Rough start

[maydog]

I thought I would shoot this question out just before I hook the laptop up to the car...

The past week my car has been running very rough for the first 10 - 30 seconds after starting the car. After that period everything runs fine. It is only rough from a cold start. I am going to do some troubleshoothing this weekend, so any ideas on what to check.

Things to think about:

I recently had some exhaust work done to make room for a trailer hitch (drawtite makes an excellent hitch). They replaced the mufflers I had with new ones, significantly quiter and I think they flow less as the buttometer is seeing less activity and the tires dont break free on a WOT as often. I didn't really trust the clowns working on my car, see the post on the broken ride height sensor, but I have no access to pipe benders and welding equipment. They may have screwed something up.

My water pump is leaking pretty bad, I will replace it this weekend - maybe water is getting onto electronics.

I have a host of other electrical gremilins - for example my memory seat module throws all possible control codes and twitches over bumps. There may be an electrical wiring issue here

... Thats all the known conditions with the car. I was thinking that maybe an 02 sensor could not be warming up. I can leave the car in the on position for a minute and it will still be rough upon starting. Does anyone know when the car is supposed to go closed loop.

I have an elmscan box that I can hook to my laptop and view the sensor outputs so that should be a pretty easy diagnostic to perform. Anything else I should try?

[maydog]

Ok, here is the update. I hooked up the computer and all the sensors seem to be working fine. The starting problem seem to come and go. It usually happens when the engine is cold. I also notice extra steam from the exhaust when it is running rough. I have not seen any bubbles in the coolant resivor however.

I have my suspicions - I hope that they are not true. What are your opinions?

[navion]

Maydog,

To verify your suspisions, I would wait until the car was dead cold, start it, give it a few seconds, go back & sniff the steam. (Gently now, No deep breathing. ) See if you get a sweet smell. (Dexcool smells sweet dosen't it? ) A perscription of Bars Leak Pills may be in order. Or serious surgery!

Possibly it is just cold outside & you are getting parinoid about the steam!

Lets hope that the (excess) steam is from the cold.

Good Luck,

Britt

[maydog]

I think I smell coolant, problem is that I have been fighting off a cold for the past few days. I had added 2 tubes ot bars leak last weekend since I was fixing a leak in the lower radiator hose. I may be running out of options.

Is there any way for me to do a pressure check at home. I have an air compressor and /or a bike pump I could use.

[navion]

Maydog,

I had a similar situation with my 1994 SLS. The ole girl would start & miss on one cylinder for about 30/45 seconds. Then it would smooth out. It would run fine until shut down again. If restarted while warm, it was about a 50/50 chance that it would be smooth or miss. But if let set for an hour or more that miss would be there. It drove me NUTZ! It also had the mysterious loss of coolant. About every 6 weeks the coolant low message would greet me. I attributed the coolant low message to the incessant small leaks that kept cropping up on the radiator and heater hoses. There always seemed to be a small spot of green on the floor in the garage.

Last month I bit the bullet and installed the six pellets of the Bars Leak that is recommended here on the board. It didn't come in tubes. (Check Scotty's posts, he attached a picture of the correct Bars Leak product.)

Now, after changing the plugs (twice) ignition wires once, cleaning injectors, rerouting the ignition wires & extreme hair pulling. (I haven't needed to go to a barber since this started! ) VOILA!! The old girl has stopped missing, period!

Now, is this a result of the Bars Leak treatment? Who knows. It sure is coinceidental, but I did nothing else to the car. I had almost decided to live with the miss. (I needed to grow some hair back! ) But I haven't had to add ANY antifreeze since adding the Bars Leak. And over the next few days after adding the Bars leak the cold miss dissapeared! Coincidence? He!l, if I know! (I will probably get the low coolant message now that I have said something.

The Bars Leak pellets are the same as the GM coolant supplement tabs. (So I have been told.) They are completely different than the Bars Leak that comes in tubes. I don't know if it is adviseable to mix the two types of product, But if your situation dosen't improve, I would consider it.

By the way, right after I installed the Bars Leak pellets per the instructions on the package, I went on a 300 mile trip. That could have helped the product perform.

As far as doing a pressure check, you need an aircompressor that is capable of supplying a t least 3 CFM or more, an adaptor to screw into the spark plug hole & the proper hose hookup. I have found that, in my experience, the test for combustion products in the coolant is much easier to do and will detect even minute leaks that a pressure sheck might not show.

Oh! Also, those minute antifreeze leaks that I mentioned earlier, they seem to have dissapeared also!

Hey, You guys at Bars Leak, contact me for the address to send my check to!

Good Luck with you leak detection & get over that cold!

Britt

[maydog]

Hmm, I assumed that the bars-leak powder tubes and the pellets were the same thing. I would have to think that any type of sealant type of repair would only give temporary results? Thanks for the suggestion.

[navion]

Maydog,

I share your feeling that the sealant's results could only be tempoary. But this particular product is recommended by GM as a supplement for the 4.9, 4.5, 4.1 and the Northstar. It is recommended even if you don't have an issue with the engine. I beleive that if there is a small leak, it will seal it and prevent it from becomming a major one. These GM supplement tabs or Bars Leak tablets have a finite life and need to be replaced every couple of years. I don't remember the exact schedule.

I was skeptical (and still am to some extent) that this material cured (for now at least) my cold miss problem. However, even if it is "temporary" and I get another year or two before I have to perform major surgery, then it has been worth it.

I bought mine at NAPA for less than $ 2.00. I thought that price was too cheap to do any good, but, what can I say? I suppose that you could jerk the heads, install the thread inserts & new gaskets and seals for a two or three grand. Or you could try this. If it dosen't work, all you are out is a few bucks for trying.

Britt

[maydog]

I borrowed someones nose today and they confirmed that the exhaust stunk of coolant.

I am pretty sure the sealer tabs and the powder are the same, but I need to make a run to the parts store tonight anyway. Are there any suggestions for fittings or adapters needed to do a pressure test.

Also, I was wondering if anyone has had luck with the "head gasket repair" type sealers out there. My leak is still pretty small, will these buy me some time or will they just mess up more things in the engine?

Thanks