use2windsurf

Both, and even when only the sunroof is open. The intensity varies, from nothing to full on brain cell killing...

1987 Red 944 N/A

chriscross

Yeah, those are cast - someone must have replaced the original ones. Do you smell it at all while idling with the hood up or does it only happen at speed (that would be more in line with what others are saying about plugging holes)?

You could jack the car up and search for leaks. Just in case you haven't seen them yet - there are threads on here that show the proper jack points or just use some ramps.

HICKS

Do you still have a cat? Is the cat original? Original exhaust tip?

use2windsurf

it seems to be when at speed, i sniffed all around the engine compartment, under the car, at the exhaust and couldnt find. I live two blocks from a muffler shop, think Its time to make a stop and let them put it on the rack.

1987 Red 944 N/A

use2windsurf

I think it has the orignal cat. not sure about the exhaust tip

1987 Red 944 N/A

Jamesr6967

There is a threaded hole that should contain a plug just ahead of the cat, could be missing. If you live in a state that does emission testing , the PO may have removed it or drilled a hole in the exhaust ahead of the cat to pass the test. It's an old trick to get an old cat to 'light up' by feeding it extra fresh air.

ZR8ED

This may not sound like a complete solution, but it sure beats dying of fumes in the cabin. Extend your exhaust tip. There is a large dead air space behind the car while it is travelling down the road, and exhaust can get caught in this area and get sucked into the cabin through one of many holes/seals etc. Old Datsun Z cars suffer from this, and after I replaced and sealed everything I could find, I extended the muffler tip 3 inches, and the car got 100 times better. (pointing the tip towards the ground will help as well.) It had a side benefit of the car being cleaner as the exhaust was no longer getting the back of the car dirty.

goodluck!

Racerstev

I had-have the same problem with my 87. I tyred new manifolds, sealing all
the holes I could find, new shift boot. By far the biggest improvement was
from the rear hatch. I got new hatch pins (mine were seized) and got rid of
90% of the fumes.

Thinking the rest could be gotten rid of with a side exit exhust in the back..

Steve

odurandina

just looking at the thread title, my first inclination would be to get suspicious about a possible cracked header.... but then, then engine would be noisy.

next suspicious area to investigate would be the overall seal at the rear hatch.

maybe line the entire hatch seals with window putty and take a short drive

and check if the situation has improved.

william_b_noble

the hatch glass is glued to the aluminum frame - the bond fails at the top and this lets water and sometimes fumes into the car - check that. If it is coming debonded, there is an on-line FAQ on how to reseal - be sure to use both primers if you do this or it won't stick (personal experience)

Racerstev

For a temporary fix I used black electrical tape across the top of the hatch.
Blends into the black frame nicely and it keeps the water and fumes out..

Steve

beamishnz

I had the same on an '88 944S. It got worse if the sunroof was open because that caused a venture sucking air through anything unsealed at the rear hatch. I tweaked around with the rear seal (pulled it off slightly and adjusted the latches to make the lid close tighter - but no so tight that it wouldn't release ... that worked for me. I also looked at why it smelt so rich as well ... it was rich on WOT and that made the problem worse ... still working on that problem

use2windsurf

Update: I took the car down Friday and had the exhaust inspected. no leaks, but the catalytic converter appeared to the the original. It was completely burned through and the rattling I thought was a heat shield was the loose guts of the converter. I opted to have it replaced with a standard unit and installed a new exhaust tip. It dramatically improved the issue. I can still occasionally smell exhaust it has a different odor and is much less offensive. Seems to occur worst between 70-80 mph.
Additionally I installed the hatch pin seats from only944.com http://only944.com/partscatalog/only/hatchpinseats.html which also gave me a better seal by eliminating the vibration of the pins in the seats which keeps the seals firm against the deck. Also got rid of the annoying rattle. I can hit speed bumps now with no rattle from the hatch.

use2windsurf

sounds like our problems are almost the same, I have also have a rich mixture. I am replacing the 02 sensor and DCM temperature sensor which many on here say can be the cause. I'll post back with an update. thanks, this forum has been a life saver.

beamishnz

Glad to hear that you are making progress. Be interested to see how you get on with the rich mixture issue. I was thinking O2 sensor too. Wilks who supplied my performance chip have suggested I check the mixture setting on the DME too .. just not had the time