mat in tn Posted November 2, 2021 Share Posted November 2, 2021 i have had three senders fail in as many days. finishing up a frame off resto of an 86 l b with 351ho. i have been reading on this site for two days since i discovered it. first time ever joining in any site but decided to because i feel right at home in this arena. just a little stumped by this issue Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 2, 2021 Share Posted November 2, 2021 Matt - Glad you joined. And you will fit right in, I’m sure. I saw that because you missed the request to go to the New Members Start Here folder and introduce yourself. And about half of new members do. On the oil pressure sender, how are they failing? Are they leaking? Or also they suddenly give the wrong reading? Link to comment Share on other sites More sharing options...
mat in tn Posted November 2, 2021 Author Share Posted November 2, 2021 Matt - Glad you joined. And you will fit right in, I’m sure. I saw that because you missed the request to go to the New Members Start Here folder and introduce yourself. And about half of new members do. On the oil pressure sender, how are they failing? Are they leaking? Or also they suddenly give the wrong reading? well let me start by saying that i have been reading many of your answers to other posts and that has had me looking at many things over the past few days. unfortunately i answer one and get three more to answer as a result. i started with a new standard PS60 oil sender on this resto , and it worked . but as i was installing many things in sequence i can not say how long it was before i noticed it not working. replaced it again and it worked then failed in short order. i checked grounds to the cluster and noticed temp reading high but not overheating. noticed fuel reading below e so i put 5 gal in. still reading low. either tank. next i tried another icvr off the shelf. no change. added an additional ground from icvr ground screw to firewall and now the temp shows correct. sufficed to say im chasing something not wanting to be found. these trucks are what i do and yet this is a first for me. however i subscribe to the old line 'there are not stupid questions' but there are stupid answers. haha Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 2, 2021 Share Posted November 2, 2021 well let me start by saying that i have been reading many of your answers to other posts and that has had me looking at many things over the past few days. unfortunately i answer one and get three more to answer as a result. i started with a new standard PS60 oil sender on this resto , and it worked . but as i was installing many things in sequence i can not say how long it was before i noticed it not working. replaced it again and it worked then failed in short order. i checked grounds to the cluster and noticed temp reading high but not overheating. noticed fuel reading below e so i put 5 gal in. still reading low. either tank. next i tried another icvr off the shelf. no change. added an additional ground from icvr ground screw to firewall and now the temp shows correct. sufficed to say im chasing something not wanting to be found. these trucks are what i do and yet this is a first for me. however i subscribe to the old line 'there are not stupid questions' but there are stupid answers. haha I'm guessing that you have a wiring problem. Pull the wire off the sending unit and ground it. The gauge should go to the far end of the scale if the wiring is good. If not, it is a wiring problem. And, you can do the same for the temp or fuel level gauges. All three are driven by the same ICVR and all three use the same scale and resistance range of sender. So you can actually use the temp sender to run the oil pressure or fuel level gauges for testing purposes. Link to comment Share on other sites More sharing options...
mat in tn Posted November 2, 2021 Author Share Posted November 2, 2021 I'm guessing that you have a wiring problem. Pull the wire off the sending unit and ground it. The gauge should go to the far end of the scale if the wiring is good. If not, it is a wiring problem. And, you can do the same for the temp or fuel level gauges. All three are driven by the same ICVR and all three use the same scale and resistance range of sender. So you can actually use the temp sender to run the oil pressure or fuel level gauges for testing purposes. yes i am certainly looking at the wiring at this time. i have proven the guages as you suggest and have proven them from the sender ends to include full circuits also. one thing that i have been questioning . i have cluster on the bench and out of the way. looking at cluster plug and identifying the resistor wire i noticed there is another black wire paired in the factory crimped terminal with it. two resistors? as to an earlier writing of yours , yes trying to get an icvr output voltage using a dvm can give you a migraine . Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 2, 2021 Share Posted November 2, 2021 yes i am certainly looking at the wiring at this time. i have proven the guages as you suggest and have proven them from the sender ends to include full circuits also. one thing that i have been questioning . i have cluster on the bench and out of the way. looking at cluster plug and identifying the resistor wire i noticed there is another black wire paired in the factory crimped terminal with it. two resistors? as to an earlier writing of yours , yes trying to get an icvr output voltage using a dvm can give you a migraine . I don't remember seeing a 2nd wire crimped with the resistor wire, but maybe I missed it? The schematic below shows there are two R/Y wires coming out of the connector, but not black at the insulator. Could you take a pic of that and post it? As for the ICVR output, it is so rough that it is surprising anything works off it. Link to comment Share on other sites More sharing options...
Rembrant Posted November 2, 2021 Share Posted November 2, 2021 I checked grounds to the cluster and noticed temp reading high but not overheating. I had this same issue after rebuilding the 302 in my '84. I screwed around with a bunch of different things, but the temperature always checked out fine with a IR gun. However, the gauge always read high, but not overheating. In my case, it turned out to be the parts store sender I had installed. I went to the local Ford dealer and ordered an OEM replacement, and bam, my temperature gauge worked perfectly after that. At exactly 195F the gauge was reading straight up in the middle (I assume this is what Ford had intended). Can't help with the oil pressure sender though. My parts store senders worked fine, on a couple engines. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 2, 2021 Share Posted November 2, 2021 I checked grounds to the cluster and noticed temp reading high but not overheating. I had this same issue after rebuilding the 302 in my '84. I screwed around with a bunch of different things, but the temperature always checked out fine with a IR gun. However, the gauge always read high, but not overheating. In my case, it turned out to be the parts store sender I had installed. I went to the local Ford dealer and ordered an OEM replacement, and bam, my temperature gauge worked perfectly after that. At exactly 195F the gauge was reading straight up in the middle (I assume this is what Ford had intended). Can't help with the oil pressure sender though. My parts store senders worked fine, on a couple engines. Corey - That's good to know. I'm sure that Ford intended the gauge to read right in the middle at 195F as that's the temp 'stat that all of the vehicles had. So that makes sense. Link to comment Share on other sites More sharing options...
Rembrant Posted November 2, 2021 Share Posted November 2, 2021 Corey - That's good to know. I'm sure that Ford intended the gauge to read right in the middle at 195F as that's the temp 'stat that all of the vehicles had. So that makes sense. I find the Bullnose gauges work quite well when everything is operating as it should. My temp and oil pressure gauges would show fairly small fluctuations. People often say that they're just "dumb" gauges and not very accurate, but my opinion and experience is the opposite. I don't think it hurts to go a bit overboard...even a bit OCD, when it comes to proper grounding in these trucks. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 2, 2021 Share Posted November 2, 2021 Corey - That's good to know. I'm sure that Ford intended the gauge to read right in the middle at 195F as that's the temp 'stat that all of the vehicles had. So that makes sense. I find the Bullnose gauges work quite well when everything is operating as it should. My temp and oil pressure gauges would show fairly small fluctuations. People often say that they're just "dumb" gauges and not very accurate, but my opinion and experience is the opposite. I don't think it hurts to go a bit overboard...even a bit OCD, when it comes to proper grounding in these trucks. I agree - when everything is "right" the gauges work well. And in my experience a replacement ICVR helps that a bunch. My gauges never glitch, and you can map them very well to the aftermarket gauges - although the factory gauges are slow to react since they are really just thermometers with heaters in them. So it takes a while to warm up or cool off. Link to comment Share on other sites More sharing options...
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