biggentplayer

I have been having this issue with my 1990 240sx for the past six months and I cannot figure out this issue. I have owned the car with the swap for three years and have never had any other issues with it running, until now. I would greatly appreciate any input that may help me solve this issue, please help!

Issue: S13 SR20det engine cranks but does not start.

Symptoms:
1) Engine has spark to all four cylinders.
2) Injectors are firing. (spark plugs smell like fuel)
3) Fuel pump is working. (48-50psi at the fuel rail)
3) Engine will start with starting fluid and dies.
4) If started with starting fluid and the throttle held open, it runs but breaks up and back fires out the exhaust.
5) If I unplug the CAS and plug it into my old CAS (not installed in engine) and rotate the shaft I can hear the injectors clicking.

Solutions I have tried:
1) Plugged my ECU into a friend's car with same swap and his car ran perfectly.
2) Replaced the Cam Angle Sensor and set timing according to the FR Sport guide.
3) Replaced main engine harness with new harness from Wiring Specialties.
4) Checked ignitor chip per FSM specifications. (I have spark so this can't be the issue anyways)
5) Checked Start signal wire(orange) from the ignition to ECU and it is working fine.(10-12 volts)

I am not sure what else there is to do to try and fix this! Any help is greatly appreciated! Thank you

ISSUE RESOLVED: The injectors were not receiving the full constant 12 volts they require. The injectors receive constant 12 volts from the chassis plug (gray) located behind the passenger side headlight in the fender. This is where the main engine harness connects into the chassis harness. A solid red wire on the main engine harness plug is what sends the injectors a constant 12 volt signal.

Big thanks to Yury at Wiring Specialties for the information that helped solve this issue!

jbretz

is the fuel pump working? i just had a similar issue this morning. i replaced my plugs and took it up the street and car shut off. could crank but wouldnt start. I checked for spark and was sparking on all four. turns out the fuel pump assembly had a bad connection right at the pump inside the tank. it doesnt hurt to try it. not sure if this helps ya

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biggentplayer

Thanks for the reply man. I checked fuel pressure at the rail while trying to start the car and I was getting a solid 48-50psi so I think the fuel pump is working fine. I did try your suggestion anyways and everything checked out. I am beginning to think there may be an issue with the start signal that is sent to the ecu from the ignition but I am not sure how to fix that if that is the issue. Any more suggestions are more than welcome!

Jesse SR20

Unplug your MAF.

If it starts, the MAF is dead. My Z32 maf died, and my car wouldn't start.

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biggentplayer

Yea, I tried unplugging the MAF and it still wouldn't start. So, the MAF isn't causing the issue. Thanks though. Any other ideas?

Jesse SR20

As long as you've got a buddy with the same swap, do some part swapping.

Swap mafs with him, rule that out.

Swap injectors with him, rule that out.

Coilpacks, ignitor, etc etc

But don't neglect the basics. Have you done a compression test ? It sounds like a fuel delivery problem to me honestly.

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89_SR20

Check your grounds and fusebox wires. My car had the exact same symptoms. I had a wire exposed and rubbing on the fender. Pull the wires away from the body and see if that works. Also check your vacuum line from the Fuel pressure regulator, if it has fuel in it. its the FPR. Those are my two cents based on my experience.

mr2gons14

if it starts for a second then dies immediatly check ur intake mani and iacv. I am having the same issue with my car right now. I am pretty positive it is due to my intake mani pretty much rotting away so i have a new one coming.

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zilvia.net/f/cars-sale/517359-95-240sx-sr20-swap-uras-greddy-apexi-ect.html

biggentplayer

Update:

1) Checked coilpacks: All coils produced a strong spark when checking each one individually.

2) Swapped MAF sensor from a buddy's car and still no change.

3) Swapped out the ECU from my buddy's car and the car ran perfectly for about 10 hours and then same issue occurred again.(weird) Plugged his ECU back into his car and it ran perfectly.

4) Fuel injectors are fine(i think): I pulled all the spark plugs, and each of them was covered in black at the electrode and wet from fuel, so I replaced them with Iridium spark plugs and no change.

I have been wondering if it may be my IACV giving me trouble but I am not sure how to check it. Any advice? Thanks for the replies thus far. Much appreciated guys!

ultimateirving

Check all wires on back of ECU because something could be loose, especially if it ran flawless for a short while, possible that a pin is loose/broken
Vac leak would be my next stop but it shud idle with maf unplugged if thats the case

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Z32 with lq4 swap
Desert Street Scene || Dssevents.com

biggentplayer

I was thinking the same thing about the ECU plug having issues with contacting the ECU pins so I replaced the old harness with a new main engine wiring harness from Wiring Specialties and no luck again. The last thing I suspected that could cause what seems to be a wiring issue at the ECU is the start signal(orange wire) being sent from the ignition switch, and that checked out just fine with (10-12 volts).

biggentplayer

Any suggestions are appreciated. Still no progress in getting this starting problem fixed!

bluejeansonfire

I had a similar problem. Can you get it to sputter?.. or its just compression cranking? Try taking the filter off and chocking the maf with your hand while someone is cranking. To be honest I'm not sure this diagnoses more than a shared issue because I haven't solved the issue that it totally starts when I do that, but it runs super lean under 2500rpm.

godsmack

maybe your injectors aren't firing when they should be. are your injectors wired properly? i would check and make sure the no. 1 injector plug goes to the proper spot at ecu pin and go down the list. and when starting with starting fluid are you spraying it in right at the throttle body? if so it will break up since you're not supplying air from turbo.

biggentplayer

Ryans s13

So I have a s13 hatch with a sr20det. I did some exhaust work today then started my car let it warm up and drive off. It's started po perfect and ran and drove perfect. Then bog bog off. The car will turn over but won't start. None of the coils are firing. I've checked all fuses and relays fixed a few potential shorts or soon to be shorts anyways. I've got a wire specialties engine harness. I just got this car 1month ago. I was reading something about the egi relays being crap and or poping due to shorts. I need help bad guys. I'm kinda of un educated on 240's. This is my daily driver. I drove the car earlyer today and it ran just fine