Check engine

pryornfld · #1 12-22-2004, 09:11 AM

Hello All,

Just had a quick question. Right now I have the check engine light and it is pointing to both O2 sensors as being bad. Since Xmas is just around the corner and I really don't have the time or resources to check these sensors, is there a way I can reset the computer so that the check engine light won't come on. My gas milage is really bad since the light came on. I guess when it comes on, it puts the computer into some kind of idle mode, and fuel comsumption really suffers because of it.

12Ounce · #2 12-22-2004, 09:19 AM

Lifting the battery cable will make the light go away...but does nothing to fix the problem ...and the light will return in a few hundred miles or less. Don't assume the sensors are bad...in fact, there are other more likely problems.

Why don't you get the actual alpha-numeric codes (not what someone tells you they mean) and report them back here. AutoZone provides code scanning as a free service ... but make sure you have the CEL light before you go there.

pryornfld · #3 12-22-2004, 09:49 AM

Quote:

Originally Posted by 12Ounce

Lifting the battery cable will make the light go away...but does nothing to fix the problem ...and the light will return in a few hundred miles or less. Don't assume the sensors are bad...in fact, there are other more likely problems.

Why don't you get the actual alpha-numeric codes (not what someone tells you they mean) and report them back here. AutoZone provides code scanning as a free service ... but make sure you have the CEL light before you go there.

Got the codes scanned and it came back P171/P174. I think it meant Oxygen 1 sensor lean, Oxygen 2 Sensor rich. I had the same problems about 2+ years ago, O2 sensors replaced. SO this time I don't think that its the sensors. My mechanic said that sometimes when you have a misfire it can foul up the sensors, and he found that if you let the sensors sit in a bowl of coke/pepsi for about 1 Hr , they usually can be saved. Hopefully the case!! He checked for leaks, but there was no leaks to be found.

12Ounce · #4 12-22-2004, 10:25 AM

Your problem is at the top of the engine...vacuum leaks. If you do searchs here you will find several instances of folks correcting vacuum leaks. For the 3.8 this often means replacing the isolator bolts in the upper intake manifold. Not a big job .... about $50 in parts.

pryornfld · #5 12-22-2004, 11:43 AM

Quote:

Originally Posted by 12Ounce

Your problem is at the top of the engine...vacuum leaks. If you do searchs here you will find several instances of folks correcting vacuum leaks. For the 3.8 this often means replacing the isolator bolts in the upper intake manifold. Not a big job .... about $50 in parts.

Do you have a procedure or pictures of how the bolts should be replaced? I have an idea, but I'm not 100% sure if we are on the same page.

Windywoes · #6 12-22-2004, 12:20 PM

Quote:

Originally Posted by pryornfld

Do you have a procedure or pictures of how the bolts should be replaced? I have an idea, but I'm not 100% sure if we are on the same page.

Also look at TSB 3-16-1 at All Data. This procedure fixed my 171/174 problem. I was fortunate in that the dealer only charged me $100 deductible for the work. Others were paying over $700. I am not sure the average Joe can do all the work outlined in the TSB.

pryornfld · #7 12-23-2004, 06:31 AM

Quote:

Originally Posted by Windywoes

Also look at TSB 3-16-1 at All Data. This procedure fixed my 171/174 problem. I was fortunate in that the dealer only charged me $100 deductible for the work. Others were paying over $700. I am not sure the average Joe can do all the work outlined in the TSB.

For more difficult repairs I have a friend who is a backyard mechanic, and I know he can do the job. Haven't steered me wrong yet. Where would I go to get the TSB 3-16-1?

DRW1000 · #8 12-23-2004, 12:58 PM

It is in this forum about a month back. Search for 171/174 or isolator bolts or....

rodeo02 · #9 12-23-2004, 04:05 PM

Quote:

Originally Posted by pryornfld

Do you have a procedure or pictures of how the bolts should be replaced? I have an idea, but I'm not 100% sure if we are on the same page.

Is this in regards to a 1996 windstar?? (per your profile) No isolator bolt problems with the pre 1999 windstar as far as I know. It's very likely you have vacuum leaks somewhere (IMRC shafts vac leak or plugged EGR passeges maybe?). The 1995-1998 typically had head gasket issues. How many miles are on the van?
G/luck
Joel

wiswind · #10 12-23-2004, 07:05 PM

I agree with rodeo, the 96 through 98 windstars use a different upper intake manifold than the '99 and newer. The TSB that is talked about is for the '99 and 00 years. However, vacuum leaks still are a problem on the older (pre '99) vehicles. Just a different cause. The upper manifold bolts are fine for the '96 through 98. Check you PCV line....from the top of the upper intake manifold....next to the throttle body, and all the way to the PCV valve. Also, there are many vacuum connections on the back of the upper intake manifold. These hints will apply to all years.

Please post back what you find.
I had a pesky vacuum leak that ended up being on the inside of the elbow that is on the top of the upper intake manifold.....next to the trottle body....this is in the PCV line. Several other people have had this also.

pryornfld · #11 01-05-2005, 09:29 AM

Quote:

Originally Posted by rodeo02

Is this in regards to a 1996 windstar?? (per your profile) No isolator bolt problems with the pre 1999 windstar as far as I know. It's very likely you have vacuum leaks somewhere (IMRC shafts vac leak or plugged EGR passeges maybe?). The 1995-1998 typically had head gasket issues. How many miles are on the van?
G/luck
Joel

Rodeo02
I have a 96 Windstar with 172,000KM.How would I check for the head gasket?Also the mechanic couldn't locate any leaks.Would this indicate that the gasket is ok? Also had problems similar to this before and had the EGR ports cleared.Worked fine for about 2+ years. Could this be a cause of all my problems?

Thanks
Pryornfld

pryornfld · #12 01-05-2005, 09:30 AM

Quote:

Originally Posted by wiswind

I agree with rodeo, the 96 through 98 windstars use a different upper intake manifold than the '99 and newer. The TSB that is talked about is for the '99 and 00 years. However, vacuum leaks still are a problem on the older (pre '99) vehicles. Just a different cause. The upper manifold bolts are fine for the '96 through 98. Check you PCV line....from the top of the upper intake manifold....next to the throttle body, and all the way to the PCV valve. Also, there are many vacuum connections on the back of the upper intake manifold. These hints will apply to all years.

Please post back what you find.
I had a pesky vacuum leak that ended up being on the inside of the elbow that is on the top of the upper intake manifold.....next to the trottle body....this is in the PCV line. Several other people have had this also.

Wiswind: I had the mechanic check for leaks, and he said that he couldn't find any. Could it be possible that the PCV be blocked or some other sensor. How would I check this?

Thanks
Pryornfld

wiswind · #13 01-07-2005, 11:57 PM

On the '96, the PCV valve is in the BACK valve cover. I pulled mine out of the valve cover to verify flow condition.
If you replace the PCV valve.....take note that some have had an issue with after market PCV valves....that have had too much airflow.

The sensor that comes to mine that would be worth checking....would be the MAF (MAss Air Flow)sensor. This is the large part of the air intake that is right next to the air filter. When you release the band that holds the air filter assembly.....it comes apart in 2 parts.....1 part holds the air filter, the other part is the MAF.

Looking into the MAF sensor from the air filter side....you will see a screen.....through the screen, you will see a black plastic "bar" that goes across the bore. In this bar, there are 2 holes....one facing you (screen side) and one at the other end of the bar.....facing away from you. Air flows in one hole and out the other hole.....and the actual sensors are inside the bar.

To clean the MAF sensor, you need to spray non-residue electronic cleaner so that it goes in one of the holes in the bar....and flows out of the other hole. Make sure that the air intake hose, and filter assembly are reassembled so as to not have any leaks.

There is a thermal sensor that is mounted on the front side of the flexible hose.....electrical connection with wires.

There is also a stiff plastic tube that connects to the rear side of the flexible hose....nearly opposite the thermal sensor. Make sure that this tube is in place. It goes to the FRONT valve cover....and is the fresh air supply to the crankcase.....to replace the air drawn out through the PCV valve. The air flows out of the flexible hose....and into the crankcase.....and....thus....is measured as part of the airflow through the MAF sensor. In other words, the PCV flow into the manifold, is measured along with the other air going into the manifold.

You could also check to make sure that the bolts that hold down the upper inake manifold (12 bolts) are snug (do not overtighten....they do not require much torque).

NYranger · #14 01-09-2005, 12:54 PM

You are very good Wiswind!

9civic5 · #15 01-10-2005, 01:54 PM

I'm currently having the same problems with a 99 that my mother-in-law gave my wife (P0171/P0174).

A dealer mechanic said that the problems were in the sensors and charged her over $300 to replace. Then the light came back on and now they're saying it is something else besides the intake manifold. She bit and now out another $400 for some work I have no clue about.

Anyway, after researching the code problems on this forum, I'm about 99.9% sure that the problem is the intake manifold. Now, my problem is that I'm looking for someone in Southern California (Orange County or Riverside County) to do the work and not charge me a arm and a leg. Or help me in doing the work if they've done it themselves.

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