Surge in idle

[ReverendRevival]

First off I'm new, so hi.
Secondly I wanted to take a second to mention what a great forum this is.

Now to the nitty gritty. I just bought an 84 Grand Marquis LS with 62000 original miles and a gorgeous interior. on the way home battery went. Now the alternator but still got a good deal. But my idle surges and will occasional stall when I stop. I was thinking throtle position sensor. Anyone have an idea before I start replacing wrong parts.
Thanks

[KING BIOHAZERD]

HI IAM NEW TO MINES DOING THE SAME THING AND THEN IT STOPS MABE MINE NOT HAS BAD HAS YOURS YET BUT I HEARD THAT THE PART U SPEAK OF IS THE PROBLEM

[1987cp]

, guys.

Just to start with the basics, have you chased around and made sure there are no vacuum leaks? Most of these cars tend to have a LOT of vacuum lines running all over, and can be a common source of funkiness.

As a side note, my '79, which uses the same 1G alternator as your '84, had a really annoying surging and dying problem when I first got it, with the headlights flickering somewhat and the whole deal. It got a lot better once I spent $10 on a new external voltage regulator. Now the problem is nonexistant, and it's still running on mostly original wiring.

[ReverendRevival]

I did check for vaccum leaks as a first course.
External Voltage Regulator huh.
Have a link to a specific piece I would need, for ten buck can't really beat huh. Worth a shot atleast.


|Rev.

[1987cp]

I figured that was the problem after AutoZone told me my charging system was bad and a new alternator didn't help the situation. If you were to have them test it and tell you that you need an alternator, you can start by just buying a regulator instead. Also, there's a thread somewhere where Tiggie and I were posting schematics for the 1G charging circuitry .... it's actually pretty straightforward, so if you know what needs to connect to what else, you can do some continuity checks to verify that the wiring is still doing its job. I'll try to take a look around for that thread later ....



--- EDIT -----

Here's the page with links to the schematics we posted. Incidentally, as I recall, this guy's problem turned out to be an aftermarket ammeter that'd somehow been wired incorrectly or something.

http://www.grandmarq.net/vb/showthread.php?t=19887&highlight=1g&page=2

[Bloovic]

Welcome to the forum people! My 90 CV had the same issue and after the codes were pulled it did indeed turn out to be the TPS. After replacing with a new part, the problem was gone, and as an added bonus the gas mileage improved too.

[ReverendRevival]

Now I guess my next question would be how hard is it to change the throttle position sensor?
Like I said I am a noob, but anything I can do I myself I would like too. This is my baby after all and I would like to know every inch of her.
Thanks for all the help.

[1987cp]

Very easy to change the TPS. Pretty sure it's just held in with a couple of Phillips screws. Might need calibration once it's installed, but that's also pretty straightforward.

Have you pulled the error codes yet? It's easy to do at home with just a jumper wire, or ask your local discount parts store to do it for you.

[86VickyLX]

Very easy to change the TPS. Pretty sure it's just held in with a couple of Phillips screws. Might need calibration once it's installed, but that's also pretty straightforward.

Have you pulled the error codes yet? It's easy to do at home with just a jumper wire, or ask your local discount parts store to do it for you.

He has CFI I heard that it was a bitch to change on CFI.

[ReverendRevival]

Hell I think I am just gonna run over to the shop here in town and have em pull the codes. But that worries me a bit. Its an 84 with 67thou original, need less to say it sat for a bit.
Maybe we should start taking bets on how many it pulls.

[ReverendRevival]

Well hell if it pulls to many I may just carb her.

[86VickyLX]

Well hell if it pulls to many I may just carb her.

Go EFI. FatNasty just converted his CFI Merq to EFI. Go under the electrical section and click on 'CFI To EFI Swap.'

[ReverendRevival]

Hmm cfi to efi swap seems a bit more involved.
Deffinetly a bit outta my league.

[86VickyLX]

You can do mods just like you could do with a carb except you don't have to worry about it being a bitch to start in the cold

[ReverendRevival]

I was thinking after getting her puring right maybe make her suck more air. Is there a larger bolt on intake I could use to give her a bit more bite to match the bark? Also what would be a good set of after market cats?



God I love this forum. So much knowledge so little time