Aerodeck issues on start up

farlow · Post by **farlow** » Thu Jan 29, 2015 4:34 pm

Right guys, I've been having a spot of bother with the deck recently on start up, well it might have started last year so I'll start from the beginning.

As some of you may know I had some trouble getting it through its mot last year on emissions. I put the cat back in, replaced it with a new cat, had it terracleaned, refitted the original ECU etc etc... Anyway after replacing the original ecu I found that it seemed to run a start a little smoother so decided to leave it in until I get the p72 chipped. A month or so after passing its mot I decided to put the decat back in but it didn't seem to run quite right, mainly on start up and wasn't quite idling as it should. I put this down to the fact that the ecu hadn't been reset but did not immediately reset it.

Anyway since the really cold weather has hit the problem has got worse. If it is really cold it won't start at all without a boot full of throttle and then won't maintain idle. It idles up and down and occasionally cuts out unless you keep your foot on the gas. Once warm the problem goes away and it will start up again no bother.

I have since reset the ecu and at first it seemed to be better but getting into it this morning after nightshift it didn't want to know. I know it is really cold and the cars getting on a bit but surely this isn't normal. Also I'm pretty sure it wasn't like this last year.

Any help would be much appreciated. I'm guessing that it may be a fault with like an iac valve or something similar but is there an easy way to diagnose such a fault.

Thanks in advance.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu Jan 29, 2015 4:41 pm

Without knowing B series engines at all really...
It sounds like either a fault with the thermo sensor for the ECU (coolant temp) or assuming it has a similar system for adjusting idle as an H series, then a coolant air lock.
So as starters, I'd suggest bleeding the coolant and testing the thermo sensor.

Alternatively, does it have any sensors by way of measuring the intake air temp?

Does it have a MAP or MAF sensor?

Do you have access to the service manuals for this car?

Post by **Lude-dude** » Thu Jan 29, 2015 4:43 pm

sounds like my lude, I'm missing the fitv valve due to removing it all together

so may be related to something similar, not sure if your Honda has fitv valve.

located bottom of throttle body on the lude

farlow · Post by **farlow** » Thu Jan 29, 2015 4:57 pm

wurlycorner wrote:Without knowing B series engines at all really...
It sounds like either a fault with the thermo sensor for the ECU (coolant temp) or assuming it has a similar system for adjusting idle as an H series, then a coolant air lock.
So as starters, I'd suggest bleeding the coolant and testing the thermo sensor.

Alternatively, does it have any sensors by way of measuring the intake air temp?

Does it have a MAP or MAF sensor?

Do you have access to the service manuals for this car?

The coolant was replaced last year when I changed the thermostat and as far as I'm aware it hasn't been touched since but I can certainly give it a bleed to see if that works.

I believe it has a map sensor but not sure about the intake air temp.

Lude-dude wrote:sounds like my lude, I'm missing the fitv valve due to removing it all together

so may be related to something similar, not sure if your Honda has fitv valve.

located bottom of throttle body on the lude

IIRC It doesn't have that valve or if it has it is located somewhere else. I did the same with my lude but that didn't even try to find idle that was just flat until it warmed up. This fault seems different.

I don't currently have access to the workshop manual for this one but I will check out the other civic manuals tomorrow after work to see if they are the same.

mercutio · Post by **mercutio** » Thu Jan 29, 2015 5:08 pm

it should have a fitv valve but i think its actually part of the throttle body

farlow · Post by **farlow** » Thu Jan 29, 2015 5:21 pm

Just been out to double check and it seems that where the fast idle valve is on the lude there are two coolant hoses connected but it looks like they just pass through the throttle body. It is difficult to tell mind due to the duel runner intake as the throttle body is tucked way down in the bay.

farlow · Post by **farlow** » Thu Jan 29, 2015 5:22 pm

It still didn't start either

Post by **NafemanNathan** » Thu Jan 29, 2015 8:23 pm

farlow wrote:
wurlycorner wrote:Without knowing B series engines at all really...
It sounds like either a fault with the thermo sensor for the ECU (coolant temp) or assuming it has a similar system for adjusting idle as an H series, then a coolant air lock.
So as starters, I'd suggest bleeding the coolant and testing the thermo sensor.

Alternatively, does it have any sensors by way of measuring the intake air temp?

Does it have a MAP or MAF sensor?

Do you have access to the service manuals for this car?
The coolant was replaced last year when I changed the thermostat and as far as I'm aware it hasn't been touched since but I can certainly give it a bleed to see if that works.

I believe it has a map sensor but not sure about the intake air temp.

I'd echo Iain's thoughts.

The thermo sensor isn't the same as the thermostat though. The thermo sensor is what tells the ECU the current engine temp and if the ECU thinks the engine is warmer than it is (Due to a dud thermo sensor) it might not produce enough fuel on start up and you will experience troubles like you're having.

farlow · Post by **farlow** » Thu Jan 29, 2015 11:48 pm

Seems logical, I'm gonna need to find said sensor and swap it for the one on the spareodeck, see if that works. I'll get on it tomorrow.

Post by **NafemanNathan** » Thu Jan 29, 2015 11:49 pm

Just go easy removing it and replacing it. They quite like to shear