Help me bias my amp...Please

[walter]

My '88 K2500 was hard to start and ran rough, I ohmed the temp sensor at cold and hot. It had a range, but was shifted from the chart. Replaced it and the truck starts right up and idles smooth when hot.  I also had an '88 ford with dead temp gauge, the shop wanted to tear into the dash. I located the sensor and replaced it with a potentiometer to verify that the wiring and the gauge function. Replaced the sensor to restore function to the gauge. I suppose you could replace a sensor to the ecu with a pot, just make sure it's limited to the specified range, for troubleshooting purposes.

 

[scott2000]

Dirty jack? Cold solder connection? Does the sound change with percussive troubleshooting (tap components with a pencil eraser)?
JR

No finds with chopsticking.....I did clean the input jacks with some Deoxit and a couple of the board terminals.....It has been quiet ever since...

If it bothers you chase the different voltages around the circuit to find the difference, but don't blow anything up.we all participate in your success (or failure). I'll take success.  8)

JR

I will leave well enough alone.....for now ;D

Thanks for all the help!!!!!

I located the sensor and replaced it with a potentiometer to verify that the wiring and the gauge function. Replaced the sensor to restore function to the gauge. I suppose you could replace a sensor to the ecu with a pot, just make sure it's limited to the specified range, for troubleshooting purposes.

A pot would be a neat solution....Bias my truck...lol

everything is working now in regards to the sensors..... My thermostat isn't opening soon enough though I think.....I have a 195 in there and the temperature from the ecm stays at 205 to 208 for a couple of minutes before it starts to drop...... I may try a 180 just to see.........or I wonder if my brand new sensor is out of spec.....I guess I should check that too.....

When I got the truck it had a 160 in it and ran fine but I heard it's not good to have it too cold because of deposits building up......

Since everything has been replaced more or less.....

....I'm guessing my random miss could be coming from an intake gasket leak.....I wish I had a way to smoke test it.....I haven't tried propane yet but have tried starter fluid,etc...... with no luck....

I'm going to put some new parts in the tbi and get an adjustable fuel regulator too before I look at the other stuff....

Work in progress......

 

[scott2000]

Just wanted to update....

I couldn't leave well enough alone with the bit of dc I was getting at my outputs.....And the varying readings I was getting while trying to bias....plus I was still getting  random crackles although very seldom.........

I went ahead and reluctantly picked up some nos MPL01 from sh-halbleiter which was recommended somewhere on another thread as a good source for some hard to find stuff ..... they have an Ebay store too.....

so I went ahead and replaced the front end transistors as it was mentioned...............

Everything is perfect now and I can recommend them too......