Suddenly no throttle

[Will L.]

Yeah, there is a couple YouTube videos on how to make the diy pop tester. For quite a while there was ones you could buy in ebay for like $100 or something. The gauge wasn’t good but swap innthe good gauge you plan on using and done.

 

[MrMarty51]

I think I had seen some cheap injector testers in ebay or some such. I thought that would be a lot easier than building one from a jack. Only thing I would change on the cheap tester would be the gauge.
I doubt You ruined your injectors by not torquing them down. About the worst part of it would be filling the threads with carbon. You should have a thread chaser, not a thread tap, and clean the treads on the injector holes and the glow plug holes too.

 

[MrMarty51]

Yeah, there is a couple YouTube videos on how to make the diy pop tester. For quite a while there was ones you could buy in ebay for like $100 or something. The gauge wasn’t good but swap innthe good gauge you plan on using and done.

Haaaa, you beat me toooit.

 

[dbrannon79]

well the code is back! along with a couple of others. everything has been fine and I can still hold the idle steady at 1k or any rpm while in park, but I decided to hookup GMTD basic to see if anything was going on since my fuel mileage went south and oddly noticed a slight exhaust tone change after the south Texas freeze! here is what I got..

current codes:
41 - Brake switch circuit fault (brake lights are still working)

Historic codes:
41 - Brake switch circuit fault
65 - App position 3 circuit range fault (replaced new from local auto parts store weeks ago)
68 - Trans component slipping
78 - Wastegate solenoid fault ( I knew about this just haven't replaced it )

I did notice since the freeze that when the truck hasn't warmed up fully the TCC overdrive wont engage. but I figured that was a normal thing but now I'm worried seeing that code 68! I did and always do my normal checks, the trans fluid is full and nice bright red although I myself have not changed it. it's been that way since I bought it a year ago. maybe the code 41 and 68 are related and it's not fully kicking into overdrive which equals my 11 mpg's I am getting the last two tanks of fuel from the 14 I was getting before the cold weather came.

as for the reappearance of code 65 without any throttle issues I'm not sure what to do or what steps to take trying to troubleshoot that one. I know it was mentioned that it could be a ghost code, I just want to be sure I don't have jack in the box fixing to pop!

I figure at least I probably need to replace the brake switch and go from there. any other ideas help or suggestions?

 

[ak diesel driver]

clear them and see what come back

 

[dbrannon79]

clear them and see what come back

right now just the brake switch code comes back as soon as I step on the pedal, but I haven't driven anywhere since I pulled the codes.
I'll get that replaced this week and check again and see what I get. Honestly nothing seemed wrong driving other than my dropped mileage. I sure hope the brake switch is the cause of the trans code!

I do have a question since I found out it's ether the overdrive or the TCC isn't locking when it got cold (not sure which one since I just noticed I was missing a shift feeling). On normal operating temps, the previous owner had a low temp thermostat installed, the max temps I've seen on the engine is 170ish since I've had it. would it be better to go back to the OE thermostat for engine performance and economy? I haven't bothered to change it since it hasn't been an issue

 

[Stoney]

I'm waiting to see the answer to that..I put a set of 170 thermostas in mine to make it run cooler, have wondered if that's what's causing my problems... Maybe could put cardboard in the grill to block air flow, get engine to run hotter and see if it helps.

 

[ak diesel driver]

The brake switch has 3 sets of contacts in it. One is the brake light one is the TCC and one is the CC IIRC. So theoretically it could affect the lock up. Also the PCM wants to see 170* to lock up the TCC, so you might want to see what the scanner is showing for engine temperature. It's possible the t-stats are too cold.

 

[dbrannon79]

I'm waiting to see the answer to that..I put a set of 170 thermostas in mine to make it run cooler, have wondered if that's what's causing my problems... Maybe could put cardboard in the grill to block air flow, get engine to run hotter and see if it helps.

I do know that the lower the engine temp the more fuel it uses, but I don't think it's much more. Although on the 90's era gassers and probably diesels, if you unplug the ecm temp sensor making the computer think it's 40 below it sure does blow some smoke!

I've had thoughts of not changing the thermostat because more heat is a bad thing but to wire in a resistor to ground off the ECT signal wire to offset the signal to the PCM making it think it's at 210 when it actually is 170 or something like that. as long as it stays within range not to trigger the SES light it may consume slightly less fuel! as long as the gauge still reads what the actual temp is so you can keep an eye on things in case it springs a water leak. of course the ECT stays connected along with the resistor to ground so the PCM would see a constant increase of about 40 degrees from what it actually is.

 

[dbrannon79]

The brake switch has 3 sets of contacts in it. One is the brake light one is the TCC and one is the CC IIRC. So theoretically it could affect the lock up. Also the PCM wants to see 170* to lock up the TCC, so you might want to see what the scanner is showing for engine temperature. It's possible the t-stats are too cold.

when I had the laptop connected right after the drive home from work, I did look at both the engine and trans temps. engine was sitting at 172 and the trans was at 150 or so not sure if 150ish is too cold for the trans. outside temp this afternoon was around 75 deg.

 

[ak diesel driver]

Ferm probably needs to jump in here but I think the trans needs to be 170* too

 

[dbrannon79]

I went ahead and ordered a new brake switch and an OE temp thermostat. since the engine runs consistently at 170ish and it does take a good 20 minutes to get to that temp, I figure it can't hurt anything. running at 170 it's hard to determine what temp thermostat it actually has since the only other two it could be is a 160 or a 180, or it might just be not closing completely. heater doesn't work all that great ether! I do still plan on replacing the water pump and fan before the Texas summer hits. just haven't decided what to go with yet. OE pump and fan clutch or the 97 model pump with ether a duramax fan or go electric fans. I know my fan clutch is on it's way out and my AC isn't gonna do well with the summer heat unless I replace or upgrade the fan.

the only reason I'm debating on the duramax fan vs electric cooling is because I know the larger fan and fan clutch is gonna lower my fuel mileage, but by how much I don't know. with fuel prices going up, I want as much mileage as I can get!

 

[JMJNet]

I went ahead and ordered a new brake switch and an OE temp thermostat. since the engine runs consistently at 170ish and it does take a good 20 minutes to get to that temp, I figure it can't hurt anything. running at 170 it's hard to determine what temp thermostat it actually has since the only other two it could be is a 160 or a 180, or it might just be not closing completely. heater doesn't work all that great ether! I do still plan on replacing the water pump and fan before the Texas summer hits. just haven't decided what to go with yet. OE pump and fan clutch or the 97 model pump with ether a duramax fan or go electric fans. I know my fan clutch is on it's way out and my AC isn't gonna do well with the summer heat unless I replace or upgrade the fan.

the only reason I'm debating on the duramax fan vs electric cooling is because I know the larger fan and fan clutch is gonna lower my fuel mileage, but by how much I don't know. with fuel prices going up, I want as much mileage as I can get!

For AC, what alternator do you have in there? If it is still the small CS130, it will cause the AC not to work good in TX heat.
I put an AD244 and it gives enough amp to run the AC properly.
As it is, the AC is not that efficient to begin with, it needs a lot of amp.

Another neglected part is the evaporator behind the blower fan.
You need to take off the blower fan and then clean the evaporator from blower fan hole.
This is free to clean it, well may be buy some cleaning solutions and use a good vacuum/air compressor.

 

[dbrannon79]

For AC, what alternator do you have in there? If it is still the small CS130, it will cause the AC not to work good in TX heat.
I put an AD244 and it gives enough amp to run the AC properly.
As it is, the AC is not that efficient to begin with, it needs a lot of amp.

Another neglected part is the evaporator behind the blower fan.
You need to take off the blower fan and then clean the evaporator from blower fan hole.
This is free to clean it, well may be buy some cleaning solutions and use a good vacuum/air compressor.

Yeah I figured if I go with electric fans i defiantly would need a bigger alternator. but I need to make sure I don't have a transmission issue starting to rise up first. the wife is already wanting for me to find another truck lol she keeps telling me "if it's not one thing it's another" calling it a money pit! "but honey it's a classic and I like it"

 

[JMJNet]

Even without electric fan, I don't have electric, you still need a better alternator.

I am not sure if electric fan will work in TX heat or not, though.
I think a lot of people have tried it without any good results and they don't even live in TX.
You can search electric fan in this forum and other 6.5L forum like DP to read other people's experience.

 

[dbrannon79]

Even without electric fan, I don't have electric, you still need a better alternator.

I am not sure if electric fan will work in TX heat or not, though.
I think a lot of people have tried it without any good results and they don't even live in TX.
You can search electric fan in this forum and other 6.5L forum like DP to read other people's experience.

I think your right. I'd rather stick to the fan clutch like it was designed for, at least that's what I'm leaning towards. I'm betting the duramax style fan will pull enough air at idle to keep the ac condenser cool enough to work properly

 

[Will L.]

Well, depending which fan you have- yes or no. The 9 blade metal pulled more air than the dmax does.
think about the set up am diesel driver did VERY seriously.

You’re already buying a new clutch and fan, and considering waterpump right?
Do it like he shows. Then you can have the a/c kick in the fan when it needs to. Or the ect to kick it in/ out as needed.
Plus if you are ever towing heavy up hills, etc. and know that the thing is gonna get hot by time your are at the top of the hill- just add a switch and you can engage it when you choose.

This option is one that not a ton of people are using because one reason- lack of marketing. If a vendor here, hummer forum, etc had partnered with him on this - they would be flying off the shelf. But because it is 1guy not selling a plug and play kit- it isn’t in everyone’s trucks yet.

The other advantage to this solution is for offroaders that go into water. Crossing water breaks fans or bends metal ones into radiators all the time. That switch that can manually demand it, can be a 3 position switch to shut it off for water crossing too. Idk if that is anything you do with your truck- not a lot of 6.5 pickups get offroaded hard.

 

[dbrannon79]

I have the 6 blade metal fan with the bolt on style clutch (old school) Ill have the search him up, I'm assuming he has a thread on it here in the TruckStop forum. it does sound very interesting. I don't do any offroading unless they call the occasional grass patch or semi-smooth gravel offroading just the every day in town and highway driving, honestly I haven't towed anything but a garden trailer in the past year! ya I know that's sad for a redneck in Texas but I do plan to invest into ether a travel trailer or a truck bed camper soon for fishing trips.

 

[Will L.]

Yeah, you NEED to find that thread from @ak diesel driver (Can we call that the akdd cooling mod or the LES HEAT mod?)

Completely control when the fan kicks in and out so you can use it less and in theory should save on mpg even along with better cooling for engine and a/c.

 

[ak diesel driver]

Electric Fan clutch

So for those who want accurate fan clutch engagement this could be for you. I know on my 96 the fan clutch has never engaged the entire time I've owned it. Living in cooler climates does have it's advantages. I even tried modding the spring to no avail. This clutch will only work with the spin...

www.thetruckstop.us

Part numbers are towards the end