This seems a little to dumb to post in technical section, so here goes.
Never had a B pillar panel off, so maybe not that dumb......

88 GT, automatic.....

Reason I ask, is that I have been chasing a knock / thump, just behind my head, when going over relatively large bumps in the road.
Almost like a rattle, but a bit heavier.
Thought I had it today with a very loose air filter housing, but that was not it.

Anyone with pictures of what all is back there that could possibly be loose?

I do plan on taking it off and replacing the speakers soon, but I am really curious as to what all could be in there knocking to get in or out?

Much appreciated,
railshot

Fuel door cable? It might be loose and banging around.

quote Originally posted by ARKaiser: Fuel door cable? It might be loose and banging around.

Thanks ARKaiser for the reply, but this just sounds a little heavier than that.
I was really excited when I found the air filter housing not mounted properly today, as that is about the "weight" it sounded.

Anything else back there in that area?

not much their or near by...
Seat Belt retractor and guides and bolts to attach all.
Handle for gas cover
Speakers
part(s) of rear clip
"Bolt" for door latch.
plastic vent "screen" near bottom of B pillar

Near by...
Air "muffler"/water trap for engine has 1 bolt but made of plastic.
V6 air cleaner
EVAP can
Front mount of cradle
Gas fill pipe and hardware

load noise could be loose door latch or seat belt.
SB retractor only attach by 1 bolt. Most SB bolts are T50.

Could be in engine bay and just hear it on B pillar.
or frame has problems.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

quote Originally posted by theogre: not much their or near by... Seat Belt retractor and guides and bolts to attach all. Handle for gas cover Speakers part(s) of rear clip "Bolt" for door latch. plastic vent "screen" near bottom of B pillar Near by... Air "muffler"/water trap for engine has 1 bolt but made of plastic. V6 air cleaner EVAP can Front mount of cradle Gas fill pipe and hardware load noise could be loose door latch or seat belt. SB retractor only attach by 1 bolt. Most SB bolts are T50. Could be in engine bay and just hear it on B pillar. or frame has problems.

Much appreciated theogre.
Guess I will have to dig into it this Saturday to see.

I really could not visualize much being in that area on the interior, that is why I was looking at the engine bay today and found the air filter base not locked into the frame, but the bottom tab just dangling on the outside of the frame.

Time to shop for speakers and start taking it all apart.
It would be a hoot if my speaker was loose!

The door latch "bolt" (striker) at the rear of the door is a common thing if you have a higher milage fiero or just
the striker bolt is now undersized due to wear. Realistically, the door is hopping up and down over bumps making
a heavy thumping noise. I replaced my door hinge bolt with a bigger diameter bolt. Its Help ! # 38421.

I installed this upgraded striker bolt, and the noise is gone. It lifts the door up a bit so you don't have the "thumping"
noise from big street bumps.

I will be doing this upgrade to my other 88GT soon.

Hope this helps...

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fierogt28

88 GT, Loaded, 5-speed.
88 GT, 5-speed. Beechwood interior, All original.

Thanks fierogt28 for those numbers. You saved me a search.
I was reading about this fix for the doors in some older posts, and it is on my Saturday to do list for both sides.
Could be the cure!

While I am at it, I will be taking the drivers side door apart to do the other dew wipe, passenger side is done already, and fix the loose exterior door handle.

At least I know what that noise is.... now, the t-tops are a whole nother ball game with rattles.

Worst comes to worst, I will purchase all new seals for them if I can find them.

Ah, the pleasures of owning a one off 28 year old car.

Anyone have any replacement speaker suggestions?

I bit the bullet and bought the fiero store's door panels with speakers, and their rear wall speaker panel. Having replaced the stock speakers once already, this option gives you easy access for future speaker options and replacement. Something worth considering, as the B pillar speakers are pretty disappointing anyway. Not to mention I never need to remove my dash speaker grilles and risk cracking a good dash.

I don't know about your specific noises, but my fastback clip was transplanted onto what used to be a notchback car.
It creaks and thumps as the car moves and flexes.

Since the T-tops theoretically compromise the roof section, perhaps the noise is part of that structure. (Perhaps where the T-frame is riveted in?)
Does it do it with the T-tops removed? Maybe it's just the glass bumping against the opening.

quote Originally posted by railshot: Thanks fierogt28 for those numbers. You saved me a search. I was reading about this fix for the doors in some older posts, and it is on my Saturday to do list for both sides. Could be the cure! While I am at it, I will be taking the drivers side door apart to do the other dew wipe, passenger side is done already, and fix the loose exterior door handle. At least I know what that noise is.... now, the t-tops are a whole nother ball game with rattles. Worst comes to worst, I will purchase all new seals for them if I can find them. Ah, the pleasures of owning a one off 28 year old car. Anyone have any replacement speaker suggestions?

Ohh, just 2 things...
The door striker bolts are originally for a Ford. You'll need to pull off the plastic sleeve that is on the bolt.

And 2nd, you'll also need to adjust up and down the striker bolt on the mounting hole for perfect functional fit.

Look underneath at the water rail support bracket. A rusted or broken support can allow the end of the rail to bump the underside. Is the fuel filler tube solidly mounted?

Is the bump coming from upper, middle or lower part of the car?

quote Originally posted by fierofool: Look underneath at the water rail support bracket. A rusted or broken support can allow the end of the rail to bump the underside. Is the fuel filler tube solidly mounted? Is the bump coming from upper, middle or lower part of the car?

Thanks fierofool,
The sound is almost directly behind my head and to the left.
Possibly the door, possibly anything as sound seems to get transferred easily with the space frame.
Very solid car with only minor surface rust, but I will be looking under it to see what I can see.

I really do not like working on a car someone else has had apart already, you never know what was and was not done.
I found the air filter mount loose as a goose, but that was not it.
Might just have to take everything off and put it all back on again to find the noises.......

Someone else has had the engine and transmission out, so who knows what was not bolted down properly.
Already found several missing screws in just what I could see!

Maybe the roof panel slightly moving against the rear panel at the seam.

Door, subframe, exhaust, suspension, engine mount, rear side cover.... lots of things can cause rattles that transmit into the cabin

Sail panel inner trim piece, engine vent, loose speaker or oversise speaker that couldn't be properly secured.

OK guys, you talked me into it!
I am just going to disassemble the whole dang car and put it back together again!

Hehehe!

Seriously, thanks for all the input!