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View Full Version : Sr20det no start please help


jwizzle
08-07-2022, 09:59 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

tunermt
08-17-2022, 10:11 PM
You did great checking: compression, fuel, spark.

Being you have confirmed all 3 seem to be functioning yet no attempt to start/fire I would check your CAS. It’s possible it slipped and moved the base timing way out causing the no start. (Use i timing light to test/reset).

Being it attempted to start after you pulled the fuel pump fuse it could also be a sign the engine is getting flooded with fuel do Stuck open injector/s or leaking FPR (fuel into vacuum line off FPR). Less likely to cause a no start.

Thursday7
08-18-2022, 10:00 AM
X2 on what tunermt states. Has to be one of the 2.

Try priming the fuel pump with the rail pulled (don't crank) and see if the o-rings are holding fuel in the rail. Won't always cause a no-start but I've seen it happen.

tunermt
09-01-2022, 02:12 AM
Any luck getting it started yet?

jedi03
09-01-2022, 11:41 AM
just finished diagnosing a corolla which had slipped a few teeth...still had compression but was enough to not hit the valves or allow it to start...redoing the timing now starts right up!

tunermt
09-23-2022, 03:24 AM
Did you retune the sr already then?
Sr20det with a timing chain is much less likely to
Slip a tooth unless the tensioner is completely shot.
Worth a check though if you fear it’s off for any reason.