MAJOR PROBLEMS!!!!!!!!!!!

[Wray-Wray]

1987 mercury grand marquis mostly stock


ok so i've puked my 3rd heater core...they last 6-8 months and blow. I've bought one from Advanced Auto, Auto Zone and NAPA. The system has been flushed before I put the last new heater core inn.(i just by passed it with a piece of pipe) I tryd bars leak and nothing, so I bypassed it again. I'm running a 7PSI radiator cap. That shouldn't blow a heater core!


I replaced the ignition switch(brandy new from advanced) not to long ago.(maybe a year) But now my car will shut off while I'm driving.(At any speed) If I get a piece of wire and put it on the positive terminal on the batt, and connect it to the positive terminal on the plug that goes to the coil. Most of the time she fires up and runs but others she fires up and die right after. (i took the MSD blaster coil off and put a stock one on it and no change). It makes no difference if she's cold or hot. (loves to quit randomly)

Shes doing a lot of serging while driving down the road. If I'm going 65 or higher she won't serg at all anything below that its so bad I think shes going stall.


I'm having another problem my transmission is acting funny too.

What I mean by that is
If im driving down the road it will go into a coast for like a 15 Mississippi count. Than jump like you were on the gas and put it in drive and continue on like nothing happened. She also used to have a considerable amount of pressure when she would shift out of OD to D compaired to my buddy's townie(86) and my dads townie(89) and now I can't even tell if its shifting out of OD. Fluid level is perfect and she doesn't leak. Fluid is still really red and no burnt smell.


To top it off shes got a gas leak now and its the tank not the line!



let me know what you guys think. I'm at the point where i want to junk her I'm so frustrated. She needs so much work. I have ziltch to work with money wise. Winters around the conner. I need something that has no electrical problems, gas leaks, vacuum leaks(that i can't find for the life of me) and doesn't blow heater cores regularly. HELP!

[Deadarf]

Ack!

In my opinion, the issue with it shutting off seems to be a short somewhere, or maybe the computer.

The "If I get a piece of wire and put it on the positive terminal on the batt, and connect it to the positive terminal on the plug that goes to the coil. Most of the time she fires up and runs but others she fires up and die right after" thing sounds like the old school way of hot wiring a car. At least the way I did the few times I hot-wired a car. If that is the correct term. I'm rather certain I wouldn't do that to a modern engine, what with the computer and all.

The surging issue seems to be a distributor issue, or it could have something to do with the computer. I recommend having it plugged into a diagnostic computer.

It also seems you need a new tranny and a new gas tank. I'd recommed parking the Merc and getting a commuter car to drive while you fix the issues.

I've replaced very few heater cores, and never one in a Ford product. I've never heard of; let alone dealt with a heater core that lasts such a small amount of time. These are my ideas based on my old car experience, my '85 Merc is the most modern car I've worked on. All I've done so far is a basic tune up on it. I'm rather unfamilar with EFI or CFI for that matter.

Twelve years ago when I was 20, my car was a '66 Impala. Now don't get me wrong, I love my '85 Merc and my '68 Cad, I just greatly miss that Impala. It had a 327cid with a 2 speed auto tranny.

I have a picture of it taped to my bathroom mirror.

So don't sell the Merc!

[Wray-Wray]

to the coil wire remark....


I was only doing that to find out if I have a short to my coil and it seems like I do. Yes, that is one way to hot wire a car but there are other steps to be taken in the process as well. Like the ignition switch and jumping the starter sili.... to name a few

only one other problem i have no where to park it. I would love to keep it and turn it into a full on drag box. But I have no where to do the work. I called a few storage places they won't let me put a car in because of issues of oil or gas leaks etc. They can't be liable for that they said. I live in an apartment and I am only allowed one parking spot in the parking lot. I've asked a few people if I could stuff her in one of there barns for a while. Nobody has room. I'm in a bind here. I love this car but i don't have the means or the time to dick with her anymore. Beside the point I want a '83 two door to build. maybe when I get my own house and have a place to keep another one. I will surely go out and find one.

[gadget73]

you have serious electrical problems. First place to start is to clean all the connections at the starter relay, and the battery to block and block to body ground cables. It might not fix it, but it won't hurt.


as for powering the coil directly, you can hot wire an EFI car like that, but it will only give you ignition power. You also need to power the ECM to get it to actually do anything. Since it dies right after, I'd say the problem is on the ECM side, not the igntion side. The ECM relay is a possible problem, since if that quits working, you lose injector pulse, and the fuel pump shuts off too. The ECM itself seldom dies, so I wouldn't suspect that right away. I'd be more inclined to think wiring problems. The harness around the relays on the front driver's fender tends to get real crispy and nasty. See if there are any bare wires or green fuzzy connections. Repair/replace as needed. The fuel pump relay is right up there too, and those connections also get nasty. I think the green one is the fuel pump and the brown is the ECM. Black should be AC. I could be wrong on the colors but 2 of the 3 need to work to make the car run.

[Wray-Wray]

I have another car lined up if i get the loan im taking it. If not im buying an explorer motor and a used AOD and doin my other build that everyone helped me out with information before in the "Motor Swap" thread

As far as hot wiring i kno i need to get power to the fuel pump n ECM I only named "A Few" things because im not giving sum random guest that comes in here the tools to hot wire a car.... ya kno what i mean

i don't know if the problem is on the fuel and ECM side because my fuel pump turns on and i have plenty of pressure with the key one engine off test(where you push the little valve stem like thing(for lack of a better explanation) that squirts out fuel to check for fuel pressure)

[86VickyLX]

You should buy a heater core from team ford. It's more expensive than the ones from autozone etc, but it's actually an OEM part. OEM parts last longer. Team ford is also cheaper than your local ford dealer.

For the surging and dying, I remember on Vicky when I had her in the school, the computer didn't give any signals to the diagnostic computer when I had hooked it up. The problem was that the ground for the ECM wasn't attached. It was an orange wire with a round end on it. It was bolted somewhere on the back of the engine, on the driver's side. Anyway, it's possible that the wire had broken off and is just hanging there. look around on the back of the cylinder head on the driver's side and see if the wire is attached.

[mrltd]

There is probably something else wrong causing the heater cores to blow.

It sounds like you don't have OD anymore, and if you are revving the hell out of it in D on the highway it's going to blow heater cores.

[Wray-Wray]

highways i drive in od...and no i don't rev the shit out of a stock lopo(thats asking for trouble with any stock motor)no all three heater core were broke on a 45 mile an hour road with a few stop lights(same road each time)....the motor already has a rod knock so i was being especially careful(meaning im not flooring it from the stoplights)