Repair, write up, thread, FAQs

[kennythewelder]

ATTENTION ALL MEMBERS....
If you have a write up, on something that you have done to your truck, this is where to post it. Repairs, or custom work, it doesn't matter, just as long as it can help another member out.

 

[kennythewelder]

The "programming kit" includes a jumper that plugs in behind the cluster, you then supply 12V to the jumper and it blows all the fuses inside the cluster that are used as switches to configure the speedometer. You then replace the fuses with jumpers that you break off corresponding ones to act as replacement switches for the now-blown fuses. It works fine but it's a hokey arrangement if you ask me. However, it does avoid anyone having to go "inside" the cluster and work with the sensitive electronics, do any soldering, etc.


Yep! Much the same as we modify the 1992-1995 gmt400's DRAC module with a bank (or two, depending on design) of DIP switches, one can modify the 1988-1991 gmt400 gauge cluster. ONLY if you have reasonable electronics soldering experience, though. It's easy work, but if you aren't familiar, please farm it out to someone that does this type of work. Guys that do gaming console "mods", radio/amplifier repairs, stuff like that.

My write-up is on Chevytalk but as I've become used to saying these days, my host provider (godaddy) sucks so my picture links may appear broken. You can either choose to right-click the broken pics and "open in a new tab", or "allow insecure content" on Chevytalk. (Chevytalk is https, and my site on godaddy where I host the pics is http)

Recalibrating 1988-1991 gmt400 speedometer: https://www.chevytalk.org/fusionbb/showtopic.php?tid/258562

I may as well just re-create the write-up here, since I can upload the pics directly. Let's give it a shot in the next reply:

Richard

Adding DIP switches to speedometer that is off, part 1 of 2

 

[kennythewelder]

Part 2

Continued...

DIP switch soldered in and the far right row soldered up although nothing is in it. That step isn't really necessary but it's habit, so I did it.

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Here's GM's supplied chart for use with their recalibrating kit.

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DIP switch set with 1,4,6 OFF – 2,3,5,7 ON – corresponding to settings on the chart for 3.42 gears and a 225/75/15 tire.

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Sharpie warning on the back of the cluster to not attempt using a GM reprogramming kit on it (in case anybody happens to have one) as it will no longer work on this modified cluster (actually, a programming clip WILL still work, though there's no need to zap the fuses anymore since they're gone - just set all the DIP switches to "OFF" for the same effect. However the DIP switch makes it pointless to bother with a programming clip anyway.)

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What I usually do at this point is leave the front of the cluster in its current disassembled state, but with the metal plate reinstalled on the back – install it into the truck, temporarily mount the speedometer by plugging it back into the cluster but leaving the screws out, and go verify the speedometer reading against GPS. If it's accurate, then go ahead and put all the pieces back together and you're done.

Richard

 

[kennythewelder]

This is a 2 page write thread on making 02 simulators.

remove your cats, and make a mini cat for your rear 02 sensors.

First off, know that by removing your cats, your truck will not pass emissions testing. But if you want to remove your cats, or you have already, here is how to trick the rear 02 sensors, so that you don't need to reprogram the ECM. click the web sight and you can order these...

www.gmt400.com

 

[HeavyAsAChevy]

This is a 2 page write thread on making 02 simulators.

remove your cats, and make a mini cat for your rear 02 sensors.

First off, know that by removing your cats, your truck will not pass emissions testing. But if you want to remove your cats, or you have already, here is how to trick the rear 02 sensors, so that you don't need to reprogram the ECM. click the web sight and you can order these...

www.gmt400.com

I’m going to use this on my Lexus! I’ve been trying to figure out how to do this and now I got it! Thanks!

 

[stutaeng]

We need a sticky on how to do BASIC diagnostics. Like check for fuel pressure, spark, and things like that.

I see too many newbies coming and asking to help them out because their truck doesn't start...after changing half a dozen parts!

Even if it's a sticky with some website link I think it will be helpful.

 

[kennythewelder]

We need a sticky on how to do BASIC diagnostics. Like check for fuel pressure, spark, and things like that.

I see too many newbies coming and asking to help them out because their truck doesn't start...after changing half a dozen parts!

Even if it's a sticky with some website link I think it will be helpful.

That's pretty much what this thread is for. Do the write up, and post it here, or find a write up, and post it here. I will go through this thread, (in time), and clean up all the post that have nothing to do with repair info.

 

[Supercharged111]

How about a write-up section? Could make it easier to find stuff by making it less cluttered.

 

[PlayingWithTBI]

I'll throw this up and see if it sticks, ha ha. If you guys don't think it belongs here, go ahead and delete it...

www.gmt400.com/threads/electrical-upgrade-just-do-it.51911/post-1145987

Electrical Upgrade? Just do it!

I was looking under the hood of my truck and decided the Mickey Mouse wiring I did for my sub woofer and A/C compressor coil looked like crap. If I wanted to do a "4 Hi" mod or add something else, it'd get even more congested. You can see here the way I tapped the in-line fuses and mounted the...

www.gmt400.com

 

[evilunclegrimace]

We need a sticky on how to do BASIC diagnostics. Like check for fuel pressure, spark, and things like that.

I see too many newbies coming and asking to help them out because their truck doesn't start...after changing half a dozen parts!

Even if it's a sticky with some website link I think it will be helpful.

AND how about a list at the top of requirements?
Like, Name. location, truck year, make, model, engine, tranny, diff, Etc. so that we do not have to guess what the person is trying to fix or ask a bunch of questions to get to the root of their problems.