87 302 part

[jim]

What's the name and function of the part aft of the line of the outer edge of the upper intake, mounted on the fire wall, with three electrical, and one vacuum, connections? This is with a 302 in an '87 Grand Marquis.

[87gtVIC]

Map sensor?

[85crownHPP]

Sounds like it - and yes, it is important.

[Toploader]

As those of you can attest who have read my recent posts, I had hoped that changing the MAP and the vac hose would cure a problem that just will not go away, after many years!.......when car is in drive and stopped she will surge and the rpms will go up and down.......in P or N no problem, runs beautiful!.......I have changed the following items all to no avail, although she does run a bit better, but not cured!!...and now the list:
New ECU, new MAP and vac hose, new O2 sensors, new air and water sensors, new EGR and all parts that attach to it, new plugs, new wires, new cap and rotor, cleaned out the TB assembly, checked TPS it's spot on, Ford dealer had car for 6 months, and gave up claiming I need rebuild. So before I die I will give the car to a brave soul, and I will look down from heaven to see if the problem could ever be fixed!!

Sounds like it - and yes, it is important.

[zoomie]

i had a line of mine once, it sounded like a b cam lol

[85crownHPP]

What about the IAC (idle air controller)? It's job is to keep it smooth when idle-load changes, like when it's in gear and when the A/C is on, during high power steering demands. Maybe its only happy place is free-idle.

[gadget73]

if someone swapped the oxygen sensor connectors side for side, it can make it surge and act stupid. The rolling idle thing is really common, but its potentially caused by so many things its hard to say with absolute certainty what to change to fix it. It often has something to do with bad vacuum lines though.

[Toploader]

Every vac line changed, Ford dealer said needs to be rebuilt, but I said that is nuts, except for stopped in drive the car is terrific, tons of balls up till 80mph with no breakup whatsoever!

if someone swapped the oxygen sensor connectors side for side, it can make it surge and act stupid. The rolling idle thing is really common, but its potentially caused by so many things its hard to say with absolute certainty what to change to fix it. It often has something to do with bad vacuum lines though.

[gadget73]

how much vacuum does it pull at idle? If its at least 17", its OK. If its less, either the motor has valve problems or there are leaks somewhere. The old "it needs to be rebuilt" answer is usually code for "I have no idea". If there is reasoning behind it, like compression and leakdown tests, and maybe an oil analysis or something thats actually hard data, thats a different story. Elsewise, I call BS.

[sxcpotatoes]

I second the IAC. They get dirty, clogged, make the car stall out or idle up and down, usually down to stall or almost stall and then back up to normal.

[L1011tristar17]

3rd with the IAC. Looks like it's one of the few parts you haven't replaced yet! Tips on cleaning/checking it here:

http://www.lincolnsonline.com/tech/00017.html

and here:

http://www.lincolnsonline.com/tech/00187.html

I put new air and water temp sensors on my car and I had to disconnect the battery for 30 minutes so the ecu could "learn" the new sensors. It's worth a try in case the dealership skipped that step.

[Toploader]

Gadget, the Ford dealer in NYC (largest in the USA) did not only compression test, but leak-down tests.......all normal! I have to have some trust due to the fact the former service manager was a client of mine (sold Chilton labor guides there for years) and allowed the car to remain for six months, and when the techs had some spare time, they would tend to it....I have all the invoices, and truth be told he basicly charged me almost nothing for all the time spent on the car....I even rode along side his head tech so he and his line mechanics could "see" what I was talking about. I guess I could check the vac reading again, but if I needed a valve job would I not have other apparent issues? This shit only happens in drive while stopped!....car idles beautiful in N or P and goes as I said past 80MPH with no breakup or problems!!!...when first started in the morning the fast idle is as it should be, then drops to the proper level! As to the suggestion of bad IAC, let me say that this problem existed before and right after a new IAC was put in at the Ford dealer, and last year at my friends shop he took apart the TB and cleaned the insides completely as well as the IAC....nothing changed....only thing found subsequent to that was a code 33 which is EGR, but I laugh because even with new Ford EGR and attaching parts the situation was no better???[QUOTE=gadget73;725450]how much vacuum does it pull at idle? If its at least 17", its OK. If its less, either the motor has valve problems or there are leaks somewhere. The old "it needs to be rebuilt" answer is usually code for "I have no idea". If

[sly]

as stated other places... new parts don't always work.

[Toploader]

Very true, but when new parts do not make the situation any better, one has to consider the problem can not be rectified:-(
So, when stopped at a light, I just toss the car into N, when light turns green, toss into D.

[gadget73]

code 33 means the egr valve isn't closing. It may be the sensor is messed up, a hunk of carbon is in there, or you might have to convince the ECM that the valve is actually closed by filing down the end of the position sensor so it ends at the right voltage. Sometimes you gotta cheat to win. If the valve is hung open a bit, it may be the problem.

If it passed compression and leakdown tests, you don't have valve problems. If it doesn't have the no oil pressure light on at hot idle, the bottom end is good enough. For all practical purposes, there is nothing a rebuild is likely to fix. If on the other hand, it did not pass those tests, it still might run OK but not be entirely right. I drove mine for a while with low compression, excessive leakage, and a cam that was a tooth off. It still ran, and it mostly didn't even hunt at idle, but it still wasn't right in a lot of ways.