My Park Avenue thinks it's a diesel ???

[TopherS]

I had something happen today that I can't figure out what happened. I was stopped at a stop sign, waiting to pull into traffic. I was sitting there for about 30 seconds or less, then pulled onto the highway. As I accellerated, the engine sounded like my neighbor's SuperDuty Diesel truck and plumes of brown/black smoke poured out the back. When I got to speed (45 mph), I let off the gas and everything was back to normal. This happened one other time, about 2 weeks ago, where a car in front of me slowed and turned, so I slowed, then when I accellerated back up to speed...same thing (but I did not look to see if there was any smoke that time). In case it matters, it is about 65 degrees F outside.

Normally, I haven't had any driveability problems with the car. I recently (w/in past year) had new plugs/wires. I don't feel any missing going on. I haven't changed gas. So this is strange to me. Of course, my extended GMPP warranty expired 3 weeks ago, so it's time for some things to start going on .

Any ideas???

[bigsky]

Topher...any update on this? I don't know but was thinking maybe something with the muffler? Sounds like the engine was running ok, just more noise than usual...but then there is the black smoke. (BTW...still waiting for some KYB front struts on backorder.)

[TopherS]

No update at this point...so far, it's just happened twice. But, it "felt" as though it were the engine that was acting up. The only thing that I have come up with as a possibility is that there was a major misfire going on...but I don't know enough about engines to really say. It was very strange, though. Lots of noise and LOTS of smoke. It had cooled down here the last couple weeks, and it's possible that it may have something to do with the temps. We are warming up, though...we may hit 78-80 degrees this week, so we'll see if it has any effect.

Be sure to let me know about how how your struts work out for you...I'm VERY interested in getting some feedback about replacement struts for this car. Thanks.

[bigsky]

Did you check if it set any codes? My understanding is that a code can sometimes be stored without setting the "service engine" light. Also, I recently set the light for a transmission shift problem (want to replace that PCS soon), and the light eventually went off.

[imidazol97]

Originally Posted by TopherS

I had something happen today that I can't figure out what happened. I was stopped at a stop sign, waiting to pull into traffic. I was sitting there for about 30 seconds or less, then pulled onto the highway. As I accellerated, the engine sounded like my neighbor's SuperDuty Diesel truck and plumes of brown/black smoke poured out the back. When I got to speed (45 mph), I let off the gas and everything was back to normal. This happened one other time, about 2 weeks ago, where a car in front of me slowed and turned, so I slowed, then when I accellerated back up to speed...same thing (but I did not look to see if there was any smoke that time). In case it matters, it is about 65 degrees F outside.

Normally, I haven't had any driveability problems with the car. I recently (w/in past year) had new plugs/wires. I don't feel any missing going on. I haven't changed gas. So this is strange to me. Of course, my extended GMPP warranty expired 3 weeks ago, so it's time for some things to start going on .

Any ideas???

Are you losing any coolant from the reservoir bottle? The last person I knew that had a 98 Bonneville that said their car sounded like a diesel had their upper intake manifold fail on them. The coolant seeping into the intake air chamber gets ingested into the cylinders affecting the combustion.

A 2001 should be better designed than the early GM originals after 1995 that had the problem.

[imidazol97]

I'd suggest stopping at your friend Advanced Auto and letting them connect the code reader and they'll give you a printout indicating any codes and the meaning of those codes. Remember a code may only indicate the symptom of the real problem. Don't start replacing parts without certainty that part is what is causing the code.

Other stores also do reading. I just had a good experience with Advanced Auto after replacing my upper intake manifold which was leaking coolant past the seal. It was my second only because the original failed at 75K mi and Gm put on a GM replacement which has the same design problems. I used a Dorman this time. Pefect.

[TopherS]

I didn't get any lights on the dash when that happened, but I did not know that a code could be stored w/o the light going on. I'll take it to my mechanic and have him scan for codes.

I don't know if I'm losing coolant...it's possible, as the Buick dealer told me that my water pump is starting to leak a little. They said it wasn't bad, but definitely needed attention in the nearer, rather than the farther, future. At the end of next month, we are taking the car on a 3000+ mile "Clark W. Griswold, going to see the world's largest ball of mud" vacation ...so the water pump will be replaced within the next few weeks, before we go.

As for the upper intake manifold, I had the problematic gasket thing replaced about a year ago (by the same mechanic). Hopefully, there isn't a problem with the repair. I will have him look into it, though. Thanks for the ideas...I'll post back the results.

[bigsky]

As you probably know, the plastic (!) upper intake is a very very common issue with the 3800 series II non-supercharged engine. My 97 is on its third one (Dorman now with a metal sleeve insert and smaller stovepipe...just need to work on the transmission now). Did they just replace a gasket or did they replace the upper plastic plenum/intake as well?

To do a full fix this is my understanding: 1. Replace the lower intake gasket with the aluminum framed one (bnaylor posted part #'s for pinned/unpinned in the tips/maintenance section). 2. Replace upper intake and all related gaskets with a Dorman kit (can add a "sleeve" for extra protection) or the APN "sleeved" intake and gaskets (also see bnaylor's post in above section). 3. Since they have the engine apart replace the water pump (which is quite inexpensive and since the engine is apart will save on labor costs). 4. Consider going to the Prestone "complete" antifreeze instead of the Dexcool which some believe is hard on the gaskets if not changed regularly. The goal in all of this is to shoot for the 250k that some owners have obtained with these cars. This is the route I am planning to pursue with a 99. Some would say it is overkill, but then it might also be 200k+ protection.

[TopherS]

Here's the latest/greatest...the car, as we speak, is with the mechanic now. I described the "diesel" problem and his thoughts are that it is "predetonation", that the injectors are staying open longer, thereby dumping too much fuel into the cylinders. He's not sure if it's mechanical (sticking open) or if it's electrical (something in the computer is not signaling to the injectors to close when they should). He's going to scan the car for codes to see if any exist.

As far as the Intake Manifold issue, I'll call him and see if he can tell me if he did the complete fix or the abbreviated version. My understanding is that we replaced both the plenum/intake and the gasket, but I couldn't say for certain. Thanks for the details on this...now, I have reference on the subject. He feels that since the repair was done about a year ago, that it has nothing to do with my "diesel" problem. But I now want to know more about the repair he did do.

I have to have the coolant system flushed, since the water pump is being replaced, so I'll also talk to him about the "complete" antifreeze v. Dexcool option.

Reaching 250k on this car sounds good to me . So far, I've had 178K on a 1984 Olds Cutlass Supreme (3.8L V6 - California Emissions) and 205K on a 1985 Lincoln Town Car. I believe I detect a challenge for myself here. My Park Avenue only has 88K at the moment, so it will be a while.

Thanks again

[HotZ28]

First of all, let’s not confuse Detonation with Pre-Ignition, in addition, there is no such thing as “Predetonation”! This Link may help you and your mechanic, understand the difference here.

[Mag00]

Originally Posted by bigsky

As you probably know, the plastic (!) upper intake is a very very common issue with the 3800 series II non-supercharged engine. My 97 is on its third one

interesting.
My 95 PA has 114K miles, and I have had no problems of the sort.

[HotZ28]

Originally Posted by Mag00

interesting.
My 95 PA has 114K miles, and I have had no problems of the sort.

The VIN “L” 1995 PA is not an issue when it comes to UMI failures. This started with the VIN “K” - normally aspirated (NA) in 1996. This is not to say, that eventually you may have an LIM gasket leak, however, usually the LIM will leak to the outside of the engine first. You beat the UIM problem by one model year!

[Mag00]

Originally Posted by HotZ28

The VIN “L” 1995 PA is not an issue when it comes to UMI failures. This started with the VIN “K” - normally aspirated (NA) in 1996. This is not to say, that eventually you may have an LIM gasket leak, however, usually the LIM will leak to the outside of the engine first. You beat the UIM problem by one model year!

ohh!
thats very good.