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View Full Version : Sr20 has rough start

jdm213
09-23-2017, 07:03 PM
I have to literally press the gas pedal and it struggles then after that it stays on and idles fine and runs really well this happens more when the engine is cold after that it's easier but still struggles and want to know how to diagnose
jr_ss
09-24-2017, 06:54 AM
Hard starts can be the result of a lot of things. What does you setup consist of? AFRs? Any over heating issues?
OnTheChip
09-24-2017, 09:39 AM
There is a wire from the ignition switch, through the fuse box, to ECU pin #34 that should be 12V when the ignition switch is turned to START and the starter is engaged. This tells the ECU to use the batch fire cranking fuel tables. Check ECU pin #34 for 12V with starter engaged. If that fails, check fuses.
jdm213
09-25-2017, 02:41 PM
Hard starts can be the result of a lot of things. What does you setup consist of? AFRs? Any over heating issues?

No overheating it's actually always at 170-180*f and it's bone stock I just changed the thermostat and there's no air pockets or anything like that and the cars sensor has been replaced 5k miles ago
jdm213
09-25-2017, 02:43 PM
There is a wire from the ignition switch, through the fuse box, to ECU pin #34 that should be 12V when the ignition switch is turned to START and the starter is engaged. This tells the ECU to use the batch fire cranking fuel tables. Check ECU pin #34 for 12V with starter engaged. If that fails, check fuses.

What color is the wire ... ok Ima check pin 34 so check it before I crank it and while I crank correct ? And the fuses to check in the engine bay or inthe driver side
OnTheChip
09-25-2017, 02:51 PM
What color is the wire ... ok Ima check pin 34 so check it before I crank it and while I crank correct ? And the fuses to check in the engine bay or in the driver side

Correct.
I'm not sure which box the fuse is in. If you don't have a FSM, you can probably find one here: http://www.nicoclub.com/archives/use-nicoclub-coms-factory-service-manual-database.html
jdm213
09-28-2017, 01:30 PM
Correct.
I'm not sure which box the fuse is in. If you don't have a FSM, you can probably find one here: http://www.nicoclub.com/archives/use-nicoclub-coms-factory-service-manual-database.html

I checked and I think I have no power to the fuse box because the fuse is good and I checked for power and all the fuses power up except that one so where else can I check to see if it’s getting power
OnTheChip
09-28-2017, 01:51 PM
Follow the wiring diagram in the FSM from ECU pin#34, through the fuse, to pin #5 on the ignition switch connector.
jdm213
09-28-2017, 02:44 PM
Follow the wiring diagram in the FSM from ECU pin#34, through the fuse, to pin #5 on the ignition switch connector.

I figured it out so I put a fresh 10 amp fuse and tested it and there was no power and put the key to on and no power but when I cranked it , it got power for a few seconds then shut off so I did what you said and it was a corroded fuse blade even tho it didn’t look burned.
OnTheChip
09-29-2017, 02:54 PM
I figured it out so I put a fresh 10 amp fuse and tested it and there was no power and put the key to on and no power but when I cranked it , it got power for a few seconds then shut off so I did what you said and it was a corroded fuse blade even tho it didn’t look burned.

Glad that's all it was.