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Jun 21, 2017 14:01:24 GMT
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As title currently have a old sapphire Cosworth I'm putting back on the road after a long layup (7yrs) The fault is that it currently idles fine and runs perfectly well But as soon as you prod the accelerator it dies and won't rev or cuts out ?? If you gently ease the accelerator it will rev and clear higher up rev range after nursing it to begin with Really beginning to puzzle me now Anyway that's the issue I have will now give a rundown on what's been changed and done so far as I'm thinking it's a fuel related issue or possibly weak spark ?? Engine is fully rebuilt not even ran in yet , Timing is spot on ,no air leaks and everything as should be Have tested the seperste engine loom for tolerances along with all sensors as per the book This includes Map sensor Act sensor Ecu temp sensor Ignition amp Coil Crank sensor Phase sensor Tps sensor Have also swapped out the majority of sensors with no change It's had a new fuel pump fitted and voltage checked whilst running and showing a healthy 12.3 v under load Also changed the fuel pressure regulator for a known working one which strangely made the fault worse Injectors are clean as is the air filter too and fuel filter Fuel return is free and not blocked either Ecu itself is also fine as tested that on a mates car no problems Really beginning to puzzle me now and at a loss Anyone throw some fresh light on it for me please ??
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froggy
Posted a lot
Posts: 1,099
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Jun 21, 2017 19:32:22 GMT
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Checked fuel pressure with a guage ?
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Jun 21, 2017 19:39:22 GMT
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Could it be something as simple as bad plugs / wrong grade?
Would they need to be a different grade from standard because of the mods etc?
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Jun 21, 2017 19:43:04 GMT
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Fuel pressure is fine according to tester Running the std 3.5 bar with vac pipe off on idle ? Plugs are fresh and the correct standard plugs which ironically are better than do called uprated plugs
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ben-dover
Part of things
You can't polish a turd, but you can roll it in glitter...
Posts: 360
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Jun 21, 2017 20:52:04 GMT
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This is screaming fuel starvation to me. Have you got 12v at the injectors?
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ben-dover
Part of things
You can't polish a turd, but you can roll it in glitter...
Posts: 360
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Jun 21, 2017 20:52:42 GMT
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Tried a throttle position sensor?
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Jun 21, 2017 20:58:47 GMT
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Hopefully I don't insult your intelligence here but... The fuel isn't 7 years old is it?
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Al.
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Jun 21, 2017 21:01:02 GMT
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I had the same with two Mitsubishi Starions that had been laid up for years. The fuel pump just didn't cut it, it wasn't enough umph for the injectors. Have you checked if the tank isn't half full of rust? It may block the fuel filter and possibly injectors.
I also had the same with an MGF and a Metro GTi, it was the rotor arm.
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Jun 21, 2017 21:08:36 GMT
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This is screaming fuel starvation to me. Have you got 12v at the injectors? I thought starvation myself but plenty of pressure at the rail and according to fuel pressure gauge , also confirmed by fuel exiting via the return side of fpr to tank Tank has also been removed ,cleaned and refitted and also changed pump and filters too Have had rail out and cranked injectors spray a nice neat and uniform pattern too ?? Also used a noid light to double check injectors are being pulsed correctly which they are Also the fuel is fresh too was empty during layup anyway I'm pretty competent in terms of span wrong but it has me stumped tbh Also checked hoses for boost leaks and the wastegate flap is free and opens shuts correctly Am proper puzzled tbh Also had a nice big spark at the plug end on all 4 leads
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Jun 21, 2017 21:11:03 GMT
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It's a long time since I worked on these, is the phase sensor correctly timed, I seem to remember getting this the wrong side of the crank pulse can cause all sorts of problems, If i remember correctly they run pretty much OK with it unplugged, try unplugging it and see if the issue changes.
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Jun 21, 2017 21:24:56 GMT
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Yeah phase sensor lives in the dizzy and sits on a small bracket with two screws keeping it in place , I've changed that also for a new one as it's what pulses the injector (trigger) It's gapped correctly and also timed up correctly too
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Jun 21, 2017 21:28:45 GMT
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Tps tests as working correctly too as it runs l6 ecu which means it has an idle switch until throttle is pressed I've used multimeter and set it correctly It runs backwards eg sees 4.94 v at idle then with throttle fully open drops to 0.33 v so well within range inc the idle switch which shows open circuit @ idle
Like I say proper stumped and I'm not easily beaten normally
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ben-dover
Part of things
You can't polish a turd, but you can roll it in glitter...
Posts: 360
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Jun 21, 2017 21:48:53 GMT
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when it dies and cuts out, are the plugs wet with fuel or dry?
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ChasR
RR Helper
motivation
Posts: 10,188
Club RR Member Number: 170
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Jun 21, 2017 21:51:23 GMT
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I have a few questions but as you know alot of questions have been answered. It looks on the face of it like all is in order.
What brand of plugs do you have and where did you get them from? If it were me I'd either get NGKs from a known source which are made in Japan (the yellow boxed items) or get genuine Ford plugs ; they are not too horrendously pricey on ebay.
On my Stag I had a similar issue which was down to 3 things. The Coil being bad which oddly was the new item I fitted. The second was down to a few of the new Spark plugs being bad. At full throttle it would begin to backfire at high RPM through the exhaust.
Did you test the fuel pressure while trying to rev the engine? It would be interesting to see if it drops. It sounds like a fuel pressure issue anyway.
Another thing is does the ECU have any form of diagnostic port on it. I know the NA MX-5s had a diagnostic where you could hook up an LED and read the codes out in a primative way as did the 944 Turbos running Bosch Motronic. On the former it came it quite handy.
The only other thing I can think of is that you have the wrong injectors on the car but that is a long shot. What spec is the car and what chip does it have? Are they a match for the injectors?
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Jun 21, 2017 22:14:36 GMT
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Yeah cheers for the input everyone Chip is indeed matched to the injectors ,and all in order too as both were previously used on another car of mine and ran perfectly well for 2 yes until it was removed and drystored I've fried ngk pfr in it and even gone both up and down with the heat range to no affect at all ? Currently using genuine ford original plugs AGP,s Like I say idles fine can even tease it to rev up and seems to clear until you let revs drop or press acc pedal sharply Gonna check the fuel pump relay tomorrow and make sure it's not getting hot and going soft possibly but can't really see it myself tbh ,just grasping at straws now Won't be long before it's a case of gallon of unleaded and box of matches haha Killing me this after spending last 2 yrs building the car and prior to that being off road 5-6 yrs Would have been nice to use it this summer lol
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Jun 21, 2017 22:29:49 GMT
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Oh and fuel reassure stays at constant 3.5 bar as it should do until it sees boost then raises 1psi of pressure for everyone psi of boost afyer atmo ! It also sadly has only the most primitive of diagnostic plug which tbh is about as much use as tits on a fish being an early e reg car
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froggy
Posted a lot
Posts: 1,099
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Jun 21, 2017 23:56:40 GMT
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Id be inclined to try another pump as the symptoms do seem like fuel starvation
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Id be inclined to try another pump as the symptoms do seem like fuel starvation Froggy the pump is the very first thing I changed in all honesty as right from the off I always suspected it was a fuel issue The pump got bit noisy if you know fords you will know how loud they are anyway haha I changed that along with dropping tank and changing filter Even cut old filter up to check how much debris was in it Although naturally there was some clogging it wasn't particularly bad in all honesty , certainly seen much worse on poorly serviced perfectly well running car hahaha It's certainly a strange one and not the first I e put together either !
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rude
Part of things
Posts: 537
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I feel for you man. This is the kind of curse word I deal with all too often. It's a lack of something on demand that's for sure. I'm currently trying to unstick suspected sticky valves in my daily... woop de doo...
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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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Jun 22, 2017 11:02:24 GMT
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^^^^^ Yeah your right wouldn't mind built the thing ground up haha no problems inc building motor although that's fairly easy
Get stuck on something that will be silly ,just wish it was as simple as sticky valves tbh haha
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