4age dies when its hot

[harmsup_jai]

Ok, I've tried a few different things now, and the common symptom of the problem is that it dies when it gets up to temp. It did develop a loping idle, but that has mostly gone away when I blocked off the Cold Start section on the bottom of the throttle.

When it gets up to temp the revs start to go up and down very slightly, then as it gets hotter sometimes it will either just die quickly or other times it sort of trys to die, then catches it before it stalls, and then does it again and again until it dies totally.

Once it has died it won't start again until it is cold.

I have tried a different water temp sensor, different dizzy caps (new and old), the coil is new and the leads are new

Any thoughts at all of what this problem could be would be great.

Thanks
Blake





Old Post:

Hi
I have a freshly rebuilt 4age bigport in my car, it is running a standard computer, and a surge tank with a VL external fuel pump.

I first started it the other night, once I sorted out all the little glitches (leads were in the wrong spot, etc.) it started fine, then after a bit it sounded like it was dropping a cylinder or something.

I took it to the exhaust place to get an exhaust made, and it started fine there but they said that when they were checking for leaks it started to struggle then stalled.

Before I left the exhaust place I bled the cooling system and after a while of running fine the idle started to lope sort of, then it started to struggle and after I turned it off I couldn't turn it back on again. When I got it towed home I found that the spark plugs were covered in fuel, so after drying them out it started fine.

I then took it for a short drive and after a minute or two of running it started to feel like it was surging like when the old carb engine ran out of fuel. I turned around and it died as I was rolling back down my hill in neutral.

Does anyone have any suggestions on what this might be?

I've checked and its getting spark, the fuel rail is getting fuel

Blake

[AmyC]

Injector/s maybe stuck open. Can you hear them clicking at idle if you can get it running again ? You should be able to feel them clicking open and closed too.

[harmsup_jai]

yup injectors are clicking, which is also explained by it running fine up to temperature

update: it dies when it gets up to temperature (about 85-90 degrees), idle starts sort of hunting, but not as bad as hunting, it'll idle fine, then drop off for a bit, then idle fine again, then drop off, and it gets worse up until the point that it dies.

I did bleed the cooling system properly last night, any ideas?

edit: does anyone know what effects a dodgy water temp sensor for the ECU would have?

[Jonny Rochester]

Did you get the diagnostic codes from the ECU light?

Do you have every single sensor and wire hooked up to the ECU?

Do you have a 5th injector?

[harmsup_jai]

<div class='quotetop'>QUOTE (Jonny Rochester @ Mar 21 2008, 02:02 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=505347)</div>
Did you get the diagnostic codes from the ECU light?

Do you have every single sensor and wire hooked up to the ECU?

Do you have a 5th injector?[/b]

code 3, and code 4
I think 3 is because it hasn't been sparking, the plugs come out wet with fuel, and 4 is because i have a feeling that temp sensor is the problem

Oxygen sensor isn't connected, and there is no cold start circuit, everything else is connected

yes, I have a cold start injector




EDIT: the dizzy is getting quite hot when it gets up to temperature, could that cause similar issues?

[AmyC]

No oxygen sensor wont help the situation but it wouldn't be this bad either. Dizzy getting hot is not normal, I can take mine for a thrash and its still cool with in reason.

Whats the inside of the cap and dizzy look like when its cold and then when its hot ?

I'm just throwing out ideas but maybe the dizzy getting hot is causing the pick up gap to be increased thus slowly loosing spark ?

[harmsup_jai]

The inside of the dizzy looks the same hot or cold, I tried a different cap - no difference.

First post edited as I have sort of found a common symptom of the problem.

About to go swap the dizzy internals

[parrot]

What Jonny said. Check you have all the sensors connected up properly and they are setup properly.

Look here (http://www.aeu86.org/index/technical-ae86-manuals/cat/9/topic=5158) and follow the diagnostic charts methodically rather than guessing.

The oxy sensor will not make any difference to your problem. Do you have a fuel pressure regulator on the fuel rail?

Check your idle dashpot settings, TPS, the vacuums etc one at a time till you find it.

Start with your codes and clear them when you resolve them.

It is unlikely to be anything faulty, rather something you have left off, not wired properly or adjusted properly.

[harmsup_jai]

Hi
I do have a Fuel Reg, its just the standard one.

I don't have a throttle dashpot, the TPS is set correctly, both air and water temp sensors are operating correctly, I have tried a different MAP sensor to no avail, and different pickups for the Dizzy

Codes I have received were 3, 4 and 7
7 was due to trying to start the car with the TPS unplugged, and 4 was due to trying to start the car with the temp sensor unplugged, 3 I cannot work out, using that diagnostic manual the wiring for the igniter checks out. (gets spark and correct voltage at the ECU)

The only vacuum lines connected are one to the MAP sensor, one to the Fuel Reg and one to the charcoal canister, and these are all connected up correctly as per my previous thread. All others are blocked off.
I am fairly confident that the loom has been done correctly as I had it totally stripped and laid out on the floor to confirm all of the wiring before I installed it into the car

The other problem I have now discovered is that before it temps up and dies, it won't rev above 2500rpm. I only just discovered this last time I started it as I have never tried to rev it whilst it was stationary.

Blake

[rthy]

wats ur idle rpm when cold?

[harmsup_jai]

I've been changing things, so I have been adjusting it, so its been different, usually around 1100-1500ish

[Sparkle86]

<div class='quotetop'>QUOTE (boh @ Mar 21 2008, 11:21 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=505289)</div>
It did develop a loping idle, but that has mostly gone away when I blocked off the Cold Start section on the bottom of the throttle.[/b]

Are you refering to the idle stepper? Did you block off the hole thing (eg, remove idle stepper and replace with blanking plate) or just the vacume lines? Are the water lines hooked up to the throttle body?

[harmsup_jai]

[attachment=24027:parts_006__Small_.jpg]
I took off the whole highlighted section and put a piece of gasket paper in to block it all off, then put it back on. I didn't have the cooling lines hooked up and thats why I did it.
I also have vacuum caps on all of the fittings, but they aren't really doing anything

[rthy]

i think i had the same problem cos i did the same thing not so long ago, can't remember what i did to fix this

when cold it would idle around 500-700 and 800-900 when warm

[harmsup_jai]

Problem Solved!
I replaced the ignitor and coil and now it idles fine, runs perfectly up to temp.
I might try and work out if it was a dodgy ignitor or if the coil I had was the wrong one for the car (Bosch GT40), but for now I'm just happy its going

Thanks Leo!!!!

[parrot]

There is your answer. You needed the right coil!