masonbm Posted September 5, 2013 Report Share Posted September 5, 2013 Im working on a 1986 Olds 98 Regency .3.8 engine. The car will start up no problem ,however has a slightly high idle when first starting and seems to run a little rough but not overly rough. I checked for vacuum leaks with throttle body cleaner with engine running nothing seem to change, I replaced spark plugs as they were not in the best shape. I replaced vac tube to egr valve as it looked cracked. I was told numerous things to try and as I am in the auto service industry I am familiar with the newer makes but without proper scan tools or diagnose tools for a 1986, its pretty hit or miss. I am leaning on the throttle position sensor , or a crank sensor. I am also leaning on the mass air flow but I unplugged it and ran worse. im sure after I replace all these parts , it will turn out I need to replace the ECM. Any help will be greatly appreciated as i don't know what to try or replace first. Im trying to fix this for a neighbor who has 5 children and hasn't had a job for 8 months and found one but cant get there because of her problem with her car. Quote Link to comment Share on other sites More sharing options...
Armybarlow Posted September 5, 2013 Report Share Posted September 5, 2013 ain't that a carb model engine? Quote Link to comment Share on other sites More sharing options...
masonbm Posted September 5, 2013 Author Report Share Posted September 5, 2013 No Army, its fuel injected 3800 Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted September 5, 2013 Report Share Posted September 5, 2013 the MAFs on the early 3.8SFI/3800s were notorious for failing randomly. the ignition(coil pack and ICM) is also suspect to failure. it is tough to diagnose without a datastream to look at, and these cars were not in any way fun or easy to communicate with. Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted September 5, 2013 Report Share Posted September 5, 2013 im thinking it could be the tcc Quote Link to comment Share on other sites More sharing options...
OneBadCutt Posted September 6, 2013 Report Share Posted September 6, 2013 Well check fuel presssure if you can Quote Link to comment Share on other sites More sharing options...
masonbm Posted September 6, 2013 Author Report Share Posted September 6, 2013 Thanks to all who responded, I got a guy who has a used ecm so I can try that and at least see if something happens. Now for the next question if I may ask? Where is the ecm at and how do I get it out,,lol I removed the bottom panel to see if I can access it, I got a diagram off of aldata but its not looking like anything im seeing, my guess is its under the glove box up inside the dash as I saw the wiring harness on the firewall going into that area. Also there were 2 little modules and a little square one mounted along the firewall . at the end of those looks like a wiring clip about 4 to 5 inches long. On the 2 little modules that has a clip connector attached , I saw what looked like black tar on the wires that go into the clip port, I thought it was burnt, but looks more like somwthing black and its hard like corn flakes. Once again any help is much appreciated These cars are a blast to work on,,,,NOT Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted September 7, 2013 Report Share Posted September 7, 2013 its below the glove compartment. remove the plastic panel under the dash Quote Link to comment Share on other sites More sharing options...
masonbm Posted September 7, 2013 Author Report Share Posted September 7, 2013 its below the glove compartment. remove the plastic panel under the dash I took off the bottom panel to dash, then I see a little steel arm that comes down from dash and secures that plastic housing that I think hold the ecm it had 2 10mm bolts, do I have to take out the glove box to access the ecm or does that steel bracket arm hold everything in place. I had 2 back surgeries and its a pain in the you know what to get under there , maybe I should change the throttle sensor first,,lol Quote Link to comment Share on other sites More sharing options...
masonbm Posted September 7, 2013 Author Report Share Posted September 7, 2013 I didn't change anything yet, but now when I start the car up and put it into reverse it will stall, not even warmed up yet.. im thinking I.A.C or TPS Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted September 8, 2013 Report Share Posted September 8, 2013 I took off the bottom panel to dash, then I see a little steel arm that comes down from dash and secures that plastic housing that I think hold the ecm it had 2 10mm bolts, do I have to take out the glove box to access the ecm or does that steel bracket arm hold everything in place. I had 2 back surgeries and its a pain in the you know what to get under there , maybe I should change the throttle sensor first,,lol this is for the 88 but should be the same for the 98 http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f8038fb18 Quote Link to comment Share on other sites More sharing options...
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