87 Grand marquis 5.0 Sefi

[87GMQ]

87 302 Sefi shuts off after it is placed into park. 9/10 It will just shut off without warning after a drive, example; today I drove into a parking lot pulled forward then put it into reverse and backed up, as soon as I put it into park it shut off. Any ideas of what it could be?this used to be a rare occurrence but it seems to be happening more often now.

[Tiggie]

I'd be inclined to look at the ignition switch if it just dies. It lives in your steering column. https://www.rockauto.com/en/catalog/...er+switch,4700

If it's more of a slow stall, maybe we can chase another problem.

[sly]

+1 I would suspect ignition switch that coming apart since park is usually the most jarring to the column.

[87GMQ]

http://www.grandmarq.net/vb/forum/technical/box-tech/1387143-starts-then-stalls

Few months ago, Anyways, what brand switch did you guys get and how well is it holding up?

[friskyfrankie]

Especially for electrical parts, I usually go with OEM. However, I am sure Standard and other companies make decent ones as well.

[sly]

I think I have either the Standard or Wells/Airtex version in my 93. The 88 I used to have got the same. Haven't had an issue with them myself. The design itself is prone to failure due to separation. I've not seen one yet that doesn't have the same fatigue points, but the fact that they still last 20-30 years, I don't think it's a major issue.

[87GMQ]

yea its still doing it, New switch exact same issue. One thing I can say for sure is it only happens after driving for more than a few minutes. Only happens once the car is placed into park, the sudden change in the rpm seems to cause it to stall. I could restart the car right away glide the shifter through all the gears then back into park and it wont stall, any ideas?

[VicCrownVic]

ECT and IAT(ACT) might be worth checking. Often those will cause a stall when coming to a stop if they are out of spec, but I suppose a change in engine load by putting the car in park could also be a condition where one of those two temp sensors being wrong could cause stalling.

ECT: https://grandmarq.net/oldfuelinjection/page28.html
ACT: https://grandmarq.net/oldfuelinjection/page29.html

[gadget73]

A sticky idle control motor can also do this. if its trying to back the RPM down when it comes out of gear and overshoots it might just cut the air entirely and cause a stall. Most of the time you can simply unbolt it and give it a flush to dissolve out the gunk inside. Its the tubular thing bolted on the back side of the throttle body. 2 bolts and a plug.

[friskyfrankie]

A sticky idle control motor can also do this. if its trying to back the RPM down when it comes out of gear and overshoots it might just cut the air entirely and cause a stall. Most of the time you can simply unbolt it and give it a flush to dissolve out the gunk inside. Its the tubular thing bolted on the back side of the throttle body. 2 bolts and a plug.

If one is going to spray it, make sure it is facing down so as not to get cleaner into the electrical parts. At this point, I'd replace it since it is somewhat difficult to access, but that's just me!

[sly]

And maybe give it a shot of silicon lube where the plunger goes into the motor/solenoid.

[87GMQ]

I cleaned that a few months ago to fix a similar issue (dont know how I forgot that) I'll try it again, cause the cleaning helped to keep it operating normally up until about two weeks ago. If it still continues i'll buy a new one.

[gadget73]

If one is going to spray it, make sure it is facing down so as not to get cleaner into the electrical parts. At this point, I'd replace it since it is somewhat difficult to access, but that's just me!

IAC on a box is actually very easy to access, its a bit of a PITA on the 4.6 though.

I've seen goofy things with non-OE parts on these, so I've kind of gotten to the point where I'll try and fix an original before replacing it just because I've had better luck with that.

[friskyfrankie]

Forgot he has an '87 - was thinking about the '93 that was mentioned. In reference to cleaning or replacing the IAC, I meant to say replace it with an OEM one as opposed to aftermarket.

[Toploader]

While on this subject, its a good idea to carry a Ford TFI module in the trunk, when that craps out its lights out and no start!........simple to R&R in the "field".........I learned the hard way;-(