First post here.  Have a 91 Zuke with only minor mods.  Mostly stock vehicle with just a small lift and that's about it.  Of course then it is fuel injected and when I driving and let off the gas (to turn, shift or whatever) I get a strong exhaust smell.  It only happens when I do let off the gas.  Any suggestions on the cause and a fix? 

At the risk of being misunderstood - let me be the one to ask - what exactly is a 91 Zuke?

Is it a Swift?  a Samurai?  a Vitara?  a Sidekick?  2 door?  4 door?  convertible?  hard top?

Possible causes will vary with the model, and body style and range from the exhaust being defective, or possibly incorrectly routed, to having the rear windows (on a soft top) set incorrectly.

Oh - welcome!!

Good followup Fordem... It'll be interesting to see a respond on the vehicle. I'm betting it's a Samurai with an exhaust that goes straight out the back.

-Eric

It's a samurai soft top and my first thought was as you kind of stated it might be with the exhaust sucking back in.  But I tried rerouting the exhaust out the side and it made no difference.  Also I have a hard top that I put on in the winter and it makes no difference.  I still get the smell.  To be more clear it's not even like a pure exhaust smell.  I can't even explain it for sure, but it's the worst when I have been cruising along and then either need to shift or just let off the gas for any reason.

Thanks!

It almost sounds more like engine smells and a small exhaust leak .

It's a samurai soft top and my first thought was as you kind of stated it might be with the exhaust sucking back in.  But I tried rerouting the exhaust out the side and it made no difference.  Also I have a hard top that I put on in the winter and it makes no difference.  I still get the smell.  To be more clear it's not even like a pure exhaust smell.  I can't even explain it for sure, but it's the worst when I have been cruising along and then either need to shift or just let off the gas for any reason.

Thanks!

The engine runs a little rich when it decelerates, hence the reason why you smell the exhaust with your foot off the gas. 

I have also found that simply routing the exhaust to the side still results in some exhaust smell.  It needs to be routed to the side and exited down, just like the stock tailpipe.

It's a samurai soft top and my first thought was as you kind of stated it might be with the exhaust sucking back in.

From the other replies, I guess you've already figured out that the exhaust routing on a Samurai has to be carefully done to prevent the fumes from getting inside.

But I tried rerouting the exhaust out the side and it made no difference.  Also I have a hard top that I put on in the winter and it makes no difference.  I still get the smell.
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Assuming your hardtop seals properly (which it may not), this would suggest that you have body rot somewhere that is allowing the fumes to be drawn back in.

My buddies 87 does this, he had a hair line crack right on the seam of a weld which was directly underneath the driver seat.

If its fuel injected then it should shut fuel off under deceleration. I would check the exhaust manifold for cracks and then work backwards. Does the Check Engine Light come on at key on and then go off once its started?

Thanks for the additional replies.  I am going to do a front to back inspection of the exhaust.  The body is solid and rust free.

If its fuel injected then it should shut fuel off under deceleration. I would check the exhaust manifold for cracks and then work backwards. Does the Check Engine Light come on at key on and then go off once its started?

What would that indicate?

1)  That the Check Engine Light is working.
2)  That there are no emission system failure codes.

1)  That the Check Engine Light is working.
2)  That there are no emission system failure codes.

oh gotcha, its just another way of saying the CEL stays on after starting (if there are codes)

Not as much as it confirms that there are no codes.

Do you really look at the dash lights at key on, before engine start?  If the low oil pressure light wasn't working how long would you take to notice it?  ABS light?  SRS (air bag) light?

A number of used cars have been sold with the CEL bulb removed, making it not immediately obvious that there is a problem, so the regulars have learned to ask the question - asking if the CEL is on, does not necessarily get you an accurate answer, but asking if it's on before the engine is started leads to the discovery that the bulb is missing.