car starting badly. getting worse :(

dac69er

Super Moderator
just another small update. when the car starts and runs crap it seems as though it fires too early. you turn the key and it fires straight away. when the engine is warm then thats fine, but when cold it seems to cause this problem.
if it takes even a second or 2 to start then it will be fine. it is a strange one anyways!
 

fastglanza

Member +
problem is still there :(

its such a pain in the ring. im gonna throw on my stock leads. they are ancient but ive had trouble with magnecor before so ill eliminate that being a problem, just incase!!!

dac69er, texx and the other experienced guys...don't mean to interfere with this thread etc...i've always wondered what's a decent reading when testing plug leads say stock leads
 

Texx

Super Moderator
i've always wondered what's a decent reading when testing plug leads say stock leads

You wouldn't want to see a resistance reading of more than 25kΩ for each lead.

Generally the best way to test them is with the distributor cap removed and the leads still attached to the cap. You then take your resistance reading between the spark plug connector of each lead and the corresponding contact in the distributor cap. If you get a reading close to or more than 25kΩ, remove that lead from the cap and take another reading from each end of the lead. From there you should be able to determine if any increased resistance is within the lead or down to a poor connection at the distributor cap.
 

Texx

Super Moderator
any other ideas???

Have you tried another distributor? The pick-up coils may share a common ground. Any resistance to ground could cause some interference with the position signals that the ECU is unable to filter out.
 

dac69er

Super Moderator
Have you tried another distributor? The pick-up coils may share a common ground. Any resistance to ground could cause some interference with the position signals that the ECU is unable to filter out.

i havnt. was thinking of changing it.

what about adding an extra ground point from the distributor itself to the battery - and then to the body too? or would the coils not ground through that way?

if that doesnt work ill try and get myself another dizi :)
 

Texx

Super Moderator
It wouldn't hurt to try, but if an increased resistance exists internally between the pick-up coils and the body of the dizzy, an extra external earth won't likely make a lot of difference.
 

dac69er

Super Moderator
It wouldn't hurt to try, but if an increased resistance exists internally between the pick-up coils and the body of the dizzy, an extra external earth won't likely make a lot of difference.

well it wont cost me anything to try so worth a crack. ill try and get one made up tomorrow and see what happens.

if not ill pick up a distributor and see if that works!
 

Texx

Super Moderator
tried another distributor, no change :(

Seem to be running out of ideas now. :(

Have you tried another IAT sensor? I know you've tested the resistance of the one fitted, but it's easy enough to swap out. Did you test the IAT sensors resistance at the sensor and at the ECU?


Toyota Series - Engine Performance - Thermistors said:
One strategy the ECM uses to determine a cold engine start is by comparing the ECT and IAT signals. If both are within 8°C (15°F) of each other, the ECM assumes it is a cold start. This strategy is important because some diagnostic monitors, such as the EVAP monitor, are based on a cold start.
 

dac69er

Super Moderator
i did test at the sensor and at the ecu for both the cts and iat sensor.

i have had another idea which im trying.

the standard plug gaps are meant to be 1.1mm mine were set to 0.8. smaller plug gaps can give poor starting. as this car is just a runabout it will often get driven granny style ;) as the plugs are heat range 7 they would be more liable to choke up than standard heat range 6 plugs if just poodling about doing shorter distances.

that is my theory anyway. will just see what happens!
 
dac69er
i'm not sure that will work...but worth a try

i've seen plugs from 6 to 8 ran on these engines and plug gaps from 1.1mm to 0.5mm ran......and the cars still started fine and performed fine also......so, i'm not sure the above will solve your problem...........but try anyways:cool:
 

HYBRID

Super Moderator <a href="http://www.toyotagtturbo.
im running heat range 10 plugs without any problem, gap is at 0.6 iirc :) i agreee fully with what gorganl said above :)

kon
 

dac69er

Super Moderator
agreed, i have never had any problems with my other GT with various plugs and gaps, but im running out of ideas as ive tried pretty much everything else!!!

why are you running such a small gap kon? 1.1 is the standard gap
 
the guys run smaller gaps for a number of reasons....but in a lot of cases to stop the spark from being blown out when running high boost pressures
 

jamhustla

Member +
I've been having this same problem for the past few days. My mech suggested the fuel pressure may be the issue but i haven't got a chance for him to check it. It really irritates me...:mad::mad:
 

dac69er

Super Moderator
i know mate. mine has been like this for a good few months now and still dont know if its sorted. its intermittent to just have to wait and see very time im change something to see if it cures it.
 
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