SR20DET NO START PLEASE HELP

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jackwarrington
Posts: 3
Joined: Sun Jul 31, 2022 1:05 pm
Car: ???? Nissan 180SX Type-X SR20DET

SR20DET NO START PLEASE HELP

Postby jackwarrington » Sun Aug 07, 2022 7:36 am

So I have a 180SX with a blacktop straight cam. The other day it cut out completely whilst the throttle was wide open and would not start again after. I have spent days on it and tested the following, but still won't start, just cranks with no sign of firing:

- Probed ECU pins with multimeter and oscilloscope to check it has power, is sending injector pulses, etc (which all seems to be working as it should).
- Compression, all good on all 4 cylinders
- Ignition, a strong spark on all 4 plugs
- Fuel, tested fuel pressure ~40psi and also pulled the injector rail out and tested them. All 4 spray in batch mode whilst cranking
- disconnected MAF, still no start
- Pulled fuel pump fuse, this is the only thing that makes it cough and try to start. When pulled out, after a few cranks it splutters and seems like it wants to start, but doesn't (very strange). But then when the fuse is put back in, back to cranking with no sign of starting.
- Have even tried easy start sprayed into the throttle body with no sign of starting

Please could someone offer something that would cause this issue, as I am tearing my hair out! The only thing I haven't tested is timing, now if the chain had skipped a few teeth, you'd surely expect a backfire though? not just cranking without anything? If it had slipped any more then you'd expect no compression?

Thanks in advance


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VStar650CL
Posts: 5354
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Re: SR20DET NO START PLEASE HELP

Postby VStar650CL » Sun Aug 07, 2022 8:18 am

Is it flooding? Nothing Nissan will start with fuel-fouled plugs, even with starting fluid applied.

jackwarrington
Posts: 3
Joined: Sun Jul 31, 2022 1:05 pm
Car: ???? Nissan 180SX Type-X SR20DET

Re: SR20DET NO START PLEASE HELP

Postby jackwarrington » Sun Aug 07, 2022 8:35 am

VStar650CL wrote:
Sun Aug 07, 2022 8:18 am
Is it flooding? Nothing Nissan will start with fuel-fouled plugs, even with starting fluid applied.
So it could be, but when taking the plugs out blasted all fuel out of the cylinders with compressed air and it still didn't start. If it is, what could be causing the flooding and could that cause it to cut out even with WOT and high up in the rpm range, as that is when it first died?

User avatar
VStar650CL
Posts: 5354
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Re: SR20DET NO START PLEASE HELP

Postby VStar650CL » Tue Aug 09, 2022 4:56 am

If there was enough fuel to need blasting out then something is messed up. Either the fuel that's going in isn't burning or there's too much of it to burn. Are the rail seals into the manifold any good? It's very suspicious that yanking the pump fuse makes it try. I'd blow out the cylinders and plugs again, then leave the fuse out and see if it will start on supplemental fuel down the barrel. If so, you can be confident it's flooding and at least you'll know which tree to bark up.


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