finally got the 97 351 i installed in my 92 flareside to fire up and run.i used the 97 firewall-forward harness, and only switched a few wires for the wipers and the stereo in the c202 connector to make it work. i used a 97 351 ecm,as my motor came from a over 8500gvwr f250. my only problem now is my factory tach and gauges are wrong. the tach, and volt dont move at all, the oil pressure reads so low it would be knockin like heck if it was right, didnt let it run enough to see about the water temp, and the fuel gauge reads about a half-tank higher than it should. im afraid to run it without gauges, ive got too much time invested to risk trashin a good engine. please help, im not even sure where to begin.

 

Pick ONE gauge, and diagnose it. After it's fixed, recheck the others. If any are still malfunctioning, pick ONE, and continue. Read these captions:

 

ive decided to use aftermarket gauges, the fuel gauge i can work on later. my plan is to run the voltmeter wire thru an unused spot on the c202, and connect it to the big yellow wire on the side of the underhood box.is this acceptable, or is there a better way?
my new oil and water gauges are mechanical, wheres the best place to run the senders thru the firewall?
and finally, if i replace my factory senders with my new mechanical ones, will it upset my ecm? thank you.

 

The PCM uses the ECT sensor in the T-stat housing. The gauge uses the sender in the block. As long as you leave the ECT sensor intact, the PCM will neither know nor care.

Are you doing this without a shop manual? You need to get one.

 

It's acceptable because it's how the factory voltmeter is hooked up already. So it's a waste of time & $$ to do the same thing again. Just fix the factory gauge - it'll be cheaper, quicker, and better-looking.Do you really want a tube running into the dash that could potentially carry scalding engine oil or coolant inside? The factory gauges work, and show everything you need to know. Just repair them.The gauges aren't used by the EEC - it has its own sensors.