my 5.0 Feels weak... Just purchased.
11-16-2006, 05:36 AM
#11
3rd Gear Member
Join Date: Nov 2006
Location:
Posts: 711
RE: my 5.0 Feels weak... Just purchased.
ORIGINAL: Dearborn5.0
I'm a tech in training as well. I'm taking an Engine Diagnosis class. Let me take a few educated guesses...
Causes of lean misfire include:
Lack of fuel:
-Fuel pressure too low (pump is going bad)
-Cloged Fuel Filter
-Plugged up injector
Ignition:
-Base timing is wrong
-bad plug/wire/cap rotor
Air:
-TPS sensor not properly calibrated (0.99V at closed throttle)
-Vacumn leak causing extra unmetered air to enter system and run lean
-EGR stuck open
Electrical:
-Battery/Alternator going bad and confusing sensors.
-loose/bad oxygen sensors
So, that being said I would recomend:
Check the Battery for proper voltage at idle
make sure ignition wires are "clicked" into plug tops/cap
Check base timing (10 BTDC with "Spout" jumper removed)
You can check for a vacumn leak by spraying around the intake and vacumn
hoses with carb cleaner. It the engine stumbles or dies when you do this, you
have a vacumn leak.
I'm going to get flames here, but keep your egr. EGR does not operated when under high load or Wide open throttle. EGR increased your fuel economy when you are cruising around.
That said, you can disable egr by blocking its ports in the intake (either one)
with a solid gasket.
I have a SD mustang too. I personally like SD. I do not think that SD mustangs can be tricked by "unmetered" air like a MAF.
ORIGINAL: 88gtboy
As the title says thats most important here is I just purchased the car. so i dont know what the "NORM" is here.
I had a 02 gt And It felt much faster comparted to this thing.. Thats all i have to compare it to. Im beginning to wonder if something isnt right with it. It just feels weak.
Its a 88 GT with an AOD All stock Believed 150k miles(not sure if the engine has been rebuilt/replaced), While my 02gt was a 5spd. I know its an auto but damn its pretty slushy. How long should It take from a stop to get to say 100mph?
I have a snap on scanner and I did pull a couple codes with it. Ill have to go get them again but the main ones I recieved were:
EGR-(still installed should I remove it? I dont have emissions)
Oxygen sensor detects Lean condition
TPS - Out of range.
At times when i drive i feel a misfire, and I also feel it idleing relitively rough at stoplights. Im hopeing these are some issues I can clear up. What should I be looking for?
As the title says thats most important here is I just purchased the car. so i dont know what the "NORM" is here.
I had a 02 gt And It felt much faster comparted to this thing.. Thats all i have to compare it to. Im beginning to wonder if something isnt right with it. It just feels weak.
Its a 88 GT with an AOD All stock Believed 150k miles(not sure if the engine has been rebuilt/replaced), While my 02gt was a 5spd. I know its an auto but damn its pretty slushy. How long should It take from a stop to get to say 100mph?
I have a snap on scanner and I did pull a couple codes with it. Ill have to go get them again but the main ones I recieved were:
EGR-(still installed should I remove it? I dont have emissions)
Oxygen sensor detects Lean condition
TPS - Out of range.
At times when i drive i feel a misfire, and I also feel it idleing relitively rough at stoplights. Im hopeing these are some issues I can clear up. What should I be looking for?
Causes of lean misfire include:
Lack of fuel:
-Fuel pressure too low (pump is going bad)
-Cloged Fuel Filter
-Plugged up injector
Ignition:
-Base timing is wrong
-bad plug/wire/cap rotor
Air:
-TPS sensor not properly calibrated (0.99V at closed throttle)
-Vacumn leak causing extra unmetered air to enter system and run lean
-EGR stuck open
Electrical:
-Battery/Alternator going bad and confusing sensors.
-loose/bad oxygen sensors
So, that being said I would recomend:
Check the Battery for proper voltage at idle
make sure ignition wires are "clicked" into plug tops/cap
Check base timing (10 BTDC with "Spout" jumper removed)
You can check for a vacumn leak by spraying around the intake and vacumn
hoses with carb cleaner. It the engine stumbles or dies when you do this, you
have a vacumn leak.
I'm going to get flames here, but keep your egr. EGR does not operated when under high load or Wide open throttle. EGR increased your fuel economy when you are cruising around.
That said, you can disable egr by blocking its ports in the intake (either one)
with a solid gasket.
I have a SD mustang too. I personally like SD. I do not think that SD mustangs can be tricked by "unmetered" air like a MAF.
Hmm, lol on a lighter note, I know my car is a sn95 but, it's still a 5.0. My car felt real sluggish to me too, like I held it to the floor and it kinda hesitated, the engine seemed to be giving it hell but where was the power?? I don't know if it helped but I ran some fuel injector cleaner through it 2-3 times for a week and bumped the timing up it has not hesitated again and it's been about 3 months. Whether the timing was wrong or the injectors we're clogged, I still recommend you bumping your timing up, you'll be able to tell a noticable increase in response to throttle as well as accel..
11-16-2006, 07:01 AM
#13
2nd Gear Member
Thread Starter
Join Date: Sep 2006
Posts: 159
RE: my 5.0 Feels weak... Just purchased.
ORIGINAL: Ninety5five0
I'd change out the plugs, wires, and cap n rotor, maybe get a new blaster coil. Also see what your timing is at, it might need bumped.
I'd change out the plugs, wires, and cap n rotor, maybe get a new blaster coil. Also see what your timing is at, it might need bumped.
I checked out the ignition componets, It looks like someone has attempted to work on it. It has a new coil... Its real shiny you can tell its new, New plug wires, cap and rotor is new. And the plugs look new they are bosch platinum.
I was looking at the map sensor and I noticed that the vaccum line to it was so dryrotted and collapsed that it was gettin g sucked in by vaccum. I shortened it and re routed it It appears to be woring better- I cant get to the line because it appears to go way under the manifold out of reach..
It does seem to run better but It still didnt make more power. If there is something wrong with the car It probally is in the fuel system.
What should the fuel pressure be?
What does advancing the timing to like 13 degrees do for power?
11-16-2006, 11:24 AM
#14
Join Date: Nov 2006
Posts: 13
RE: my 5.0 Feels weak... Just purchased.
If there is a "dead spot" in your tps then it would feel like it was bucking, normally at cruise because thats where a tps gets worn the most. If there was a vacuum leak the nyour map sensor wouldnt pick it up and you would run lean.
11-16-2006, 05:11 PM
#16
2nd Gear Member
Thread Starter
Join Date: Sep 2006
Posts: 159
RE: my 5.0 Feels weak... Just purchased.
for kicks What should a 88 gt with like 150 K auto trans dyno in at the wheels? I might just pay to get a baseline before i do my mods anyway And see if its really just me use to more powerful newer cars or if its really just me.
11-16-2006, 06:38 PM
#20
5th Gear Member
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
RE: my 5.0 Feels weak... Just purchased.
fix your issues,
green wire on tps.099 postive key on, black lead on meter- groound, 12v scale. adjust or replace
O2, BAD just replace em, there switching slow.
EGR valve, i took mine off.
Obviously whoever had this car before you didnt take care of it.
Next take your crappy timing of 8 degrees and advance it to 14 degrees with 89 octane min.
Every 5.0 ive run across, was poorly tuned
green wire on tps.099 postive key on, black lead on meter- groound, 12v scale. adjust or replace
O2, BAD just replace em, there switching slow.
EGR valve, i took mine off.
Obviously whoever had this car before you didnt take care of it.
Next take your crappy timing of 8 degrees and advance it to 14 degrees with 89 octane min.
Every 5.0 ive run across, was poorly tuned