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Dan
Dan, Technician
Category: Car
Satisfied Customers: 24442
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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1999 Mercury Villager 1. Car may run fairly good when

Customer Question

1999 Mercury Villager
1. Car may run fairly good when starting cold or experience a rather choppy misfire that is unlike familiar smooth misfiring.
2. Takes about 2-3 times usual duration to reach normal operating temp. Checked radiator while starting. Water is not swirling then. On a*****during a 60 F degree day, engine remained 40 degrees below normal (195.8 is normal).
3. After reaching normal, sometimes the idle ratchets itself up to between 1500 and 1600 rpm. Unless turning off the engine, for no known reason and with no dramatic temp change the idle will bring itself down to the more typical 800 or so.
4. AC works. Turning it on merely rushes the onset of running rough while driving and maybe increase of idle speed.
5. Symptoms began with hooking up jumper cables backwards. Afterward, vehicle cranked but would not start. Changing fuel pump relay got it to start and brought me to the place described above.
Submitted: 1 year ago.
Category: Car
Customer: replied 1 year ago.
1. Car may run fairly good when starting cold or experience a rather choppy misfire that is unlike familiar smooth misfiring. Like cutting completely out for half a second rather than merely one or two cylinders missing in a more loping way.2. Takes about 2-3 times usual duration to reach normal operating temp. Checked radiator while starting cold. Water was not swirling then. On a*****during a 60 F degree day, engine remained 40 degrees below normal (195.8 is normal).3. After reaching normal, sometimes the idle ratchets itself up to between 1500 and 1600 rpm. This may occur while in gear or after putting into Park. Unless turning off the engine, for no known reason and with no dramatic engine temp change the idle will bring itself down to the more typical 800 or so in 3-5 minutes.4. AC works. Turning it on merely rushes the onset of running rough while driving and maybe increase of idle speed.5. Symptoms began with hooking up jumper cables backwards. Afterward, vehicle cranked but would not start. Changing fuel pump relay got it to start and brought me to the place described above.
Expert:  Dan replied 1 year ago.

Hello, my name is***** your check engine light on or does it ever come on? Thanks.

Customer: replied 1 year ago.
I wish there were a check engine light on. Moreover, in hooking up a scanner with bi-directional controls, nothing unusual could be found. I activated the radiator fan and some other things presently forgotten. I also knocked out each cylinder one at a time. Each one produced a dramatic change, so failed to identify at the moment any problem cylinder.
Expert:  Dan replied 1 year ago.

So the problem is vehicle runs rough when first starting and idle intermittently goes too high? Did both start after installing battery backwards?

Customer: replied 1 year ago.
Engine sometimes runs okay when starting. OR it might have that choppy effect that can even be felt when backing out the driveway without accelerating at all. Kind of like running over small boards as if trying to stop the motion. Very weird. Feels like perhaps all power drops for half a second rather than a single cylinder or two. Then does the same thing in Drive. This condition may change within half a minute to run okay. But if driving more than a few miles, that will often get the coolant temp up near normal (later than usual, by the way). Once reaching normal, then the idle will climb up to 1500-1600 RPM about a third of the time. Both of these began after the botched jump starting of another vehicle using this vehicle. There had been a very slight misfire when at idle before is all.
Expert:  Dan replied 1 year ago.

I think you may have burned out your PCM which is the main engine computer. I'd start by disconnecting battery and touching cables together for 10 minutes with battery disconnected to reset memory. If that doesn't help then I'd go ahead and replace the PCM. Disconnecting battery backwards would not have ruined anything else. Here is a link to send your PCM out for repair which may be your cheapest option. Let me know how it goes or if you have more questions, thanks.

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http://www.ebay.com/itm/Mercury-ECM-ECU-PCM-Engine-Computer-Repair-Return-Mercury-ECM-Repair-/321532740379?fits=Year%3A1999%7CModel%3AVillager&hash=item4adcd8431b:g:h2wAAOSwPhdU9zzn&vxp=mtr

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Customer: replied 1 year ago.
I have a spare 1999 Villager and have tried pulling the PCM for exploring the possibility you recommend. Mostly got it out the other day with the loom connector pulled, I stopped when it became stuck on something unknown. If the remedy works (after figuring out how to get it completely removed), I will definitely find the eBay link for repair useful. There are fairly good instructions for removal of the PCM on AutoZone. But it might require something different to get over the last hump. Do you perhaps have anything?I am looking on eBay for a service manual and looking at subscribing to Mitchell for a month or so in the hope that their instructions are acceptable. In the past I was very disappointed by the low quality of illustrations on either AllData, Mitchell or both. That experience came when taking a couple of auto tech courses in a vocational school. They don't seem inclined toward showing illustrations in demo mode unfortunately. Anyway, I will see if your recommendation is correct, then return for a rating if permitted to delay in that way.
Expert:  Dan replied 1 year ago.

Here are replacement instructions, let me know how it goes. Thanks

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https://www.dropbox.com/s/ubxagtu39d7sq75/pcmrr1.pdf?dl=0

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https://www.dropbox.com/s/ksi88augflj7bwx/pcmrr2.pdf?dl=0

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Customer: replied 1 year ago.
I am a little unclear about the battery disconnect you mentioned, which should be tried first. I already did disconnect them the other day, to no avail. But you suggest waiting 10 minutes and holding the cables together. Would one hold them together 10 minutes or just leave disconnected 10 minutes while touching together one time? Thanks. - Randal
Expert:  Dan replied 1 year ago.

leave them disconnected from battery but touching eachother for 10 minutes. Let me know if you have more questions, thanks.

Customer: replied 1 year ago.
In three efforts, I only have the computer loose and able to move back and forth an inch or so but still restricted from removal. Front loom is unplugged. Relay on top is hitting against metal frame. And whatever is mentioned of being attached in the back, I have no idea how to get at it and disconnect.
Expert:  Dan replied 1 year ago.

Did you remove the passenger side airbag bracket?

Customer: replied 1 year ago.
I'll have to check. Seems to me I removed everything from the group of photos. But now that it's been a while, and with the vehicle away from where writing now, being sure is probably a good idea. Getting back here to respond the other day failed 2-3 times from the link in the email. Today I tried again. Another fail. I got a different idea though, simply going to justanswer.com and hoping from there. It actually worked. At any rate, I am pretty sure that bracket is out. Will verify though.
Expert:  Dan replied 1 year ago.

No problem, it really should come out without too much effort. Let me know how it goes an send me some pictures if needed. Thanks.

Customer: replied 1 year ago.
Got some photos taken. Then I adjusted a few of them for better visibility. They are large enough that if downloaded could be viewed a fair amount bigger. The metal part on the floor might be the bracket referred to. See attached.
Expert:  Dan replied 1 year ago.

It definitely looks like a tight fit. Without being there or having changed one of these recently I cannot offer much of a solution. Based on pictures I'd probably try to bend down PCM bracket so it clears. I'll open question back up to see if someone else can offer a solution from memory. Thanks.