1JZ MX83 hard to start (possible ECU issue?)

[Packy]

Hi guys, I've got a slight problem with my 1JZ MX83. Engine is from a JZX90 factory manual with a manual ECU. Over the last 6 months or so it's become harder and harder to start. If I've been driving the car and switch it off and then try and start it within 30 minutes it won't start and floods the engine. I have to pull the EFI relay out and crank it to clear the cylinders enough to start it.

I've replaced various things along the way, brand new coil packs and plugs, new 255lph pump, pulled injectors and rail out and tested for leaks and spray, replaced 3 out of 5 of the caps in the ECU (other 2 on back order), running twin batteries in the boot for extra power, TPS is giving correct readings (have AFC Neo that displays throttle position that ECU sees), AFC Neo has not been tuned and has been installed for a couple of years (slack on tuning I know )

I've tried checking fault codes by bridging the two pins in the check connector in the engine bay but not getting any output to the check engine light. Need to pull the dash out and test that it actually works. I haven't had a chance to try another ECU as I don't know anyone nearby that has one I can borrow.

Anyone got any suggestions??

[Packy]

Well turns out it was the ECU. Picked up another one Friday night and drove the car around all weekend with no issues. Now time to get it tuned....

[harolto]

Had a similar problem with my old one, ended up being a temp sensor.

[Packy]

I have noticed I am having an issue still from time to time but it isn't the hard to start issue. Occasionally when I start the car it revs up to 2500rpm and fluctuates from there to normal idle every second or so. Was going to check things like MAP sensor and I might as well replace the coolant temp sensor while I'm at it.

[Packy]

Ok so the bloody flooding issue has decided to come back. Haven't had a chance to test the CTS yet but will give it a go tonight if I get a chance. Apart from that, not sure where to go next. I also connected up a separate test light to the W terminal on the ECU to pull codes and got nothing. Thinking I may need to check it again to make sure as I had pulled the battery not long before and it only had a short drive.

[Packy]

Went and picked up a new coolant temp sensor yesterday and installed last night. Took the car for a drive for a bit and turned it off and restarted a few times. Seems to be working ok at the moment, will know for sure after driving it around more. Fingers crossed that's all it is. Should have tried that first harolto.

[Packy]

Well that seems to have fixed my problem, should have tried it months ago instead of other things. Only cost me $40 from Bursons.

[dumbass]

U should have just put a multimeter on the coolant temp wire at the ecu
Would have taken 5 minutes
Might have also been bad connections on the coolant temp plug or terminals on sensor

[Packy]

Yeah I had planned on doing that for a while but never got around to it. I only drive the car every now and then so it wasn't a big concern, just annoying more than anything.

Really I was just looking for an excuse to buy a standalone ecu