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S13 Sr20det Won't stay running

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Help!!

 

I own a 1991 240sx with an sr20det running 17psi. It has and Apexi power fc , Apexi neo, 500cc injectors, walbro 255 and some drive train mods.

 

The car was driving fine and then suddenly lost all power. Got it home checked the fuses, the fuel pump fuse was blown so I replaced it. It started but only ran for about 2 seconds before killing. Bought a new fuel pump, same thing. Bought a new fpr, same thing. clean injectors and replaced fuel filter, same thing keeps happening. Runs for a second and then dies.

 

Any ideas anyone?????

I am stumped and sick of replacing parts trying to trouble shoot

 

Kris

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Will it run really rough before dying?

 

Here's a suggestion. Disconnect your CAS. Turn it over for 3-5 seconds. Reconnect CAS and start. Does it run smoothly for a while (or until you tap the throttle)? If so, your symptoms are identical to my buddy's. His CAS was failed without warning and started giving strange firing timing to the ECU.

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Fuel pump relay?

Is there any way to test this relay

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180MikE

 

Tried what you said. starts and runs smooth. but only runs for maybe 2 or 3 seconds still. If you hold the throttle wide open it runs a little rough and it dies even sooner.

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Fuel pump relay?

Is there any way to test this relay

 

A quick test that may show up something (or may not). Locate fuel pump relay, turn on ignition, give relay a few sharp taps with the handle of a screwdriver, turn ignition to crank and start engine. If engine runs, or runs longer, then indicates relay has bad contact.

 

Another thing to check is the earth from the fuel pump to chassis. Removing earth connections, cleaning rust and oxidation then reconnecting may help.

 

Since you have a different engine, pump and ECU from stock it is hard to know if the pump is using factory wiring or has been wired up differently. You had the fuse blow, so possibly the original pump went bad. My thinking is that some other part of the wiring circuit has been stressed (maybe a plug and socket) before the fuse went and is causing a resistance that is making the pump run sluggish.

 

Ideally you need to measure the voltage across the pump while it is operating. It may be possible to access the pins in the connector near the rear shock tower where the body loom connects to the rear loom. However if you unplug the connector to get the reading it is going to unload the circuit so may give a full voltage reading when something actually is wrong. Best to identify the conductors in the connector and possibly poke some thin wires in to make a contact. Use some electrical tape to keep them in and not shorting out.

Edited by stockblues15

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Given your issues started when a fuel pump fuse blew, I'm leaning towards resolving any issues there first and just confirming that the pump is running at full output (get a workshop to run a fuel pressure gauge on the line).

 

After fuel supply, I'll tell you that the behaviour sounds exactly like how my mates car behaved. I'd look at replacing the CAS, or at minimum get someone to confirm that it's performing correctly. I believe it can be done my checking spark timing with a timing light and sparking to the rocker cover. A stuffed CAS will throw weird timing signals leading to odd spark timing.

 

EDIT - He initially thought his was pump related too, but that wasn't the case.

Edited by 180MikE

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you got a new FPR

 

so what's the fuel pressure on idle or when you're priming fuel?

Whatever the stock fpr runs at. I think it is 45psi

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