Hard start when hot, Please help!

[Nafeez2125]

Hello all,

ive been having a problem with my ep91 glanza v for a while now. it starts fine when the engine is cold but when the engine is up to temperature, turn it off and leave it for like 15 mins and start it again , it will crank for like 3 to 5 seconds and then start. i really dont know what is causing this.

Ive replaced the coolant sensor(3 pins)

Tunning development 255 lph fuel pump

Magnecor HT leads

new NGK copper core spark plugs (Heard that the irridium one can cause hard start)

new battery

new uprated alternator

new geniune dizzy cap, rotor arm

things that im a bit concerned now is the fuel pressure regulator but if it was the regulator then even cold start would have been difficult. am i right?

ignitor and ignition coil

Please help!! i really dont know what to check anymore.

Thanks guys

[funny onion]

I know it's not helpful but my GT has done this for 6 years. It's always cranked more when hot, but it's never failed to start. Usually ECU temp sensor but if you've changed it...

[Nafeez2125]

I know it's not helpful but my GT has done this for 6 years. It's always cranked more when hot, but it's never failed to start. Usually ECU temp sensor but if you've changed it...

is temp sensor the only one in charge for starting up the engine? or is there other sensor that contribute to start up

Thanks

[funny onion]

There's a lot of sensors that contribute to start up really. If you have a load of spares you could try swapping out stuff like TPS, ICV, IAT etc.

[gorganl2000]

by any chance do you have an engine code?---diagnostic???

what grade plugs?

[Nafeez2125]

by any chance do you have an engine code?---diagnostic???

what grade plugs?

no engine codes gorgan. plugs are NGK copper core heat range 7

[Nafeez2125]

Just an update, ive bridge the TE1 and E1 and start the engine when it was hot and it started straight away. does that mean anything?

[funny onion]

Just had a thought, have you ever checked the static timing? lock the timing (I can't remember which ports on the diagnostic to bridge but it will be on here somewhere) and get a timing strobe and check the timing. May need advancing or retarding... I think they're meant to be set to 10deg BTDC as standard

[Nafeez2125]

i heard that but never tried it.

bridge the TE1 and E1 on a warm engine

set the idle to 700 rpm by adjusting the scew on top of the intake manifold

once idle is at 700 check if the timing is 10 degrees BTDC

Am i right? anyone?

[funny onion]

sounds right to me but maybe someone can confirm, I'm sure there is a wiki or something on here about it

[gorganl2000]

i somehow recall someone having a similar issue a LONG time ago and it turned out to be some relay (maybe efi or something along those lines) that was going bad.

but that's just somewhat of a thought stuck in my head----i could be wrong

maybe take a look at your fuse box to make sure no corrosion and everything is in order there----certainly can't hurt

Edited March 30, 2017 by gorganl2000

[Nafeez2125]

i somehow recall someone having a similar issue a LONG time ago and it turned out to be some relay (maybe efi or something along those lines) that was going bad.

but that's just somewhat of a thought stuck in my head----i could be wrong

maybe take a look at your fuse box to make sure no corrosion and everything is in order there----certainly can't hurt

okay, i will have a look this week end. hopefully i found something wrong in the fuse box.

Thanks again for your help.

[Nafeez2125]

Hi Guys,

Quick update, ive checked all the relays and all off them are in good shape. resistance across the coils was around 87 to 89 ohm and the contact wasn't burnt. ive open all of them. the only relay with a black contact was the MG CLT relay under the bonnet but its got nothing to do with ignition its for aircon.

after doing some research i found out that the EFI wouldn't trigger until it senses 300 rpm. so for my situation im thinking when the engine is cold and the starter is cold is easy to get 300rpm and it turns on straight away but when the engine is hot the starter get a heat soak and becomes lazy, therefore takes longer to reach 300 rpm and trigger the EFI and fuel pump. so i think the problem is the starter motor maybe needs new brushes or armature. starting to get weak after 19 years

what do you thing guys?

Thanks again

[Starlet__SR]

Hi Guys,

Quick update, ive checked all the relays and all off them are in good shape. resistance across the coils was around 87 to 89 ohm and the contact wasn't burnt. ive open all of them. the only relay with a black contact was the MG CLT relay under the bonnet but its got nothing to do with ignition its for aircon.

after doing some research i found out that the EFI wouldn't trigger until it senses 300 rpm. so for my situation im thinking when the engine is cold and the starter is cold is easy to get 300rpm and it turns on straight away but when the engine is hot the starter get a heat soak and becomes lazy, therefore takes longer to reach 300 rpm and trigger the EFI and fuel pump. so i think the problem is the starter motor maybe needs new brushes or armature. starting to get weak after 19 years

what do you thing guys?

Thanks again

Was just about to suggest the starter motor. Seems quite apparent on a few cars from what I've seen lol. Corolla D4D is an example. Even my 16 plate vivaro has the same issue lol.