1JZ MX83 wiring problems - MAP sensor?

[Jabtronic]

I'm almost finished converting a 1JZGTE into my series I MX83, just up to the part where i turn the key and expect the bastard to start.

The 1JZ was from a JZA70, but had already been converted into mumblezzz's Series II MX83.

I've swapped the engine and wiring straight from mumblezzz's written off cressy, his was a series II though and there was be one plug that had an extra wire (not related to engine stuff anyway I don't think, was the white plug for the dash cluster)

Anyway, when I crank the engine over, it starts and runs for a second or two then stalls. The fuel pump primes properly so I don't think thats the problem. I replaced the spark plugs and they all spark properly.

I have since checked the engine codes and got code 31. According to this http://mkiv.supras.org.nz/articles/engine_2_31.htm it means something to do with the MAP sensor?? (That page says AFM??) How do I go about checking this properly?


Anybody got any ideas on what else I can check? I'm a bit of a noob to the wiring stuff, I copied the wiring wire-for-wire from mumblezzz body plug as I was expecting it to simply.. plug and play.
Now that I havn't got it running, I got a hold of the wiring diagrams and learnt how to read them etc.. but this has got me stumped.

I've been posting this on toyotacressida.net and have so far been recommended to check the MAP sensor, and check for leaking ECU capacitors. Will have a look this weekend but I don't know how to test the sensor.

Thanks

[Jabtronic]

Also, I'm willing to pay someone who can get it running. I've got it booked into an autoelectrican on Wednesday but I don't know if he'll be able to do it or not. Will just be a waste of a tow if he can't.

I'm located on the Gold Coast.

[brett_celicacoupe]

ive came across a problem like this before. wasnt map related but the symptoms sound the same.

its possible the fuel pump is only cutting in when you have the key in the start position. when the engine is running, but not cranking, the fuel pump relay uses a signal from the ECU to tell it when to be on. if you have missed this trigger wire to the relay then the fuel pressure will slowly drop while the engine is idleing and consequently die.

try bridging FP and +B in the diagnostic box in the engine bay. this just hard wires the fuel pump

[Jabtronic]

Well it's not the fuel pump, hard wiring it doesn't make any difference.

I'm now getting error codes 14 and 41, and sometimes 31. Will try replacing the capacitors on the ECU as they look like they're leaking.

[Jabtronic]

Replaced the capacitors on the ECU and the car started and idled for a minute or so before stalling, then it was back to where I started. However difference is I can now keep the engine running under revs but it won't idle, before I replaced the caps, revving the car didn't help it to start.

Still bring up one error code.. 14 or 41 (can't remember off top of my head - it WAS bring up 14, 41 AND 31 at one stage) but I'm towing it to an autoelectrician tomorrow so will see how it all goes.

[The Witzl]

some other threads that are helpful:

http://www.toymods.net/forums/showth...highlight=code
http://www.toymods.net/forums/showth...highlight=code

do some more searches for code 14.
Sounds like it's definitely leaky capacitors.

[Jabtronic]

Well I've replaced the caps.

On first start it started and sat there idling nicely. Then eventually it stalled and now I'm back to where we started.

Might have to pop the ECU back open again and test the caps to see if they havn't blown or anything.

It definately seems to be ECU related now anyway, my auto electrician has said it seems to be the ECU.. or something to do with the spark amplifier (can anyone correct me on what that is?)

EDIT: I might just replace them all again anyway, it only costs $3 or so to get the 5 from Jaycar. Well 6 cause I had to use a 10uF and 4.7uF in parallel instead of the 15uF capacitor.

[Ribfeast]

Might be better to chop the legs off the crook ones and solder the new caps to them, instead of risking lifting the tracks.

[JP]

try bridging the main relay output in the fuse box. The ecu controls the main relay trigger, and I've had one 1J ecu where the trigger's transistor was failing after a few minutes causing the car to just die. If the main relay was bridged then the car would continue to run when the MREL output on the ECU gave out.

[Jabtronic]

Well I tried replacing the capacitors again, and accidently lifted one of the tracks thought I better not do any more to it for now, I'll just send it to a mate of mine who can fix it.

In the meantime, a member from supraforums.com.au has offered to test his ECU in my car this weekend so I'll see how that turns out.

[Jabtronic]

ECU seems to be the culprit, tried another one and the car ran fine. So I've bought another ECU just waiting for it to arrive.

Might also send off my old one to see if it can be checked and repaired.