Cold start issue 4th gen jdm vtec - any suggestions?

Post by **vanzep** » Sun Oct 30, 2016 1:17 pm

Ive had a starting issue from cold on my BB1 - it turns over fine and almost catches but not quite - takes around 4 or 5 cranks to get it going. Once running it runs spot on and restarts all day on the first crank.
Ive replaced and cleaned quite a few items and checked disti timing etc

This morning i used some Holts Cold Start spray - sprayed for 2 seconds into intake manifold - and the car started on the first crank.
I also noticed the fast idle was slightly raised to around 1800rpm whereas before it had always been dead on 1500rpm.

This is encouraging to say the least

and im sure this helps narrow down where the fault is...but not being a mechanic im open to suggestions as where to go from here.

Thought some of you might be able to shed some light

Post by **ek9sid** » Sun Oct 30, 2016 4:31 pm

Compression ok? Coolant bled ok?

Post by **newkid** » Sun Oct 30, 2016 4:32 pm

FPR or pump.

Post by **vanzep** » Sun Oct 30, 2016 9:33 pm

ek9sid wrote:Compression ok? Coolant bled ok?

Coolant is all ok - flushed rad and put new coolant in and fitted new rad cap.
Also swapped out the IACV and bled&topped up the system.

Dont think iv checked the compression yet as i dont think there is any issue there

newkid wrote:FPR or pump.

any idea if there is any easy way to test the FPR?
Ive run a couple of courses of fuel line / injector cleaner through there just in case but not really seen any improvement.
I can hear the pump prime and main relay click but i guess its worth checking again

Post by **newkid** » Sun Oct 30, 2016 10:02 pm

I've honestly no idea bud.

Post by **NafemanNathan** » Sun Oct 30, 2016 10:40 pm

Battery? Dizzy?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sun Oct 30, 2016 11:23 pm

Coolant temp sensor reading correctly? (ecu uses that to richen the mixture when cold)

Post by **vanzep** » Mon Oct 31, 2016 9:35 am

NafemanNathan wrote:Battery? Dizzy?

Ive fitted a new Honda Battery and swapped out the dizzy for a good 2nd hand one - got a new dizzy which i can fit but dont think its the problem. Also checked voltage from alternator.

wurlycorner wrote:Coolant temp sensor reading correctly? (ecu uses that to richen the mixture when cold)

Now that has been mentioned to me before and i do have a replacement temp sensor. This is the one that screws into the side of the head under the dizzy. Im assuming its easy to swap it out.
Think i will look at doing this in the next day or two.

Thanks for all the suggestions.

Post by **NafemanNathan** » Mon Oct 31, 2016 10:10 am

vanzep wrote:Now that has been mentioned to me before and i do have a replacement temp sensor. This is the one that screws into the side of the head under the dizzy. Im assuming its easy to swap it out.
Think i will look at doing this in the next day or two.

That's the one, but go oh so careful removing it and screwing the new one in. As they're a themostat they are hollow and so can shear really easily.

Regarding the battery, I've experienced multiple times on various Preludes (3rd, 4ths and 5th) that if the battery is slightly under fully charged that there can not be enough get up and go to turn the engine over and fire.

Post by **vanzep** » Mon Oct 31, 2016 7:20 pm

thanks nafe - i will be careful removing and refitting the sensor
and i will double check voltage on the battery before cranking.....

i was also wondering if it could be a problem with the TPS

is that a possibility? ive got spare TPS sensors if it worth a shot....