Rough idle and stalling after in idle for a while

[emir]

Hello all,

I have just registered on this forum. I am a proud owner of 1987 Mk1b. Just one of two of these great cars in Bosnia and Herzegovina (south-east) europe. its red of course.
The car has quite a few problems, and i knew this before buying it, but decided to do it anyway and get it into proper shape.
it has the 5th gear pop-out, passanger window not working, oil pressure gauge not working, a rough idle, cracked sunroof, etc. Good thing is it has almost no signs of rust, or welding. The bodywork is very nice.

I decided to tackle the problems on the car one by one, replace parts etc. until i get the car into great shape.

The first thing i want to tackle is the rough idle thing as it is very annoying.
Basically when the car starts it sits close to 2.000 rpm in idle which is fine. As the idle drops and the car warms up, a misfire can be noticed. As minutes go by, the misfire gets worse and worse and the car eventually stalls. when that happens the engne runs as low as 500 rpm.
I replaced the battery and bought and installed proper spark-plugs. No effect.
I tried disconnecting the cable on the side of the t-vis inlet manifold - No effect
I can prevent the car from staling by turning the screw that is on the t-vis inlet manifold which increases the idle speed. this just makes the car run a fast idle. it wont stall like this, but i can still hear the damn misfire in the background of the loud engine noise. it does reduce a bit, but still.
Tomorrow I am going to drain/bleed/refill coolant to see if this resolves it as I have heard it can cause a rough idle.
Anyone experienced this before, ideas, suggestions, anything is welcome. I am thinking it might be the head gasket (hope not) or maybe i can solve this by replacing the whole t-vis thing. The car has been sitting ina garage un-driven for quite some time. Perhaps I should clean something? replace the distributor? i dont even know here to start
Cheers

[kaiowas]

I'd start with making sure the ignition components are all in good shape. Leads, dizzy cap and rotor are an easy and cheap starting point.

[emir]

I'd start with making sure the ignition components are all in good shape. Leads, dizzy cap and rotor are an easy and cheap starting point.

Sorry, english isnt my native. Leads are the wire things that connect to the spark plugs right? 4 of em.

Do i need to replace the distributor as a whole or just the cap. i found a cap and rotor on two r us. So I might order those.

[Lauren]

Replace the distributor cap and rotor arm. Use genuine parts.

If the leads are Toyota I'd likely leave them. I wouldn't use cheap alternatives like Magnecor etc.

I would say change the dizzy cap and rotor arm as a starting point.

[tottacrolla]

Check for error codes stored in the ecu.

http://myweb.tiscali.co.uk/jimilawson/V ... Codes.html

[emir]

Check for error codes stored in the ecu.

Not a single warning light is lit on the dashboard, all go away after the turn of the key. Does the ECU even store something when the engine check light isnt on?

[Lauren]

That doesn't necessarily mean there aren't error codes.

ECU stores error codes check for them, it's not hard.

[oukie]

Replace the distributor cap and rotor arm. Use genuine parts.

If the leads are Toyota I'd likely leave them. I wouldn't use cheap alternatives like Magnecor etc.

I would say change the dizzy cap and rotor arm as a starting point.

Thats not the best advice, I would hardly call Magncors a cheap alternative, or unless you think £80 is cheap

In fact I would call them a bloody good quality item that have outlasted my Toyota set.

@OP

I would hold off draining the coolant just just yet, do as others have suggested and check all ignition componants, coolant change is a big job and one that must be done correctly to get all the air out of the system.

Also there might be an air leak between one of the little air hoses and the TVIS as I had a similar issue which was resolved by replacing these.

Your passenger window, have you tried the window lock button?, thats on the drivers door control, these easily get pushed and then people think the passenger window is broken when all it is, is the the switch has turned it off.

Brakes, have you looked at the brakes yet? as the car has stood for some time I would expect the rear calipers to be seized, they are very prone to this.
Chris

[Lauren]

At £80 Magnecors are still a cheap alternative compared to £112 or so for OEM leads.

However, Mark had a set of Magnecors years ago that fell apart. They are not as good quality as OEM leads which will last 15 years or so easily.

When it comes to ignition components OEM is best. That's good advice.

[tottacrolla]

At £80 Magnecors are still a cheap alternative compared to £112 or so for OEM leads.

However, Mark had a set of Magnecors years ago that fell apart. They are not as good quality as OEM leads which will last 15 years or so easily.

When it comes to ignition components OEM is best. That's good advice.

I would go further and say for any standard replacement part OEM is best.
My AE86 rear calipers are a good example, to the eye the pattern part looks exactly the same as the original but when you dig a little deeper you find that the genuine Toyota part uses a nicely engineered roller bearing supported hand brake mechanism. The pattern part uses a bronze bushing that seizes for fun.

[elbon50]

Have you tried checking for engine codes yet Emir ?

There may be something stored even though the check engine light isn't coming on

That's the first step I would take

[Lauren]

I would go further and say for any standard replacement part OEM is best.
My AE86 rear calipers are a good example, to the eye the pattern part looks exactly the same as the original but when you dig a little deeper you find that the genuine Toyota part uses a nicely engineered roller bearing supported hand brake mechanism. The pattern part uses a bronze bushing that seizes for fun.

Totally agree.

The only time I don't use OEM parts is say for stuff like HKS cams or high end JDM tuner stuff or the equivalent from the UK. The upshot is, for all the time I've had Toyotas they've been reliable. OEM parts are key.

Something else I noticed with Bluprint parts, is that Mark had a Bluprint waterpump on one of his SC's, when we replaced it the impeller had dissapeared to nothing as it was just a ferrous metal. The Toyota one we replaced it with had a brass impeller. Things are generally cheaper for a reason I find.

[emir]

Have you tried checking for engine codes yet Emir ?

There may be something stored even though the check engine light isn't coming on

That's the first step I would take

I ordered a distributor cap and a rotor arm and will replace them as soon as they get here.
I wanted to do the engine code thing until they get here. First thing I dont know is what is a service wire? just a piece of regular wire? Also, my car doesnt have a resonator like the one in the instructions. that black plastic thing. My car has a big metally thing there, i think its a map or maf or something. i have no idea where are the terminals i should short?

I replaced the coolant and the thermostat the other day. Although I am no mechanic it wasnt as scary as I initially thought it would be. The car didnt overheat and the engine temperature gauge worked fine after i replaced the thermostat (so bloody hard to get at). I put pink ethilen-glycol based coolant in. The weird thing is that even after i poured 12,4 litres of coolant into the car. the coolant still didnt show up at the water filler cap. engine didnt overheat, and i drove it quite hard for a bit just to test. stood rock solid at middle. I will check tomorrow to see if more coolant can be added. a bit puzzled. The rough idle didnt go away, but i dont think the rough idle is due to air in the cooling system anyways. sorry for the off-topic.

[Lauren]

Five seconds on google turns up your answer.

http://www.club4ag.com/faq_and_tech_pag ... 0Codes.htm

http://www.challoner.com/mr2/tech/diagnostics.html

The service wire is any old paper clip you happen to have lying around. Short terminals TE1 and E1.

[emir]

Five seconds on google turns up your answer.



The service wire is any old paper clip you happen to have lying around. Short terminals TE1 and E1.

I'm sorry but I donth think you understood what I was asking.
"Short terminals TE1 and E1 of the check connector of the diagnosis connector cluster."
It says this in all the instructions. I understand this. But i dont get where is the giagnosis connector cluster, where the terminals are. thats what I am asking.

[Lauren]

Okay it should be on the rear engine bulkhead.

[emir]

Okay it should be on the rear engine bulkhead.

Thank you, Im gonna go find it and see what it says.

[Lauren]

It's a small black box that has a lead coming off it. Should be fairly easy to spot.

Sorry I can't find a pic, I'm sure someone else will have one.

[elbon50]

The diagnostic connector is a small black plastic box with a lid Emir

It's fastened to the rear engine bay bulkhead at the gearbox end of the bay

Lift the lid of the box & you'll see the connectors

There are markings on the lid that show which are E1 & T

A "service wire" is just anything you have to hand .... a bent paperclip is good

Bend the paperclip so you can put one end into E1 & the other into T

Then switch on the ignition & see what pattern of flashes you get

[emir]

The diagnostic connector is a small black plastic box with a lid Emir

It's fastened to the rear engine bay bulkhead at the gearbox end of the bay

Lift the lid of the box & you'll see the connectors

There are markings on the lid that show which are E1 & T

A "service wire" is just anything you have to hand .... a bent paperclip is good

Bend the paperclip so you can put one end into E1 & the other into T

Then switch on the ignition & see what pattern of flashes you get

Ok, i got to it today, printed the instructions from several pages on how to do this. got a bent paper clip and went for the diagnosis. Nothing, there's nothing stored in the computer. I just get the intermittent quick flash.
My rotor arm and distributor cap also arrived today and I replaced them as well. I also saw the old ones were both looking very fine once i removed them, but i put the new ones in just to be sure.
The stupid rough idle with a stall after a while is still there.
Whats next? I guess the leads, or the T-vis? Should I get rid of the whole T-vis thing or just the part where the throttle body valve thing is?

Thanks to everyone for all your kind help and great advice, feels better when having someone helping