CDLong Posted October 7, 2023 Share Posted October 7, 2023 Attached is what I found on checking the gauge from my E Books purchase, but I want to check here first before I tear the dash apart. I checked the connector at the sending unit with a 12V test light. I checked the light on the battery before checking the plug at the sending unit. Plug has no power in either wire. The fuel, amp & oil pressure gauges are working as they should so I figure fuse box fuse #11 15A Gauges & Warning Lights is good. I didn't find anything related to this when I searched the forum. ( On the E book purchase, I wouldn't buy it again). Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 7, 2023 Share Posted October 7, 2023 Your EFI engine has both a sender and a sensor. (ECT) The sensor is two wire and tells the computer to richen the mixture of a cold engine. The sender is single wire and grounds the gauge with variable resistance so the needle moves. With a good meter you should see approximately 5.5V pulsing on this wire. Ground the (#39 R/W) wire and the gauge should full temp (don't do this for long or you will damage the instrument) You should familiarize yourself with the 1985 EVTM (Electrical and Vacuum Troubleshooting Manual) It can be found under Documentation/Electrical/EVTM/1985 EVTM. https://www.garysgaragemahal.com/1985-evtm.html You can usually find these used on eBay for ~$25 delivered..... Link to comment Share on other sites More sharing options...
CDLong Posted October 11, 2023 Author Share Posted October 11, 2023 Your EFI engine has both a sender and a sensor. (ECT) The sensor is two wire and tells the computer to richen the mixture of a cold engine. The sender is single wire and grounds the gauge with variable resistance so the needle moves. With a good meter you should see approximately 5.5V pulsing on this wire. Ground the (#39 R/W) wire and the gauge should full temp (don't do this for long or you will damage the instrument) You should familiarize yourself with the 1985 EVTM (Electrical and Vacuum Troubleshooting Manual) It can be found under Documentation/Electrical/EVTM/1985 EVTM. https://www.garysgaragemahal.com/1985-evtm.html You can usually find these used on eBay for ~$25 delivered..... Thank you again. I forgot to check the auto notification box. Link to comment Share on other sites More sharing options...
CDLong Posted October 19, 2023 Author Share Posted October 19, 2023 I have power to the sending unit. Now the problem is to id the correct sending unit. Mine has 2 wires but not a 2 wire listed for 1985? NOTE: the clips are broken off my plug. Maybe it's not making ood contact Link to comment Share on other sites More sharing options...
FuzzFace2 Posted October 19, 2023 Share Posted October 19, 2023 I have power to the sending unit. Now the problem is to id the correct sending unit. Mine has 2 wires but not a 2 wire listed for 1985? NOTE: the clips are broken off my plug. Maybe it's not making ood contact As Jim said the 2 wire plug you pictured is for the EFI NOT the gauge. The temp gauge is a single wire 90* rubber push on plug and as a guess is in the intake manifold. Most of the time to the left (when in drivers seat) front top corner but could be wrong as you have EFI where do they put the temp sender? Dave ---- Link to comment Share on other sites More sharing options...
CDLong Posted October 19, 2023 Author Share Posted October 19, 2023 As Jim said the 2 wire plug you pictured is for the EFI NOT the gauge. The temp gauge is a single wire 90* rubber push on plug and as a guess is in the intake manifold. Most of the time to the left (when in drivers seat) front top corner but could be wrong as you have EFI where do they put the temp sender? Dave ---- Thanks Dave. I guess I didn't understand what Jim said. I'll keep searching. I did pull the starter and get the engine serial number. Wanted to make sure one of the PO's didn't do a swap. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 19, 2023 Share Posted October 19, 2023 Thanks Dave. I guess I didn't understand what Jim said. I'll keep searching. I did pull the starter and get the engine serial number. Wanted to make sure one of the PO's didn't do a swap. That is not a "serial number". It is a casting number. And all you can tell from it is that it was cast in 1985 given the E5 in the number. Link to comment Share on other sites More sharing options...
CDLong Posted October 20, 2023 Author Share Posted October 20, 2023 That is not a "serial number". It is a casting number. And all you can tell from it is that it was cast in 1985 given the E5 in the number. Thanks Gary. I'll keep looking to see if I can find any other numbers. Link to comment Share on other sites More sharing options...
CDLong Posted October 20, 2023 Author Share Posted October 20, 2023 As Jim said the 2 wire plug you pictured is for the EFI NOT the gauge. The temp gauge is a single wire 90* rubber push on plug and as a guess is in the intake manifold. Most of the time to the left (when in drivers seat) front top corner but could be wrong as you have EFI where do they put the temp sender? Dave ---- Found the sending unit. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 20, 2023 Share Posted October 20, 2023 Found the sending unit. Yep, that looks like the one. Link to comment Share on other sites More sharing options...
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