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1989 Polo 'breadvan' puzzle
Car starts and runs perefectly normally but stalls randomly at distances from 5 miles to 40 every trip After one hour almost to the minute it wil restart and run normally, until next time Have replaced all ignition electrics except the distributor sender module and the voltage amplifier that's bolted to the bulkhead area. Also fitted new tank, fuel pump and all fuel pipes in the engine bay. The carburretor to manifold rubber washer/gasket was shot and is replaced. Fitted a new temp sender in the radiator even though the temp gauge was and is showing rock solid centre so no overheating with the electric fan running on for a minute or so after a run. No coolant whatever is being lost. On immediate investigation there is always both a healthy spark and petrol spurt from the pump
Couple of questions -
Is the voltage amplifier common electronic circuitry and can be replaced with a non-VW unit if the pinning is respected? (For test purposes - as I'm not up for buying this expensive item onkly to discover it's not at fault) Does anyone have a link to the electric circuit schematicfor the sender and/or the amplifier?
There's a voltage measurement procedure in the workshop manual but doesn't seem relevant to my stalling problem
As I appear to be getting a good supply to the carb is it possible that the float is sticking (Weber TA32) and releases itself after the hour's cooling? Of cdourse I've checked the fuel filter in the cab which was clean anyway. In spite of the engine temperature reading normal on the gauge the ambient temperature in engine bay is terribly high during running and is so hot the fuel pump and distributor body are too hot to touch. If you own a breadvan or coupe, is this normal for the model?
Any advice appreciated
TT
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does it have the standard air cleaner set up? they can suffer badly with carb icing when you have a sports filter
the fan didnt ought to run on after a run in normal cicumstances , bet my fan doesnt come on 3 times a year
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91 golf g60, 89 golf 16v , 88 polo breadvan
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rude
Part of things
Posts: 537
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Don't know man, but immediately in my head came fuel evaporation. Check this report. link
It's all I've got right now. I've had a few... Polos and beers! If you think your engine is getting too hot then you should check that the cooling system is operating correctly from blocked rads to poor thermostats.
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1986 Haunted BMW E24 635CSi 1999 Povo spec BMW E36 1.8i Touring Work Hack 2001 Petrol annihilating Discovery V8 2000 Jaguar S Type 3.0 V6 ~NEW~
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If the fan is running when the car is turned off the fan will continue to run until the switch in the rad senses that the coolant is cool enough. It could be that some one has fitted a low temp fan switch. When the car is running does the fan switch on and off by itself, or does it run constantly once it comes on until you turn the car off?
The fuel pump and dizzy are bolted to the head so it is normal for these to get hot if the engine has been running for a while.
What you describe with it cutting out and restarting fine after it has cooled sounds like you could have an electrical component in the ignition system breaking down. The hall sender in the dizzy can be a bit of a weak point and gives those symptoms when they are on their way out. I've had a fair few go on me over the years and they have always caused the car to cut out be start and run fine once it had cooled down. When the car is refusing to start does it spark still? If so that rules out the hall sender.
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Last Edit: Aug 3, 2017 19:40:34 GMT by roccoguy
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Darkspeed
Club Retro Rides Member
Posts: 4,849
Club RR Member Number: 39
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1989 Polo 1L Breadvan Woes Darkspeed
@darkspeed
Club Retro Rides Member 39
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Check the fuel cut off solenoid on the side of the carb it can create similar symptoms.
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Great fast responses. Apologies for slow reply. First time user - what an active forum! does it have the standard air cleaner set up? they can suffer badly with carb icing when you have a sports filter Ans: Standard filter with those gismo valves ? and pipes
the fan didnt ought to run on after a run in normal cicumstances , bet my fan doesnt come on 3 times a year like Ans: Interesting. Is your climate cold?
Don't know man, but immediately in my head came fuel evaporation. Check this report. Ans: Good prospect, especially as the engine bay seems to get so hot
It's all I've got right now. I've had a few... Polos and beers! If you think your engine is getting too hot then you should check that the cooling system is operating correctly from blocked rads to poor thermostats. Ans: Only thing is that the temp gauge shows normal always - unless it's faulty of course
Aug 3, 2017 at 8:38pm QuotePost Options Post by roccoguy on Aug 3, 2017 at 8:38pm If the fan is running when the car is turned off the fan will continue to run until the switch in the rad senses that the coolant is cool enough. It could be that some one has fitted a low temp fan switch. When the car is running does the fan switch on and off by itself, or does it run constantly once it comes on until you turn the car off? Ans: The switch is brand new from a reliable co. and correct part no. It only runs intermittently eg. when waiting at traffic lights etc or in heavy traffic but temp gauge always normal. It runs very briefly after parking up
The fuel pump and dizzy are bolted to the head so it is normal for these to get hot if the engine has been running for a while. Ans: Logical
What you describe with it cutting out and restarting fine after it has cooled sounds like you could have an electrical component in the ignition system breaking down. The hall sender in the dizzy can be a bit of a weak point and gives those symptoms when they are on their way out. I've had a fair few go on me over the years and they have always caused the car to cut out be start and run fine once it had cooled down. When the car is refusing to start does it spark still? If so that rules out the hall sender. Ans: Yes these two are top of my suspect list on account of the distributor body heat. I suspect this sender is solid state/transistor based with an upper heat limit. So I'd better bite the bullet and substitute them. (I have a running scrapper so maybe swap the dizzy first and then the amplifier) I can probably buy a re-manufactured guaranteed dizzy for less than a new sender! I'll have to check again re spark after stalling. I'm always alone at that time and the starter solenoid is quite inaccesible for hooking on a jumper but I'll give it another go
Aug 3, 2017 at 9:07pm QuotePost Options Post by Darkspeed on Aug 3, 2017 at 9:07pm Check the fuel cut off solenoid on the side of the carb it can create similar symptoms. Ans: Wil do. Only thing I've done with this is to disconnect/connect the wire and noted the click which sound normal TT
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Sept 1, 2017 21:58:20 GMT
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Thanks again roccoguy for Hall sender tip As i've been using another car of late I really haven't done enough to road test the swaps I've made of used components. In the meantime a friend has given me a brand new Polo distributor he no longer needs (sold his car). It looks physically identical in every respect to mine EXCEPT that the new one does not have the vacuum advance/retard mechanism (diaphragm?) Questions are: 1 Assuming that it's otherwise a match electrically and physically will the car run badly without the vacuum? 2 If this distr is for a later Polo or the 1.3L how do these later cars function without the vacuum mech? 3 The external connxn to the Hall effect sender module looks identical too and if true could I swap in the new module into my distr for my old one? Many thanks TT
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