hodge Posted June 1, 2011 Share Posted June 1, 2011 Hey The car has developed a backfire. It all began when the water temp sensor became brittle and broke causing the car to overfuel horrendously. I drove the car maybe 1/2 mile max but not at anytime did the Defi temp gauge go above 92 degrees. I found the damaged connector and replaced it. Now on start up the car backfires before it starts and not splutters but sounds like a machine gun if I increase the revs and hold them with the pedal. When Ryan was up last Wednesday we seemed to think there is an issue with my injectors. Maybe not the underlining problem but a contributing factor as there not responding as they should. I've also checked the cam timing ETC and it's all fine. Any thoughts on what could be wrong. I've already done a compression test and all cylinders were 175 psi. Ryan mentioned a leak down test also but I just wanted some of your input into what could be causing this. Thanks John Quote Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted June 1, 2011 Share Posted June 1, 2011 your not low on fuel are you mate ? we have seen this with big HP cars when low on fuel.. (excat same issues) (sometimes the fuel gauge or sender has been faulty) stick £10 in and try it. Quote Link to comment Share on other sites More sharing options...
Lude Posted June 1, 2011 Share Posted June 1, 2011 the sparg plugs wet with fuel? Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 I've got a quarter of a tank of fuel. I'm not sure if I have an exhaust valve stuck open or not shutting correctly. Quote Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted June 1, 2011 Share Posted June 1, 2011 I've got a quarter of a tank of fuel. I'm not sure if I have an exhaust valve stuck open or not shutting correctly. stick some fuel in mate, we have had cars in past with faulty senders saying qaurter tanks half tanks.. try it. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 I'll give it a go bud but I just put 30 quid in the other day. Quote Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted June 1, 2011 Share Posted June 1, 2011 I'll give it a go bud but I just put 30 quid in the other day. we had a single turbo do that, it sounded like a machine gun going off lol said it had plenty of fuel.. but sender was wrong Quote Link to comment Share on other sites More sharing options...
suprafan72 Posted June 1, 2011 Share Posted June 1, 2011 I'll give it a go bud but I just put 30 quid in the other day. Whats your fuel pressure John on Static Idle? Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 we had a single turbo do that, it sounded like a machine gun going off lol said it had plenty of fuel.. but sender was wrong It's certainly worth a try mate that's for sure. Quote Link to comment Share on other sites More sharing options...
suprafan72 Posted June 1, 2011 Share Posted June 1, 2011 I notice when mine goes very low on fuel my fuel pressure started to go allot lower and it sounded kind of rough too. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 Whats your fuel pressure John on Static Idle? 2 bar Andy. Ryan said that would be fine for now. I have tried raised and lowered pressure though but with no effect at all. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 I notice when mine goes very low on fuel my fuel pressure started to go allot lower and it sounded kind of rough too. Mate is sounds horrendous. Even on cold start it backfires which is why I'm swaying towards an exhaust valve. Quote Link to comment Share on other sites More sharing options...
aman00123 Posted June 1, 2011 Share Posted June 1, 2011 Tried the fuel mate? If not whats the afr gauge showing? Other than that it could be sticky intake or exhaust valves? Might be the fuel pressure is too low? Possibly timing? Taken from wikipedia: "When starting an engine, timing that is too advanced will fire the spark plug before the intake valve is closed. The flame front will travel back in to the intake manifold, igniting all of that air and fuel as well. The resulting explosion then travels out of the carburetor and air cleaner. A common air filter will allow the gases to escape, but will block the flame front" Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 Tried the fuel mate? If not whats the afr gauge showing? Other than that it could be sticky intake or exhaust valves? Might be the fuel pressure is too low? Possibly timing? Taken from wikipedia: "When starting an engine, timing that is too advanced will fire the spark plug before the intake valve is closed. The flame front will travel back in to the intake manifold, igniting all of that air and fuel as well. The resulting explosion then travels out of the carburetor and air cleaner. A common air filter will allow the gases to escape, but will block the flame front" Ignition and cam timing is both spot on, whilst Ryan was here we checked and double checked both of these. He also ssid the fuel pressure was fine. I really am in 2 minds wether to just pull the head off and have a look. Will only take me a couple of hours. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 I'm hoping chris Wilson see the thread. I'd be interested in his input on it. Quote Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted June 1, 2011 Share Posted June 1, 2011 It's certainly worth a try mate that's for sure. please try it before you pull head off.. single turbos with no fuel in my experience have had symptons like yours. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 Michel Lane is kindly lending me a leakdown tester so I can confirm either way wether the head needs to come off or not. He has also offered to lend me parts from his white monster so I can narrow down what has actuallly gone wrong. Thanks mate, I owe you a big favour. Quote Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted June 1, 2011 Share Posted June 1, 2011 have you tried the fuel ? its sounds crazy but it has worked in past Quote Link to comment Share on other sites More sharing options...
aman00123 Posted June 1, 2011 Share Posted June 1, 2011 Hopefully it's a reasonably quick fix mate, let us know what is was when you find out though Quote Link to comment Share on other sites More sharing options...
Robzki Posted June 1, 2011 Share Posted June 1, 2011 Not sure if anyone has mentioned, but are you low on fuel? Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 have you tried the fuel ? its sounds crazy but it has worked in past I've got the injectors and fuel rail out at the min mate. I've ordered a set of ID1000s but there going to take 2 weeks to arrive. Michel Lane said I can try his rail and injectors so that's the 1st port of call I think, as well as the leakdown test as that only takes a few mins and will put my mind at rest. I'll bung some more fuel in before I fire it up but I'm sure there is atleast a 1/4 of a tank in easy. Hopefully it's a reasonably quick fix mate, let us know what is was when you find out though Certainly will bud. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 1, 2011 Author Share Posted June 1, 2011 I just think it's all too much of a coincidence with this water temp sensor issue. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 2, 2011 Share Posted June 2, 2011 I would put a set of NEW plugs in it, after having spun it over perhaps 20 times with the fuel pump disconnected, all the old plugs out, and the throttle held wide open. I think the plugs have fouled due to the mad rich mixture before. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 2, 2011 Author Share Posted June 2, 2011 I would put a set of NEW plugs in it, after having spun it over perhaps 20 times with the fuel pump disconnected, all the old plugs out, and the throttle held wide open. I think the plugs have fouled due to the mad rich mixture before. I was hoping you'd reply Chris. Do you think there could have Bern any damage inside the engine due to this. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 2, 2011 Share Posted June 2, 2011 Nah, try some plugs first, should be fine. Check all hoses if it backfired through the intake though, in case it's blown anything off, or loose. Quote Link to comment Share on other sites More sharing options...
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