Odd odor on startup...
Thread Starter
Melting Slicks
Joined: Mar 2003
Posts: 2,898
Likes: 0
From: Oklahoma City Oklahoma
Odd odor on startup...
This is actually a two part thread....
1. Over the last few months, my 85 has been taking a little longer to start, and once it starts, I'm smelling something like a combination of raw gas and starting fluid. My wife made the comment the other day that it was putting out a little black smoke for a second or two when I started it. Sounds like it's running rich, but I have not noticed any difference in performance when driving it, and my fuel mileage has not changed in the least. 20.5 City/26 Hwy
2. I can go out and start this car 10 times in a row, and 10 times in a row, it will start at different RPM's. I varies from 680 RPM's (where it has always idled) all the way up to 1500 RPM's with a VERY slow drop back to 680.
NOTE: This is happening when the engine is warm. Also, when I am driving the car, and pull up to a stop light, the engine will stay at around 850/900 RPM, and then slowly drop back to idle, and with the AC on, it will drop down to 450 or less when stopped, and sometimes die altogether. It will restart immediately, right back up to the high RPM's, and then SLOWLY drop back.
This car is getting harder to figure out every day. Thanks in advance for any ideas, and or tips.
1. Over the last few months, my 85 has been taking a little longer to start, and once it starts, I'm smelling something like a combination of raw gas and starting fluid. My wife made the comment the other day that it was putting out a little black smoke for a second or two when I started it. Sounds like it's running rich, but I have not noticed any difference in performance when driving it, and my fuel mileage has not changed in the least. 20.5 City/26 Hwy
2. I can go out and start this car 10 times in a row, and 10 times in a row, it will start at different RPM's. I varies from 680 RPM's (where it has always idled) all the way up to 1500 RPM's with a VERY slow drop back to 680.
NOTE: This is happening when the engine is warm. Also, when I am driving the car, and pull up to a stop light, the engine will stay at around 850/900 RPM, and then slowly drop back to idle, and with the AC on, it will drop down to 450 or less when stopped, and sometimes die altogether. It will restart immediately, right back up to the high RPM's, and then SLOWLY drop back.
This car is getting harder to figure out every day. Thanks in advance for any ideas, and or tips.
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
Re: Odd odor on startup... (White85InOKC)
no ideas on #1, but for #2, i'd check to see if the IAC valve is stuck or partially stuck. it can accumulate a lot of crap on it which can cause what you are describing. i'm sure if you do a search you can find quite a few posts on how to clean the valve properly. if you do it wrong you can damage the valve.
Race Director
Joined: Feb 2002
Posts: 11,268
Likes: 14
From: Honolulu, HI
Re: Odd odor on startup... (White85InOKC)
I'm no expert but black smoke on startup is typically a sign of leaky valve seals. But on a fuel injected car it's also a sign of leaky injectors.
Ohm out your injectors to make sure they're o.k.
Ohm out your injectors to make sure they're o.k.
Pro
Joined: Jul 2002
Posts: 729
Likes: 4
From: Yukon OK
Re: Odd odor on startup... (vvv90)
Ohm out your injectors to make sure they're o.k.
Might crank the engine when cold with the ignition disconnected so it won't fire and then check plugs to see if one of them is wet with fuel. This should identify if one of the injectors is leaking. Won't check for the cold start valve though.
I am not 100% sure on this. Anyone else???
Race Director
Joined: Feb 2002
Posts: 11,268
Likes: 14
From: Honolulu, HI
Re: Odd odor on startup... (LaVidaLoca)
Ohm'ing the injectors will show indirectly whether your injectors are working properly, even with sealing. Afterall, if the coil is caked with buildup and won't open properly, it probably won't seal properly either.
My point was that if the injectors don't ohm out high enough they need to be replaced anyway so it's a good place to start. Especially on an older car.
My point was that if the injectors don't ohm out high enough they need to be replaced anyway so it's a good place to start. Especially on an older car.
Le Mans Master
Joined: May 2003
Posts: 5,203
Likes: 0
From: Las Vegas Nevada
Re: Odd odor on startup... (vvv90)
I have been having the same problem on my 85. Yesterday I fired it up and it sounded like it backfired on kickoff. I have no mufflers so it was loud. first time its ever done that. Thoughts? :confused:
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Odd odor on startup... (Southern Comfort)
Black smoke is fuel.... a very rich burn.
Leaky valve seals puffs out a whitish bluish smoke. And it's right at startup, not after. And it never seems to have an effect on cranking time.
It sounds like tuning the IAC and TPS would help. It didn't cure my probs witht idle, but it helped.
Leaky valve seals puffs out a whitish bluish smoke. And it's right at startup, not after. And it never seems to have an effect on cranking time.
It sounds like tuning the IAC and TPS would help. It didn't cure my probs witht idle, but it helped.
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Pro
Joined: Jul 2002
Posts: 729
Likes: 4
From: Yukon OK
Re: Odd odor on startup... (Southern Comfort)
How do you tune the IAC and the TPS?
1. With IAC connected, ground diagnostic lead.
2. Turn on ignition, do not start engine. Wait 30 sec.
3. With ignition on, disconnect IAC electrical connector.
4. Remove ground from diagnostic lead and start engine. Allow engine to go to closed loop.
5. Adjust the idle stop screw to desired minimum RPM
6. Turn ignition off and reconnect IAC connector.
7. Adjust TPS to .54 volts.
8. Start engine and check for proper idle.
:cheers: