Misfire at tickover.
#12
08-12-2012 | 02:15 AM
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Junior Member
Joined: Feb 2011
Posts: 10
I've been driving about listening to the CPS squarewave. Never seems to miss a beat, but the issue of it being inverted has never been resolved. Haynes one way. A major helpline, the other.
Talking of injectors. I pulled the 10A fuse and by chance selected a perfect filament bulb to take its place. 7W. The cold resistance of that works the injectors a treat.
IGN on, Bulb lights bright as all injectors are given a blast. when the normal sequence starts, I got an even 5v waveform across the bulb, with it flickering as one might expect. The evenness of the waves told me there was no major electrical fault with the entire circuit, but of course didn't confirm they were passing fuel. Quite a nifty little test. Yes, I know, it's probably been done a million times.
I ordered a 'new' PCM from an e-bay site. They check them and flash one's details on. They also give a briefing on how to reset it when it's installed.
A fraction of the price of an Autozone unit, and you get to keep the old one for breakdowns. We'll see how that goes.
Any problems and the PS pump will be out within the hour.
Talking of injectors. I pulled the 10A fuse and by chance selected a perfect filament bulb to take its place. 7W. The cold resistance of that works the injectors a treat.
IGN on, Bulb lights bright as all injectors are given a blast. when the normal sequence starts, I got an even 5v waveform across the bulb, with it flickering as one might expect. The evenness of the waves told me there was no major electrical fault with the entire circuit, but of course didn't confirm they were passing fuel. Quite a nifty little test. Yes, I know, it's probably been done a million times.
I ordered a 'new' PCM from an e-bay site. They check them and flash one's details on. They also give a briefing on how to reset it when it's installed.
A fraction of the price of an Autozone unit, and you get to keep the old one for breakdowns. We'll see how that goes.
Any problems and the PS pump will be out within the hour.
#14
08-29-2012 | 08:45 AM
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Junior Member
Joined: Feb 2011
Posts: 10
Not really. Van is drivable, so not so much pressure to fix it.
The PCM arrived, and I trained it to the car. Took 30 mins. Ran okay, apart from the slight misfire.
Within a day or so, the Cam warning came on again. Back to square one.
I built a simple filter to smooth rather spiky supply to the CPS and it seemed to go longer before a fault. But the fault did come back.
I guess the next thing is the sensor itself. It's just the garage is so hot right now, and I have things I should be doing.
Don't want to let it beat me, but it's not fun anymore.
The PCM arrived, and I trained it to the car. Took 30 mins. Ran okay, apart from the slight misfire.
Within a day or so, the Cam warning came on again. Back to square one.
I built a simple filter to smooth rather spiky supply to the CPS and it seemed to go longer before a fault. But the fault did come back.
I guess the next thing is the sensor itself. It's just the garage is so hot right now, and I have things I should be doing.
Don't want to let it beat me, but it's not fun anymore.
#15
08-29-2012 | 09:12 PM
Member
Joined: Jul 2012
Posts: 51
Not really. Van is drivable, so not so much pressure to fix it.
The PCM arrived, and I trained it to the car. Took 30 mins. Ran okay, apart from the slight misfire.
Within a day or so, the Cam warning came on again. Back to square one.
I built a simple filter to smooth rather spiky supply to the CPS and it seemed to go longer before a fault. But the fault did come back.
I guess the next thing is the sensor itself. It's just the garage is so hot right now, and I have things I should be doing.
Don't want to let it beat me, but it's not fun anymore.
The PCM arrived, and I trained it to the car. Took 30 mins. Ran okay, apart from the slight misfire.
Within a day or so, the Cam warning came on again. Back to square one.
I built a simple filter to smooth rather spiky supply to the CPS and it seemed to go longer before a fault. But the fault did come back.
I guess the next thing is the sensor itself. It's just the garage is so hot right now, and I have things I should be doing.
Don't want to let it beat me, but it's not fun anymore.
I have a 1996 Lumina that about got me to the point of "not haviing fun" with running, SEL Light. After time, it runs great! Took alot of intense work, something the dealer would not even handle.
Sticking with my 1970 deta 88, times were so much easier then.
#16
08-30-2012 | 10:19 PM
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Junior Member
Joined: Feb 2011
Posts: 10
Yes, the square wave is a mystery. I sent this off to one useful site just now.
http://easyautodiagnostics.com/ignit...ule_test_2.php
I didn't get a reply last time, but hey, it's a great site to get this far.
http://easyautodiagnostics.com/ignit...ule_test_2.php
Still, after 6 weeks, still looking for solution to my van's problem. Rough tick-over. P0341 code sets, and poor gas mileage.
I've even changed the PCM !!
However, I haven't changed the sensor cos I can't get the pump out of the way, and there were other reasons to believe the PCM was at fault.
I drove for miles LISTENING to the wave from the cam sensor. Never missed a beat.
I even devised a way to get a wave off the injector input, but that's another story.
Just need to know one thing.
Cam sensor - is the wave out DEFINITELY negative going? You emphasize this with an extra paragraph. Haynes agrees with you, but another site and indeed the car, show it going from zero, with a POSITIVE square wave.
I've even changed the PCM !!
However, I haven't changed the sensor cos I can't get the pump out of the way, and there were other reasons to believe the PCM was at fault.
I drove for miles LISTENING to the wave from the cam sensor. Never missed a beat.
I even devised a way to get a wave off the injector input, but that's another story.
Just need to know one thing.
Cam sensor - is the wave out DEFINITELY negative going? You emphasize this with an extra paragraph. Haynes agrees with you, but another site and indeed the car, show it going from zero, with a POSITIVE square wave.
I didn't get a reply last time, but hey, it's a great site to get this far.
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