ignition coil replace? July 04, 2017, 04:53:43 PM car(3.8 cfi) starts and runs fine in town but on wot or big throttle input struggles to get going checked over a few things and found the coil resistance at primary 3.1 ohs secondary 8.13k ohms tho just within limits should i replace it?. Quote Selected
ignition coil replace? Reply #1 – July 04, 2017, 11:10:38 PM I just replaced mine when I installed a MSD 6A. I'm pretty sure it was the original coil. 30 years old. Car runs great. You can get a Motorcraft coil from Rock Auto for $36. Quote Selected
ignition coil replace? Reply #2 – July 04, 2017, 11:47:59 PM Ive never had to replace one. Don't see alot of point in replacing it unless the car doesnt start. Quote Selected
ignition coil replace? Reply #3 – July 05, 2017, 08:45:11 AM Quote from: Haystack;461764Ive never had to replace one. Don't see alot of point in replacing it unless the car doesnt start.Agreed coils rarely fail... No doubt 99% of the coils replaced are someone throwing parts at a problem, or they just want that warm and fuzzy feeling of having a new part...Mr Glee your problem sounds fuel related, weak ignition will cause lots of intermittent misfires, most certainly at light to moderate throttle opening... Quote Selected
ignition coil replace? Reply #4 – July 05, 2017, 09:34:28 AM 3.8L drivability issues could be numerous, unfortunately...- TFI module- Slackened timing chain- Clogged catalytic converter- Slow/dying fuel pump(s)- Faulty EEC moduleLikely the problem is in there somewhere. I once had an intermittent inertia switch that caused all kinds of starting issues (spring mechanism rusted and kept popping up), but since your car starts and runs, we can likely rule that out. Agree with everyone above, probably fuel related, which means fuel pump(s). NOTE: the 1984 CFI models had 2 pumps (internal/pusher, and external/puller). Those got combined into one pump starting in 1985. Quote Selected
ignition coil replace? Reply #5 – July 05, 2017, 02:39:38 PM Check the fuel pressure first, usually you can do this at Oreilly for free, or rent the tool, do it at home, return it, get all of your money back.That said, I DID have to replace the coil on an '89 Tbird (3.8 obviously), and the symptoms were rough idle, shiznitty economy, little power, hesitation, backfiring and stalling. Of course I had spare parts so the cash outlay was nil and the fuel IIRC was acceptable....after the coil was swapped out, it ran great. Ran right up to the day we parked it and started driving a car that the glass went up and down in, and didn't have rust holes as big an elephant's ass in the quarters and rear pan..So, there's that. Good luck, mano. Quote Selected
ignition coil replace? Reply #6 – July 05, 2017, 04:40:07 PM When i was 16 i replaced my coil because it was covered in rust. Made no change in the way it idled or drove. Threw alot of money into that car chasing problems thst didnt actually exist. Now my philosophy is if it ain't broke, dont fix it. Often times replacement parts arent as good of quality as the 30 year old oem parts.One of my cars i threw a brand new water pump on. Didnt even get the cheap one, it was listed as "new" not rebuilt from orlieys. The next day (day before thanksgiving during a snow storm btw) while driving down the highway i heard a loud clunk. Figured i hit something in the road and didnt notice. 2-3 miles down the road when i stopped at the stop light, white smoke was blowing everywhere. I pulled off the road and popped the hood and couldn't beleive what i saw.The clunk was my fan coming off the water pump shaft, breaking the fan shroud and tearing a hole in my brand new radiator. I figured i forgot to tighten down the water pump bolts and they fell out. Pushed the car into a parkinglot and came back out to fix it on thanksgiving think i hust had to thrkw some water pump bolts in it.Turns out the on the end of the shaft wasnt pressed on straight. Ate my belt, fan clutch (which was sitting on the crank pulley, also brand new)fan shroud and radiator. I ended up throwing a cheapie autozone water pump in, and when i went back to orileys with boxes full of you should have seen the manager face.They did give me a refund on everything, though they refused to give me another water pump. Said i must have "abused" it. Quote Selected
ignition coil replace? Reply #7 – July 05, 2017, 11:04:26 PM In my particular case mentioned prior to your post, I had no spark on that car. Since I had a box with a spare coil or three, I figured it was an easier (attempted) fix than swapping the TFI. Worked for me, but yeah, usually not the case. Quote Selected
ignition coil replace? Reply #8 – July 06, 2017, 02:07:56 AM Ok thanks for the info everyone.from the list that ericcoolcats gave I think it's probably the timing chain as it has 10-11 degrees of slack.looked at rockauto choice of three chains melling,cloyes and sealed power any of these to avoid? Guides and tensoiner replace?.also timing cover gasket set 3 engine code?Repair sleeve?(repair what)3 engine code with fuel injectionNot sure which to order.Oil pan gasket there appears to be three different sorts Any other parts I need and tips would be most welcome.1986 3.8 cfi Quote Selected
ignition coil replace? Reply #9 – July 06, 2017, 02:31:08 PM Quote from: mr glee;461776Ok thanks for the info everyone.from the list that ericcoolcats gave I think it's probably the timing chain as it has 10-11 degrees of slack.looked at rockauto choice of three chains melling,cloyes and sealed power any of these to avoid? Guides and tensoiner replace?.also timing cover gasket set 3 engine code?Repair sleeve?(repair what)3 engine code with fuel injectionNot sure which to order.Oil pan gasket there appears to be three different sorts Any other parts I need and tips would be most welcome.1986 3.8 cfiMy bet is a timing chain won't fix it either... While there is some performance loss at low speeds, generally retarded cam timing actually increases performance at higher RPMs... Of course this assumes ignition timing has been adj to spec... Quote Selected
ignition coil replace? Reply #10 – July 07, 2017, 04:53:55 PM My timing chain was stupid stretched and it still ran fine. 260k miles on it. Quote Selected
ignition coil replace? Reply #11 – July 08, 2017, 06:55:38 AM Ok I'll leave the timing chain for now just had my yearly mot and failed on high co2 emissions 5.3% (4.5%max).smog pump bypassed and de-cat.changed the oil,air filter is clean and ignition timing spot on.only thing I can find out of spec are both injectors show 2.4ohms a little higher than they should be.both tests show 11 pass.changed the o2 sensors since last year's test(4.1% pass).don't know what else I can do to get the level down. Quote Selected
ignition coil replace? Reply #12 – July 08, 2017, 08:13:22 AM Quote from: mr glee;461793Ok I'll leave the timing chain for now just had my yearly mot and failed on high co2 emissions 5.3% (4.5%max).smog pump bypassed and de-cat.changed the oil,air filter is clean and ignition timing spot on.only thing I can find out of spec are both injectors show 2.4ohms a little higher than they should be.both tests show 11 pass.changed the o2 sensors since last year's test(4.1% pass).don't know what else I can do to get the level down.Fix the smog pump and install a cat, it'll likely pass emissions... May pass with just the pump reconnected, though once it's known the cat is gone, they'll probably can you on a visual... Don't worry about injector resistance, they vary somewhat and aftermarket rarely are same as orig... Quote Selected
ignition coil replace? Reply #13 – July 08, 2017, 10:59:12 AM Smog pump is now back on and the death rattle is back.car is pre-cat regulated due to its age and it passed it's last two mot's with smog bypassed and decatted 2015 3.57% 2016 4.1%.when it had the cat and smog running it was 0.14% .retest on Monday will find out then. Quote Selected
ignition coil replace? Reply #14 – July 17, 2017, 12:50:30 PM Just passed the emission test was co 5.3% with smog pump connected now 0.24% very happy with that now to take it off again as bearings are badly worn I need it for next year thanks for the help. Quote Selected
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