Engine cut out

Paul-C · Dec 28th, 2010, 17:25

Any advice on this one?
Driving the car 960 3ltr auto (on LPG) and the engine cut out, pulled over, and tried the engine (petrol start up) no joy.
Could not find anything obvious so rang the AA. The mechanic checked what he could and said "its LPG cannot touch it " so the car is now at the garage where it was converted and it will be next week before it is looked at.
What I have been trying to figure out is what connects the two systems, "petrol and LPG" together electrically as I think this is the probable common denominator to this problem
What do you think?
Thanks
Paul C
ps no fault codes show suggesting an LPG problem

capt jack · Dec 28th, 2010, 20:13

What connects the petrol and LPG systems electrically? Not much really! The latter effectively switches the former off, and the driver has the option of turning off the LPG system, reverting the car to petrol.

Given that the car will not start or run on either fuel I'd be more suspicious of an ignition fault, and probably / hopefully something quite trivial.

Does the engine turn over on the starter? Do all the warning lights come on at switch-on?

Possible culprits could be the ignition switch, the battery and connections, the distributor, rotor or coil (if fitted), or one of the engine management system sensors.

Is the car an automatic? If so then the automatic gearbox inhibitor switch could have gone bad. Did you happen to notice if the reverse lights have been working OK lately. They are controlled by the same switch, and one warning sign of problems is the reverse lights not working.

I think it's true to say that the 900-series uses the same set-up as the 850 and 70-series. If you search under 'PNP switch' you'll find lots of references here.

Can you tell us a bit more about what the AA patrolman tried? Did he check to see if petrol was being delivered OK?

Cheers

Jack

PS: When you say 'no fault codes' how was this determined?

Paul-C · Dec 28th, 2010, 20:50

Thanks jack that quite a response I couldn't ask for more
The engine turns over on start "yes"
All warning lights on when ignition is turned on "yes"
The car is an Auto transmission and the sequence of events were as below
car running ok after topping up the LPG at Asda then it cut out. (it had half a tank in it but I cannot pass Asda without a visit
After pulling up at the roadside I fit my Diagnostic reader ( that I carry for these occasions) into the socket and got a code 0705 (I think that was the code and I know it relates to the PNP switch) I then cleared it as I didn't know how long this code had been on. I then tried to start the car and it turned over ok but did not start.
I then checked for codes and the reader said no codes which I presumed would be because of the add on of the conversion not being recognized by the onboard diagnostic system
I had problems with the PNP switch earlier this year (the yellow arrow syndrome) and I stripped the switch down, cleaned and re-greased it and after refitting it had no more problems
What I DIDN'T Do was move the selector numerous times to hopfully clear the problem if it is at the PNP switch
The AA mechanic was limited because of the LPG system apparently health and safety issues but thought it was some electrical feature common to petrol and LPG
I think I know what your response is going to be (replace PNP switch) but await your info with interest
Thanks
Paul

capt jack · Dec 28th, 2010, 20:59

That Asda at Monk's Cross by any chance?

I think that the likely culprit is the PNP switch.

It would be really bizarre for both fuel systems to fail at once!

I think partsforvolvo have new switches for around £60, or about double that from Chapmans.

Hope you get it sorted quickly.

cheers

Jack

Paul-C · Dec 28th, 2010, 21:45

Asda at Monks cross York is the one, where ever i'm bound I always end up there.
Jack, can the PNP switch `fault' whilst in "drive mode"? as my thinking was that a fault would occur when moving the selector not whilst driving and the selector not in use.
Having said that it is a fault that would give the car the symptoms it has.
First thing tomorrow I will be at the garage where the car is (ELvington) and try moving the selector to clear the fault then I will replace the switch as soon as I can
Thanks for your help
Paul

capt jack · Dec 29th, 2010, 14:10

Been up to Asda this very morning myself Paul!

With regard to the point at which the switch failed, I guess that anything is possible. You'll only know for sure one way. If the switch has broken even moving the selector back and forth a few times won't fix it, but it's certainly worth a shot.

Hope you get it sorted

Cheers

Jack

Paul-C · Dec 29th, 2010, 16:02

Jack, I went to the car this morning (at Elvington) and played around with the gear selector to try and "change" the situation if it's there.This was to no avail.
I rang Parts for Volvo's and they are not at work yet (£55 online price 3/4 days del. when they start up)
Chapmans were open and are getting me one (here tomorrow £120) but it's not mine until I take it out of the packaging, so I have something, at a price.
Steve Gledall (mechanic) is not at work until next Tuesday apparently so I have placed a thread on the 900 section to see what other idea's there are.
One question Jack, is it possible to diagnose the switch being good or bad without changing the switch?
I'm tempted to go to the car with my trolley jacks and change the switch before the weeks out as I know the access to the switch will be reasonably easy. The switch was off the car about a month ago when the oil seal was changed on the same shaft the switch sits on
Thanks
Paul

capt jack · Dec 29th, 2010, 18:18

Phew! Is it possible to confirm the diagnosis of a faulty switch without taking things apart?

Hmmm.

Well thinking about what the PNP switch does as it opens and closes circuits, I guess it should be possible to confirm what's happening electrically at each stage, but it'd probably be quicker and cheaper to swap the old for a known working switch.

One thought is bothering me, my V70 is an auto too, but when the gear selector is in a 'non-starting' position, ie: R, D, 3, 2 or L, then the starter won't operate at all. What puzzles me is that your engine will turn over. In other words, the PNP switch prevents starting at the wrong time by in effect switching off the starter motor, but clearly, this isn't the case here.

Thinking about it some more I'm less convinced that the PNP switch is necessarily at fault.

You mention in the other thread that you've removed the battery to re-charge it. Certainly a dodgy battery will cause the car not to start, even though the motor will turn over, but I'd have assumed that the AA man will have checked the condition of the battery?

Apart from a lack of fuel, and discounting timing belt failure, the only other possibilities are electrical / ignition or an immobiliser fault.

I guess the other possibility is that the car's petrol ECU thinks that it's running on gas, but that there is a gas problem. Could you disable the LPG system completely by removing it's fuse I wonder? This might stop the LPG ECU telling the petrol ECU not to work!

Before committing to a new PNP switch, is there any chance you could get the AA back to the car, on the basis that the garage they've taken you to can't fix it? If at all possible and the AA will help out, could you get the car to Dyrdal's in Fulford?

Sorry I haven't a definitive answer for you. I do suspect the PNP switch, but I'm not 100% certain.

Cheers

Jack

Paul-C · Dec 29th, 2010, 20:20

Jack,
I didn't try the car with the selector in any other position than `N' or `P' but normally it needs to be in either of the above to start
The battery was well charged before the problem but because of trying to start the engine during this period, and because the car is stood outside the garage until next week I thought I would re-charge it.
I was thinking that the fault, probably being electrical, could be connected to both fuel systems that's why I brought it to this garage as the LPG conversion on the car was done here.
You mention Dyrdal's because they are Volvo people I presume but it's one of those situations that until the fault shows it's a guessing game.
Thanks
Paul

ddahaa · Dec 29th, 2010, 21:23

Doesn't sound like the pnp switch at all to me due to the engine turning over, though I would think you could short out the connectors on it to prove the point.
I would be thinking more along the lines of crank or camshaft sensor stopping the sparks.
Can you remove a plug and turn the engine over to see if you are getting a spark?

Dec 28th, 2010, 17:25	#1
Paul-C Member Last Online: Apr 8th, 2024 16:24 Join Date: Jan 2006 Location: Riccall Nr. York	Engine cut out Any advice on this one? Driving the car 960 3ltr auto (on LPG) and the engine cut out, pulled over, and tried the engine (petrol start up) no joy. Could not find anything obvious so rang the AA. The mechanic checked what he could and said "its LPG cannot touch it " so the car is now at the garage where it was converted and it will be next week before it is looked at. What I have been trying to figure out is what connects the two systems, "petrol and LPG" together electrically as I think this is the probable common denominator to this problem What do you think? Thanks Paul C ps no fault codes show suggesting an LPG problem

Dec 28th, 2010, 20:13	#2
capt jack VOC Member Last Online: Apr 20th, 2024 18:56 Join Date: Jun 2006 Location: Selby, North Yorkshire	What connects the petrol and LPG systems electrically? Not much really! The latter effectively switches the former off, and the driver has the option of turning off the LPG system, reverting the car to petrol. Given that the car will not start or run on either fuel I'd be more suspicious of an ignition fault, and probably / hopefully something quite trivial. Does the engine turn over on the starter? Do all the warning lights come on at switch-on? Possible culprits could be the ignition switch, the battery and connections, the distributor, rotor or coil (if fitted), or one of the engine management system sensors. Is the car an automatic? If so then the automatic gearbox inhibitor switch could have gone bad. Did you happen to notice if the reverse lights have been working OK lately. They are controlled by the same switch, and one warning sign of problems is the reverse lights not working. I think it's true to say that the 900-series uses the same set-up as the 850 and 70-series. If you search under 'PNP switch' you'll find lots of references here. Can you tell us a bit more about what the AA patrolman tried? Did he check to see if petrol was being delivered OK? Cheers Jack PS: When you say 'no fault codes' how was this determined?

Dec 28th, 2010, 20:50	#3
Paul-C Member Last Online: Apr 8th, 2024 16:24 Join Date: Jan 2006 Location: Riccall Nr. York	Thanks jack that quite a response I couldn't ask for more The engine turns over on start "yes" All warning lights on when ignition is turned on "yes" The car is an Auto transmission and the sequence of events were as below car running ok after topping up the LPG at Asda then it cut out. (it had half a tank in it but I cannot pass Asda without a visit After pulling up at the roadside I fit my Diagnostic reader ( that I carry for these occasions) into the socket and got a code 0705 (I think that was the code and I know it relates to the PNP switch) I then cleared it as I didn't know how long this code had been on. I then tried to start the car and it turned over ok but did not start. I then checked for codes and the reader said no codes which I presumed would be because of the add on of the conversion not being recognized by the onboard diagnostic system I had problems with the PNP switch earlier this year (the yellow arrow syndrome) and I stripped the switch down, cleaned and re-greased it and after refitting it had no more problems What I DIDN'T Do was move the selector numerous times to hopfully clear the problem if it is at the PNP switch The AA mechanic was limited because of the LPG system apparently health and safety issues but thought it was some electrical feature common to petrol and LPG I think I know what your response is going to be (replace PNP switch) but await your info with interest Thanks Paul

Dec 28th, 2010, 20:59	#4
capt jack VOC Member Last Online: Apr 20th, 2024 18:56 Join Date: Jun 2006 Location: Selby, North Yorkshire	That Asda at Monk's Cross by any chance? I think that the likely culprit is the PNP switch. It would be really bizarre for both fuel systems to fail at once! I think partsforvolvo have new switches for around £60, or about double that from Chapmans. Hope you get it sorted quickly. cheers Jack

Dec 28th, 2010, 21:45	#5
Paul-C Member Last Online: Apr 8th, 2024 16:24 Join Date: Jan 2006 Location: Riccall Nr. York	Asda at Monks cross York is the one, where ever i'm bound I always end up there. Jack, can the PNP switch `fault' whilst in "drive mode"? as my thinking was that a fault would occur when moving the selector not whilst driving and the selector not in use. Having said that it is a fault that would give the car the symptoms it has. First thing tomorrow I will be at the garage where the car is (ELvington) and try moving the selector to clear the fault then I will replace the switch as soon as I can Thanks for your help Paul

Dec 29th, 2010, 14:10	#6
capt jack VOC Member Last Online: Apr 20th, 2024 18:56 Join Date: Jun 2006 Location: Selby, North Yorkshire	Been up to Asda this very morning myself Paul! With regard to the point at which the switch failed, I guess that anything is possible. You'll only know for sure one way. If the switch has broken even moving the selector back and forth a few times won't fix it, but it's certainly worth a shot. Hope you get it sorted Cheers Jack

Dec 29th, 2010, 16:02	#7
Paul-C Member Last Online: Apr 8th, 2024 16:24 Join Date: Jan 2006 Location: Riccall Nr. York	Jack, I went to the car this morning (at Elvington) and played around with the gear selector to try and "change" the situation if it's there.This was to no avail. I rang Parts for Volvo's and they are not at work yet (£55 online price 3/4 days del. when they start up) Chapmans were open and are getting me one (here tomorrow £120) but it's not mine until I take it out of the packaging, so I have something, at a price. Steve Gledall (mechanic) is not at work until next Tuesday apparently so I have placed a thread on the 900 section to see what other idea's there are. One question Jack, is it possible to diagnose the switch being good or bad without changing the switch? I'm tempted to go to the car with my trolley jacks and change the switch before the weeks out as I know the access to the switch will be reasonably easy. The switch was off the car about a month ago when the oil seal was changed on the same shaft the switch sits on Thanks Paul

Dec 29th, 2010, 18:18	#8
capt jack VOC Member Last Online: Apr 20th, 2024 18:56 Join Date: Jun 2006 Location: Selby, North Yorkshire	Phew! Is it possible to confirm the diagnosis of a faulty switch without taking things apart? Hmmm. Well thinking about what the PNP switch does as it opens and closes circuits, I guess it should be possible to confirm what's happening electrically at each stage, but it'd probably be quicker and cheaper to swap the old for a known working switch. One thought is bothering me, my V70 is an auto too, but when the gear selector is in a 'non-starting' position, ie: R, D, 3, 2 or L, then the starter won't operate at all. What puzzles me is that your engine will turn over. In other words, the PNP switch prevents starting at the wrong time by in effect switching off the starter motor, but clearly, this isn't the case here. Thinking about it some more I'm less convinced that the PNP switch is necessarily at fault. You mention in the other thread that you've removed the battery to re-charge it. Certainly a dodgy battery will cause the car not to start, even though the motor will turn over, but I'd have assumed that the AA man will have checked the condition of the battery? Apart from a lack of fuel, and discounting timing belt failure, the only other possibilities are electrical / ignition or an immobiliser fault. I guess the other possibility is that the car's petrol ECU thinks that it's running on gas, but that there is a gas problem. Could you disable the LPG system completely by removing it's fuse I wonder? This might stop the LPG ECU telling the petrol ECU not to work! Before committing to a new PNP switch, is there any chance you could get the AA back to the car, on the basis that the garage they've taken you to can't fix it? If at all possible and the AA will help out, could you get the car to Dyrdal's in Fulford? Sorry I haven't a definitive answer for you. I do suspect the PNP switch, but I'm not 100% certain. Cheers Jack

Dec 29th, 2010, 20:20	#9
Paul-C Member Last Online: Apr 8th, 2024 16:24 Join Date: Jan 2006 Location: Riccall Nr. York	Jack, I didn't try the car with the selector in any other position than `N' or `P' but normally it needs to be in either of the above to start The battery was well charged before the problem but because of trying to start the engine during this period, and because the car is stood outside the garage until next week I thought I would re-charge it. I was thinking that the fault, probably being electrical, could be connected to both fuel systems that's why I brought it to this garage as the LPG conversion on the car was done here. You mention Dyrdal's because they are Volvo people I presume but it's one of those situations that until the fault shows it's a guessing game. Thanks Paul

Dec 29th, 2010, 21:23	#10
ddahaa Junior Member Last Online: Jul 12th, 2011 16:40 Join Date: Oct 2006 Location: Durham	Doesn't sound like the pnp switch at all to me due to the engine turning over, though I would think you could short out the connectors on it to prove the point. I would be thinking more along the lines of crank or camshaft sensor stopping the sparks. Can you remove a plug and turn the engine over to see if you are getting a spark?

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