If you have a vehicle with the GM 3800 Engine which stalls randomly and may not always restart, then you likely have a bad crankshaft position sensor. If you…
Crank Position Sensor Replacement – Stalling 3800 3.8 Engine
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Great video!
Just wondering, have you ever heard of a 3800 running rich (and also
sputtering and stalling) due to a bad crankshaft position sensor? I am
curious, because I am at my wit’s end with my 1991 Toronado. I have no ECM
codes, replaced the MAF, replaced the fuel pressure regulator, replaced the
O2 sensor, fuel filter, and it keeps running erratically and running rich
and stalling.
When it’s cold, it starts and runs fine until it heats up. Then for some
reason (inexplicably), it goes into Open Loop and starts sputtering and
stalling, most of the time it won’t restart until it cools down. And also,
immediately when it starts stalling, I smell unburned gas.
This problem is driving me INSANE!
Thanks for your (or anyone else’s) help!
Have u replaced the timing chain and gears ?
Does the series 2 3800 crank comes off with the center pushrod method…im
really in a pinch
Another great video! Only thing to offer would be to add a note in the
video to disable the ignition coil if you are going to use the starter to
remove the balancer bolt. I’ve always done that with the belt still
connected and holding the engine back with a pry bar through an accessory
like the power steering pump. Just a thought.
Great video ty it helped alot!
Good to no very helpful…
Just had bad CPS on dodge 4.7L. It didn’t stall, but bucked and chugged,
especially when you pulled out into traffic and really needed it to
accelerate. :-o
Great video and one of the more comprehensive CPS videos out there. Thanks
to your video I was able to save some cash doing it DIY style.
Thank you very much for posting this video, I was able to fix my 1992 buick
regal 3.8 CPS :)
+knurlgnar24 I spoke too soon… I just went outside to start it again…
Wouldn’t start–AGAIN! It just refuses to start when the engine is hot.
Anyway, at least now I have a new camshaft sensor! LOL
I’ll try to repost again if I ever get this thing running, before it goes
to that great boneyard in the sky…
Did that solve your problem? My 90 olds 98 runs fine till get temp up to
205* then shuts off, runs rough when you try to start still hot. Changed
plugs, wires, fuel filter, checked vacuum leaks, cleaned throttle body.
Could it be throttle position sensor or idle air control valve or pcv valve?
Thanks for such awesome accurate video. We used similar tools as yourself,
however our breaker bar broke on 3rd try. No luck initially with impact
wrench. We then put a small plumbers torch on the bolt taking care not to
heat anything but the bolt for a few minutes, got it hot, put the impact
wrench on the bolt and off it came easily. You are right, bloody bolt
almost beat us! Anyway, rest of job piece o cake. Thanks again for such
detailed info – job well done!
+knurlgnar24 For some reason it won’t let me reply underneath your
response… Anyhow… It was the old CAMshaft position sensor putting out
an erratic camshaft-sync signal when hot, thus causing the intermittent
rich condition and stalling. What was happening was the injectors were
getting an erratic signal and lengthening the injector pulse width. That
allowed too much fuel to the cylinders. Then the O2 picked up the rich
condition and started to lean everything out. So meanwhile, both systems
kept fighting each other and made it run horrible and sputter and stall.
(All without any Trouble Codes either!) After a while, the cylinder walls
got so unbelievably wet that the mixture would just not fire.
I diagnosed this by reading my 2-inch-thick direct-from-GM 1991 Toronado
shop manual, and it said something to the effect of: “If you unplug the
camshaft sensor plug and the engine runs, check for a Code 41. If you get
a Code 41, replace the sensor… When the sensor is unplugged, the ECM
sets a default injector-spray sequence, which allows at least 1-in-6 of the
injectors to spray to coincide with the correct ignition firing.”
So, I replaced the sensor, and after clearing the Code 41 I got from
unplugging it, it warmed up and the ECM “re-learned” after 3 or 4 start-run
cycles, the sputtering smoothed out and the acceleration flat-spot smoothed
out tremendously.
See, and this is what the strange part was– I never originally got a Code
41 until I unplugged the sensor. I guess this was because the break in the
camshaft sensor signal never exceeded what the ECM was looking for.
Well, so the next time someone (like me) spends $350 on parts and towing in
order to track down this elusive condition on their 3800, it just very well
may be the last thing there is to replace!! The CAMshaft sensor next to the
water pump!!
I hope this might also anyone else as well!
Thanks, knurlgnar24 for your help!
+knurlgnar24 What bolts do you use for the Harmonic Balancer Puller? The
bolts for the attachment puller? The kit doesn’t come with the right ones
🙁
thanks this is really what I needed to see…..
Great video
Good to no very helpful…