1UZ MX83 Conversion -- Won't rev above 2.8 cold, lacks power under 2.8 walm

[moonman]

Hey Guys,

Not really sure how in depth information you need to begin with, but I'll list what I know.

1UZFE Converted MX83, from what I can tell/read the engine came from a LS400.

At the moment, its having some weird issues, on a cold start, it won't rev past ~2.8 (Fuel cut by the sounds of it) and picks back up at 1.1 -- it just bounces between those RPM at WOT.
No, I'm not doing this as soon as I start it, after a minute or so of sitting. It will also do this when its just under temperature (JUST under, about 1/8th or something)

I can drive the car to the shops (get it warm), turn it off and do some shopping, come back (still warm ish, but below temp) and it won't rev again
When its warm and revving OK, it will be sluggish below 2.8, and picks back up over that. When free revving when warm, it will be sluggish also, and exhaust note changes dramatically at 2.8-3.

Secondly, when starting and putting the car in drive, it will VERY slowly shift into drive, over a period of a about 6 seconds. After that its OK.

I'm really at a loss, as I purchased this converted.

Any help would be appreciated, if you need further info, please ask and I'll do my best to get/figure it out.

[BLSTIC]

For the gearbox, check (a) that it has good condition fluid and (b) that it's the right stuff. Autos are ridiculously sensitive to fluid (the same stuff transfers power in the torque converter, lubricates the gears, keeps the clutch packs alive while simultaneously not making them too slippery, provides corrosion protection AND cools the whole shooting match. It HAS to be perfect) so if it looks and smells anything other than new correct grade stuff, flush your gearbox.

For the engine... I'm at a loss. I have heard some cars that impose different RPM limits depending on temperature so if it thinks the temperature is outside normal range it could cause some strange symptoms.

If you are feeling brave, locate any coolant and oil temperature sensors/switches on the engine and disconnect them. The factory ECU will compensate by using a limp home mode that is either (a) assume extreme temperature range, protect the drivetrain, impose operational limits or (b) assume sensor fault, replace with default value that allows normal operation, light up the dashboard. But the important point is that it will be constant and you will have narrowed down the cause.

Also note that fans will be triggered incorrectly, gauges won't work, the trans won't shift nicely if it's under ECU control, and it won't run properly on a cold start, so don't run it for much longer than you have to.

[CrUZida]

Another simple test, unplug the TPS and try it again.

[dumbass]

Fk u must have got it cheap
I neve rounder stand y people's buy shit
eBay makes it even worse where I've tried to fix cars bought by idiots on eBay without looking at car
And give them a thousand dollar repair bill and watch their faces drop hahahaha

Check for air leak
If u have air leak engine will rev to 2000 or so then drop to 1000 then back to 2000 and so on like a two dollar hooker
Like crusy said disconnect tps and if it cures it then look for air leak
Could also be stuffing air flow meter signals up with air leak

99% of auto problems are low oil so add two litres see if it gets better
U never know if dickhead who did conversion used wrong dipstick

There are so many joys and disappointments when buying someone else's fkt up conversion

[Z2TT]

I bet the joy is bragging about how cheap you got it and what a steal it was.

ECU Could be faulty, some of those early 1uz-fe's had ECU capacitor problems.

[moonman]

Just so there's not un-answered threads here, cause I hate that...

Turns out this was the case so far:

1) The engine warning light wasn't connected, so no engine codes could be read. I found: Crank angle (Default map running, hence power, this was intermittant)
2) Error 65 - Hydrolic fan sensor error (Cleared by grounding some wires - contact me if you need the solution0
3) the slow shifting was a dying automatic
4) the OD light wasn't connected, so no Auto error codes also....

Thanks for the opuinions guys.

And as for buying a car like this, I know the risks when purchasing something like this, and actually enjoy fixing them....

[zahmad]

Good to hear it all worked out!