I still have a minor problem with my TP sedan being reluctant to change from 1st to 2nd. It is fine if driving hard - changes perfectly at about 4500 to 5000 rpm. But if trying to drive quietly and smoothly it stays in first gear too long. This is annoying because otherwise the car is near perfect to drive.

The TPS checks out OK and auto itself is perfect. The fact that only the 1-2 change is poor points to the TCU as the probable cause.

I'm thinking of going to Pick N Payless this weekend to grab one but it is pot luck whether I'll get one that is any better. Also they may not have a carby tp with auto.

So, is the TCU the same in the EFI auto as the carby, bearing in mind that carby autos don't have an ECU ? Does anyone have one that is known to be good and is from a carby TP auto?

regards, Coldamus

no, it isnt

tcu is seperate from fuel system, minus that of the tps, which is basically the same output, input signal is the same.

Main thing you want is to get the same ecu, reason being TN- TP were diff, TP had pwr/ eco mode, that not supported by TN ECU

Just to be clear. The carby model doesn't have an ECU at all. I'm not going to do an EFI conversion. I'd love to but don't have the time or money to do it or the space to wreck a donor car.

Or when you said ECU, did you mean TCU?

I still have a minor problem with my TP sedan being reluctant to change from 1st to 2nd. It is fine if driving hard - changes perfectly at about 4500 to 5000 rpm. regards, Coldamus


perfect thats ringing the crap out of your engine and might be wearing it quicker.
the tappets i think it is bleed out a 5500rpm.
My tp changes gear at about 2000rpm. me thinks u need the flush the old tranny fluid take off the pan and fit a new filter/o-ring and gasket also checking the magnets for chunks ( as an indication of how worn it is then clean em) then refit the pan and go from there before u try anything else.

I've already replaced the filter and transmission oil etc. That has nothing to do with it. The transmission itself is fine. The car has done less than 70,000 km. When driving it hard, it is supposed to change up at about where it does, still well below the red line. If it changed up at 2,000 on full throttle, the performance would be woeful.

The thing is that I don't normally drive it hard and I would like it to change at 2,000 rpm or less when I'm driving it quietly with less than 1/4 throttle. It doesn't do that. It changes at 3,000 to 3,500. It will change at less than that if I lift my foot off the throttle completely, but that is confusing for anyone driving behind.

I've already explained why I think the problem is the TCU. The change points are programmed into the TCU. I have the graphs somewhere showing where the changes are supposed to occur in each gear at various throttle openings. Mine is close enough to the chart figures at full throttle but not at low throttle.

The TCU reads the throttle opening from the TPS. Since the problem is only with the 1-2 change, I don't think the TPS is to blame. Besides, I've checked it with a multi-meter and the resistance readings are correct. So I am going to try swapping the TCU.

All I need to know is whether I need to specifically look for a TCU from a carby model TP. I am fairly sure that's the case and Astron Boy seems to confirm it. As he said, it definitely has to be from a TP because of the power/economy mode box. However if the TCU from the EFI TP was the same, that would make it easier to find one.

regards
Coldamus

both TCU carby and EFI should work the same auto box to TP specifications
just diffferent serial mumbers

TCU carby will be different in the wiring from a EFI TCU

but will have the set up internally for the TPS and the 2 memory chips

one for power one for economy

The TPS and all the voltages working in the box are the same for carby and EFI

the EFI will have wires running to the ECU for the EFI setup

and the TPS

when was the last auto service

what happeded after resetting the computer ?

with overdrive off

first going to second either up or down driving normally

should be approx 900 rpm - 1500 rpm power or economy

if nothing changes another TCU

when was the last auto service
Less than 500km ago. I hardly drive it.


what happened after resetting the computer ?
There isn't one. However the battery has been disconnected a number of time so the TCU would have been reset. Don't make no difference!



with overdrive off

first going to second either up or down driving normally

should be approx 900 rpm - 1500 rpm power or economy

if nothing changes another TCU

That's what I figure. I could swap from my wagon but it is EFI and anyway, that would be at least double the work. I will see whether Pick N Payless have one.

Transmission ECU = TCU ;)
And I know carbs don't have ecus, That's why there better :badgrin:
I have a carb wagon, and EFI sedan, best part about first gens, is just how much of there stuff is interchangeable without having to do any major surgery.

definitions :nuts:

first gen only
from the repair manuals

carby models automatic
TCU = transaxle control unit ..for gearbox
TPS throttle position sensor ..passengerside lower carby

EFI automatic

ECU = electronic control unit ..for motor different location on loom
TCU = transaxle control unit ..for gearbox on floor below radio
TPS throttle position sensor throttle body
etc

I have a carby TCU sitting here, are you in Vic?

I THINK (can not remember for sure) that the TCU is the same, I know that the trans is the same as the EFI TP I am doing at the moment has the Carb trans in it at the moment.

PM me if you are interested however I would openly state that the likely hood of your TCU being the issue is remote although I would not want much for the TCU so may be a cheap way of finding out

I can confirm they are the same as my gearbox in the wagon was removed from a then fuel injected tn se, and it mated with my tp tcu no probs.

it's 100% the same as the feed signal from the tps is the same, as well as all wiring connecitions.

Transmission ECU = TCU ;)
And I know carbs don't have ecus, That's why there better :badgrin:
I have a carb wagon, and EFI sedan, best part about first gens, is just how much of there stuff is interchangeable without having to do any major surgery.

Mine are the other way round. Carby sedan and EFI wagon. The reason the sedan is carby is that I purposely went looking for one.

My wagon had heaps of problems when I bought it and I blamed them on the EFI - stupid computers and all that. So, having previously had a carby TN that was totally reliable, I went out and bought a carby sedan.

Anyway the problems with the wagon are all sorted now and had little to do with it being EFI. Replacing the valve stem seals made a huge difference. Its other problems were mostly caused by its aftermarket immobiliser and the shoddy wiring job by whoever installed it.

Given the choice again, i'd go EFI. The wagon goes like a blur. The sedan is not bad either but doesn't have the same instant response.

I've never driven an EFI manual sedan but a good one must be fun.

I have a carby TCU sitting here, are you in Vic?

I THINK (can not remember for sure) that the TCU is the same, I know that the trans is the same as the EFI TP I am doing at the moment has the Carb trans in it at the moment.

PM me if you are interested however I would openly state that the likely hood of your TCU being the issue is remote although I would not want much for the TCU so may be a cheap way of finding out

I am in Sydney but I am interested if you are prepared to post (at my cost of course). I will send a PM. Thanks, Coldamus