Been struggling to get the zx10 started.
Have a spark and decent fuel pressure but the fuel isn't getting through. Can't smell it from the inlet.

Possible causes are, I haven't done anything with the clutch wire (red/green) should I earth this.
I also have 2 faults showing on the clock that could be related. 25 and 34 codes.
25 is a fault with the gear position switch, but the clocks show a neutral position.
34 is a fault with the butterfly valve from the exhaust. Obviously I don't have one so not connected. I've read on the ZX forum that this might cause a fault with the gear position switch.
What have others done with the butterfly valve.

Regards

Brad

Brad, when you ignition on does the pump prime or run for a few seconds then stop?
I left the servo motor connected with no cables and mounted it under the scuttle though you can buy an eliminator that plugs in place of the motor.

Brad, when you ignition on does the pump prime or run for a few seconds then stop? What pressure are you getting?
I left the servo motor connected with no cables and mounted it under the scuttle though you can buy an eliminator that plugs in place of the motor.

Hi Rich.
Heard you the first time. Sorry, couldn't resist.
Yes, pump primes then stops. It's a new injection pump.
What does this servo eliminator do.
Thanks

The eliminator just fools the ECU to think it has a servo fitted so gets rid of the fi lamp. What fuel pressure do you have? Believe from memory it's 42psi. Also what have you done with the tip over switch?

The pump is rated at 8.5bar max. The tip over switch is mounted to the scuttle in the correct direction. I thought if the worst happens it will kill the engine.

I assume it's cranking? Daft one but have you got the fuel feed and return lines the right way around?

Cranking fine.
There is no fuel return.

quote:

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Originally posted by roadrunner
Cranking fine.
There is no fuel return.

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I guess you have an external pump instead of the in tank bike type. What pressure regulator are you using? Have you just run a pump direct? . Just trying to get an idea of your fuel system

Defo got fuel upto the engine and I've fitted an in line pump direct without a regulator.
Was going to earth the clutch switch tomorrow to see if that helps.

[Edited on 22/6/20 by roadrunner]

Doesn't the single line system have s regulator built into the in-tank pump?

You must fit a regulator . Direct pressure from the pump is far too high. This may cause the injectors to jam or if it does start the fueling will be very rich all the time. If you say the pump is 8.5 bar rated it's trying to push 120 psi or so into the fuel rail. I'm surprised it's not leaking on the joints etc.

quote:

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Originally posted by adithorp
Doesn't the single line system have s regulator built into the in-tank pump? [/quote

Spot on. 😁

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roadrunner - 23/6/20 at 05:29 AM

OK. So which one do I need.
Done a quick search and there are so many options.

Brad

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adithorp - 23/6/20 at 12:16 PM

Can't say what you need specifically (never had to do it) but a couple of thoughts...

You could modify the tank to take the original pump. Think I've read where that's been done but maybe not the easiest answer.

Otherwise you need to put a pressure regulator on it. Which one I don't know but get a good one and not a cheap copy from eBay/china/etc; I've heard of people having issues with them.

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roadrunner - 23/6/20 at 12:19 PM

quote:

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Originally posted by adithorp
Can't say what you need specifically (never had to do it) but a couple of thoughts...

You could modify the tank to take the original pump. Think I've read where that's been done but maybe not the easiest answer.

Otherwise you need to put a pressure regulator on it. Which one I don't know but get a good one and not a cheap copy from eBay/china/etc; I've heard of people having issues with them.

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Thanks.
The only problem I have with fitting a ZX10R pump is that my tank is plastic and I believe they fit from the bottom.

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JimSpencer - 24/6/20 at 06:56 AM

Hi

The car pictured in my avatar runs a ZX10R, alloy tank, external pump and regulator, down to the 3 bar? (IIRCetc)

So your tank and Pump will, probably, be fine - just need to know the output pressure of the pump and get a regulator to suit.

If you're looking for brands then ones I've used and would be happy to use again (but there will be lots of others):-
Malpassi or Sytec, both do adjustable injection regulators with gauges, so you can fit and adjust yourself.

HTH

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roadrunner - 24/6/20 at 07:48 AM

I'm using a sytec pump.
Max pressure of 8.5 Bar.
Max flow rate 264 ltr/hrs.
Flow rate at 3 bar 201 ltr/hrs. (44psi)
Flow rate @ 5 bar 165 ltr/hr. (73psi)

Brad

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JimSpencer - 24/6/20 at 09:38 AM

Hi

Ok so way over pressure, but a simple fix, get a sytec pressure regulator to drop that down to 3 bar and you're sorted.

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roadrunner - 24/6/20 at 09:47 AM

Thanks Jim, Adi and Rich.

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roadrunner - 25/6/20 at 12:12 AM

One last question.
Would it be OK to mount the regulator at the back of the car so the return is shorter or is it best practice to mount in the engine bay.

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JimSpencer - 25/6/20 at 06:46 AM

Hi

As I understand it (Adi and Rich will probably have more relevant direct experience here) it's technically correct to have the regulator near to the fuel rail to ensure even fuel pressure when using it 'enthusiastically'!

On my installation it's actually adjacent to the pump, which is right next to the fuel tank, but that's immediately behind me in the tub and the engine bolts to the back of that, so the fuel line is only half a meter long or so!

If I was running one in a seven from a rear mounted tank then I'd mount the regulator in the engine bay and have a long return myself - but I've no experience of doing this to confirm it's required.

Sorry this doesn't really help!

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bigrich - 25/6/20 at 07:29 AM

Modern vehicles regulate in the tank so I see no issue keeping the return short and fitting the regulator on a T piece just after the pump.

I would use a metal T piece over plastic just because of the high pressures involved

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adithorp - 25/6/20 at 08:05 AM

All things being equal fitting near the tank is the simpler solution. Only issue with that I can see is if the pipe to the front is small diameter, then with lower pressure you might not get the flow rate required.

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roadrunner - 25/6/20 at 08:47 AM

Thanks fellas.
I need to completely redesign my fuel pipes.

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adithorp - 25/6/20 at 01:39 PM

Note, above I said feed diameter "might" be an issue. It won't stop it running but could restrict it at full chat. So I'd try with the existing line and change it IF you experience problems... Unless you just want to sort it all at one go.

What size is it now?
5/16"- 8mm probable/might be OK.
3/8"- 10mm upward I'd expect to be fine.

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roadrunner - 25/6/20 at 04:45 PM

Well I have ignition, Well sort of.
It's chugged into life but I didn't want to keep it going until I have fitted regulator that I've just ordered.
Steady progress.

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kajzw - 25/6/20 at 09:07 PM

Hi Brad,

The Guys have all made valid points, and worth following for sure. I'm going to throw a curve ball in here having experienced something very similar on my own ZX10 3rd Gen. I bought the car as a project and one of the jobs was to tidy up the loom, which in itself was okay, however, on reconnecting the throttle body harness there are two connectors (on the rhs) sat very close to each other for the throttle and choke flaps, both of which are exactly the same fittings apart from the fact one has a grey underside and the other black. The respective potentiometers are colour coded the same way. If these are connected the wrong way round, regardless of what fuel pressure is present the engine will struggle to start, if at all. Worth a few minutes to check, had me confused for a while!

Best Regards,

Keith

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roadrunner - 25/6/20 at 09:38 PM

Thanks Keith.
Will check that one out.

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