Check Engine Light

[ROX]

I had the H2 out in the Sand last weekend, and the check engine light came on. I checked the gas cap to make sure it was tight, and after a long day wheeling, I decided to call BlondeStar and have them run a diagnostic. They said; You have a problem with the emissions, take it to the dealership within 7 days. At the dealership, the tech hooked up the little black box and reset a CAT 1 code. Then told me that the there are two sensors, pre- and post- catalytic convertor. I asked if one of the sensors could be bad and he stated that new cats are covered under warranty until 60k miles and that the 2 sensors come with it. He didn't tell me if one of the sensors was loose or full of sand and mud or anything. He said to drive it and see if the code comes back up. It did, after about four more key cycles, or about 40 miles.

I was considering upgrading the headers and cats instead of going back to stock. (I tried to search, but it says its unavailable.) Is this a good upgrade? I tow a small trailer, and I could use a few extra HP, but I'd like to know if it's worth the money. I just don't want to spend a bunch for 10 more horsies, unless they're race horsies.

Any info would be very helpful. Thanks.

[ROX]

I had the H2 out in the Sand last weekend, and the check engine light came on. I checked the gas cap to make sure it was tight, and after a long day wheeling, I decided to call BlondeStar and have them run a diagnostic. They said; You have a problem with the emissions, take it to the dealership within 7 days. At the dealership, the tech hooked up the little black box and reset a CAT 1 code. Then told me that the there are two sensors, pre- and post- catalytic convertor. I asked if one of the sensors could be bad and he stated that new cats are covered under warranty until 60k miles and that the 2 sensors come with it. He didn't tell me if one of the sensors was loose or full of sand and mud or anything. He said to drive it and see if the code comes back up. It did, after about four more key cycles, or about 40 miles.

I was considering upgrading the headers and cats instead of going back to stock. (I tried to search, but it says its unavailable.) Is this a good upgrade? I tow a small trailer, and I could use a few extra HP, but I'd like to know if it's worth the money. I just don't want to spend a bunch for 10 more horsies, unless they're race horsies.

Any info would be very helpful. Thanks.

[wilfred]

I have Edelbrock headers, Borla exhaust, Magnecor spark plug wires, & True Flow air filter on my '03. HP gain is definitely noticeable but not neck snapping. And I don't know the exact HP gain in terms of numbers.

My advise is to stay away from Borla headers! Long story short, I had problems with it and Borla did not take care of me. I ended up taking it out and replaced it with Edelbrock.

For the exhaust, I only have minor installation difficulties with the Borla. But because Borla was such a poor company to deal with and the fact their exhaust is pricey, I wouldn't recommend it to anyone. See if you can use the search function at a later time because quite a few members on this forum are running Flowmasters and they seem to be very happy with theirs. Not to mention Flowmasters are very reasonably priced

I have not messed with the stock cat so I'll leave that up to someone else that has to give you advice

[NoMoGMPG]

The sensors are oxygen sensors. While running in the sand, you were under full load for quite awhile probably burning a very rich mixture which can load up an O2 sensor. Give it a week of normal driving first. That will give it time to burn off, if not and you keep setting codes, then consider having the cats replaced under warranty first, get the new sensors with it then put your headers/exhaust on, that way you get fresh stuff. I recommend Corsa exhaust.

Dave

[ROX]

Thanks! I forgot to mention that I already have a Flowmaster exhaust.

They told me they would only replace the cat with the problem. That means one new and one with 50k miles on it.

One other question: If you're adding an aftermarket exhaust system, wouldn't you want to add high flow catalytic converters as well? Otherwise, you'd have one little link in a big chain.???

[KenP]

There has been some discussions about the cats in the past. The ones that come stock are high flow converters, but more than person has changed them out and liked the results. kdio is one of them.

I have Borla headers and have had no problems at all with them, but wilfred did as have others. The Borla products are expensive.

Corsa exhaust, as Dave recommends, is often available from the dealer. That means it should be warranted under your vehicle plan, but will cost a few dollars more. You can get it many places and have any shop install it. I have the B&B Tri-Flow and love it.

Get the O2 issue covered first, you don't want the dealer jerking you around.

[ROX]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KenP:
Get the O2 issue covered first, you don't want the dealer jerking you around. </div></BLOCKQUOTE>

Good point.
I'm calling the tech in the morning, because I'm sure he said to change the cats to high flow. I'll let you know what he says this time.

[ROX]

I did a search this morning, and found some very good information.

I did find one thread that says the factory cats are not high flow, and to make sure and change them because higher exhaust temperatures will burn them out prematurely if you don't, and its even more important if you have a super charger.

Here are some of the threads I found in case anyone is interested.

http://elcova.com/groupee/forums/a/tpc/f/6706011751/m/639607...396078553#6396078553

http://elcova.com/groupee/forums?a=tpc&s=2826088551&f=6706011751&m=918601756 5

http://elcova.com/groupee/forums?m=6826020973&a=tpc&cdra=Y&s=2...551&f=51060 11751&q=Y

I do have an appointment to have the existing check engine light fixed tomorrow.

P.S. dont search for the word cats, it really pulls up some c r a zy stuff!

[ROX]

Ok. I thought I'd update this post just for an fyi.

I took Kens advice and before upgrading any headers and such, I just took it in for the warranty cat 1 code. (check engine light) The dealership replaced the catalytic converter on the drivers side. I'm driving along 2 days later and there's the light again. Now they are replacing the vent hose and overflow cannister. I'm hoping that they were smart enought to order a new gas cap while they're at it, since that thing has always given me trouble.

While I was waiting for the cat. to show up at the dealership, I took a little off road trip and blew out the front differential. That was scarey! Come to find out, when I got it to the shop, the tech says, "oh yeah, remember when you had us change the oil before you went to Moab? You had a crack in the front diff. then." So now I've learned that GM doesn't recall problem parts, they just wait for them to fail first. I'm glad we bought the extended warranty! I'd be shelling out $1500.00 for the repairs. They also told me that this is something they knew about in the older models, but since then has been fixed. Newer models shouldn't have this problem.

So, if this subject hasn't been visited in a while, I hope this helps someone else.


Happy Trails!

[TheSkeptiks]

H2 Rocks...you said in your post..." They also told me that this is something they knew about in the older models, but since then has been fixed. Newer models shouldn't have this problem."
Does this mean pretty much ALL 03 H2's have problems like this? Or was there a recall to fix these problems?

I'm looking to purchase an 03, but I don't want to buy a problem. Would I be better off spending more for an 04? Are the 04's less problematic?

I know thats a lot to answer.
Thanks

[ROX]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TheSkeptiks:
H2 Rocks...you said in your post..." They also told me that this is something they knew about in the older models, but since then has been fixed. Newer models shouldn't have this problem."
Does this mean pretty much ALL 03 H2's have problems like this? Or was there a recall to fix these problems?

I'm looking to purchase an 03, but I don't want to buy a problem. Would I be better off spending more for an 04? Are the 04's less problematic?

I know thats a lot to answer.
Thanks </div></BLOCKQUOTE>
I was told that on the 03 model year, there were problems with the dowel pin in the front differential. This can cause a crack. Then the crack can give way over time. Some with heavy wear and tear, and some that never leave the street. GM did not do a recall on the front differential and instead went ahead and fixed it in the following model year. Another hummer owner that I know said he has seen it happen in other, older model H2's, and has since had his fixed. They redesigned the part, and have been using it ever since.

Like I said. I had no idea about this problem until after it broke, and I thought I'd share my experience on how it was taken care of. The extended warranty just paid for itself with that repair.

I think if I was looking at a used 03, I'd run the service records and check the differential for a small (tiny) oil leak, but I wouldn't let it scare me from purchasing the Hummer experience. These things were so new on the market they were bound to have things like this come up. Think about getting a warranty with it if you can.
Hope this answered your questions. I'm not the expert, just a gal trying to get back to Moab.

Good Luck finding an H2!

[TheSkeptiks]

Thanks.
Once the problem is fixed,...is it fixed for good? Or is it reocurring?

If you know.
Thanks for your help.

[KenP]

Thanks Rox. We'll check ours soon. Gotta be ready for MOAB!

[ROX]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TheSkeptiks:
Thanks.
Once the problem is fixed,...is it fixed for good? Or is it reocurring?

If you know.
Thanks for your help. </div></BLOCKQUOTE>
It's fixed. If the next one breaks, you're a baaaaaad boy. ( or girl whatever the case may be). Truley, I'm not worried, and I will be wheeling again! Soon.