Work In Progress...

[Ranger]

Carla, you are correct, your engine does not have the type of overpressure relief valve that Jim is talking about. On the '93 & '94 the manifold cover actually lifts to vent the pressure in the event of a backfire. That is why there are rubber grommets I believe and torque values are important. It should not be torqued down real tight.

[CarlaValentine]

It's hard to be exactly on the nose with the torque wrench I have at that low of a spec, but they are all torqued between 9-10 Nm. The plastic wiring cover under the manifold cover specifies between 8-11 Nm for the cover bolts, as you can clearly see in the picture, so I know there's no issue there. And yes, there are rubber grommets that go under the bolts between them and the cover, and I also made sure the gasket under the cover was still in good repair.

Just to be sure I checked the FPR right, I assume the place I was supposed to be looking for leaking fuel when I turned the key to the "on" position is that metal tube/nipple thing sticking up from it in the picture. Am I right? If not, then I was looking in the wrong place, and I would like to know before I pull the cover back off to change the MAP sensor.

[PAUL T]

Carla, I would locate the PCM. My book says it is located under the dash on the passenger side. See if you can pull it down and check the connection. It can also get wet if the heater core is leaking. Leave it down and see if tapping on it when the car acts up has any effect. I would almost bet that it might be going bad. Part of the diagnostics of the MAP is a bad PCM. But make sure you check the battery connection first. Make sure it is tight because a loose battery connection can cause the same problems.

[jackc]

On the '93 & '94 the manifold cover actually lifts to vent the pressure in the event of a backfire. That is why there are rubber grommets I believe and torque values are important. It should not be torqued down real tight.

FYI - The 93-94 manifold cover bolts have collars above the threads that bottom-out when tightening the bolts. There should not be a danger of overcompressing the rubber grommets. The low torque value is to keep you from pulling the threads in the manifold.

[CarlaValentine]

Carla, I would locate the PCM. My book says it is located under the dash on the passenger side. See if you can pull it down and check the connection. It can also get wet if the heater core is leaking. Leave it down and see if tapping on it when the car acts up has any effect. I would almost bet that it might be going bad. Part of the diagnostics of the MAP is a bad PCM. But make sure you check the battery connection first. Make sure it is tight because a loose battery connection can cause the same problems.

I have ruled out the battery and the battery connections. The car had a new battery, cables, connector bolts, and starter installed a month or so before I bought it back in late August. Also, when I had the battery disconnected to change the spark plugs and wires, I checked the connections and as expected with brand new cables and all, everything was spotless, and I made sure they were tightened down well when I hooked everything back up.

I'm a little weary when it comes to touching anything electronic (fire and electricity are my 2 biggest fears) but I will try to overcome that and pull out the PCM and check it if I can keep the car running long enough to do so.

I went out this morning to try and drive the car around the back streets by my house. It started fine, but idled very low (400-ish). I got it in gear fine, and it drove ok for about 5 minutes before the SES light came on and it died. I got it started again, spitting and sputtering but didn't sound like a misfire, AWFUL smell of gas and a LOT of smoke from the exhaust this time (normal grey color). I had to hold my foot on the gas for a few seconds to keep it running. SES light came on right away. I got it to my driveway and immediately pulled the codes while the car was still running.

P032: C: open MAP signal

P071: C: Intermittent MAP signal

P095: H: Engine Stall Detected

I039: C: Loss of RSS data

T027: C: LF wheel speed sensor continuity fault (disregard this one, I have already found this problem. I just haven't fixed it yet)

I would assume from this that my problem is a bad MAP sensor. Is there anything other than that or a bad PCM that could cause these symptoms? I'm going to pay for and order the new MAP sensor today, but it won't be in until Wednesday.

[PAUL T]

Carla here is the diagnostic check list for the P071 code.

1.) "ignition on" enter diagnostics

select PCM DATA PD02 (Map Sensor)

Note display

2.) 20 to 84 kPa

Replace MAP sensor

3.) 85 to 105 kPa

Remove intake cover

Connect vacuum source to MAP sensor

Note PCM Data parameter PD02 as you slowly apply vacuum

to the sensor up to 20". Each 1" of vacuum should result in a 3 to 4

kPa drop in PD02.

Watch for a skip or jump in parameter PD02 value. A skip or jump indicates a bad MAP sensor

With 20" of vacuum applied note PD02 Parameter

4.) 35 to 103 kPa or 14 to 25 kPa replace MAP sensor

5.) 26 to 34 kPa

release vacuum to sensor

does display return to original reading?

6.) If yes

perform powertrain ground check

Powertrain grounds are located: 1.) right front corner of engine compartment in front of the battery (ground for battery)

2.) right rear corner of the block and to the right of the rear exhaust manifold (ground for all powertrain electronics including PCM)

3.) front side of left rear seat diagonal brace.(ground for fuel pump)

7.) If no

Replace MAP sensor

End

[CarlaValentine]

Carla here is the diagnostic check list for the P071 code.

1.) "ignition on" enter diagnostics

select PCM DATA PD02 (Map Sensor)

Note display

2.) 20 to 84 kPa

Replace MAP sensor

3.) 85 to 105 kPa

Remove intake cover

Connect vacuum source to MAP sensor

Note PCM Data parameter PD02 as you slowly apply vacuum

to the sensor up to 20". Each 1" of vacuum should result in a 3 to 4

kPa drop in PD02.

Watch for a skip or jump in parameter PD02 value. A skip or jump indicates a bad MAP sensor

With 20" of vacuum applied note PD02 Parameter

4.) 35 to 103 kPa or 14 to 25 kPa replace MAP sensor

5.) 26 to 34 kPa

release vacuum to sensor

does display return to original reading?

6.) If yes

perform powertrain ground check

Powertrain grounds are located: 1.) right front corner of engine compartment in front of the battery (ground for battery)

2.) right rear corner of the block and to the right of the rear exhaust manifold (ground for all powertrain electronics including PCM)

3.) front side of left rear seat diagonal brace.(ground for fuel pump)

7.) If no

Replace MAP sensor

End

Ok, I'm pretty sure I understand this right but I just want to make sure. by "ignition on" in step 1, I assume you mean without the car running, correct? I know the manifold cover could not be removed in step 3 with the car running.

[Cadillac Jim]

Well, it certainly is an electrical problem with the MAP wiring. The MAP performs several functions related to mixture and idle speed control. Once the code is set CURRENT the software will make assumptions about things and the car should run OK but the transition can be rough, as you described. Perhaps some of the wiring fixes you put in came undone with a rough start? Or, another spot of bare wire?

[PAUL T]

Ok, I'm pretty sure I understand this right but I just want to make sure. by "ignition on" in step 1, I assume you mean without the car running, correct? I know the manifold cover could not be removed in step 3 with the car running.

Yes, engine off. Jim is right it could be another short in the wiring to the MAP.

[Ranger]

Just to be sure I checked the FPR right, I assume the place I was supposed to be looking for leaking fuel when I turned the key to the "on" position is that metal tube/nipple thing sticking up from it in the picture. Am I right?

Yup, that's the way to do it.

FYI - The 93-94 manifold cover bolts have collars above the threads that bottom-out when tightening the bolts. There should not be a danger of overcompressing the rubber grommets. The low torque value is to keep you from pulling the threads in the manifold.

Thanks Jack. Never had one so I was going from what I remembered here.

[CarlaValentine]

Well, it certainly is an electrical problem with the MAP wiring. The MAP performs several functions related to mixture and idle speed control. Once the code is set CURRENT the software will make assumptions about things and the car should run OK but the transition can be rough, as you described. Perhaps some of the wiring fixes you put in came undone with a rough start? Or, another spot of bare wire?

There's no way the tape could have come off. I used thermal electrical tape. It looks kinda like duct tape, but way more sticky, and it's meant for high-temp electrical applications. I figured plain old electrical tape just wasn't gonna cut it. I scanned every millimeter of wiring that I could see under that cover and didn't see another bare spot anywhere. The ONLY other thing that comes to mind as far as possible wiring problems is this:

There is oil spray under the cover (yes I know this is normal and nothing to be concerned with). I also noticed that there is a coupler where 2 wires run into 1 coming from the wiring off of the MAP sensor. According to the service manual my father has, that coupler is supposed to be there, so that's not my concern. What I am wondering however is if there is a possibility that some of the oil spray could get into that coupler and interfere with the wiring/current? Or if it's possible that oil could get into the connector plug that hooks into the MAP itself and pose a problem there? I pulled the plug off and it appeared clean to look at it, but that doesn't mean there couldn't be oil hiding in it somewhere. If either of these could pose an issue, then putting a new sensor in isn't going to solve my problems without taking care of the wiring.

Another thing just occurred to me. I have no idea whatsoever if this has anything to do with anything...but I figured I would mention it anyway. My car has spent its ENTIRE life in Texas until this last summer. This is the first time it has ever seen very cold temperatures, and it ran PERFECT until it started to get really cold out. Could the fact that the car spent 15 years in warm weather and now all of a sudden it's in below freezing temperatures have anything to do with its sudden problems? I imagine it could be a sort of "shock" to any system.

Also, for the record, while looking through service records for my car today (which are few and far between) I found that the spark plugs I just took out and replaced were only about 30,000 miles old. You wouldn't think that to look at them. The wires however were not replaced with the plugs. If they were, the receipt doesn't say so.

[Cadillac Jim]

Going by the codes (open MAP signal, intermittent MAP signal) it looks like a bad connection to the MAP sensor. Perhaps the terminals in the connector are loose? Did the connector pull off a little too easily? Also, you might check the cable on the other end: the PCM.

As far as temperature goes, I don't think it's shock so much as any car will get a little cranky when parked outside in the wind when it is verrry coooold. I think that your dimmer switch problem is an example of that. The slightest condensation from whenever, frozen, becomes a tiny ice crystal to prop up the wiper on the potentiometer inside the dimmer in the light switch. Or, it might have been just a little sticky or stiff and not made good contact. The same holds for connectors and contacts in the wiring harness, etc. But, I don't think that having been in Texas made the car any more susceptible to the cold. Sitting for a long time without being driven might make the car more susceptible to the cold because any condensation that would occur in the night wouldn't ever be dried out by driving the car, warming everything up, etc. I think that once you get the MAP problem cleared up and start driving the car every day, the cobwebs will fall away.

From your excellent photographs of the spark plugs earlier in the thread, I thought that they looked pretty good to me. I would hope that they would look that good at 30,000 miles. I think it's bad luck to change the plugs without changing the plug wires, but that's just me. The plugs come from the factory gapped and with just the right anti-seize on the threads for trouble-free use, and the wires come with just the right sealing in the plug boots to seal moisture and prevent arcing in the plug wells, and it's necessary to duplicate that when putting together a kit or in replacing everything. Also, if you don't use AC/Delco wires, they can give trouble or not last like OEM plug wires.

[CarlaValentine]

Going by the codes (open MAP signal, intermittent MAP signal) it looks like a bad connection to the MAP sensor. Perhaps the terminals in the connector are loose? Did the connector pull off a little too easily? Also, you might check the cable on the other end: the PCM.

As far as temperature goes, I don't think it's shock so much as any car will get a little cranky when parked outside in the wind when it is verrry coooold. I think that your dimmer switch problem is an example of that. The slightest condensation from whenever, frozen, becomes a tiny ice crystal to prop up the wiper on the potentiometer inside the dimmer in the light switch. Or, it might have been just a little sticky or stiff and not made good contact. The same holds for connectors and contacts in the wiring harness, etc. But, I don't think that having been in Texas made the car any more susceptible to the cold. Sitting for a long time without being driven might make the car more susceptible to the cold because any condensation that would occur in the night wouldn't ever be dried out by driving the car, warming everything up, etc. I think that once you get the MAP problem cleared up and start driving the car every day, the cobwebs will fall away.

From your excellent photographs of the spark plugs earlier in the thread, I thought that they looked pretty good to me. I would hope that they would look that good at 30,000 miles. I think it's bad luck to change the plugs without changing the plug wires, but that's just me. The plugs come from the factory gapped and with just the right anti-seize on the threads for trouble-free use, and the wires come with just the right sealing in the plug boots to seal moisture and prevent arcing in the plug wells, and it's necessary to duplicate that when putting together a kit or in replacing everything. Also, if you don't use AC/Delco wires, they can give trouble or not last like OEM plug wires.

The plugs didn't look terrible, as I said before, but a few of them were much darker than the rest and they were ALL over-gapped, most of them by at least .005. Changing the plugs and wires seems to have cleared up my issues with the misfire/dead cylinders. If I can manage to get the car to stay running long enough I would like to do another Fuel Injector Disable check via PCM Override and see how the cylinders pan out with that. My high/erratic idle issue was resolved by cleaning and readjusting the ICM. I'm really hoping the MAP is the root of my stalling problems.

I dread pulling the PCM to check it. I really do. I think my biggest fear is pulling something loose or breaking something....or possibly shocking myself. What are the odds of any of these happening? Are there any screws I have to take out of it? Should I disconnect the battery before I go checking out wiring connections on it so I don't screw anything up? I'd hate to have to replace the PCM because I messed it up. I also have no idea where to look for the MAP connector on it... I just don't like to delve into things I have no understanding of. I feel it's better to admit you don't know something than to pretend you do and break it.

Also, the connector on the MAP sensor was a PITA to get off....especially since it had oil on it to make it nice and slippery, lol.

[CarlaValentine]

I have in front of me a brand new MAP sensor. Unfortunately however, I also have 2 sick kids home from school today, and my boyfriend and I are sick as well. He went to work anyway, but I have a feeling he will be coming home early. I really want to go put this new sensor in, but I feel like I got hit by a dump truck that mercilessly left me to live and suffer through the pain. I think for once I am going to ignore my stubborn "do it anyway" attitude, and give myself some apparently needed rest. I'll be on here throughout the day, as I usually am, but I don't think I am going out in the cold for any reason short of my house catching on fire today. Blah...I feel awful.....

[Ranger]

Wise decision. The car will be there tomorrow.

[Cadillac Jim]

The odds of getting shocked are nil unless you are working with the ignition of a running car these days. The biggest danger from the electrical system is shorting to ground through a ring, watch, bracelet, or some such, which can result in burns that can be very serious. Experienced mechanics always remove their watches and rings before sticking their hands into an engine compartment when the battery is connected. When you disconnect a battery, disconnect the ground terminal first because it isn't "hot" and once it's disconnected, the positive terminal isn't hot either. So, that way, you never have to work with a wrench on hot terminals.

I wouldn't remove the PCM. The odds of it, or any module, being bad are slim to none. You'll recall that I said in an earlier post that these don't go bad unless someone reverse-connects jumper cables from another car with a better battery, putting negative voltage on your electronics, or over-Voltages it by using a fast charger without disconnecting the battery, or pops a terminal with static electricity. All are pretty difficult to do, and if your car runs at all you have a functioning PCM. Also, your best method of checking an PCM is to put it in a car and start it and look for codes, which you can do now. However, check the connector for being clean, its terminals being tight, and the connector being on properly and firmly.

Take care of yourself first. Once you are done with the MAP sensor and its wiring, and have the wheel speed sensor fixed, you will have that car for a long time.

The wheel speed sensor supports ABS, Stabilitrak, and the ride sensing suspension. When that wheel sensor is fixed, your car will be as safe as a new Cadillac, assuming that the tires are good and properly inflated, the brakes are in good condition, etc. which in your case I do believe is a pretty safe bet.

[CarlaValentine]

When that wheel sensor is fixed, your car will be as safe as a new Cadillac, assuming that the tires are good and properly inflated, the brakes are in good condition, etc. which in your case I do believe is a pretty safe bet.

The wheel sensor just needs a new connector to the wheel hub. It's badly corroded.

It's got one rotor on the rear driver side that has a little bit of warp to it, but it's not severe. It developed when the weather started to get really cold. I only really notice it if I apply the brakes at speeds higher than 40 mph or so. At low speeds you barely know it's there. It's getting all new rotors, pads and calipers in the spring though, so I won't have to worry about that for long. They are still in good shape, but I want them to be in perfect shape. Those brakes have a lot of car to stop. The tires are all new. My father had just bought a set for his Chrysler that were the same size my car has, and when he learned my car needed new tires after I bought it he gave them to me instead. They are Goodyear all season something-or-others...I can't remember exactly. They are pretty good on my car. It's a tank in this snow!

[jackc]

You might check the cable on the other end: the PCM.

On a 93 (and I assume a 94), there is another connection to check - where the manifold harness plugs into the main harness. The manifold harnesses (pretty sure there are 2) exit the bottom of the manifold just forward of the throttle body, where they go down and plug in (to the left of the throttle body - if you're standing at the drivers fender looking in). Just feel around the bottom of the manifold for the harnesses and follow them down to the plugs.

As for the issue of this being a Texas car, it is important to know if you've removed the empty beer cans from the back seat. Texas cars bond electrically to the aluminum in the cans, and removing them can cause all kinds of problems.

[CarlaValentine]

You might check the cable on the other end: the PCM.

On a 93 (and I assume a 94), there is another connection to check - where the manifold harness plugs into the main harness. The manifold harnesses (pretty sure there are 2) exit the bottom of the manifold just forward of the throttle body, where they go down and plug in (to the left of the throttle body - if you're standing at the drivers fender looking in). Just feel around the bottom of the manifold for the harnesses and follow them down to the plugs.

As for the issue of this being a Texas car, it is important to know if you've removed the empty beer cans from the back seat. Texas cars bond electrically to the aluminum in the cans, and removing them can cause all kinds of problems.

Hahaha, I guess someone must have beaten me to the cans. The car was pretty clean when I got it except for a small red wagon full of old Matchbox cars in the trunk. (my 6 yr old son LOVED that)

Thanks for the info on the manifold harness. I briefly tried to follow it when I had the cover off the other day, but it was so cold out I didn't have the patience to spend much time on it. Not to mention how crowded everything is under that hood. It was like looking for a needle in a haystack. I lost my flashlight into that abyss. Thank goodness it was on or I never would have found it! Lol. I can see why they had to put the starter inside the engine, under the manifold...they ran out of room to put it anywhere else.

Hopefully I'll be feeling better tomorrow. I really want to get my car done as soon as I can. Me and the boyfriend have a trip planned for next weekend for our anniversary, and I'd really like to be able to take my/our own car.

[Cadillac Jim]

... It's got one rotor on the rear driver side that has a little bit of warp to it, but it's not severe. It developed when the weather started to get really cold. I only really notice it if I apply the brakes at speeds higher than 40 mph or so. At low speeds you barely know it's there. It's getting all new rotors, pads and calipers in the spring though, so I won't have to worry about that for long. They are still in good shape, but I want them to be in perfect shape. Those brakes have a lot of car to stop. The tires are all new. My father had just bought a set for his Chrysler that were the same size my car has, and when he learned my car needed new tires after I bought it he gave them to me instead. They are Goodyear all season something-or-others...I can't remember exactly. They are pretty good on my car. It's a tank in this snow!

You can almost certainly re-surface your rotors and won't need to replace them. Even if you get new rotors it would make sense to resurface them lightly to ensure that they were really flat. Just be sure to sequence and torque the lug nuts properly so that they stay that way once back on the car. And, be careful and don't drop them on the bearings or hubs.

[CarlaValentine]

... It's got one rotor on the rear driver side that has a little bit of warp to it, but it's not severe. It developed when the weather started to get really cold. I only really notice it if I apply the brakes at speeds higher than 40 mph or so. At low speeds you barely know it's there. It's getting all new rotors, pads and calipers in the spring though, so I won't have to worry about that for long. They are still in good shape, but I want them to be in perfect shape. Those brakes have a lot of car to stop. The tires are all new. My father had just bought a set for his Chrysler that were the same size my car has, and when he learned my car needed new tires after I bought it he gave them to me instead. They are Goodyear all season something-or-others...I can't remember exactly. They are pretty good on my car. It's a tank in this snow!

You can almost certainly re-surface your rotors and won't need to replace them. Even if you get new rotors it would make sense to resurface them lightly to ensure that they were really flat. Just be sure to sequence and torque the lug nuts properly so that they stay that way once back on the car. And, be careful and don't drop them on the bearings or hubs.

I was thinking about getting the bad one resurfaced for now, until I get the new ones on in the spring. If I do one I should do them all, right?

[Ranger]

No need to do all 4, but you should do both front or both rears. Don't just do one side.

[CarlaValentine]

No need to do all 4, but you should do both front or both rears. Don't just do one side.

Thanks.

I've been having a stare-off with my car out the window all day. I want it running, now. I think I can hear the new MAP sensor talking to me, lol. Everyone in my house is still sick. My daughter has thrown up on me, my boyfriend has been in the hospital all day...I still feel half-dead. This better be over with soon so I can finish my car.

[Bruce Nunnally]

Hope you feel better soon.

[CarlaValentine]

Hope you feel better soon.

Thank you Bruce.