posts: 1,541
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Jun 2001
Posts: 1,541 |
My vote is fuel pump. Since you have the pump code, here's my theory: FP is on its way out, so your fuel pressure is low. The pressure is lower than it is supposed to be, so the PCM is adding fuel trim (opening injectors longer) to compensate. Once the long term fuel trims get large enough, the PCM will throw those O2 codes you have.
But, before you go and replace the pump, I'd check the fuel pressure first.
|
|
|
|
|
Joined: May 2000
Posts: 1,359
Webmaster
|
|
Webmaster
Joined: May 2000
Posts: 1,359 |
My thoughts exactly. Check fuel pressure and replace pump if the pressure is below 25psi. Standard psi seems to be in the 27-32 range, regardless of what the service manual says.
-Lance
Lance Kinley
CEG Webmaster
95 SE, "Cassandra"
10 years!
|
|
|
|
|
Joined: Aug 2002
Posts: 23
New CEG\'er
|
|
OP
New CEG\'er
Joined: Aug 2002
Posts: 23 |
I check out the fuel pressure. I have to find some place to borrow a gage to use. 
Cranky
|
|
|
|
|
Joined: Aug 2001
Posts: 2,061
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Aug 2001
Posts: 2,061 |
dumb question time....would do u go about checking the fuel pressure 
99 expedition eddie bauer, 5.4 v8, k&n drop-in, 3" magnaflow catback and gas mileage that makes the contour look like a hybrid
|
|
|
|
|
Joined: Jun 2001
Posts: 1,541
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Jun 2001
Posts: 1,541 |
On returnable fuel engines (not sure about returnless), there is a Schraeder valve on the fuel rail - looks just like the valve on your tires, because that is a Schraeder valve as well. I had trouble finding the one on a 96 Zetec (but eventually found it), and the Duratec's is pretty much right under the accordian tube IIRC. Just go into any parts store and ask for a fuel pressure gauge. Make sure it has the adapter for a Schraeder valve (it'll probably say "for Ford vehicles" or something similar on the packaging.) IIRC I paid $20 for mine. Pull the cap off the valve and put the gauge on. Careful - you're messing with gas now and a little will escape. Start the engine and let it get to a steady idle. Read the gauge per the instructions with the gauge. The idle pressure should be right at the spec Lance quoted. And now you know how to use a fuel pressure gauge.
|
|
|
|
|
Joined: Dec 2001
Posts: 667
Veteran CEG\'er
|
|
Veteran CEG\'er
Joined: Dec 2001
Posts: 667 |
Originally posted by CrankyCrankPot:
543 - Fuel Pump Circut
P0543??? I don't see no stinkin' P0543!  Do you mean P0453 (Fuel Tank Pressure Signal circuit Input above maximum)? If so, then the following is from the Ford TSP: HX33 DTC P0453: CHECK FOR HIGH FTP SENSOR VOLTAGE
Diagnostic Trouble Code (DTC) P0453 indicates that Self-Test has detected a FTP circuit input above the maximum.
Possible causes:
-- FTP open.
-- FTP short to VREF or VPWR.
-- VREF shorted to VPWR.
-- SIG RTN open.
-- Damaged FTP sensor.
-- Damaged PCM.
* Key off.
* Connect scan tool.
* Key on, engine off.
* NOTE:
FTP sensor input with no pressure/vacuum on the fuel tank (fuel filler cap open or not open to atmosphere) is 2.37 to 2.97 volts.
Access FTP V PID.
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
|
|
|
|
|
Joined: Jan 2001
Posts: 122
CEG\'er
|
|
CEG\'er
Joined: Jan 2001
Posts: 122 |
Originally posted by GeoPappas:
P0543??? I don't see no stinkin' P0543!
Do you mean P0453 (Fuel Tank Pressure Signal circuit Input above maximum)?
We're talking OBD-I here if I'm not mistaken... Pnnnn is an OBD-II code. Or is that what you were getting at by inserting a winky guy ?
//> //> //> //> //>
Garrick
2006 Mazda6 Grand Sport wagon, silver, MTX
I'll never forget you: Silver E0, #3895 of 6535, built 10/2/97 
|
|
|
|
|
Joined: Dec 2001
Posts: 667
Veteran CEG\'er
|
|
Veteran CEG\'er
Joined: Dec 2001
Posts: 667 |
Originally posted by garrick:
We're talking OBD-I here if I'm not mistaken... Pnnnn is an OBD-II code.
Sorry, my mistake.  I overlooked the fact that the car was a 1995. Please ignore my previous post.
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
|
|
|
|
|
Joined: Aug 2002
Posts: 23
New CEG\'er
|
|
OP
New CEG\'er
Joined: Aug 2002
Posts: 23 |
Still haven't found a fuel pressure gage. Murry's didn't have one. Anyway, re-ran the codes today. Now I'm getting the following:
172 Heated Exhaust Gas Oxygen (HEGO) sensor - voltage signal indicates "lean" (Bank #1)
538 - Insufficient RPM change during dynamic response test (engine run self-test) or invalid cylinder balance test - throttle position movement or invalid cylinder balance test - cylinder identification problems.
Well, that narrows it down???
Any one had a throttle position sensor go bad? What are the symptoms?
Thanks,
And I'm still
Cranky
|
|
|
|
|
