A Grand Marquis far from home - Life with my 1988 Mercury Grand Marquis GS

[friskyfrankie]

friskyfranky wrote: The top photo is the TPS. "Since it has Philips screws, it is probably not the original." ALL my cars have phillips screws from day one.
Also, there in NO vaccum lines hooked up to a TPS! WagonMan

True enough. However, many OEM TPS units did not have Philips screws which is why I mentioned it as people tended to replace the OEM fasteners. My references to vacuum lines was a general statement as it is correct the TPS has no vacuum line - only an electrical connector.

[Tynnerstroem]

Thanks gents! I'm ordering stuff from RockAuto as we speak.

I was wondering if you guys had any input on the "lopo knock" which my car suffers from. When I start the car cold it runs on high idle and sounds great, but as soon as it comes off of it that knocking sound comes out. My amateur diagnosis with a stethoscope says that the noise comes from the bottom end of the motor. It goes away when I either rev the engine or the engine comes under load when driving it. It also goes away once the engine starts to warm up. Since it doesn't knock under load and goes away when warm I haven't really worried about it, but I'm a bit curious - what could be the cause? Do I need to worry?

I also have noticed that the smog pump is sounding pretty tired, as it gives off a rattling noise (checked it with a stethoscope). I have read around a bit and when they get really bad they can seize up. Now I'm aware that many just elect to remove it but I'm not a huge fan of such solutions, I'd rather just swap it out. However I note that the Cardone one on RockAuto is listed as out of stock. Realistically, could they be rebuilt? How worried should I be about it seizing up? For all I know it's the original one from 1988 and it could fail tomorrow.

[Tiggie]

That knock is piston slap. It's basically harmless. Once the pistons warm and swell up, they fit the bores fine. I'm not sure why these engines are so prone to that but almost all of them have that issue. My 88 has been accused of being a diesel for the sounds it makes while warming up.

As far as the smog belt, I would not hesitate to bypass it. I believe a lot of the pumps of the era use the same housing, so you can find them for other applications or on eBay and run one if you want. They were spec'd for specific applications but I'm sure would interchange for each other outside of a slight difference in flow.

[Tynnerstroem]

Thanks Tiggie. That diesel-likeness is very appropriate for how it sounds when it's really cold outside. I suppose I should have my mechanic check the oil pressure on it but it sounds like it's good to keep driving without worries.

As for the smog pump I have looked around a bit more and note that they're not exactly free once they can be found. On the one hand I would assume that the engineers that designed this drivetrain figured that the car needed the smog pump for proper operation, but on the other hand if it's already broken or breaking now then the car doesn't seem to suffer for it anyways. If I were to do that, the belt would only run on the A/C pulley and the crank right? Is there any belt then that is the perfect size for bypassing the smog pump? Would I have to remove the smog pump physically from the engine, or could I just put a belt on that doesn't utilize the pulley on it? Does the smog pump suffer in any way by being bypassed if left on the motor?

[DerekTheGreat]

The smog pump primarily serves to dilute the exhaust gas for emissions purposes. There's also a benefit for sorts for it feeding air to the cat when cold started to help prolong their life. Although that's just what I've read over the years, not sure if it's necessary. I'll say this though, when the unit on my Town Car goes, it will be removed without replacement.

[Tiggie]

I deleted my smog pump about 65k miles ago. No regrets. I did not run the A/C on that car so I don't have a belt for you but some folks do. Check out this thread, or I'm sure one of those folks will jump in with the part number. Not sure what type of inspections you have or if it would be frowned upon like some states here. https://www.grandmarq.net/vb/forum/t...og-pump-bypass

[Tynnerstroem]

Thanks guys! I’ll try to read up on it. I’m thinking I’ll leave it in place and just run a shorter belt that doesn’t touch the smog pump. Because my car is older than 30 years it’s subject to bi-annual inspections, but they only measure tailpipe emissions (don’t check whether the individual emissions equipment works, and don’t care about check engine lights or fault codes). It’s my understanding that the smog pump only helps warm up the cats, but that they still should work even without the pump, right? If so I’m expecting it to fly through inspection regardless.

[Arquemann]

Thanks guys! I’ll try to read up on it. I’m thinking I’ll leave it in place and just run a shorter belt that doesn’t touch the smog pump. Because my car is older than 30 years it’s subject to bi-annual inspections, but they only measure tailpipe emissions (don’t check whether the individual emissions equipment works, and don’t care about check engine lights or fault codes). It’s my understanding that the smog pump only helps warm up the cats, but that they still should work even without the pump, right? If so I’m expecting it to fly through inspection regardless.

Yes the cats work just fine without the pump. Though they are still old cats and without the air pump or stratified cold start, they will take quite a while to warm up to full efficiency. Just a bit longer drive before heading to the inspection. I usually take mine on a quick motorway blast, 5 min of 100kmh in third gear will get things properly warm.

[Tynnerstroem]

I'll be sure to take the long way to the inspection station!

Not this weekend but the one after it, I'm planning on doing the big job with removing the intake to get at the valve cover gaskets and all other vacuum hoses etc. that have been discussed before in this thread. I notice that there are several helpful videos on people doing similar jobs on Foxbody Mustangs with 302s, can I follow those videos? I know those motors had the plenum mounted the other way, but is that the only difference that's relevant here? Or will it be a wildly different job on a LoPo 302 like mine?

[Arquemann]

I'll be sure to take the long way to the inspection station!

Not this weekend but the one after it, I'm planning on doing the big job with removing the intake to get at the valve cover gaskets and all other vacuum hoses etc. that have been discussed before in this thread. I notice that there are several helpful videos on people doing similar jobs on Foxbody Mustangs with 302s, can I follow those videos? I know those motors had the plenum mounted the other way, but is that the only difference that's relevant here? Or will it be a wildly different job on a LoPo 302 like mine?

Mostly the same, some bits are flipped along with the intake. And the AC lines aren't in the way.

[Tynnerstroem]

Thanks! I've started studying already. The parts for the manifold-off job will arrive tomorrow, and I'll tear into it on Friday evening and hope to be done by Sunday evening at the latest. The car is sitting at my dads place for the time being and I'm driving the Thunderbird. I went out today to finally get the power locks working in the front doors, which they now finally do. Huge relief to finally be able to leave my laptop bag in the car when I run into a store and not have to lug it around just because the passenger door wouldn't lock (because I hadn't managed to hook the rods up properly to the locking mechanism, as you may recall earlier in the thread). I also swapped out the horrendous yellow/orange LED courtesy lights that the previous owner had put down under the dash, so now the car finally lights up almost properly when you open the door. I say almost, because the dome light does not work. But that's a job for another day. I also put my dad to work in helping me wash it. The car is not as nice as the pictures make it seem, but it still does clean up really good.


Alas, the old trusty Thunderbird is not long for this world. My dad was hit with it some time ago and the insurance company finally came through. The right rear fender was hit by some lady not paying attention, so the insurance company will scrap it. They're paying about double the market value for it so no sense in arguing there. I gave it a final, sentimental wash today. I woke the car up from a ten year slumber in 2017 and it has done about 30 - 35k miles in the family since that time. The odometer stopped working at 99 947 miles three weeks ago, so even though I know we have now taken it across the 100k line it still won't show frustratingly enough. There's lots of life left in the drivetrain but the body is giving out, so with the insurance company offer it now feels like the appropriate time to cash out.

[Tynnerstroem]

Okay I’m camped out at my dads for the weekend, and the intake is off. It went a lot smoother than I had anticipated, but maybe that week spent watching people doing this job on Foxbody Mustangs helped.


The EGR-ports really were vile and it wouldn’t surprise me if it’s been the same valve since the factory. I noticed that the valve wasn’t stuck however, which I was expecting it to be.


Todays job is replacing the valve cover gaskets, vacuum lines, the air temperature sensor that’s screwed into the intake and the EGR cooling lines. After that, basically putting everything back together and praying like hell that I haven’t missed anything.

[Arquemann]

Sometimes we overthink way too much and when we finally get to the doing part, you kinda realize the hardest part is in your head.

Also, your distributor condom is backwards.

[87gtVIC]

Sometimes we overthink way too much and when we finally get to the doing part, you kinda realize the hardest part is in your head.

Also, your distributor condom is backwards.

I agree with the overthinking…. I do it myself sometimes.


what’s wrong the distributor Cover? The ford logo is facing forwards.

[Arquemann]

I agree with the overthinking…. I do it myself sometimes.


what’s wrong the distributor Cover? The ford logo is facing forwards.

Oh, I thought the text was supposed to up front and the sides wrap behind it, out of sight.
Didn't quite see the orientation of the text and I haven't had one of those meself.