1UZ-FE running problem

[MaccyD]

Ok, so i have my engine in the car. It starts and runs sweet as you like for a few seconds then turns off much the same as this guy:

http://www.lextreme.com/forums/showthread.php?t=15137

I havent had the chance to check through everything suggested on there yet, but someone worried me by telling me i need the immobiliser/key and all sorts to make it run right as its a 96. However, when doing a little research it seems people only discuss immobiliser problems with the vvti model (which came in end of 96 i think). Can someone put my mind at ease and tell me i can run standard ECU in a conversion with a NON vvti engine. Otherwise i might cry lol.

 

[Bushwhacker]

Looking back through your previous posts, you have a 1UZ from a '97 LS?
In that case your ECU is immobilised I'm affraid.

The easiest way around that is to get an ECU from an earlier LS, '95/'96 and swap the IGF wires around.

 

[MaccyD]

Mines an R reg 1996, pre vvt. PLEEASE say thats ok.

 

[MaccyD]

OK so apparently an R reg is a 1997. So if i get hold of an older ECU as you suggest, its the same model so should have the same plugs? Will it not just plug straight in?

Getting an older ECU seems like an ok fix, enough cars are being broken for spares on ebay. Do you know what i need to do with the IGF wires?

 

[Bushwhacker]

The pre-VVTi ECUs are also immobilised, especially the '96/'97 ones.

I had the same problem last year with a 'N' reg LS ECU, fitted an ECU from an earlier LS (eBay £40) swap the two IGF wires around at the ECU plug and the engine fired up and ran fine.

 

[MaccyD]

Ok, so which date LS400 do i need to get the ECU from?

And im being a bit dense but its been ages since ive looked at the wiring diagrams. Which are the IGF wires? did they just switch + and - around? If you can help me out ill wing you some beer money as id really apreciate it.

thanks

 

[Bushwhacker]

Ok, so which date LS400 do i need to get the ECU from?

And im being a bit dense but its been ages since ive looked at the wiring diagrams. Which are the IGF wires? did they just switch + and - around? If you can help me out ill wing you some beer money as id really apreciate it.

thanks

Sorry I meant the IGT wires, not IGF.

Look in this diagram it'll be relevant to your engine......

http://www.lextreme.com/PDF/96ls41.pdf

pins 24 & 25 (IGT1/IGT2) on the 34 pin plug, just snip and swap them over.

Look for a '94 or '95 ECU to replace yours, the plugs/sockets are the same.

 

[Bushwhacker]

Same senario here........

http://www.lextreme.com/forums/showthread.php?t=14950

 

[MaccyD]

Thanks mate. Already on ebay getting prices for an ECU from an M or N reg vehicle. Really pleased its that straight forward, its not going to blow up or anything if i dont swap the wires correctly im guessing? (as a precaution!). I have really good wiring schematics for my engine so i will just find the wires you mention and swap them over. Ill see how i get on and will send you a few bucks for a pint IF its successful lol. Will get up a couple of videos tonight too.

 

[Bushwhacker]

Basically all you're doing is swapping the igniter signal wires so the ignition timing is correct.
If you don't swap the wires when you plug in the older ECU the engine won't crank properly as the spark timing is all out.

 

[MaccyD]

Cheers bushwhacker. Sorry to keep bombarding you. Part number 89661-50251 is the ECU i need to make it work from the looks of that other thread. I found one by searching that number rather than searching LS400 and came up with this:

http://www.ebay.co.uk/itm/Toyota-Le...arts_Vehicles_CarParts_SM&hash=item19d4c1fbf1

The part number is correct but its from an LS430. Would it still work? Sorry i know this probably seems like amateur hour over here!

 

[Bushwhacker]

Yes, that one will work but it's not from a LS430 though. Must be a typo from the seller.

 

[MaccyD]

Yeah its a bit weird, would be a double mistake as its also written on the ECU itself. Hopefully a guy on ebay is getting back to me after he checks the number on the ecu on a 95 LS400 so if thats right ill get that. Gives me a chance to sort the plumbing.

 

[Bushwhacker]

As long as you receive the one in the ad, it'll work.

LS430 ECU's look like this.....

http://www.ebay.com/itm/2002-Lexus-LS430-ecm-ecu-computer-89661-50660-/150797096999

 

[MaccyD]

As promised, i have a video, this is with my full exhaust attached so a bit better than last time. Runs for a short period then dies as i mentioned. I di try a bit of throttle and it just spluttered and struggled. Could this be linked to the same thing or should i expect this problem to be there when i get the new ecu. Idle also seems high. Im trying not to tackle too much stuff at once so waiting til the new ECU is sourced.

http://www.youtube.com/watch?v=npmw9tZNBpE&feature=plcp

 

[Zuffen]

Your second Youtube vid is better for diagnosis.

The puff of smoke from the idle motor plumbing suggests you don't have the hoses connected correctly or at all.

This would create a large vacuum leak which will make it run lean and spit when you try and make it accelarate.

The vac leak will also give ahigh idle.

 

[MaccyD]

Cheers Zuffen. Im temporarily using the standard intake piping now to eliminate that from the running issues.

There is a vacuum sized hose that comes off a sensor on the front right side (as you look into the engine bay from the front) of the intake plenum, and it clips into a clip on the plastic cam cover trim. I dont have anywhere for this to go. Is it something to do with the A/C? Im not sure what the sensor is. It also has a larger diameter pipe that goes to the throttle body.

Hoping to get the new ECU in the car and wired this weekend for more videos.

 

[MaccyD]

Ok the guy i contacted said the part number is 89661-50250 not -50251. Im guessing that means its no good?

 

[Bushwhacker]

Ok the guy i contacted said the part number is 89661-50250 not -50251. Im guessing that means its no good?

That one will work OK as it's slightly older. Same period though.

 

[Bushwhacker]

Cheers Zuffen. Im temporarily using the standard intake piping now to eliminate that from the running issues.

There is a vacuum sized hose that comes off a sensor on the front right side (as you look into the engine bay from the front) of the intake plenum, and it clips into a clip on the plastic cam cover trim. I dont have anywhere for this to go. Is it something to do with the A/C?

That would have originally connected to the charcoal canister in the Lexus.
Just leave it open or unplug the sensor and throw it away.

Im not sure what the sensor is. It also has a larger diameter pipe that goes to the throttle body.

That could be a couple of things, got a photo?