Ford Taurus Check Engine Light

Reply

  #1  
Old 09-08-04, 01:33 PM
Member
Thread Starter
Join Date: Sep 2004
Posts: 238
Ford Taurus Check Engine Light

My problem started with a burst heater hose. Since replacing the hose, in the morning after 10 minutes of driving I often feel a slight stumble followed shortly by a check engine light that randomly comes on and goes off seemingly without regard to how I am driving. Other than the slight stumble (miss?) it drives fine. The car is a '94 Ford Taurus with 147,000 mi and 3.0 l V-6 engine.

Here is what I did:

1 I had Auto Zone read the code. It was a 332, no evidence of EGR, and they sold me a EGR valve for about $50.

Nothing changed.

2 I then had a shop look at it. They pulled a 565, canister purge failure, a 172, cyl 1-3 too lean, a 173, cyl 1-3 too rich, a 452, no data from vehicle speed sensor and another code, neutral safety switch out of range. He said the burst heater hose had nothing to do with the problem, and you can take a bath with modern engines. He said a bad ignition switch was tricking the computer and installed a new one for $121.

Nothing changed, so I went back the second day for my $121. He said he would have another look. He called, and said that I needed the switch PLUS a mass air flow sensor for an additional $250. He could not explain why the MAF sensor was fooling the computer as had the ignition switch the day before, so I cut my losses and passed on additional work from this guy.

3. After toiling for a few more days on my own, I went back to Auto Zone for another reading. They pulled the same codes as the guy above with the addition of 332.

4. I finally took it to the dealer and they tried to sell me a computer, a EGR pressure sensor and a MAF sensor cleaning for about $550. I paid them $70 for the advice and passed on the work. When I told him about the heater hose break just prior to the problem, he just stared at me and did not respond.

5. I took the EGR pressure sensor to Auto Zone and had them do a bench test. The guy said it was fine and compared to one in the box. I also got 15" vacuum at the valve while revving the engine, so the valve must be opening.

6. Finally I figured out how to read the codes by connecting a jumper wire and counting check engine light flashes. Also, once I was able to see the car in full sunlight, I noticed orange silicone sealant where the EGO sensor and VSS wire come out of the harness. In the past (factory floor?) someone repaired stripped wire with sealant. The burst heater hose had loosened most of this and bare copper was visible on all six wires to these 2 sensors.

I believe I repaired the wiring. To test this, I pulled the 80 ? pin connector at the fire wall and checked for continuity at two EGO sensor wires. I got no continuity between the wires or to ground from each. I reconnected the wiring harness and turned the ignition to run. Here I tested the other two EGO sensor wires, the heater wires, and I got 12 V.

On the VSS, working again at the 80 pin connector, I got 26,000 ohms to ground on one side and 0 on the other. My wiring diagram from the Auto Zone web site shows one side grounded. Is the 26,000 ohms a problem? Should it be infinite? The actual sensor was disconnected, since I was only testing the wiring. I also tried it with the sensor connected and record infinite resistance, but I did not check it on the 1K scale and maybe it was 26,000 ohms too.

5. Since my wiring repair, the check engine light comes on just as it did the day after the heater hose broke. However the range of codes is much smaller. After each drive where the check engine light comes on, I check the codes and then clear them. I always get a 172, too lean and 332, no EGR. Approximately 80% of the time I get a 452, no VSS data. Approx. 30% of the time I get a 173, too rich. Maybe 10% of the time I will get a 565, canister purge failure or a neutral safety switch out of range.

What is going on? I plan to switch the two EGO sensor to determine if it is a sensor or wiring/ computer problem. BUT... maybe an injector is failing making it too lean the computer compensates and then it starts working again making the mixture too rich. Maybe random missed spark will do the same thing? The injectors and plug wires also took a bath in hot coolant.

What about the 332? The EGR valve is opening since I have vacuum, but the solenoid valve that controls the vacuum also took a bath. Maybe it shuts of vacuum to the EGR valve at random too?

Any suggestions?
 
Sponsored Links
  #2  
Old 09-08-04, 04:06 PM
Desi501's Avatar
Member
Join Date: Oct 2003
Location: Boynton Beach Florida
Posts: 2,207
Well where do we start. First, stay out of Auto Zone with this car. They cannot read codes on a 94 Taurus. They can only read OBDII generic codes and your car doesn't use that system. The only shop you visited that seemed to have any clue was the dealer. There are 3 places to get codes on a Ford and your only getting one. You need to distinguish between hard and soft codes before you proceed. This isn't really a job for a DIYer without the right equipment. Fords can be tough if your not real familiar with them.
 
  #3  
Old 09-08-04, 09:58 PM
squidgrouch
Visiting Guest
Posts: n/a
The computer relies on info from the o2 sensor, to verify egr operation. The egr may be opening, but is there egr flow? Since the lean, and the rich code are for right bank, it is possible that the o2 sensor for that side has failed. Typically, a maf sensor problem affects both banks, and usually a 171, and 174. But whatever you do, use factory parts. The new egr valve you installed is probably inferior to the used one, that most likely is still functioning. One more ? How hot did the engine get, when the hose blew?
 
  #4  
Old 09-09-04, 03:51 AM
Member
Join Date: Dec 2001
Posts: 2,538
I would suspect the ford dealer was correct about it needing a dpfe sensor or egr pressure sensor as it commonly fails, if it is the dual overhead cam 3.0 liter the egr passages is likely plugged which could also cause code 332.
you can check the maf by removing the 2, t20 security torx screws and checking the 2 wire elements for any build up on them if there is any a quick spray of carb cleaner usually cleans them up and then just reinstall. ford has issued technical service bullitons recomending not to clean the maf sensor and instead just replacing the sensor, however cleaning the sensor if needed usually saves you from buying a new sensor and is commonly done instead of folliwng ford's tsb.
I would start with the above if you are going to attempt to fix it yourself and then see what codes return and if the check engine light comes on again, as desi said some codes may not be a soft code and not set off the check engine light or cause driveability problems.
 
  #5  
Old 09-09-04, 09:35 AM
Member
Thread Starter
Join Date: Sep 2004
Posts: 238
Thanks all for the input.

I'm driving my '67 bug now, so the Taurus is cool enough to work on before it gets dark in the evening. The bug has taken to backfiring while coasting in gear with the throttle shut (coasting down hill or coasting to a red light). I just replaced the carb (previous one leaked gas at throttle plate shaft and no one in town would re bush it) with a new stock-type Brazilian one. The guy I buy air-cooled VW parts from said the muffler is bad. The instructions in the box said not to ever adjust the closing point of the throttle plate and to only adjust idle speed with the bypass screw. I set the idle mixture as I have allways done on VW.

Any thoughts on the VW?

BACK TO THE REAL PROBLEM:

No one said anything about the 452, no data from vehicle speed sensor.

Desi501:
Ok, I'll stay out of Autozone. Maybe thier bench test of the EGR pressure sensor was no good. The guy had a Wells instruction binder and followed the directions. That was the first time they tried NOT to sell me something. More background: the dealer replaced that and the canister purge valve 17 months back.

Per my Haynes book there are 3 classes of codes. The KOEO is a test routine with the key on engine off. The 565 was a KOEO. The second group the book called constant memory, codes set while on the road. The C codes are 172, 173 and 452. The final group KOER is a test routine done parked with the engine running. Here the 332 showed.

Squidgrouch:
I'll pull the EGR pipe off the EGR valve and then open it with a vacuum pump at idle and see if the car dies or if I can feel suction at the pipe connection.

I will proceed with my planned switching of my 2 o2 sensors to see if the problem moves to bank 2 along with the presumed bad sensor.

The engine did not get hot when the hose blew. I was about 100 yards from home. The hose sprayed hot water on the back of the engine for about 10 minutes as presssure vented and the car cooled while parked in front of the house.

bejay:
I will check for EGR flow as stated above.
No it is not a dual overhead cam engine. It is a garden-varity single cam pushrod engine as manufactured since the dawn of time.
I will also look at the MAF sensor. I already sprayed carb cleaner down the throut. I guessed there was nothing to clean in the attached plastic box. But now I will get a center pin torx driver and open it up.
 
  #6  
Old 09-09-04, 06:45 PM
Desi501's Avatar
Member
Join Date: Oct 2003
Location: Boynton Beach Florida
Posts: 2,207
Originally Posted by peabees
Per my Haynes book there are 3 classes of codes. The KOEO is a test routine with the key on engine off. The 565 was a KOEO. The second group the book called constant memory, codes set while on the road. The C codes are 172, 173 and 452. The final group KOER is a test routine done parked with the engine running. Here the 332 showed.

Squidgrouch:
I'll pull the EGR pipe off the EGR valve and then open it with a vacuum pump at idle and see if the car dies or if I can feel suction at the pipe connection.
Your correct on the code info. As far as testing the EGR, we don't generally remove the exhaust tube. The stalling effect is caused by the exhaust being drawn in. It won't stall with the pipe off. That would just give it a vacuum leak. Watch to see if your vacuum pump leaks down or holds vacuum also.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes