Need mechanic in Phoenix

[Backporch73]

Guys I've been chasing problems for over a year and I think it's time for me to seek some outside assistance. Does anyone know of an honest, decent Hummer mechanic in the Phoenix area? Or any other members in the phoenix area willing to lend a hand if I bring the beer/food/whatever? As there are several of us in this area I'm hoping to get some advice, thank you

 

[alrock]

What type of problems? Different mechanics have different specialties.

 

[Backporch73]

Truck drives fine for a while, then starts the losing power/idle stumbling at slowdown (stop and go traffic is the worst) almost dies, etc. I've done mostly everything I've read about here (MAF cleaning of assembly and sensor many times, new spark plugs, changed out exhaust and intake side Cam Position sensors, changed out motor mounts....) and all of that helped for a while, but now I've got more issues with it and I'm suspicious of a possible vacuum leak or something idk.

I have had no codes whatsoever while doing all of this until recently......I got a P2431 code that came on once then went away, if that helps at all.

 

[rascole]

Year, engine, any upgrades? Fuel pump maybe going out?

 

[Backporch73]

Sorry...here's the History as best as I can remember....sorry for the long post

I purchased a 2007 Hummer about a year ago with a hundred and twenty-seven thousand miles or so. The biggest problem I had was it dying and idle and especially when applying the brake so I start searching forums.

Upon inspection the MAF assembly was horrendous....it was completely covered with fillth...thoroughly cleaned the MAF assembly and sensor. I changed out the spark plugs and installed a new "Specter" reusable air filter. I pull the cam position sensors intake and exhaust side and visually inspect them... to the best of my knowledge and without extensive testing..... the sensors look okay to the naked eye, not worn out afraid or anything like that. I pull the VVS sensor and the screens look good everything looks fine as best as I can tell. After all of this the truck runs great and I'm very happy.

Things Ran 100% better for about 5000 miles, had lots of vibration had to replace the motor mounts, everything's fine again for a while.

So now I'm at a hundred and forty four thousand miles and I'm here at this point.....I do some more research and decide to change out the cam position sensor on the exhaust side simply because it helped other people's trucks when doing this even if they had no check engine lights. I switched the cam position sensor on the intake side for good measure.....2 days later I got the code....P2431 .... It's all about the secondary air system but it seems strange that it happened after I changed the intake sensor. Truck still runs like crap after about 20 minutes of driving it, any help is appreciated. Im wondering if I have a vacuum leak or something.

 

[Backporch73]

*Update* Today it actually died when I started it up which was really weird. I have an appointment tomorrow morning with a local mechanic who supposedly has good reviews. We'll see what happens

 

[fanugy]

Where are you at in valley? I’ve got access to a tech II and a lift off Mesa Dr and 60


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[fanugy]

Also have a spare frame. Some stuff too good to throw away


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[SlcHummer]

Where are you at in valley? I’ve got access to a tech II and a lift off Mesa Dr and 60

Now I know where I'll be searching for my next home

 

[fanugy]

My neighbor is a machinist...


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[Jeepwalker]

Did you ever actually replace the MAF? I've had vehicles where 'cleaning' the maf made a difference but barely put it back in 'spec' according to scanner live data. Replacing with a new MAF made all the difference. This was in a truck, not a H3. But I've read a number of reports of guys having the same experience ..cleaning, for many, is a 'sometime' improvement. Just throwing that out there.

Couple things come to mind which you may have done ...but I didn't see mentioned. A good mechanic should look at:
1) What's the vacuum reading? Could there be some leaks ...low vac?
2) Evap system inspection/test?
3) Throttle positioning (TPS) valid?
4) Throttle body deposits?
5) Fuel pressure?
6) O2 readings?
7) Coil packs?

A good mechanic with a good scanner/scope and vac gauge should be able to provide answers. Someone needs to do basic troubleshooting (not saying you didn't) and work out from there. You're wise to look for another set of eyes. These things are really frustrating, hope he resolves it. And by the way, ours died for the first time last night on my wife ..way home from work. So you're not alone!

Let us know what he finds and if it helps.

 

[alrock]

I had occasional stalling issues when my head was failing, but I don't think your symptoms match that. I wonder if you're getting a fuel delivery issue, like a weak fuel pump. I do think putting a Tech II on it is a good idea.

 

[citiboy]

Did you clean the throttle body?

 

[Jeepwalker]

If you coast up to a stop, not using the brakes, does it still want to 'die'?

 

[Backporch73]

Thanks for all the replies guys and I'll definitely take you up on that offer with the lift Fanugy!! I would have helped a lot when changing out the motor mounts
I went to a local shop that has a several hundred 5 star reviews, the techs seem like really good guys and they had the truck all day. Main mechanic said said he did extensive test driving and extensive testing, they checked for vacuum leaks (none) fuel pressure etc etc...they found nothing wrong with anyting ......EXCEPT!!! that the catalytic converter was showing 8 pounds of backpressure.....
Normal is 1.5 or less??? Do you guys agree that this would explain how the truck gets worse the more that I drive, how I lose power the longer I go and why my fuel my my gas mileage is so terrible these days? And after the truck sits for an hour everything's fine again for a while??

It totally makes sense to me that if the engine can't vent it goes to hell but I'd love to hear you guys opinions, thanks!!!

 

[alrock]

A clogged cat did cross my mind but I was thinking you might get codes with that too, but maybe that's not the case.

 

[Backporch73]

Crazy huh yeah no codes at all. I haven't been in Phoenix very long....tech says he sees it all the time with the heat out here, the inside of the cats just melt. Has anyone ever replaced a cat on these rigs?

 

[Backporch73]

Did you ever actually replace the MAF? I've had vehicles where 'cleaning' the maf made a difference but barely put it back in 'spec' according to scanner live data. Replacing with a new MAF made all the difference. This was in a truck, not a H3. But I've read a number of reports of guys having the same experience ..cleaning, for many, is a 'sometime' improvement. Just throwing that out there.

Couple things come to mind which you may have done ...but I didn't see mentioned. A good mechanic should look at:
1) What's the vacuum reading? Could there be some leaks ...low vac?
2) Evap system inspection/test?
3) Throttle positioning (TPS) valid?
4) Throttle body deposits?
5) Fuel pressure?
6) O2 readings?
7) Coil packs?

A good mechanic with a good scanner/scope and vac gauge should be able to provide answers. Someone needs to do basic troubleshooting (not saying you didn't) and work out from there. You're wise to look for another set of eyes. These things are really frustrating, hope he resolves it. And by the way, ours died for the first time last night on my wife ..way home from work. So you're not alone!

Let us know what he finds and if it helps.

Thanks Jeepwalker glad to know I'm not alone LOL! And yes I actually did replace MAF assembly as well as the MAF sensor. I don't know if replacing the assembly helped or not...so yeah I have an extra one lol. I appreciate your help

 

[fanugy]

I may have a full exhaust system with my frame but it is from a burned out 3- let me dig through my pile in morning. You are welcome to it if I have it.


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[Backporch73]

Thanks alot!!!

 

[3Hummers]

CATs for an H3 aren’t that expensive.

 

[alrock]

If fanugy doesn't have one, I know a place where you might be able to get a used one super cheap. Did the tech mention if it was the primary or secondary cat, or did he know?

 

[Jeepwalker]

Yeah, that IS very interesting. I wonder if perhaps excess backpressure interferes throws off the O2 readings the computer is 'looking for', and tries to adjust to?

I'm going to check the B/P on mine too this weekend if I get a chance.

 

[fanugy]

Looks like I may have junked the exhaust system. Sorry.


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[Backporch73]

If fanugy doesn't have one, I know a place where you might be able to get a used one super cheap. Did the tech mention if it was the primary or secondary cat, or did he know?

Hey Alrock,
He doesn't know. He recommended starting with the main since it catches everything first. Quick question...honestly do I need 2 cats? I'd hate to do the main and still have issues with the secondary