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The mkiv Supra Owners Club

Running issue NA-TT


listy

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Right then, finally I have the supra back from the bodyshop! I've just been out, bridged B+ and FP. I'm guessing at this point I should hear a whir from the fuel pump? All I'm hearing is a very feint high pitched "buzz" (for lack of a better word), like a current is there but it's not doing anything.

 

From this lack of "fuel pump operating" noise I'm guessing the pump is at fault.

 

Input appreciated

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I removed everything from the boot down to where the spare wheel goes. The noise is definitely from the fuel tank area (so must be the pump) and is only a very feint high pitched "buzz". I definitely wouldn't describe it as a droning noise. I'd record it, but I don't think anything would pick it up its that quiet.

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Just squirt some Easy Start or petrol in a hand sprayer into the throttle body with the throttle held wide open, then crank it and see if it fires up for a few seconds. if it does you have no fuel from the injectors. For whatever reason. Slacken the banjo bolt on the front of the fuel filter a couple of turns. Fuel may leak out, but with the ignition turned ON and engine cranked it should gush out for a few seconds until the ecu sees a no start condition. 5 minutes to do both tests... Nothing trick required.

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You mean it runs for 10 seconds without spraying fuel in externally? if so the ecu may not be getting a run signal and is shutting the pump off. If you do the FP to B+ jumper it should continue running as you are feeding the pump power directly. Does it?

 

It starts whether FP and B+ Are bridged or not. Bridging them makes no difference. No external fuel added.

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I would suspect the pump or feedback to the ecu to tell it the engine is running. But I think bridging B+ and FP should bypass that stuff. Not 100% on that... Probably 90% sure though!

 

An 044 takes more current than the stock tank top plate connector is happy with, the terminals tend to overheat. Just put a (genuine...) Walbro in it if you want to keep it simple. I have plenty of known good stock pumps.

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Right, fuel pump changed. If I bridge fp and b+ I can now hear it working. So the last pump imo was dead. So, good call there.

However, now she won't start at all. She tries, I even get a slight rumble like she's going to burst in to life, but no joy. I've been trying for quite a while now.

I know the fuel system needs to repressurise, but I have no idea how long that should take.

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I'd get them blasted or put new ones in myself.

 

The plugs have only done about 1000 miles.

 

Took the plugs out, gave them a clean, put back in. Coil pack clips are fine. No joy.

 

If I remember rightly, when you take the fuel cap off there is usually a little "pish" sound due to the pressure of the tank. I took the cap off to see if there was any pressure but it was silent. So unless I'm mistaken it looks like I'm not getting fuel pressure. Pump is coming online when bridging FP and B+. It tries to start, but doesn't doesn't. As in, it it seems to be getting ignition but doesn't keep running afterwards. I also tried starting it with the diag pins bridged to counter the feedback to the Ecu but same result.

Still no error codes logged either, so that's no help.

 

Is there a special way to build up the fuel pressure?

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Hmmmm. It was keeping pressure before I did the pump, as it started and ran for a few seconds, so if it doesn't gain and keep pressure now, it must surely be due to something I've done when changing the pump. I'll go over what I did with the pump replacement again and see if I can find why there is no pressure. Maybe I didn't do something up enough.

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Just had a thought.....the big plastic ring which sits over/around the FP assembly. I didn't want to over tighten it because I didn't want to damage it. I'm thinking maybe I didn't tighten it enough, so the seal hasn't been made. Most obvious thing I can think of. When I get a spare half hour or so I'll have a look.

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Just had a thought.....the big plastic ring which sits over/around the FP assembly. I didn't want to over tighten it because I didn't want to damage it. I'm thinking maybe I didn't tighten it enough, so the seal hasn't been made. Most obvious thing I can think of. When I get a spare half hour or so I'll have a look.

 

I don't think the pressure in the tank matters that much to be honest, you can run your car quite happily with the fuel cap open so I doubt that's the issue.

 

You need to check for fuel and spark, take it right back to the basics. Is there noone local who can help you out? It really is getting to the point where you need to take it to someone who knows their way around these checks.

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I don't think the pressure in the tank matters that much to be honest, you can run your car quite happily with the fuel cap open so I doubt that's the issue.

 

You need to check for fuel and spark, take it right back to the basics. Is there noone local who can help you out? It really is getting to the point where you need to take it to someone who knows their way around these checks.

 

You may be right there Scott. I'll go over the pump fitting again anyway, as there may just be something I've done wrong. I don't want to transport it to a garage and find out I've made a silly mistake.

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