Taurus Car Club of America : Ford Taurus Forum banner

41 - 50 of 50 Posts

·
Registered
Joined
·
572 Posts
Discussion Starter #41
OK, got the car back the other day after getting the brake lines repaired. The guy said he couldn't find a vacuum leak and that my brake booster tested out OK. Car seems to be running better now, not sure if it was weather related as it was warm that day. The odd thing is that the brake pedal no longer appears to be stiff after sitting for a few hours. Not sure if he unknowingly fixed the problem.

Still wondering if the old battery had something to do with it running lean. The car was still running lean even after installing the new battery, but after replacing the brakes, the computer may have relearned it's idle. Perhaps the old battery did not put out enough amperage and was corrupting the memory, but that wouldn't explain the brake pedal being stiff.
 

·
Registered
Joined
·
572 Posts
Discussion Starter #42
Update

Car is running better, but still seems to lack some power at times, particularly when taking off from a stop and getting up to about 35-45 MPH. Tachometer gets to about 2000 RPM while accelerating at 55 MPH, but I can't remember if that's right.

Driving it today, the distance to empty dropped about 43 miles for a 28 mile trip. However, MPG's was a good 23.5.:huh: (I do reset the MPG's after filling the tank).

At least the car accelerates while in motion where before the engine would rev but the car would barely speed up. One thing I have noticed is that the gas petal feels firmer then usual. Brake booster reservoir appears to be holding as the petal is not stiff the next day. (I installed hose clamps on the ends of the booster hose to eliminate possible leaks). No DTC's were present during a check today.
 

·
Registered
Joined
·
572 Posts
Discussion Starter #43
^To add to the above, the brake petal tends bounce between a firm petal and and a softer, more normal petal while running. That did go away for a while after installing the hose clamps, but was also present before my issues. The booster, however, is still holding the reserve vacuum since installing the clamps.

Also, can anyone confirm what the RPM's should be at while cruising at 70 MPH? I got 2,400, which seems to be about 200 RPM's higher than before my problems.
 

·
Registered
Joined
·
572 Posts
Discussion Starter #44
I have some good news. I traced the firm brake petal and sluggish acceleration to the brake booster check valve. After replacing it, the car now accelerates the way it should and the brake petal is no longer firm while braking.

But....

Now the booster is losing the reserve vacuum again, resulting in a stiff brake petal when starting the car the next day. This happened with the old check valve, but went away after installing the hose clamps. The clamps are still installed on the new one, so I can't understand why it's losing it's reserve vacuum. Everything looks good as far as I can tell, and the engine idles smoother and has more power. Any suggestions?
 

·
Premium Member
Joined
·
1,522 Posts
Loosing reserve means either new check valve is bad, vacuum leak where it plugs into booster or booster itself is leaking.
Repl. valve may be slightly smaller where it plugs into booster than the original.
 

·
Registered
Joined
·
572 Posts
Discussion Starter #46
Loosing reserve means either new check valve is bad, vacuum leak where it plugs into booster or booster itself is leaking.
Repl. valve may be slightly smaller where it plugs into booster than the original.
Hmmm.... The new check valve has to be OK as the car performs much better than before. The replacement came with a new grommet, but I wasn't impressed with it, so I reused the original. (After removing it, cleaning it and verifying that it was in good condition). Yes, the ends of the valve were slightly smaller as I compared the two, but I pretty much had to put my body weight on it while installing, so it has to have an airtight seal. It's down as far as it will go.

The check valve isn't OEM. It is made by Dorman, which claims that it's universal with other makes and models. Seems to have mostly positive reviews.
 

·
Registered
Joined
·
3,224 Posts
Hmmm.... The new check valve has to be OK as the car performs much better than before. The replacement came with a new grommet, but I wasn't impressed with it, so I reused the original. (After removing it, cleaning it and verifying that it was in good condition). Yes, the ends of the valve were slightly smaller as I compared the two, but I pretty much had to put my body weight on it while installing, so it has to have an airtight seal. It's down as far as it will go.

The check valve isn't OEM. It is made by Dorman, which claims that it's universal with other makes and models. Seems to have mostly positive reviews.
It could still be leaking, just not as much as the old one. Or the check valve AND booster leak. What he said is pretty much spot on, you still have another leak to find. Sucks, I know.
 

·
Registered
Joined
·
572 Posts
Discussion Starter #48
The car has been running and shifting fine since the last post here. However, today the sluggish shifting started to rear it's ugly head again as described in my initial post. I'm going to get the battery load tested soon as I believe that low amperage to the PCM is what's causing the problem.

Regarding the brakes; I still have the hard petal at times while braking, but not when parked overnight. (loss of brake booster pressure). Brake petal does go down gradually to where it should be under hard braking, sometimes loosing up under gradual braking while hitting a bump. (Sticky brake pads?) I don't suspect a vacuum leak anymore, though I still can't figure out why the brake booster reserve was intermittent while originally troubleshooting the shifting issue.
 

·
Premium Member
Joined
·
1,522 Posts
Pedal drop on a bump could just be the ABS kicking in. A weak or dirty sensor can make it more sensitive though.
Booster reserve being intermittent is the check valve. Dorman parts are not that great, I only use their stuff as a last resort or temp. fix.
 

·
Registered
Joined
·
3 Posts
AX4N solenoids?

My 05 bull se (3.0L) wont shift 2-3. Changed filter & almost 7 qts fluid. Made reverse & gears 1 and 2 ALOT stronger without the lurch. Do l need sensors, solenoids, or valve body? Any thoughts appreciated. (except You, i know what youre thinking...)
 
41 - 50 of 50 Posts
Top