View Full Version : White smoke after changing starter (by removing intake manifold)

07-18-09, 07:02 PM
I am new to this forum - if this should be posted somewhere else or if I am not following some forum etiquette please let me know so I can do better :)

Here are my main symptoms. White smoke in exhaust. High idle - little rough.

I have a 1996 cadillac deville with a 4.6L northstar engine. I went to replace the starter, which is, of course, underneath the intake manifold. I replaced the PCV valve while I was under there because it was cheap. So, after I get it all back together it is running rough with a high idle and lots of white smoke coming out of the exhaust. The white smoke has an odor, but I can't tell what the smell is...I am very inexperienced.

There was a vacuum line that had fallen under the corner of the intake manifold and gotten crimped under it (I think it goes to some heat or ac something it was the vacuum line on opposite side of the manifold from the throttle body). I was able to loosen the manifold and get the hose free and connect it and tighten the manifold back down with out removing anything. White smoke and high idle still present.

I ran the car in town and on the interstate. It stayed smokey in town but cleared up on the interstate. However, I parked my car and turned it off and when I restarted it returned.

SES light came on, the code was for cylinder 1 misfire. This cylinder has always had some misfires. I changed the plugs. When I started the car (after letting it sit for a day) the exhaust was initially clear, but then gradually built up to the enormous white smokey mess it had been.

Any ideas as to what I should check and in what order?g

07-18-09, 07:06 PM
The white "smoke" is either coolant or unburnt fuel vapor. Go back and get a good whiff of it.

07-18-09, 07:08 PM
I am very inexperienced, what kind of things am I smelling for. Could you describe the different possibilities of smells?

07-18-09, 07:13 PM
Fuel will smell like gas and coolant has a sweet smell.

07-18-09, 07:23 PM
Thanks, I'll check it out tonight or first thing tomorrow morning. I can't check it right now because I have to go. I'll definitely reply by tomorrow morning though.

07-19-09, 08:15 AM
Ok, I am pretty sure it smells like gas. It doesn't smell sweet like antifreeze or smell like trans fluid (according to a friend). I am thinking it smells like gas. The only reason I am not sure is because of my inexperience and weak sniffer :P

I am going out this morning, but I definitely look forward to your reply.

07-19-09, 08:52 AM
if you still have high rough idle you still have vacuum leak somewhere

07-19-09, 09:35 AM
I say vacuum leak as well. The computer will not be able to get accurate readings and it sounds like the engine is running super rich. Have a look at the vacuum line that got crimped and see if it is torn or cracked anywhere.

07-19-09, 10:49 AM
OK, that is good. Lesser of two evils. I would first check for a leaky FPR. Very simple. The procedure is in the Tech Tips section. If that is OK, then check for a leaky (stuck open) injector. Once again, the procedure is in the Tech Tips section. And don't overlook the above suggestion regarding a vacuum leak for the high idle. Check the intake manifold overpressurization valve behind the P/S pump.

07-19-09, 02:08 PM
Okay, I just got home. My neighbor says it is definitely a gas smell. He put his meter on it and it had two codes this time. P0201 and P0301. The cylinder 1 misfire *and* and open circuit on the corresponding injector.

I popped the hood and the bottom of the injector was wet with gas. I had not seen this before - so, I don't know if this is a new problem or if it was part of the problem all along.

I will be spending part of the day researching y'alls suggestions and working through them. I will also be researching this latest development. Of course, y'all's input is invaluable to me.

Thanks so much for you all's help so far.


07-19-09, 03:45 PM
You do not need a scanner to pull codes on these cars. There is a diagnostic system built into the instrument cluster and it is controlled using the climate control buttons. Read up on it here, it's very cool to use and extremely helpful. http://www.cadillacforums.com/forums/cadillac-deville-1985-2005-including-1985/138257-how-pull-codes.html

07-19-09, 09:02 PM
If you have an injector that is wet, that's an external leak and that is NOT good. Fix that first.

07-20-09, 09:56 PM
Little bit of background - I did not take this apart so I had to guess at putting it back together.

So, upon inspecting the wet injector I notice that the o-ring has come apart. Well, I had replaced those o-rings when I took all this apart. Apparently, whatever NAPA sells is the wrong o-ring. The diameter of the ring is smaller than it should be *and* the rubber is too thick. So, when I had put it on my manifold the o-rings prevented the injectors from going into the manifold and the o-rings actually sheared into pieces. So none of the injectors were even seated properly.

Fortunately, the person who took this apart saved the old o-rings so I put those back on it. I then checked for a leaky injector by turning on the key - no leaks. I checked to see if they were all working by attempting a start - they all sprayed fuel but *then* one decided it was leaky and poured out a bunch of gas after I turned the key off.

So, I am gonna replace that one with a advance auto brand injector (because I can walk to the store [I have no other car] and they'll have it tomorrow).

So, after I get all this back together tomorrow, I'll give y'all the real update.

07-21-09, 03:59 PM
I replaced the offending o-rings and the offending fuel injector and it now appears to be working correctly!

Many thanks to you all!

Thank you Ranger, ehall, and dirt_cheap_fleetwood.

Thank you for all your help diagnosing my troubles. Thank you for the tip on using the dash to get the codes. Thanks for all the tips and tricks for trouble shooting and fixing my problem. I cannot say thanks enough.

I did end up going to the dealer for the injector, because of a miscommunication with the parts store. That cost about $50 more. Also, after replacing everything, the symptoms persisted. However I let the car run for about 15 minutes (because the battery was dead) and when I restarted it a few hours later - it had all cleared up.