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PostPosted: Thu Nov 30, 2006 10:23 am 
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Joined: Wed Nov 29, 2006 9:19 pm
Posts: 34
Hello all, first post and would appreciate some help. I have Zavoli multipoint injector system on a thor 4.0 v8, with new o2 sensors and new temp sensors on engine and vaporisor, engine only done 7,000 miles. When system new no problem but after 3-4 wks changeover degraded until not changing until warm at which point changover perfect. When new engine fitted perfect for 3-4 wks and once again degraded. If stood when warm for twenty mins changeover will be fine or when driven for 10-15 miles. Any help would be just brilliant. <BR> <BR> Cheers Nick


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PostPosted: Fri Dec 01, 2006 12:00 pm 
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Joined: Wed Nov 29, 2006 9:19 pm
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Ello again. <BR> Have just tried warming injectors with warm air for about 15 mins, car starts on petrol fine and then changes to gas with no trouble!! Does this mean that my injectors are all gummed up even though all the filters are in place? <BR> <BR> Cheers Nick


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PostPosted: Sun Dec 03, 2006 5:39 pm 
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Joined: Fri Oct 21, 2005 7:56 pm
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Location: North Wales
You could try cleaning the injectors with carb cleaner or similare. Have you beem back to the installer?

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PostPosted: Sun Dec 03, 2006 6:35 pm 
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Check your coolant level first,if you have an air lock it will cause this problem. <BR>Also drive the car and when it should have changed over , just check the temp of the reducer by hand,you will now which way to go. <BR>Cheers Keith

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PostPosted: Mon Dec 04, 2006 11:06 am 
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Joined: Wed Nov 29, 2006 9:19 pm
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Back again, <BR> Yep, been back to the installer who has been great. However went to London and on the way down it kept turning the gas off and reverting back to petrol. When i got back i took the inlet manifold off and guess what i found, when i put my lovely new engine in i rather cleverly pinched the gas supply pressure sensor pipe between the injector rail and the inlet manifold (DOH!!)and as it uses inlet vacumn against gas pressure it did not have much of a chance did it. So tomorrow i'm putting it all back together and i wiil let you know how it goes. <BR> Thaks to everyone who had a thought. <BR> <BR>Cheers Nick.


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PostPosted: Mon Dec 04, 2006 11:09 am 
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P.S, I'm having the injector's cleaned while they are off the car. <BR> <BR> Cheers Nick.


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PostPosted: Tue Dec 05, 2006 12:50 am 
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Joined: Thu Dec 08, 2005 12:00 pm
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Nick how would the temp affect this problem?? <BR> <BR>If the Vac line was piched & stopping suction why would heating the injectors alleviate this??


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PostPosted: Tue Dec 05, 2006 12:51 am 
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Joined: Thu Dec 08, 2005 12:00 pm
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Nick how would the temp affect this problem?? <BR> <BR>If the Vac line was pinched & stopping suction why would heating the injectors alleviate this??


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PostPosted: Tue Dec 05, 2006 5:33 pm 
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Joined: Sun Feb 19, 2006 12:00 pm
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That aside, I'd still be looking very hard at coolant level/temp/leaks and particularly the theromostat (likely to be a Summer 82 degree item). <BR> <BR>Also do not ignore Keith's advice on airlocking, your description reads like a textbook case of this or perhaps a coolant leak, especialy as your system has been disturbed once or twice and then topped up. The topping up could be masking a leak. <BR> <BR>Bleed any air out of coolant at the vaporiser outlet with the engine running. You may have have the vap. loose and rotate it so the air goes to the top, depending on how it is mounted. <BR> <BR>I am seriously thinking of having some nice bleed valves made up to place in the vaporiser coolant exit line (inline) to make this easier to do (unless anyone can point me in the direction of someone who can supply them?) <BR> <BR>Conversions that involve a relatively high vap. position are quite prone to vap. airlock.


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PostPosted: Tue Dec 05, 2006 5:46 pm 
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Joined: Thu Jan 12, 2006 12:00 pm
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Location: essex
Steve, Snap on do a new bit of kit for bleeding cooling systems, i think i paid about £80 or so, <BR>hav'nt had a chance to try it yet though. <BR> <BR>ATB Keith

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PostPosted: Wed Dec 06, 2006 7:27 am 
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Joined: Wed Nov 29, 2006 9:19 pm
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Hello, the pressure sensor comes off the end of the injector rail, so i'm thinking that the warmer pipe coupled with heated gas would allow the gas through. The temp sensor on the vaporiser is positioned at the top so's i can let as much off the air out as poss.


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PostPosted: Wed Dec 06, 2006 8:04 am 
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Joined: Sun Feb 19, 2006 12:00 pm
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Can't speak for Zavoli. Although our vaporisers have their temp. sensor at the top it would not allow you to use this as a bleed point - The hole is blind, the sensor measures the temp. of the metal casing, not the coolant. This is a wise move as one potential leak has been removed. <BR> <BR>Keith, that sounds useful but I was thinking more in terms of an in-line valve to fit in the out hose from the vap. The plan is to fit one to every conversion with a high vaporiser. Metros and Renault 5's always had an in-line bleed valve on the heater outlet but it is part of the hose proper, I'd like to make up a double ended unit (much like a 'power' valve) so the hose can be cut, the valve fitting inline. <BR> <BR>This would help those with leaking systems, most common being the BMW V8's. These often have a cracked header tank on the rad (a stress fracture), a leaking header tank (at the seam) or a leaking (hidden) water pump. If the owner or service garage could bleed out the air after replacing lost coolant ther would be less reason for owners to think that the 'Gas system is at fault'...... <BR> <BR>Regards <BR> <BR>Steve <BR> <BR><a href="http://www.go-lpg.co.uk" target=_top>www.go-lpg.co.uk</a>


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PostPosted: Wed Dec 06, 2006 10:18 am 
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Joined: Wed Nov 29, 2006 9:19 pm
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Hello all. <BR> Used to have a Renault 5 with that bleed valve in, but then Renault always had good idea's. <BR> The temp sensor is not blind as i have used it in conjuntion with lifting the expansion tank higher than the rest of the system and bleeding out of the top of the vaporisor which is the next highest point. I know the that it is not foolproof (never underestimate a fool, they've had all their life to practice.) but i also use a pressure tester on the coolant system. When the new engine went in it had a new rad, thermostat and hotspot, plus various hoses ( "While its in bits..." as they say.) Since its been in its had new temp senders (gas and petrol) and never fails to run beuatifully on petrol. It loses no water that i can see and when checked never needs topping up!!!!!!!! Now where's that box of matches. <BR> It does appear that the gas system is not recieving the right info. But i'm going to put it back together and see where we get to. <BR> Please keep sending your ideas as i'm not selling the vehicle and do like it very much so fixing it is the only option. <BR> <BR> Cheers Nick


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PostPosted: Sun Dec 10, 2006 9:38 am 
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Joined: Sun Feb 19, 2006 12:00 pm
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I did see a 4.2 V8 Range that lost coolant with no leaks evident. <BR> <BR>The cause turned out to be a cracked cylinder liner, the coolant being exhausted. Apparently 4.2's and 3.9's are well known for this as they have been overbored and crack the liner easily. <BR> <BR>But if it never needs topping up, it is unlikely that this is happening.....


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PostPosted: Tue Dec 12, 2006 9:06 pm 
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Joined: Wed Nov 29, 2006 9:19 pm
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Good evening all. <BR> Mine was losing coolant through a perforated liner, which is why i put the new engine in. <BR> I put it all back together having sent the injectors back to the supplier for a clean, those little pipes off the injector rails to the injectors are blimmin fiddly!!!!Reset the petrol map, parked up over night to make sure it was good and cold and started it the next morning. Useless!! I have checked the water system and i can't get any more water in it, there is gas in all the right places and the sensors are sending their info. I'm told by the supplier that if they are not working it won't try to change over? <BR> So today i borrowed a new vaporiser and put that on. Reset the petrol map again in the worst M5, J3 traffic i've ever been in, (1HR 20mins = 14.8 miles) and it's not going on gas until it's been back to the supplier on Thursday night so's he can have it from cold (again) on Friday. Incidently, It is always perfect on petrol and having run it for a fortnight on petrol (ARGHHHHHH) it presented no problems. <BR> As usual any thoughts greatly appreciated. I will let you know what happens on Friday when it has it's new gas ecu. <BR> <BR> Cheers Nick


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