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4JB1 cranky cold start

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4JB1 cranky cold start

Postby magicdeo » Wed Feb 13, 2019 5:26 am

Gday. During this time of year my 97 rodeo with 4JB1 starts great every time. With the tempurature due to drop off soon I thought i would see if anyone else has the same issue.
As said, in summer, cold start is not an issue. During the colder months however, when started the engine wants to idle at about 400rpm when started and will stall unless given a few revs. If you start it and hold the revs at about 750rpm for 30 seconds or so then there is no issue. I just use the hand throttle but to be honest i dont believe i should have to. It also blows a lot of grey smoke which wont stop until the car is hot. Please be aware that the injectors, pump and primer have all been replaced/rebuilt., (primer is a delphi CAV style with glass bowl and 296 cartridge). There was no change at all after this. I have had my issues with air leaks and know all about them but this one is different. As stated the car runs fine (apart from all the smoke) if given a few revs but i want to eliminate the smoke and the need for the hand throttle when cold. I dont believe it should be needed with new injectors and pump. Could it be something simple like timing slightly retarded?
Cheers
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Re: 4JB1 cranky cold start

Postby geeves » Wed Feb 13, 2019 2:18 pm

Do the later 4jb1s use the same cold start system as the early ones? If they do that could be normal. My 89 bighorn was like that. Fine above 15c but would smoke on start like yours from 5 to 15 but below 5 the cold start did its thing and it started perfect. On these the cold start activates below 5c and advances the timing a little and increases the glow time from 0.5s to 30s.vyou can trick it by removing the wire on the thermostat housing so it thinks its cold. Glow will be longer and it will start fine but knock under power. I did think about wiring a switch into this lead for those starts that were not quite that cold
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4JB1 cranky cold start

Postby magicdeo » Wed Feb 13, 2019 3:37 pm

Thanks Geeves. When cold, my glow plugs come on for about 15 seconds or so. Not 30 but still a fair time. The advancement also works beause she knocks until hot. When this happens it still smokes and wont idle
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Re: 4JB1 cranky cold start

Postby turnturn » Wed Feb 13, 2019 6:19 pm

I use the hand throttle (or a bit of foot pedal) every day until the engine is warm. No big deal. Early 90's 4Jb1-t.
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Re: 4JB1 cranky cold start

Postby magicdeo » Thu Feb 14, 2019 5:27 pm

Yeah I know but after 4 years its starting to wear a bit thin especially since IP and injectors are new. Its more the smoke that annoys me
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Re: 4JB1 cranky cold start

Postby geeves » Sat Feb 16, 2019 6:37 pm

The motor is a 30 year old design. Great engine but a bit of smoke on start up is not unusual
Sanding your knuckles before starting work can help. That way you cant skin them
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