Any more info? Running LPG? How many km's on engine? How cold is cold?

 

No LPG,every first start in morning 8am approx is a rough idle surging from 400rpm to 1200 for about 20 secs if it doesn't stall .Usually if it stalls the next start, idle is fine at aprox 1200 and slowly drops to warm idle of aprox 700rpm and then no probs for rest of day.....

150 k on engine..

 

Mine is doing the exact same thing.in the morning I start it and does as you say,turn it off and starts straight Back up perfect. Try turning on ignition until fuel pump stops,turn off for 5 secs and then back on till fuel pump stops and see what happens. I'm hunting for answers on this too

 

its your automatic choke sensor mate, cheap fix, when the sensor is playing up it will run rough, if the sensor is completely stuffed it will stall. only when motor is cold.

If its doing the same thing but when the motor is hot, i dare say it would be your maf.

 

The idle air control valve??

 

Where would I find the auto choke sensor ? Are you referring to etc sensor?

 

I am thinking it could be a faulty engine temp coolant sensor but did not want to spend 92 dollars until I have some further feed back.Cheers.

 

Yep mines done it on an off for the last 2 years or so, started at about 170,000kms now got 225,000 on it. My mates 2002 ti also does the same thing.

I'm on LPG venturi, he's on LPG injected. Oddly enough if I hold the overide and start it on LPG only (normally starts on ULP and switches over to LPG) it does not do it. So it's actually a ULP problem.

Never been able to work it out.

Normally we just tick the starter, turn it off and start it and it starts fine. Only ever happens first start of the day. Even if you let it sit all day it won't do it again unless it's over night and cold.

 

I'm exactly the same as you Jeff... Hey,does yours change gears from 2nd to 3rd and 3rd to 4th crappy when about 1/3 throttle??? Like power cuts out mid change??

This startup problem I'm thinking is fuel related.ie pressure or a temp sender problem.

Actually I have a blatz cable.in the morning I'll do a test and tell the ecu its colder that it actually is and see what it does

 

Let us know what you find out, I'd love to know what it is, it's just one of those little niggly things!

 

Mine does the same but at first i tried leaving ignition on for a bit but that didn't help so now i turn key straight away , no waiting and it starts pretty good. Only does it in mornings not later in day

 

Im on LPG and have the same drama i.e cold start rough idle, turn off and back on smooth again. only first start up in the morning or if it has sat all day at work for instance. Its a 2002 gu 2 4.8. auto.

 

howdy

hi did you solve this problem pls !tom

 

Pulled out coolant temp sensor and checked resistance in different temp water seems to be operating as per specs!

 

Left my laptop at a friends.will try soon. I actually think I have an idea of what it could be....ok follow me here

*Starts up really rough and sometimes stalls,but only after sitting a long period
*Priming fuel pump up a few times doesn't seem to make a difference(fuel pressure)
*May start better on lpg

Now,could it be leaking injectors? Sitting a long time,fuel gathers in cylinders and when started misses.

Could this be a possibility?

 

Not sure about injector leak theory so I have given throttle body clean and checked for possible air leak post throttle body.I have checked for trouble codes manually none aparent ,will check in morning to see if any different.

 

Like the leak theory mins a bit gas stinky when it starts up but that gos soon enough

 

Mine also smells fuelie when it does it. I'm still yet to connect laptop and have a look.will do soon

 

Never had a single issue but it was lumpy. I changed fuel to 100 octane and now its just a pleasure to hear it purrrrring in the drive way. I had valves clearance checked and ajusted on its first service and at 1000 k I had cyl bank compression test done. Never seen a engine so close like the 4.8 is in regards to comp ratio across all 6cyl.

 

I don't think it's an injector. I think it's electrical/sensor because if I just tick the starter for half a second, turn the ignition off all the way and start it, it's fine....

 

Ok.. Lets not worry about injectors leaking then. Lets focus on elec. Now mine smells rich when I it does it. Now,I'm thinking its spark then. Not firing in all cylinders and not burning fuel,hence the smell.

So,what could cause this?

 

Also,sometimes when it starts fine,it hunts really bad for like 4 secs. Nearly stalls to 1500 and repeats this about 4 times before leveling out

 

No luck when started in morning it was still rough but the following day when started in the middle of day it was fine.Car is garaged,fault appears to be temp related...

 

If you think its temp related bypass the sensor

 

Has anyone got a Blatz cable to do some diagnoses as Im thinking it needs a throttle learn procedure and or clearing all learnt data. With this cable you can check the temp sensor reading as this is critical to engine operation hot or cold and can not be bypassed.

 

It can be done. Look at wire diagram its a sensor or post it here and i show you how.

I look at the power valve actuator valve.

 

It can be done. Look at wire diagram its a sensor or post it here and i show you how.

I look at the power valve actuator valve.

Yes possible with specfic sized resistor to temp corralation. Would run like crap once warmed up tho.

 

I have the cable.will be checking in the morning. I had something interesting happenI was advancing the cam position sensor and my gear change hesitation seemed to have disappeared and starts up quicker.will connect my laptop up in the morning and data log everything and note as much as I can

 

Yeh mine was out by 6deg with the timing light, advanced it to 10deg btdc and runs heaps smoother and more responsive.