TB42e manual conversion issues, tps?

A mate of mine has purchased a tb42e that is running a bit ratty. The only way he has been able to get it to idle and drive is by disconnecting the idle air controller and adjusting up his throttle cable. I was able to have a quick look at it the other day, reconnected the iac and it revved its head off as was expected. So I backed off the cable he tightened and adjusted the air bleed/bypass screw.

It now idles but cannot get it below 1000rpm. I noticed the tps was adjusted to the maximum in one direction. Someone has obviously played with it so I decided to adjust it to see if it would make a difference. As soon as I moved the tps a loud click could be heard from the idle air controller and the engine would stall. I was running out of time, however my mate claims the owner told him that he converted it from auto to manual, my mate has confirmed this as he has found the auto computer.

My question is. What are the differences? I assume the tps and ecu would be different between the autos and manuals?

manuals dont have a tps?? The manual carby has no place to fit the tps. The tps is just for the computer to calculate which gear to be in when in an auto. Im not sure what would be happening by having an auto computer and a tps. Perhaps idle issues as you've explained.

Mine is an auto and not long after i bought it i found that it was missing the tps because someone had replaced the carby with one off a manual therefore the butterfly shaft did not have a place for the tps and so they had left it off!

Ah very interesting. Thank you for that. I shall investigate further

Hi mate the TB42E does have a TPS and they are interchangable between the manual and the auto. Bigrig is an expert in this field :) maybe he will see this thread!!

Hmm ok. I'm wondering if its still running the auto ecu.

Quote:

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Originally Posted by Airstrike

Hi mate the TB42E does have a TPS and they are interchangable between the manual and the auto. Bigrig is an expert in this field :) maybe he will see this thread!!

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Ahh yeah sorry, I was talking about the carby models. I should have read the subject better.

FanTapstic!

From my experience you can run an auto computer in a manual but not vice versa, but the TPS tells the ECU how hard your accelerating but i think you might have an air leak from the manifold or the AFM is playing up.
But check to see if the manifold is sucking air from a blown gasket first. Whats is the fuel pressure ??

Check your fuel pressure, should be at 40psi. Probably worth buying a couple of meters of vacuum tubing and replacing it all, they tend to crack, especially at the connection points. Has there been any investigation on the ignition system?
Tps voltage should be about 0.4 volts. Easy to adjust if you have ecu talk because you can just watch the figures on the screen as you make the adjustment. If it wants to die on you it might be worth increasing the idle on the aac valve, then readjust once your tps is set.

I have only had the car for 15 minutes. The owner has had the following done by 2 different mechanics

Head removed and checked as there were signs of a blown gasket between 5&6.
Cylinder head checked by machine shop ( has been reco'ed at some stage ) all ok
VRS set including new intake gasket etc fitted
Valve clearances set
New plugs and leads
Timing checked, cap and rotor button inspected, nearly new

What I found was....

With Idle air controller disconnected and manually idled up ( throttle cable adjusted up to compensate ). The thing runs well, idles smoothly and pulls through the rev range as it should. Just has no idle control, eg turn headlights on and the revs drop a little etc

Plug Idle air control solenoid back in and back throttle cable off, it will idle at 1000rpm no matter what you do. Go to give it a rev and you can hear a single loud click from the idle controller ( sounds like a relay click just a bit louder ) and the thing wants to die. undriveable. I tried adjusting the TPS to see if it will change the idle speed etc and as soon as I turn it slightly. The same click can be heard for the ISC and it will stall. Very strange..

My immediate thoughts were either a dead spot in the TPS causing a signal loss to the ISC, or a stuffed ISC itself

I have had issues with TPS and after much stuffing around with other things it was dodge wiring going into the TPS . while fixing that I swapped over the TPS with a spare I had and the car did what you described and sometimes ran fine but others it would stall and I would have to keep the revs up at the lights...

Also there did not seem to be any adjustment difference so I decided to put the original back in and straight away I could set the idle and it then ran perfect so the one I thought was good was stuffed!!!

My problem the whole time was just 3 wires but at least I know that other TPS is stuffed and just bin it!!!

On the back of the tb42e intake, there's 2 solenoids. Excuse me if I get the names wrong but one is the aac valve and the other is the fast idle compensation device or something or other. I know the fast idle solenoid makes a click when the aircon is turned on to compensate for the extra load placed on the engine. Is this the click you could be hearing?
Pull the entire valve assembly off and give it all a good clean with some good carb cleaner. There's a spring and plunger that the aac solenoid operates, ensure this operates freely. Also the plastic adjustment screw, unwind it and give the oring a moisten when vasoline.

As well as doing this, my 2nd step would be pulling the tps off and testing it with a multi meter for correct operation. It's mearly a potentiometer in a plastic box so test the resistance of it and ensure the resistance grows/drops continuously without any open circuit conditions, if that makes sence.
If all good, install it again and set it to the position it needs to be in, then go from there.

Pull the aac plug off and using a timing light ensure base timing is at 10degrees btc. Adjust if needed.

Run a tank of injector cleaner. I've used fuel doctor and it seems to work.

I've got the same engine and I had the same saga with trying to get it to idle properly, but mine runs like a dream now.