Cold start assist?

TiddlesRX7 · February 15, 2009, 10:19:53 AM

For some reason early last year my car decided it wasn\'t gonna do the cold start assist when first started. Up to this point it always did and I altered nothing to change it. Anyway I swapped ecu\'s and changed a few things with the idle as I was having problems with it. Now last week I had the car in for some (alot!) of welding so I ripped the interior out, and figured since I\'ve got my Apexi PFC I would take out my Knightsports ECU and put the stock one back in until I have funds to get the Apexi in and mapped. Now I had to reset the idle again with the stock ECU so I did that. All has been fine for a week or so (except my ears ring now from driving around with no sound proofing at all). It was still doing its usual warm up from cold start, it goes up to about 2k from cold then drops to 1.5k then very slowly drops to idle at anywhere from 800-1000rpm. So I jumped in it to come home the other night, it was very cold outside colder than usual. Low and behold it does the old cold start assist. Straight up to 3k then down to 1.5k after 20sec or so then down to idle when warm. WTF?

? I don\'t get these cars!!!!! well mine anyway!. Top and bottom of it I think the wax pellet thing might be fooked (from what I\'ve read about them). Can you inspect them to check them? where abouts are they located? and how much are they to replace?

grinder · February 15, 2009, 10:30:31 AM

do you usually start it with the clutch pressed ??

this usually bypasses the cold start - unless the new stock ECU that you are running overrides this

TiddlesRX7 · February 15, 2009, 10:48:28 AM

its the original stock ECU ( although I suspect its chipped). No I don\'t overide it with the clutch pedal, well not normally. I know you can do that. It just seems odd that one day it just stopped doing it, then out of the blue it did it again. I might add it hasn\'t done it again since the other night. But then again its not been as cold.

Oh and Stu I\'ll have to pop down next weekend or something as I spent all yesterday putting the interior back into the old girl. Today I\'ve got family up so can\'t get out and about.

pdtaylor18 · February 15, 2009, 11:28:46 AM

I can send you one to see if its the wax pellet jobby thing, There is also the AWS,you can unplug this if you want. Resistance in this should be 9.3-23.5 ohms, its this that accelerates the engine, I have one of those too. Just let me know. I got rid of all that sort of stuff on the Orange FC.

L18M · February 15, 2009, 11:56:33 AM

my cold start used to go upto 3k then drop to 1.5k
aft my fmic was put in then the cold start didnt work..
the only cold start is my right foot lol

Jimi_Hendrix · February 15, 2009, 12:09:23 PM

You may have already seen this Ade but i\'ll post it anyway just incase

http://fc3spro.com/TECH/HOWTO/OTB/otb.html

pdtaylor18 · February 15, 2009, 01:40:06 PM

That is something entirely different and all the items that affect cold start are on the UIM/throttle body.

TiddlesRX7 · February 15, 2009, 04:00:54 PM

Thanks Pete you really are a true gent. I may just take you up on that offer. Like I said earlier though, Can you visually inspect them or check them somehow? or is it just a case of tryiing a new one.

pdtaylor18 · February 15, 2009, 09:38:07 PM

No as above you can check the AWS by getting a live to it and hear the clicking and check resistances. The thermal was jobby is a bit different as thats hard to set up as you need to take the cooler off when its cold, set it up and then again when its hot but the hot bit is only really how far it all opens up to give you some more revs. Its in the workshop manual if you have it, if not its in the forum in one of the stickies i think.

TiddlesRX7 · February 15, 2009, 10:41:23 PM

Ah right I see. Will do some more reading up and see what I come up with.

Prof · February 16, 2009, 08:05:58 AM

The revving to 3000-4000 on startup is the cat warmup procedure - known officially as Accelerated Warmup System. It\'s basically the ECU operating a solenoid valve (the one that sits on the upper inlet manifold above the BAC valce. It was meant to more quickly warmup the cat\'s / converters on the stock car.

If you have an aftermarket downpipe or exhauast system - this is totally obsolete and in any case it\'s a really bad idea to rev a cold engine so much for nearly half a minute !!

It can be defeated manually by putting the car in 1st and holding the clutch (It works on just the clutch, but putting it in gear makes you keep your foot on it

). It\'s also defeated when certain sensor signals indicate it\'s not necessary (warm start) or when some fault codes are reported - I haven\'t got a list sorry - one of the many things I was going to check on the stock ECU. Almost all the chipped ECU\'s eliminate the AWS.

The normal warmup system should rev the car to 1500-2000 (2000 is spec) and as the car warms up the wax pellet device should slowly rotate a cam as it warms, lowering the throttle value. It\'s easy to visually see this behind the alternator - and with the emanage measuring throttle position, you can see the lower throttle limit drop to 0 as the car warms up. This system can fail because the water pipe get\'s blocked - check the car when warm to make sure the side of the BAC valve is warm/hot - this indicates water flow. The Wax pellet itself can fail, and the system can get \'sticky\' with dirt and old lubricant - and not rotate as freely.

One of the causes of hunting around 1500 rpm is down to sticky throttle and badly adjusted TPS.

Adam fc · February 16, 2009, 08:18:16 AM

sorry to be such a noob but i always start my egi with my foot on the clutch pedal,is this a bad idea?ive had the air pump removed so ive got an aftermarket header aswell.

TiddlesRX7 · February 16, 2009, 10:03:59 AM

That makes a lot of sence, Cheers Prof. So I think it will be sticking cause of the age of it. I have freed it off once before as I thought it was a bit lumpy. I will check the solenoid and see that it is operating correctly too. I know the one on my spare engine is damaged so Pete if mine is kapoot then I will be in touch for your spare one.
Thanks for all the help peeps as always.
Ade

Prof · February 16, 2009, 11:04:22 AM

Quote from: Adam fc;584817sorry to be such a noob but i always start my egi with my foot on the clutch pedal,is this a bad idea?ive had the air pump removed so ive got an aftermarket header aswell.

Nope - not a bad idea

pdtaylor18 · February 16, 2009, 06:35:46 PM

Quote from: TiddlesRX7;584839That makes a lot of sence, Cheers Prof. So I think it will be sticking cause of the age of it. I have freed it off once before as I thought it was a bit lumpy. I will check the solenoid and see that it is operating correctly too. I know the one on my spare engine is damaged so Pete if mine is kapoot then I will be in touch for your spare one.
Thanks for all the help peeps as always.
Ade

just let me know what you need and I will send it, as I stated I have both the AWS and wax thingy. These are quite common also to having the vacuum connections either breaking off or certainly hoses going brittle cos of the heat. Defo worth a check though.

Cold start assist?

Jimi_Hendrix