AhHa!
It would help if I had called the valve thing by the right name! Fuel check valve - not hot start valve!
here you go:
http://forums.tipec.net/viewtopic.php?f=25&t=15176&hilit=fuel+check+valve
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| poor starting when hot https://forums.tipec.net/viewtopic.php?f=25&t=19290 |
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| Author: | HUBBA.HUBBA [ Sat Feb 07, 2015 7:04 pm ] |
| Post subject: | poor starting when hot |
944 s2, starts fine when cold, but when I go for a spin and turn the engine off for about 10 mins, come back to it and the starter spins fine. But it takes more turns to get it going ( and didn't start at all at one stage). Had a look a air filter (k&n) and one end was dirtier the other so I just span it round for now. I also checked the plugs, which are the right colour.Insidently there was what looked like a piece of rubber stuck round one of the plugs which I assumed was a part of a spark plug socket that someone had left on a previous plug change. I suspected that this was not letting the ht lead sit properly on the plug. After a test drive the car runs much better and feels at full power. But still hard to start when hot. Any ideas anyone? On another note there was oil down the bores on top of plugs 1 and 4, could that be a leaky cover gasket or something and the oil is dripping down onto them? Cheers |
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| Author: | timmyturtle [ Sat Feb 07, 2015 7:25 pm ] |
| Post subject: | Re: poor starting when hot |
Oil most likely the cam cover middle gaskets leaking |
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| Author: | robmal [ Sat Feb 07, 2015 8:20 pm ] |
| Post subject: | Re: poor starting when hot |
My money is on the hot-start valve on the fuel pump starting to weep and not holding fuel under pressure. I have the same problem and am putting off repair whilst is so cold and wet outside.... Do a search and you will see that Jon described a while back how fuel under pressure will not evaporate as quickly as at the lower pressure that occurs when the valve leaks fuel back by the return pipe. Because it has evaporated due to a hot engine when you come back then ten minutes later it takes longer to drag fuel back up. If its only five minutes since you last switched off then evaporation hasn't taken it all away and the car starts. Of course the problem is even worse on a hot summers day. Well that's my understanding of it all anyway Cheers Rob |
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| Author: | HUBBA.HUBBA [ Sat Feb 07, 2015 9:56 pm ] |
| Post subject: | Re: poor starting when hot |
timmyturtle wrote: Oil most likely the cam cover middle gaskets leaking Sounds simple enough. I'll have another look in a couple of weeks to see if the oil is back. Cheers |
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| Author: | HUBBA.HUBBA [ Sat Feb 07, 2015 10:00 pm ] |
| Post subject: | Re: poor starting when hot |
Trying to find it, but no joy. What are the best ways to find it? robmal wrote: My money is on the hot-start valve on the fuel pump starting to weep and not holding fuel under pressure. I have the same problem and am putting off repair whilst is so cold and wet outside....
Do a search and you will see that Jon described a while back how fuel under pressure will not evaporate as quickly as at the lower pressure that occurs when the valve leaks fuel back by the return pipe. Because it has evaporated due to a hot engine when you come back then ten minutes later it takes longer to drag fuel back up. If its only five minutes since you last switched off then evaporation hasn't taken it all away and the car starts. Of course the problem is even worse on a hot summers day. Well that's my understanding of it all anyway Cheers Rob |
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| Author: | robmal [ Sun Feb 08, 2015 7:29 am ] |
| Post subject: | Re: poor starting when hot |
AhHa! It would help if I had called the valve thing by the right name! Fuel check valve - not hot start valve! here you go: http://forums.tipec.net/viewtopic.php?f=25&t=15176&hilit=fuel+check+valve
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| Author: | HUBBA.HUBBA [ Sun Feb 08, 2015 8:57 am ] |
| Post subject: | Re: poor starting when hot |
Could it be a DME relay? sounds as if you should always carry a spare by the sounds of things. The Clarkes Garage site is very informative, v impressed. |
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| Author: | WazzerM [ Sun Feb 08, 2015 10:30 am ] |
| Post subject: | Re: poor starting when hot |
Someone in the know told me that hot start problems can be battery related. Try a different (new) battery? (long shot from someone who knows little). |
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| Author: | HUBBA.HUBBA [ Sun Feb 08, 2015 7:07 pm ] |
| Post subject: | Re: poor starting when hot |
WazzerM wrote: Someone in the know told me that hot start problems can be battery related. Try a different (new) battery? (long shot from someone who knows little). Battery is pretty new and it has an indicator on the top to show if it needs charge. Just resoldered the dme relay, so I'll see if that makes any difference. The only thing is the dme relay didnt look old and looks in good condition |
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| Author: | blackadder30 [ Sun Feb 08, 2015 10:49 pm ] |
| Post subject: | Re: poor starting when hot |
I understand the DME Relay can be affected by heat whether new or old.... although a 10min run shouldnt get that area too hot... the Clarkes Garage emergency fix using a jumper cable between 30, 87 and 87b could tell you if its the relay or not. It hot starts using the jumper, its likely a relay problem. If not, the relay is fine.... Have just used this on my 968 in sorting problems on my own DME Relay electrical gremlin. Hope this helps. Good luck!! |
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| Author: | HUBBA.HUBBA [ Mon Feb 09, 2015 6:39 pm ] |
| Post subject: | Re: poor starting when hot |
Well the soldering hasnt worked. Will try the emergency jumper wiring tomorrow. blackadder30 wrote: I understand the DME Relay can be affected by heat whether new or old.... although a 10min run shouldnt get that area too hot... the Clarkes Garage emergency fix using a jumper cable between 30, 87 and 87b could tell you if its the relay or not. It hot starts using the jumper, its likely a relay problem. If not, the relay is fine....
Have just used this on my 968 in sorting problems on my own DME Relay electrical gremlin. Hope this helps. Good luck!! |
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| Author: | HUBBA.HUBBA [ Tue Feb 10, 2015 7:12 pm ] |
| Post subject: | Re: poor starting when hot |
Tried the Clarks Garage method of the emergency jumper and still no difference, when the pump energized I could hear fuel in the fuel rail. I does start, just not very well. when it does start, it labours and clings on at about 500 rpm (for 10 seconds) and gradually comes round to normal idle. If I blip the throttle it nearly dies. Suppose thinking about it, sounds a bit fuel starvation related. Does anyone know if the check valve on the pump is available to buy on its own? Any opinions gratefully received. Cheers HUBBA.HUBBA wrote: Well the soldering hasnt worked. Will try the emergency jumper wiring tomorrow.
blackadder30 wrote: I understand the DME Relay can be affected by heat whether new or old.... although a 10min run shouldnt get that area too hot... the Clarkes Garage emergency fix using a jumper cable between 30, 87 and 87b could tell you if its the relay or not. It hot starts using the jumper, its likely a relay problem. If not, the relay is fine.... Have just used this on my 968 in sorting problems on my own DME Relay electrical gremlin. Hope this helps. Good luck!! |
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| Author: | HUBBA.HUBBA [ Fri Feb 27, 2015 4:26 pm ] |
| Post subject: | Re: poor starting when hot |
Well, I've tested the check valve on the fuel pump by crimping the fuel line next to it on the outsise of the casing near the filter, Attachment: 20150227_143100.jpg just after turning the engine off. Low and behold after waiting 10mins it started up as if it was cold. So I'm looking to clean up the check valve. Before I tackle that the state on the banjo and bolt don't look the best Attachment: 20150227_143012.jpg Is it best to replace the banjo and pipe to the filter, as they probably wont reseal very well or is it a case for just using new copper washers. Any advice much appreciated. Suppose I could actually change the filter whilst im down there!? |
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| Author: | russmw [ Fri Feb 27, 2015 6:33 pm ] |
| Post subject: | Re: poor starting when hot |
When I replaced the pump on my 924 the banjo end looked more or less the same but after a quick bit of sandpaper action it turned out to be mostly surface rust. I painted them, put new washers on and it was fine. More importantly I kept the one way valve of the old pump (long story but I kind of broke the pump) and the valve was fine. Let me know if it would be of use? Thanks |
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| Author: | HUBBA.HUBBA [ Fri Feb 27, 2015 7:01 pm ] |
| Post subject: | Re: poor starting when hot |
russmw wrote: When I replaced the pump on my 924 the banjo end looked more or less the same but after a quick bit of sandpaper action it turned out to be mostly surface rust. I painted them, put new washers on and it was fine. More importantly I kept the one way valve of the old pump (long story but I kind of broke the pump) and the valve was fine. Let me know if it would be of use? Thanks Ok cheers, I let you know. Is that the check valve, the silver bit he banjo goes onto? Also, any idea what size the washers are? |
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