bluemonster Posted July 2, 2013 Share Posted July 2, 2013 Hi all, Just picked up an 87 SEV6 5-spd showing 280K miles. Truck starts fine, but has a horrible miss after warming up, not even driveable. Idle drops to around 500 while doing this. Seems to run much better when cold. Any ideas on where to start looking? I did check for codes per the FSM and have none present, and none on the dash. Any help is greatly appreciated! Thanks Bryan Link to comment Share on other sites More sharing options...
Towncivilian Posted July 3, 2013 Share Posted July 3, 2013 Seems like a recurring issue as of late and I don't mean to sound like a broken record but, engine coolant temperature sensor? Welcome to NPORA! 1 Link to comment Share on other sites More sharing options...
bluemonster Posted July 3, 2013 Author Share Posted July 3, 2013 Thanks Town civilian, will check that today. Is it a common issue? Link to comment Share on other sites More sharing options...
ThaBigPerm Posted July 3, 2013 Share Posted July 3, 2013 Another place to look is O2 sensor ... when the engine is cold the computer runs in "open loop" mode, ignoring the O2 sensor since it has to be up to operating temp before it's anywhere near accurate. After warming up, computer goes into "closed loop" mode and begins listening to the sensor. So it can at times be a culprit in problems that occur only when warmed up. Link to comment Share on other sites More sharing options...
Kingman Posted July 3, 2013 Share Posted July 3, 2013 CHTS, its sub harness, dirty MAF/connector, maybe O2 but I've never had a bad/unplugged one mess with my TBI trucks. Check the routine tune up parts as well as the fuel filter. Link to comment Share on other sites More sharing options...
bluemonster Posted July 4, 2013 Author Share Posted July 4, 2013 Thanks guys, Gonna try to find time today to check these. Will report back what I find Link to comment Share on other sites More sharing options...
bluemonster Posted July 10, 2013 Author Share Posted July 10, 2013 Thanks guys, I believe I've found my problem... CTS is broken off in the head, found the harness and new CTS hidden beneath the air filter. I guess the PO that I bought from didnt care to share that with me. The broken CTS only has a brass stud sticking up and no nut left. Nowhere left to drill and use an easy-out and to small for visegrips. Any ideas on removal? Is there anywhere else I could relocate the new CTS and function properly? Could I drill and tap the thermostat housing and install there? Or, if I knew the operating temp resistance of the CTS, I could just install a resistor in place to fool the ECU? I did place the new CTS beside of the thermostat housing for now and it already runs somewhat better. As always, any ideas or advice is much appreciated! Thanks BT Link to comment Share on other sites More sharing options...
bluemonster Posted July 12, 2013 Author Share Posted July 12, 2013 Bump... Link to comment Share on other sites More sharing options...
Slartibartfast Posted July 13, 2013 Share Posted July 13, 2013 Sounds like you found the problem alright. Can you post a pic of what's left of the old sensor? It's tough to give advice on removing something you can't visualize. So long as we're trying, though, maybe you could JB weld something to it and back it out that way? You say there's a brass post sticking out, maybe if you drill a hole in an old bolt and glue it to the post, you could wrench the whole thing off that way? Link to comment Share on other sites More sharing options...
bluemonster Posted July 13, 2013 Author Share Posted July 13, 2013 Thanks, Gonna try to JB Weld an old 1/4 socket on it today. Will report back. If that doesnt work, I may relocate the sensor to somewhere else in the cooling system Link to comment Share on other sites More sharing options...
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