DaveFromColorado Posted October 25, 2005 Report Share Posted October 25, 2005 Howdy all, I'm thinking about purchasing a 1990 Buick Regal 3.8/auto/AC/everything - it's got a new battery, but it has no spark. the car ran 4 months ago when the owner parked it, but it doesn't start now. It's got a new battery in it, the fuel pump works and gets fuel up to the rail, but there's no spark at all. I hooked my scan tool up to it last night and while cranking, I got no RPM reading at all, there's no spark on any of the coils, and it had a code 42 set in the computer. I'm thinking it's the crank pos. sensor, but I'm not sure, as I don't know the 3800's that well. Thanks in advance guys! --Dave. Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted October 25, 2005 Report Share Posted October 25, 2005 ICM or Crank Sensor, I would say more like crank sensor. But it's wierd it isn't getting a RPM reading, isn't that off of the ICM? CODE 42 Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module and the ECM grounds the EST line. It expects to see no activity on this line at this time. When the ECM enters EST mode, it applies +5 volts to the BYPASS line and expects to see voltage variations on the EST line. Reasons for the ECM to set Code 42: * System in BYPASS mode (i.e. EST line supposedly grounded) but activity sensed on EST line * System in EST mode (i.e. BYPASS line driven with +5 volts) but no activity seen on the EST line Possible causes include: 1. BYPASS line is open or grounded 2. EST line is open or grounded 3. Poor connections between ignition module and ECM 4. Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise 5. Faulty or incorrect ignition module 6. Faulty ECM Quote Link to comment Share on other sites More sharing options...
mihela816 Posted October 25, 2005 Report Share Posted October 25, 2005 The ignition modules on those old 3800's suck. They are Magnavox coils. If that turns out to be the problem, upgrade to the newer Delco units on 93+ 3800 cars. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted October 25, 2005 Report Share Posted October 25, 2005 Get a crank sensor. I'll bet that's your problem. Either that or it's unplugged. Quote Link to comment Share on other sites More sharing options...
99RegalGS Posted October 25, 2005 Report Share Posted October 25, 2005 The ignition modules on those old 3800's suck. They are Magnavox coils. If that turns out to be the problem, upgrade to the newer Delco units on 93+ 3800 cars. YES!!! Very common problem. However the one in my Riveria still works great. Unlike my firend's 1991 Olds 88, which has been through a few of them... Also the 3 seperate coil pack style goes back to 87 on the old FWD 3.8's. The swap is pretty easy. IIRC you need the ICM, Coils, and the coil base. Ask Maybe2Fast. he did this swap on his Reatta. Quote Link to comment Share on other sites More sharing options...
BlueBallz Posted September 26, 2011 Report Share Posted September 26, 2011 I know this is a really old thread but im bumping it cause i have the exact same issue with the same car. We've replaced the coil packs, ignition control module, crank position sensor, plugs, plug wires and the computer itself. Still nothing! Any ideas? Quote Link to comment Share on other sites More sharing options...
thikstik Posted September 27, 2011 Report Share Posted September 27, 2011 If coolant has ever gotton into wirepack, the wires can arc together as insulation turns to goo. Ive seen 2 cars that this happened to....one was a very nice car and it put itself into junkyard. It happens when the bypass hose blows and alot of hot coolant can get into the wire loom under that hose. It took 10 years for the wires to start melting together, even tho the hose had leaked so long ago. The insulation just turns to goo. It simply one day blew an ign fuse, and i discovered wires and just cut them out and soldered in sections. Quote Link to comment Share on other sites More sharing options...
BlueBallz Posted September 27, 2011 Report Share Posted September 27, 2011 Well it turned out to be the Ignition Control Module. It tested fine on the scanners and what not, but we got another one for the heck of it and sure enough, plugged it in and it fired right up. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted September 27, 2011 Report Share Posted September 27, 2011 ICM is one of those cases where it can "test" good but actually be bad. I've heard multiple people say to just replace. I just hit the junkyard and pick up a known good set of 3 coils and ICM. Can't lose that way. Quote Link to comment Share on other sites More sharing options...
BlueBallz Posted September 27, 2011 Report Share Posted September 27, 2011 ICM is one of those cases where it can "test" good but actually be bad. I've heard multiple people say to just replace. I just hit the junkyard and pick up a known good set of 3 coils and ICM. Can't lose that way. Well that's what i kept telling my buddy. But he thought it was something else. And since it was his gf's car and he does know a considerable more about working on cars then me, i let it go. But turns out i was right! Quote Link to comment Share on other sites More sharing options...
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