Contour Enthusiasts Group Archives Forums General Troubleshooting Hard starting, rough idle, and loss of brake boost

Here are the details:
98 Mystique Sport V6

Bought less than a month ago used, private sale.


Two weeks ago, went on a highway trip and the day after we got back started the car and had very rough idle. Cleared up after a little driving.

A week later, again after a highway trip, it did the same thing.

Then, without a highway trip, but the weather has gotten very cold (-20c) it takes 15 minutes to get the car to run, albeit at a very rough idle.

Starting routine:
1.Turn the key .... car revs to 3000rpm
2.revs drop to 500, car almost stalls
3.revs climb to 3500
4.revs drop to 500
5.repeat 2-4 several times
6.car eventually dies.
7.start at 1 again

Finally the car seems to warm up enough for it to stop hunting idle, but still very rough, and I can hear what sounds like backfires through the intake.

Pulled the plugs and they are very black (replacing with Autolite DP and new wires).
Cleaned the IAC.
Checked vacuum hoses, no visible problems.
Tested EGR ... seems to be ok

Also, found a hose that is connected under the battery (if you look straight down just to the left of the battery it is connected to a nipple on something black) but the other end is free. I have looked everywhere for where it might connect, but so far am stumped.

One more piece of info .... since it has been so hard to start the brake boost power is lost quickly. If you depress the pedal, let up, then press again when coming to a stop there is no boost (vacuum) left.

Leads me to believe some sort of vacuum leak, but I'll be damned if I can find it.

Sorry, I kind of rambled on, but I wanted to make sure I got as much detail in as possible.

Anybody have any ideas?

I really dont know the name of it but I had some leaks where those black tubes come out of the ports in the UIM. I siliconed around them to seal them up. One of the tubes goes directly into the brake vacuum. John

Sounds exactly like a vacuum problem to me, especially when you consider the rough idle problems in addition to the brake booster problem. My guess is that you have a vacuum leak somewhere at, in, or around the booster. Check the hose coming from the booster, check the connection where the hose goes into the booster, and follow the hose toward the manifold.

Concerning the "hose that is connected under the battery (....connected to a nipple on something black) but the other end is free." This sounds like a vent hose, that doesn't really connect to anything.

Backed up by a vet! Cool!

Will check that line again tomorrow, maybe missed something.

Thanks for the replies bentleywarren & jmatzick.

Any other suggestions out there?

Also, that hose that I can't find where it connects to comes straight up from the nipple, seems odd it would be a vent hose in that position .......

Does the free end have a little black plastic clip? If so, clip it on the threaded part of the battery tie down post. John

Ok, great John, thanks. When working on the Talons, I always have another car to reference from for these little oddities.

Thanks for taking a look.

Going after the brake booster line again today. Praying to the Backyard Mechanic God right now!

Jeff

sounds like you have a bad(big vacuum) leak... there should be a hose going to the brake booster(the metal can behind the master cylinder.... kinda big vacuum hose(maybe 1/2 or so)..... pull it off and put your thumb over the end of the hose where it goes (or used to go) to the brake booster..
you should feel a pretty good pull of vacuum on your thumb.. if not then you found the problem.... travel along and see if you can find any loose hoses???? and a vacuum leak will give you a bad ride also, loos of power and the engine hunting for an idle, high speed idle, etc????
the loose hose you found on the area under the battery might be the hose that you need to attach to the brake booster or somewhere along the line to the brake booster??
hope this helps.,... been there with other cars, so talking from experience....

Thanks for the tips dbird.

I did find the MASSIVE leak on the UIM, back bank, passenger side.

Used some carb cleaner and started spraying around any suspect areas. All the hoses were good as I suspected, but massive leak on the intake near the fuel line.

Thanks for everyones help.

Ordering parts tomorrow, going to pull of the UIM, LIM, and clean everything while I'm in there.

Following the FAQ on pulling it apart ..... any extra suggestions?

Jeff

SORRY, i wish it was just a hose that fell off.. i could just picture it... only problem is that after all the years of not wearing any hearing protection i cant hear any vacuum leaks.... and alot of other things.... wife will say what is that noise that the car is making, and i say,
"What noise."
mess with the car and will get here to listen to see if the noise went away... some of those high pitch sounds are hard for me to hear..... i guess with the amps in all these cars now everyone will have a hearing loss with the
bmmp, bmmp, bmmp....