TV Adjustment

[TruckCo]

Hey all,

Two tech questions.

I took the truck out for a drive the other day. Warmed the truck up, and took off. Seems like 1-2nd gear has a hard shift and when it goes into second, the rpms will hang and i have to feather the throttle before it goes into gear. The truck had a shift kit put into it form previous owner. My cousin said maybe check the TV cable. I have a multi port injection kit on it, is adjusting the tv cable the same? When i throw the throttle it seems like it goes to full throttle then it goes a little farther if i twist the linkage a little harder. Not sure which part is full throttle. I see the tv cable but there is also another looking tv cable on the same mount above that, that goes right into a rubber diaphragm. Its a 700r4. Heard too push the adjustment button, push the sleeve in, then hit full theottle and it will click, others say to hold that button, go full throttle then release it to make it easier on the locking tabs, what do you guys think.

Second thing is my coolant temp only goes up to 110. I unplugged the wire to the sensor and it dropped, so i know the sensor is working, im wondering if people take the thermostats out of these things? But i am confused with it being efi wouldnt you want the temp to be up for it to run better?

Thanks for the help

 

[gmbellew]

the items attached to the throttle, from top to bottom, are 1) throttle linkage, 2) cruise control, 3) TV cable.

TV cable adjusts like you said. push sleeve back and then open full throttle on the throttle body. if the TV cable angle had been changed. I have heard that can cause issues. But a very hard 1-2 shift and hanging 2-3 shift sounds like maybe the cable is too loose? somebody more knowledgeable will hopefully chime in.

your thermostat could be stuck open if it isn't getting up to operating temp. EFI will usually be happier at higher operating temps and often have a 195deg thermostat. potentially the gauge is off. and you could check with a thermo gun or even just touch the hoses and see if they are getting warm.

 

[SirRobyn0]

I'm hardly an expert where it comes to transmissions, but I'll give you my experience as a long time technician.

The cable should be guitar string tight when the throttle is wide open.

But there is also pull rate of the cable to be concerned with. There is specific geometry the cable needs to operate correctly.

If the multiport system was made for the 700R4 then it should be ok, but if not then you'll need to take a close look at this and make changes to achieve it.

Link: >> https://static.summitracing.com/global/images/instructions/700r4 cable adjustment instructions.pdf << Page 2 shows that there needs to be 75 degrees between closed throttle and open. If there is more than that then you'll end up with the cable to loose at lighter throttle even though it is adjusted tight at WOT. Something to think about.

You can base line it, by adjusting the cable tight at WOT and then playing with a click or two one way or another to see what happens. Just remember if you run around with it to loose for to long you can burn up the transmission. Even if it's tight at WOT, if the geometry is wrong you can still burn it up. I'm not trying to be dramatic just letting you know the importants of getting this sorted out.

 

[TruckCo]

Awesome thank you for the replies. I've also searched it obviously may be a thermostat, or a temperature sensor or switch. I believe with the EFI there are two "sensors" one is for the gauge and one is for the EFI? Would the EFI Temp sensor cause this to not come up to temp? I will check it with a thermo gun tomorrow and see if the top hose is coming up to temp. If the thermostat is stuck open the two hoses should read the same temp. If the top is what it should be at operating temps i'll look more into the gauge.

 

[gmbellew]

Awesome thank you for the replies. I've also searched it obviously may be a thermostat, or a temperature sensor or switch. I believe with the EFI there are two "sensors" one is for the gauge and one is for the EFI? Would the EFI Temp sensor cause this to not come up to temp? I will check it with a thermo gun tomorrow and see if the top hose is coming up to temp. If the thermostat is stuck open the two hoses should read the same temp. If the top is what it should be at operating temps i'll look more into the gauge.

depends on the EFI, i suppose. the GM TBI has the ECM sensor by the thermostat and the gauge sensor in the head between cylinders 1 and 3. I think the gauge sensor may be specific to certain year gauges, like they had different resistance values. but I am not 100% sure on that.

 

[TruckCo]

Guess i have some diagnosing to do. I have a multi port fuel injection. I guess I assumed the gauge worked cus when i unplugged it from the sensor it dropped down to all the way on the left. I figured those gauges read right or didn't work at all. Maybe I have a bad coolant sensor. The truck seems to run fine, which is why I think the 2 Wire EFI sensor is fine but i guess i'm not sure. I hope when I test the hoses tomorrow both will be the same temp and cool so i know it will be the thermostat.

 

[gmbellew]

Guess i have some diagnosing to do. I have a multi port fuel injection. I guess I assumed the gauge worked cus when i unplugged it from the sensor it dropped down to all the way on the left. I figured those gauges read right or didn't work at all. Maybe I have a bad coolant sensor. The truck seems to run fine, which is why I think the 2 Wire EFI sensor is fine but i guess i'm not sure. I hope when I test the hoses tomorrow both will be the same temp and cool so i know it will be the thermostat.

it should be running richer if it never gets up to operating temp, I'd think.

 

[TruckCo]

it should be running richer if it never gets up to operating temp, I'd think.

Yah seems to run fine. Doesnt smoke or smell excessive fuel. I think testing the temps of hoses will point me in the right direction. Can rule out thermostat, if i know its not the thermostat and it is up to temp, ill look for something with the gauge sensor.

 

[SirRobyn0]

@TruckCo it would probably be helpful if you mention what multiport system you are running. I don't think there was a factory EFI system for the 350 in 87, unless it came off a car, but if it's aftermarket that would be good to know.

If your running the factory gauges on the inside they are not known to be the most accurate, so like Glen said the first thing is to establish if the engine is actually reaching operating temp. If your going to shoot temps with a IR gun don't use the hoses. For one thing the upper hose is after the thermostat and it's rubber so you'll likely get a little lower temp reading. It's not as simple as engine warms up and thermostat opens, it does do that but after that first bit of fluid flow it either shuts again, to reopen later or partially closes. Regardless the thermostat should be constantly working to maintain proper temp, so if you shoot the hose you might get a false low temp. If you can shoot the temp of the thermostat area below the top housing on the manifold that's best, next best is the actual housing.

 

[TruckCo]

I noticed while driving the heat was very minimal so its probably an engine issue and not a gauge problem. The engine runs “fine” so I dont think its the efi sensor. If i can see the engine gets up to temp then ill chase the driver side gauge sensor and or gauge / wire. What should the temps be for the top manifold? This trucks also from Maryland. Not sure if they kept a thermostat in it or not but i nust cant see howd that be benifical for an efi unit. Also its some edelbrock 8 injector efi. Im not sure of the model other than it said it was a multi port fuel injection.

 

[Matt69olds]

Step one, make sure the throttle opens all the way with the gas pedal. Sometimes linkage flex, floor mats, etc will prevent the throttle from opening all the way.

Next, make sure the TV cable throttle travel maxes out at WOT. If so, take it out for a test drive. You might need to adjust the cable a click or 2 either direction to fine tune the shift points.

 

[Ricko1966]

If it's aftermarket EFI you to do some research. If the TV geometry is not right,it's not going to shift right and your transmission isn't going to live. I do not know if the geometry is right on edelbrock efi with a 700 or if the previous owner did it right,but you better find out.

 

[Turbo4whl]

Seems like 1-2nd gear has a hard shift and when it goes into second, the rpms will hang and i have to feather the throttle before it goes into gear....... When i throw the throttle it seems like it goes to full throttle then it goes a little farther if i twist the linkage a little harder. Not sure which part is full throttle. ....

You should have full throttle when pressing the accelerator pedal. If not check the floor mat or carpet at the pedal like Matt said. The PO may not have got the throttle working right to start with. You are dealing with non stock parts.