Wrenchin... Adventures under the hood... Put em here.

**El Chupacabra** · 02-21-2018, 12:16 PM

Anyone have any tips on tracking down a problem in the HVAC system? On my 2000 GMC Sierra, I have weak airflow out of the vents when accelerating, but it gets stronger when I take my foot off the pedal. Fan speed selection works, as does the direction control (windshield vs straight out vs floor). I replaced the blower motor resistor awhile back when I lost fan speed control.

I'm guessing it's a vacuum leak, but don't know where to start looking. The HVAC controls on the dashboard are electronic (no vacuum lines to the controls), and are simple blue/red dial type, not thermostat/automatic type.

**basinbeater** · 02-21-2018, 01:12 PM

Pulled the seats to go to the upholsterer

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**Conundrum** · 02-21-2018, 03:03 PM

Originally Posted by The Reverend Floater

Threw some Fox BDS 2.0's on the F350. Per tradition, I missed the shock towers/bushings on all four corners when cutting the retention tape, turning an easy job into a real knuckle scraper.

Truck rides much, much better now. Pretty stoked on the results and value.

I'm an idiot. What's retention tape?

**shafty85** · 02-21-2018, 03:09 PM

I’d assume he’s referring to the tape/strap retaining the new shocks, meaning he had to compress the shocks while getting aligning them. But I may also be an idiot and have completely misunderstood.

I hear if you eat enough spinach this isn’t a problem...

**Conundrum** · 02-21-2018, 07:16 PM

Makes sense. I just put new shocks on my 80 and thought I missed an important step and was going to be bummed...the top posts on the rear were a pain.

**The Reverend Floater** · 02-21-2018, 07:28 PM

Originally Posted by shafty85

I’d assume he’s referring to the tape/strap retaining the new shocks, meaning he had to compress the shocks while getting aligning them. But I may also be an idiot and have completely misunderstood.

I hear if you eat enough spinach this isn’t a problem...

That's it. And on 2.0 Foxes designed for 1 ton trucks, that compression is no joke. Especially if you're old and fat.

**Conundrum** · 02-21-2018, 07:33 PM

And next time I'm not going to spend an hour trying to wrench off three rusted shock nuts. The cut off wheel took less than a minute per shock. I thought it was a cool challenge to break them trying every wrench I could try. Cool challenges are for morons.

**Mazderati** · 02-21-2018, 07:37 PM

Originally Posted by basinbeater

Pulled the seats to go to the upholsterer

You recovered the seats in your 3 series. Are these more complicated or just a time thing?

**basinbeater** · 02-21-2018, 07:40 PM

I put a new kit on the Bmw, and it was affordable, a full blown leather redo kit on this car would be very expensive and it not really necessary. I think the $900 for the custom upholstery shop to bring these up to like new condition will be money well spent. They will be replacing just a couple panels, and reseting the corners that are starting to come apart, and then they will clean and redye the seats.

**shafty85** · 02-21-2018, 08:55 PM

Originally Posted by The Reverend Floater

That's it. And on 2.0 Foxes designed for 1 ton trucks, that compression is no joke. Especially if you're old and fat.

Are they designed for a stiff ride ie- towing? Or? Doing the shocks on my 3500 this spring and looking at bilstein 5100s - any thoughts on how they compare? heaviest I’d typically have is a deck and 2 sleds on it (though looking to add a cargo trailer converted into a camper to that setup, though that shouldn’t have too too much tongue weight i don’t believe). From what I’ve read the 5100 is a nice ride

**The Reverend Floater** · 02-21-2018, 09:08 PM

Originally Posted by shafty85

Are they designed for a stiff ride ie- towing? Or? Doing the shocks on my 3500 this spring and looking at bilstein 5100s - any thoughts on how they compare? heaviest I’d typically have is a deck and 2 sleds on it (though looking to add a cargo trailer converted into a camper to that setup, though that shouldn’t have too too much tongue weight i don’t believe). From what I’ve read the 5100 is a nice ride

I've run both on 1 tons and I'd say they're pretty darned comparable. Only reason I moved to Fox this go around is that peeps really seemed to like them on that truck and they were cheaper. Folks also say they do very well towing as well as offroad. Can't say id be able to tell the difference, but they are both much, much better than stock and I don't think you can go wrong either way.

**tripice351** · 02-21-2018, 09:20 PM

Originally Posted by El Chupacabra

Anyone have any tips on tracking down a problem in the HVAC system? On my 2000 GMC Sierra, I have weak airflow out of the vents when accelerating, but it gets stronger when I take my foot off the pedal. Fan speed selection works, as does the direction control (windshield vs straight out vs floor). I replaced the blower motor resistor awhile back when I lost fan speed control.

I'm guessing it's a vacuum leak, but don't know where to start looking. The HVAC controls on the dashboard are electronic (no vacuum lines to the controls), and are simple blue/red dial type, not thermostat/automatic type.

Weak airflow can be caused by a clogged cabin air filter (or HVAC box on old cars with no cabin filter).

I wouldn't think that would be variable based on throttle / load, but I would check it to be sure.

**goldengatestinx** · 02-21-2018, 09:49 PM

'98 Cherokee and '04 F-250 both have heater changing to defrost from vent or floor based on load and rpms. Figure there are vacuum leaks but haven't been annoyed enough yet to troubleshoot.

**El Chupacabra** · 02-22-2018, 12:11 AM

Originally Posted by tripice351

Weak airflow can be caused by a clogged cabin air filter (or HVAC box on old cars with no cabin filter).

I wouldn't think that would be variable based on throttle / load, but I would check it to be sure.

The truck has a cabin filter, and I checked it when I first noticed the HVAC problem. Filter was OK.

**Gerome** · 02-23-2018, 05:23 PM

Does anyone know how to trick a car computer into thinking there's nothing wrong with the engine? I have a 2002 WRX with 300,000 miles that is waiting to get thrashed on a race track. There's a monthly open track day at Thunderhill Raceway, about 2 hours north of Sacramento that looks great for my intro to racetrack driving. The issue is the engine is worn out. It needs a complete rebuild with new pistons and rings. In its computer wisdom, reading misfire in all cylinders, it will not let the motor rev over 5000 rpm. I don't have time to rebuild a boxer motor. If my son was 14 years older, I'd rebuild it with him, but the car will rot away by the time he reaches driving age. So can I trick the motor into thinking its just fine until I kill it on the raceway?

Check out the link below for race track near you.
https://www.tracknightinamerica.com/...n-by-tire-rack

**ichibaneye** · 02-23-2018, 06:12 PM

A stand alone ecu or piggy-back should help you finish her off just fine. Sometimes you can also find a used stock re-flashed ecm. Or take yours to a performance shop and see if they will be able to re-flash your original.

**detrusor** · 02-23-2018, 06:51 PM

Maybe not under the hood but under the van. Espar diesel heater stopped working, turned out there was a solid block of ice in the line just before the muffler and in the muffler. Took the exhaust line off, heat cub and compressed air in the garage. Re ran the line so no low spots...hopefully I’m golden.

Of course it was at night on one of the coldest days we’ve had....

Sent from my iPhone using TGR Forums

**k2skier112** · 02-23-2018, 06:57 PM

Originally Posted by ichibaneye

A stand alone ecu or piggy-back should help you finish her off just fine. Sometimes you can also find a used stock re-flashed ecm. Or take yours to a performance shop and see if they will be able to re-flash your original.

You would have to go with an aftermarket ECM. Anything stock will sense the misfire and go right back to where he is now.

**ichibaneye** · 02-23-2018, 07:45 PM

Originally Posted by k2skier112

You would have to go with an aftermarket ECM. Anything stock will sense the misfire and go right back to where he is now.

You've validated my point..Thanks. A reflash gets aground this too and piggy-backs too. I've done this before. I'm aware of what stock is and does. Nothing I mentioned was stock.

**gravitylover** · 02-24-2018, 07:32 AM

I've got a problem with my 06 Durango 4.7 that I can't figure out that pretty much only happens when it's wet out. Driving along and all is well until bang, a violent buck/lurch and it shuts off. I pop it into neutral turn the key off and restart it and it's fine for a little while until the same thing happens again. Battery has been tested and it's fine, a little weak at 12.3 volts but otherwise seems to be ok. It doesn't have enough power though to test the alternator so I'm thinking the alternator has an issue but can't see where that would cause the buck and shutoff. There is a broken ground strap underneath that's either a body ground or goes up between the frame rail and body to somewhere nobody seems to be able to figure out. Possibly to the starter or battery? Would a bad ground to the starter cause the problem? It doesn't throw any codes and there's nothing stored in the computer to read so no help there.

Ideas? I'd love to figure this out so my wife feels comfortable driving the beast again.

**basinbeater** · 02-24-2018, 11:23 AM

A broken ground strap should be fixed. Not having the ground from engine to frame can lead to all sorts of problems including frying your computer in worst case. Fix your ground strap, then test voltage at the battery with the car idling. You should see 13.7-14v. That tells you your alternator and voltage regulator are working properly.
Step one is get the ground strap fixed asap. If you can't find where it is supposed to go, and it comes from the engine, find a secure bolt on the frame, and scrape it to bare metal, put some dielectric grease on it and attach it there. Make sure there is enough slack to allow for the engine to rock back and forth. Are you motor mounts toast. Why did the strap come loose to begin with? Sell Durango and get 4runner. Problem solved.

**gravitylover** · 02-24-2018, 03:02 PM

Originally Posted by basinbeater

A broken ground strap should be fixed. Not having the ground from engine to frame can lead to all sorts of problems including frying your computer in worst case. Fix your ground strap, then test voltage at the battery with the car idling. You should see 13.7-14v. That tells you your alternator and voltage regulator are working properly.
Step one is get the ground strap fixed asap. If you can't find where it is supposed to go, and it comes from the engine, find a secure bolt on the frame, and scrape it to bare metal, put some dielectric grease on it and attach it there. Make sure there is enough slack to allow for the engine to rock back and forth. Are you motor mounts toast. Why did the strap come loose to begin with? Sell Durango and get 4runner. Problem solved.

Haha yeah...

The ground wire has a short loop where it attaches to the frame rail and I think it got caught on something in the snow and broke. At this point I can't tell where it went to. I had someone take pictures and it goes up between the body and frame but no idea where it goes to from there, that's the problem. I went to 3 local shops and they laughed and said the same thing 'it's just a ground, don't worry about it' and wouldn't even look. At this point I think I'm going to have no choice but to go to the Dodge dealer and let them take care of it.

**jamal** · 02-24-2018, 03:57 PM

Originally Posted by Gerome

Does anyone know how to trick a car computer into thinking there's nothing wrong with the engine? I have a 2002 WRX with 300,000 miles that is waiting to get thrashed on a race track. There's a monthly open track day at Thunderhill Raceway, about 2 hours north of Sacramento that looks great for my intro to racetrack driving. The issue is the engine is worn out. It needs a complete rebuild with new pistons and rings. In its computer wisdom, reading misfire in all cylinders, it will not let the motor rev over 5000 rpm. I don't have time to rebuild a boxer motor. If my son was 14 years older, I'd rebuild it with him, but the car will rot away by the time he reaches driving age. So can I trick the motor into thinking its just fine until I kill it on the raceway?

Check out the link below for race track near you.
https://www.tracknightinamerica.com/...n-by-tire-rack

Uh, no, not really. The computer is sensing misfires beause the car is misfiring. Changing the ecu isn't going to change that and it's still going to hesitate and stutter and run like garbage even if it revs all the way to redline. And don't do that anyway. A race track is not the place to bring a car that is fucked and runs like shit. You'll be the guy that dumps a bunch of oil on the track and gets a whole session red flagged.

You can get a used replacement engine probably in as good or better condition for a couple hundred bucks. Maybe try that first.

Also, have you done a compression test? Is it blowing a shit ton of oil into the intercooler?

**jamal** · 02-24-2018, 04:23 PM

Originally Posted by shafty85

Are they designed for a stiff ride ie- towing? Or? Doing the shocks on my 3500 this spring and looking at bilstein 5100s - any thoughts on how they compare? heaviest I’d typically have is a deck and 2 sleds on it (though looking to add a cargo trailer converted into a camper to that setup, though that shouldn’t have too too much tongue weight i don’t believe). From what I’ve read the 5100 is a nice ride

Not sure exactly how the 5100 compares to the fox but I do like Bilsteins (and am a dealer btw). The 5100 and 4600 have pretty much the same damping, but the 5100 gets you a shiny silver and blue shock and the standard ones have a little more travel to handle a 1-2" lift (but in a lot of applications the 4600 comes in different lengths too). The valving is firmer to handle bigger wheels and tires, stiffer springs, and more load than an oem shock generally.

Also, bilstein has a 5160 remote reservoir shock now too. You could consider those on the rear if you're going to have a bunch of extra weight. What truck/year? I want to say gmc HD trucks use the same shocks front and rear over a really wide year range though, like 1990 to present or something.

Check out how shiny they are:

Twice as much as the standard 5100 though