Contour Enthusiasts Group Archives Forums General Troubleshooting Warm air puffing in engine bay???

Ok, I checked the FAQ regarding the "Loss of power, sound of rushing air in engine compartment" item. And I don't believe i have the same problem.

I have a 1998 Mercury Mystique V6 automatic with 155k km on it. Its been serviced regularly, but parked outside most of its life and rarely driven now (maybe twice a week for 100 km total).

I was driving along the other day, and hammered the gas to get out of the way of somebody cutting into my lane. Car felt fine until I hear something pop and the car started puffing air when I was on the throttle. I thought the flex pipe under the car went, so I limped back home. I popped the hood to look around and I noticed air puffing at my face (when i was peaking around the EGR area).

I jacked up the car to peak around, and its not the flex pipe. I thought it was the exhaust manifold (the one close to the firewall) and I felt around looking for a gasket leak. I couldn't really get in there, but it doesn't appear to be from the manifold.

Its not a constant steam of air, it puffs away. I did a vacuum test on the EGR and it holds pressure fine, engine runs fine and surprisingly, there are no CELs. I can't pin point the exact source of the leak, but its under the EGR. The air its puffing out is hot (after the car warms up a bit). I don't believe its coming from the exhaust manifold (but i could be wrong).

Any suggestions?

Oh ya... car has no power at all now after 3500 rpm.

A pop to me gives a hint maybe your DPFE went bad. They seem to pop (the hose(s) connected to them are blown off.)

Any CEL's?

You may do a search in troublshooting for "DPFE" and you'll get some good stuff.

Good luck!

ok, so i checked out the DPFE... and indeed, the hose on the back side was off (the "high" hose). Infact, the entire hose is missing (from the DPFE to the metal hose it plugs by the manifold it plugs into). It looks like its been missing for awhile, as the nipple on the DPFE is all corroded.

I read up on the DPFE, and people say the car should drive the same and only an emmissions test would pick up on it?

So... would replacing the hose and DPFE solve both my problems? (air puffing in the engine bay and lack of power)?

Oh ya, anybody know the part # for the "high" hose? (or the diamater of it?)

thanks!

I don't know that the hose is anything more than plain vac hose - somebody confirm that for me. In the mean time, the pressure buildup that caused the hose to pop off suggests that you may have a problem with the DPFE. Put the hose on the current one to check that it's OK, but a replacement should be under $40 - even at the dealer.

In the meantime, before spending money on a DPFE, try doing TB cleaning.

Almost free, quite effective, & easy.

Enjoy!

Good point Tour!

Yeah, it's just a regular vacuum hose. I WOULD buy a DPFE and change it out. There's nothing like too much insurance! Especially if that tube has been missing, who knows what the DPFE looks like on the inside.

It's not too hard to get to. Removing some of the air intake hosing helps a lot. And use a long entension to reach the bolts that hold the DPFE to the block. Careful! Those bolts love to fall off the socket and find their way to the top of the transmission. Then you'll have to spend hours making a custom tool to pick it off... I did anyway

That metal tube the rubber tube was connected to is your EGR tube. it goes from the EGR valve the rear exhaust manifold.

Try a new DPFE, and the TB cleaning TourDeForce mentioned.
If that doesn't help, and you still have problems let us know!

Good Luck!

Ok... i went ahead and bought a new DPFE (plastic one this time). I hooked it up and the hose blew off again. No codes were thrown at all.

I decided to by pass the DPFE totally and connect the pipes together. Same thing, the hose blew off (i had to use a small hose clamp as the ports are different sizes). The hose blows off around 3500 rpm...

I had a throttle body cleaning done about 20k km ago at the dealer...

something makes me believe that one of the pipes from the manifold are clogged perhaps? I'm going to measure the voltage on the DPFE connector first...

DPFE hose blowing off is usually the sign of excessive backpressure caused by a plugged pre-cat. Unfortunately you're past the emissions warranty (130k km). Replacement of rear exhaust manifold or gutting pre-cat the usual fix.

Note also that hoses are not plain vacuum hoses, they operate under a low pressure and are subject to high exhaust gas temperatures, dealer only item IIRC.

I'm starting to think its the precat/rear manifold as well...

I don't mind doing the work myself, but seeing how rusted the nuts are, I don't think I can get it off myself. Plus the extra effort of removing the alternator....My local scrap yard has used ones for $125cdn.

Seeing you're from Pickering, do you know of any place that would either install a precat (or gut my exisiting one) for a decent price?

so any more ideas? or am i doomed to change the manifold?

How-to gut pre-cats

Suggest you review the above to determine if you wish to DIY. The firewall side manifold is the more prone to plug, perhaps due to heat build up, so just gutting it is a time-saver.

Suggest a post in Eastern Canada Forum for local shops that might do the work at reasonable cost.