car starting badly. getting worse :(

dac69er

Super Moderator
had the problem in the summer with the car sometimes being hard to start or starting and chugging away for a bit until it "cleared" itself.

changed almost everything i could think of and it never really went away. its now getting worse again and i really dont know what to try next.

when it does it you can smell unburnt fuel so im assuming fuelling side of things is fine.


this is what i have changed/checked:

changed plugs.

magnecor leads, dizi cap and rotor arm are under 2 years old and look fine.

changed coil pack and ignitor.

checked all earth points i could find.

tried a different ecu.

new lambda sensor.

checked readings of cts, tps and intake temp sensor and all read the same
as my other GT that runs fine.

changed injectors.

changed fpr.

changed fuel pump.

changed coolant temp sensor.

changed distributor.

replaced fuel filter 6 months ago.

replaced idle control solenoid valve with a good one.

battery is 6months old.

alternator replaced with recon unit.


think thats about it :p


car sometimes starts perfectly. idles fine once its cleared itself. performance is good, no misfires, smoothly pulls up to 1 bar boost without a worry.

any other ideas?
 
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Harvey

Member +
Could possibly be the distributor? Maybe try swapping the dizzy's over as sounds like you have 2 GT? See if the problem shifts!

Just remember to mark where the dizzy is now. Altho of course maybe the dizzy is wrong position timing wise... But then that would in thoery cause issue every time you try starting not random.
 

dac69er

Super Moderator
did you check the timing is bang on?

i replaced the cambelt before i put the car on the road just over 6 months ago. checked the ignition timing afterwards and it was at 0 degrees. adjusted to 10.

it was fine the 1st 2 month of driving it then it started having this problem one day.

the distributor seemed fine when i removed it to replace the leaking o'ring seal. i guess i could try another one in there. i wouldnt have thought it would just go bad for no reason? and only on cold startup?
 

madman

Member +
did you adjust it through the dizzy cap or re-do the timing belt? if you did it throught the dizzy the cam timing will be out causing her to run rough so you will need to do the belt again.
 

Harvey

Member +
My AW11 before i bought it had 'hot' starting issues apparently and was traced back to the dizzy, rebuilt was fine. Just a thought thats all, they might be able to cause random cold start issues too!
 

dac69er

Super Moderator
My AW11 before i bought it had 'hot' starting issues apparently and was traced back to the dizzy, rebuilt was fine. Just a thought thats all, they might be able to cause random cold start issues too!

when you say you rebuilt the dizi, what exactly did you do to it?

im on call for work all this week so dont really want to dismantle anything incase something goes wrong. ill have a look at it next weekend and see whats what.

one other thing. 99% of the time, if it starts to chug a bit when it starts i just touch the throttle a bit and it clears and is perfect again!
can the tps sensors get a bit intermittent? i have measured it before and it seemed fine???
 

Texx

Super Moderator
I'd check the TPS again, particularly the idle position. I'm guessing the 4E uses the later on-off type TPS that grounds the IDL when the throttle is closed?
 
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dac69er

Super Moderator
Done a compression test buddy?

done one 6 months ago and it was very good. 170 across all 4 i think it was. cant imagine it has done bad that quick with no other symptoms?

i dont think its anything to do with that, its too intermittent and clears itself almost straight away and runs perfect!
 

dac69er

Super Moderator
I'd check the TPS again, particularly the idle position. I'm guessing the 4E uses the later on-off type TPS that grounds the IDL when the throttle is closed?

it is an on/off one. has 1 common pin and switches one way at closed throttle and the other way at wot.

ill try and reset it according to the guide on here and see what happens
 

Texx

Super Moderator
Toyota used 2 different types of on-off TPS, the earlier type switched a reference voltage and the later switched a ground, I'm just not sure which type they fitted to the 4E?

It may also be worth swapping the MAP sensors and see if the fault transfers to your other car.

I've experienced your exact same problem, but it's only ever happened twice in nearly 3 years.
 

dac69er

Super Moderator
not sure what way it switches tbh mate. according to the diagrams i have it switches the voltage to ground!


yeah, i did think map sensor, it runs similarly to when you try and start the car with the map sensor not plugged in.

only thing that makes me think it isnt that is that i get no error codes and pressure snesor usually either go bad or not!

ill do the TPS first and if its still a problem ill try the map sensor.
cheers mate. gives me a few other things to try at least
 
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dac69er

Super Moderator
update.

tps was slightly out so adjusted it as per the tutorial. checked plug gaps. checked distributor to see if anything was amiss. checked pipe to map sensor wasnt blocked at all.

car started perfect this morning, then when i went to go home 8 hrs later it was crap again :(


going to change the map sensor for the one off my other GT and see what happens!
 

sx_turbo

Lifer
without sounding alarming duncan, but i had exact thing with my gt a couple of months ago, i done all the things u said and it turned out it was my headgasket,

have you done a sniffer test with the coolant?
 

dac69er

Super Moderator
its all fine last time i checked. the headgasket was new genuine toyota when the engine was fitted 2 or 3 years ago. its not using any amount of coolant or oil either.

surely if it was headgasket it wouldnt come and go like it does would it, im sure there would be other symptoms???

ill have another look over things tomorrow when its light and see what i come up with
 

sx_turbo

Lifer
mine came and went depending on how i drove it.

although it did start to use coolant.

have u tried a different set of injectors?

i'm just throwing random ideas
 

Fatman

Member +
From the sounds of things what you're experiencing is an overly rich startup condition. Based on the coolant temp sensor, the standard ECU will dump in fuel on cold start as well as activating the idle up solenoid for an appropriate amount of air to go along with that fuel. If that solenoid is bung or the wiring is dodgy then the car will stumble along under extremely rich condition until the water temp sender warms up enough to clear the cold start function. Explains why it's getting worse now (getting colder) and explains why it's intermittant. Either wiring or solenoid is sometimes firing, sometimes not.

With some additional throttle does the idle pick up and run correctly?
 
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