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Old 04-18-2005, 08:34 PM   #1
R@nger
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Update and a couple questions.

Well today I went down to the dmv and got my temporary registration for my truck. I then checked everything on my truck and took her down to the exhaust shop to have a brand new system put on .

I've got to tell ya I was nervous the whole way to the shop...with the truck being old and this being the first time its seen REAL driving in years and years and all the work I've done on it...oh man I had the windows down, it was raining and about 38-40 degrees but I was sweating. Shes more my baby then I realized .

However I made it to the shop no problem and the truck ran GREAT. Needless to say I was extremely relieved .

I did however noticed a couple things that I have some questions about.
1. First the turn signal is backwards. When you pull the turn signal knob up it turns on the left turn signal and the other way around for the right side. I think the previous owner wired it wrong...or something. Is there an easy way to fix that problem?
2. My fuel gauge always seemed to work when I would add 2 gallons or so to the tank when I was workin on it as the guage would always go up and then back down depending on the gas level. Thing is when I took it to the gas station and gave it 5 gallons the gas guage just seemed to stay stuck in the same place it was before I added gas. So I guess my second question is how would I go about checking the fuel guage. I know how the guage hooks up but once it goes into the gas tank I'm a little lost.
3. Lastly my temperature gauge is definately messed up. I say that because as soon I got down the road 2 or 3 miles the temperature gauge was slammed on hot. I pulled over and checked it out but it definately wasn't overheating...not even close. I put my ear to the radiator cap and it wasn't even bubbling so I took off the cap and it wasn't boilin at all..it was just fine. The radiator fluid was running through all the pipes just fine..I don't understand it.

I really appreciate all help on this, thanks .
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Last edited by R@nger; 04-19-2005 at 11:19 PM.
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Old 04-18-2005, 08:46 PM   #2
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On number 2, your fuel sending unit (which is housed in the tank) may be rusted or the wire connecting to it may not be attached well. On one of my trucks, that had been sitting for a long time - when I pulled the sending unit, it looked like a corral reef with all of the rust hanging onto it. Guage worked great once I got the new sending unit installed. Just one of several possibilities.
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Old 04-18-2005, 08:59 PM   #3
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#3, my dad's truck did the same thing. Come to find out the wire going to the temp sending unit was grounding out on the exhaust. Something to check at least...

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Old 04-18-2005, 09:07 PM   #4
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Ahhh thats a thought 72custom. I'll have to check into it. I don't think it's getting grounded out but hey I'm not gonna rule out anything at this point.

Rick I'll check that fuel sending unit when I pick up my truck tomorrow.
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Old 04-18-2005, 09:38 PM   #5
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#1. the wiring for rear SHOULD be dark green=backup, light green=right turn/stop, yellow=left turn/stop, brown=tail. does it have trailer light connection rigged in somewhere? possibly mixed up in that area. these colors go all the way up to the firewall.
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Old 04-19-2005, 10:59 PM   #6
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UPDATE:

I got my truck back from the shop today and man...man...o man. I'm loving it!

Sounds really good, plus I can now talk to my passengers with screaming at the top of my lungs, hehe big plus there. I'll post some pics tomorrow

It's been raining all day today so I haven't been able to look into any of your guys suggestions on my questions.

Keep the help coming...never can have to much.

I noticed a couple more things that I have some questions on. First being more of a statement really: When I'm driving and I get the truck up to about 55 and around 2500-3000 RPMS I keep waiting for it to shift again...like into an overdrive or something but it doesn't. I know thats because it only has 3 speeds but its still a new one to me . Whats the common RPMs you guys get up to when driving on the highway(so speeds for 70-75mph)? I have a TH350 trans by the way. I might have to drop a new trans in there...its just to weird not having it shift again.

Secondly it was rainin and cold today when I was bringin the truck home so I thought I'd try out my heater. The radiator hoses were both flowing in and out of the heater and both tubes were hot but I couldn't get the air hot for anything. There was lots of air coming out the vents, however it wasn't warm. Any ideas?

Sorry for the enormous amount of questions.
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Old 04-20-2005, 12:10 AM   #7
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Quote:
Originally Posted by R@nger
UPDATE:

Secondly it was rainin and cold today when I was bringin the truck home so I thought I'd try out my heater. The radiator hoses were both flowing in and out of the heater and both tubes were hot but I couldn't get the air hot for anything. There was lots of air coming out the vents, however it wasn't warm. Any ideas?
Busted heater core? When the engine is hot, are both lines going in/out of the firewall hot? Do they both have about the same pressure? Have you checked to see if the hoses to the heater core are being bypassed once they enter the housing on the firewall?
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Old 04-20-2005, 12:23 AM   #8
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I'll try and answer your questions in order here, hehe
1. A busted heater core is very possible. How can you tell if its busted? I've never taken or seen one apart to know what to look for.
2. Yes both lines are hot.
3. I'm not sure if they have the same pressure..how would I even know?
4. I haven't check to see if the lines are being bypassed.

Like I said earlier this was its first true "drive" in a long long time so I just now noticed that it wasn't getting any heat.
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Old 04-20-2005, 06:42 AM   #9
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There is a cable that opens and closes a plate that allows air to flow through the heater core, if it is not opening no warm air will come out, it operates from the heater controls and may be broken or not connected.
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Old 04-20-2005, 09:01 AM   #10
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On yor RPM question....I have a 350 engine with a TH350 tranny. At 70mph, I am hitting 3100-3200 rpm (with 3.73 gears in the rear). Getting ready to change rear ends to remedy that, though.
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Old 04-20-2005, 12:11 PM   #11
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What gears are you switchin to that will help out with that?
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Old 04-20-2005, 12:24 PM   #12
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I am going with the 3.07 gears. (some will argue that they are actually 3.08 gears....whichever!?!)
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Old 04-20-2005, 12:24 PM   #13
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My 250 6 cylinder is running also about 31-3200 rpm at 70mph. This is with a 3.73 gear and a 3 spd stick.
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Old 04-20-2005, 01:38 PM   #14
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Quote:
Originally Posted by R@nger
I'll try and answer your questions in order here, hehe
1. A busted heater core is very possible. How can you tell if its busted? I've never taken or seen one apart to know what to look for.
2. Yes both lines are hot.
3. I'm not sure if they have the same pressure..how would I even know?
4. I haven't check to see if the lines are being bypassed.
1. I would say if both lines are hot, someone is either bypassing the core, or the core is definitely getting water and returning it.
2. See #1.
3. This is really negated by #2.
4. I suppose it's possible. Before I ripped apart everything, I would look at curbyk's response a couple posts up. This is a little easier to check and I wouldn't be surprised if it's the culprit.
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Old 04-20-2005, 02:25 PM   #15
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For your temp gauge (would also apply to gas gauge) check to make sure all of your grounds are good. If they are not then the electrical in the cab will try to get a ground through the only ground wires attached to the engine. These are the sender wires. Idiot lights will only ground to the engine when the thermo switch in the sensor closes but with gauge senders they are thermistors and have a varying degree of resistance (conductivity)depending on temp. Run alot of current down that wire and it can fool the gauge and pin it. Test the theory by running a ground from the bat neg terminal to a clean ground on the cab. As for heat check for a plugged heater core or that the air door at the heater box is being opened and closed properly by the control cable. If is a factory a/c truck also check the water valve. I also have a 373 geared truck and the 3100-3200 sounds about right for cruise rpm. I've run mine like that for 12 years and still love the kick the 373's give you. I had a 3.08 in it for a while and it just wasn't as much fun. Fuel economy didn't improve either as I alway had my foot deeper in the pedal off of the starts.
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Old 04-20-2005, 02:51 PM   #16
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Doubt the heater core was bypassed inside the plenum. Everone just bypasses it at the water pump. I think curbyk is right.

You have the option of going overdrive with your tranny to drop the revs. The 3:73 700R4 combo is a good set-up with the best of both worlds. Towing ability in 3rd and best mileage possible with .74 overdrive. Rear end swap is probably cheapest way out if you are not towing anything heavy.

Checking the fuel sending unit is easiest with an analog ohmmeter. Remove sender. 1 lead to the terminal other to to the sending unit body. Actuate the float arm through its entire range looking for opens on the variable resistor. Ohm range should be.... 0-90?

Glad she is running for ya. That first drive is allways fun!
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Old 04-20-2005, 04:29 PM   #17
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Thanks for all the ideas and such.

Unfortunatly it's rainin again today so I won't be able to look into any of those possibilities until tomorrow.

I'm thinking the problem with the heater may just be like you guys said, the cable just isn't connected.
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Old 04-22-2005, 10:02 PM   #18
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Well I got to work on the truck today.

68C15, thanks to your wiring info there my turn signals are wired correctly. The problem was someone ran 2 yellow lines(the turn signals ) a brown and blue line up to the firewall instead of the way it was meant to be wired. Then right at the firewall all the lines were cut and crimped..thats were the confusion happened. All I had to do was switch the two yellow wires and tada it worked .

I also put my mirrors back on.

After next week I'm done with this semester of school so I will be able to get to all these little things. Thanks again for all the help.

Oh by the way, would anyone happen to have an exploded view of a TH350 trans...like in pdf or jpeg format? I'm trying to figure something out without taking my whole trans out. I'll post the problem later.
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