RRR007280Z Posted March 9, 2017 Share #1 Posted March 9, 2017 I recently had headers and a new exhaust installed on my late 1977 280Z coupe and since then I have had a carbon like residue on the tailpipe and bumper. I understand this is referred to as running rich, are the two related or is this just a coincidence. I am not mechanically inclined and do not have the luxury of a garage that I can use to work on my car so I was wondering if there might be something my mechanic did when installing the exhaust system and header that would have caused this condition. He's a great guy and I am not looking to blame him or anything but I want it fixed and was hoping to get any info pertaining to the subject that may be helpful to him when I go back for an inspection. I have read the Cold Start Valve/Thermo Time switch and a couple of other components might be the issue but still wonder if there might be something related to or connected with the header/exhaust installation that might be helpful in resolving this. Thanks for any and all help. Link to comment Share on other sites More sharing options...
Dave WM Posted March 9, 2017 Share #2 Posted March 9, 2017 how do the plugs look? a pic would be helpful. Link to comment Share on other sites More sharing options...
JSM Posted March 9, 2017 Share #3 Posted March 9, 2017 To those two parts specially no. However, I'm asuumimg when he pulled the old exhaust he pulled the intake too. It is possible the CTS (Coolant temp sensor) is was likely disconnected and may not be making good contact. Possible he put the thermotime and CTS plugs on in reverse or maybe if he unplugged via bullet connectors and swapped those accidentally How does it start when it's cold? Is it any harder then before? Link to comment Share on other sites More sharing options...
RRR007280Z Posted March 9, 2017 Author Share #4 Posted March 9, 2017 Mechanic says they looked fine last time I was there, after the exhaust installation, I had my fan motor replaced and since I had already mentioned it to him I mentioned it to him again and asked that he check out the plugs to see if they were fouled, so he said he pulled one of the plugs and it looked fine. A pic of the plug? I was just wondering if there are any components that might have to be removed/moved or adjusted in order to install the header and or exhaust. Thanks. Link to comment Share on other sites More sharing options...
RRR007280Z Posted March 9, 2017 Author Share #5 Posted March 9, 2017 It has a tough time starting in the cold Link to comment Share on other sites More sharing options...
RRR007280Z Posted March 9, 2017 Author Share #6 Posted March 9, 2017 turns over but not like when I pull it out of the garage. Link to comment Share on other sites More sharing options...
RRR007280Z Posted March 9, 2017 Author Share #7 Posted March 9, 2017 idles very low when cold as well, runs fine, no stalling etc… Link to comment Share on other sites More sharing options...
Dave WM Posted March 10, 2017 Share #8 Posted March 10, 2017 yes a pic of the plug will confirm the air fuel mixture. Link to comment Share on other sites More sharing options...
siteunseen Posted March 10, 2017 Share #9 Posted March 10, 2017 Try a new set of plugs, bp6es. Link to comment Share on other sites More sharing options...
JSM Posted March 10, 2017 Share #10 Posted March 10, 2017 3 hours ago, RRR007280Z said: It has a tough time starting in the cold Has this condition just started after the header swap? Link to comment Share on other sites More sharing options...
RRR007280Z Posted March 10, 2017 Author Share #11 Posted March 10, 2017 Has this condition just started after the header swap?YesSent from my iPhone using Classic Zcar Club mobile Link to comment Share on other sites More sharing options...
JSM Posted March 10, 2017 Share #12 Posted March 10, 2017 (edited) My feeling is either the plug for the CTS may be corroded or dirty or the connection itself maybe loose on the sensor. If the the thermotime plug and CTS were crossed I'm not sure how it would run, if at all. Here is the link to the 77 PDF you can give your mechanic. It has all the checkout procedures for the EFI. The CTS or WTS is on page 95. There is much more diagnosis in the EF section. Here is a snipet of page 95. These cars are notorious for running rich if the CTS doesn't have a good connection to the sensor or ECU. Plus the plug gets old over time. I put a pic of the plug at the bottom. Clean it good with Emory board and electrical cleaner. Do the sensor too. http://www.nicoclub.com/FSM/280z/1977/ Edited March 10, 2017 by JSM Link to comment Share on other sites More sharing options...
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