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 Post subject: K-Jet No Start
PostPosted: Thu Dec 04, 2008 8:07 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
Here's one for the local K-jet guru's...every time I take the 242 for a long trip, the next day it won't start. This has happened twice, but times on trips over 250 km, with the next day being fairly cold. Yesterday it was a very early morning trip to Sweetgrass, then tonight when I went to start the car it won't start.

It will sputter for a half second, then die. There is no throttle response during the starting. I crank it, it runs badly for a half second, dies again. Repeat for about 2 minutes or longer then it will finally sort of run. Once it gets warm, it seems fine.

Funny part, if I haven't driven it far, it always starts - no issues at all. Something must be getting fouled on the longer trips. Is this a cold start injector thing?

Help.

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 Post subject:
PostPosted: Thu Dec 04, 2008 8:53 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
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I always suspect the fuel pump relay first, they do funny things when the solder joints get weak. Pop the cover and reflow the main joints, it's the 6 pin relay somewhere near the brake or clutch pedal.

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 Post subject:
PostPosted: Thu Dec 04, 2008 9:28 pm 
Haha, I just built a W24 Octo-Turbo, now what?!

Joined: Wed Dec 21, 2005 8:03 pm
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That car knows you're going to start doing stuff to it. Stop it and it'll be fine... :D I never had that problem with that car and I made lots of road trips with it...

I've got loads of fuel pump relays here. I can get you a couple of spares if you want.

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 Post subject:
PostPosted: Thu Dec 04, 2008 10:04 pm 
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Joined: Thu Dec 22, 2005 12:18 pm
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Location: Calgary
Make sure your cold start injector works too. I had a hell of a time trying to get it to start after driving to vancouver.

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 Post subject:
PostPosted: Thu Dec 04, 2008 11:01 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
I'll check that relay tomorrow. I've got a spare cold start injector, but don't know if it's any good. Big test this weekend.

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 Post subject:
PostPosted: Fri Dec 05, 2008 8:37 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
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The injector is about 1000x more reliable than the rest of the cold start system. Don't change the injector until you know everything else is good (thermal time switch and the cranking power circuit.)


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 Post subject:
PostPosted: Fri Dec 05, 2008 10:11 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Plus, I'm pretty sure no cold start = hard start, not NO start, but I could be wrong. It's easy to pull an injector and see if you're getting any fuel while cranking, but the first test is jumping at the relay or fuse panel to bypass the relay and force the pumps to run.

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 Post subject:
PostPosted: Fri Dec 05, 2008 2:39 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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That's correct. Also, since the cold start injector stops working the instant you stop cranking, it wouldn't affect the after-start at all.

How "long" and "short" of a trip are we talking here, Craig?


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 Post subject:
PostPosted: Fri Dec 05, 2008 4:32 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Well the first time it happened was on the way back from Calgary last time I was in town. The last time (second time) was the other day when I picked up tires at the border. Both times I drove about 250 km. It's never happened on anything shorter.

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 Post subject:
PostPosted: Fri Dec 05, 2008 8:31 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
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Were you really low on fuel both times? i.e., below the 1/4 mark?


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 Post subject:
PostPosted: Fri Dec 05, 2008 11:19 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Ugly Duck wrote:
Were you really low on fuel both times? i.e., below the 1/4 mark?


Nope, never below 1/2. I reflowed the solder in that relay...haven't played with a 555 IC in a few years and was surprised to see one on the inside of the relay. Anyway, the relay has a date stamp on it from 2003-12-20 so it is n't the original unit. Probably not much wrong with it, but well find out tomorrow.

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 Post subject:
PostPosted: Mon Dec 08, 2008 10:12 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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OK, so it's not the relay. I reflowed the solder and then that relay died (I'm thinking I may have put a little too much effort into the IC pins. Got some spares from Dale when I arrived using a jumper to run the pumps all the way from Lethbridge!

This morning it wouldn't start again. I've got a new-to-me idle control valve to help an occasional high idle problem - but I'm thinking it could be the thermal switch not activating the cold start injector. How much fun are they to replace (given that I've just swaped out the old heater control valve - terrible job with instructions and parts that are a little on the random side and it looks like I need a heater fan (big draw on fan speed 3, haven't tried 4 yet - so I've got some relatively major surgery coming)

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 Post subject:
PostPosted: Mon Dec 08, 2008 10:36 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
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as mentioned, a non working cold start injector should only make it slow start, not no start.
check for crap build up on the air flow plate at the fuel distributor. The crankcase ventilation returns right before the throttle body so often you get oil dripping down onto the flowplate, which affects mixture.

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 Post subject:
PostPosted: Mon Dec 08, 2008 3:39 pm 
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Joined: Sun Sep 03, 2006 8:46 pm
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Location: B-Ham WA/Portland, OR USA
No cold start injector usually makes for a crappy/slow start, but the car will usually start if you keep after it. Still, on really pretty cold days, the car will barely sputter without the cold start injector/valve working, but should sputter and not be deat all together.

A bad fuel accumulator or main check valve can introduce vapor lock that takes a while to correct usually when the car sits 6 hours or longer.

A sticking airflow plate under the K-jet boot also comes to mind.

Watch out for condensation under the dist cap (maybe more of an issue in the super damp PNW) and crusty fuse boxes too.


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 Post subject:
PostPosted: Tue Dec 09, 2008 10:30 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
I was doing some research on K-Jet.org (fantastic site by the way) and found the folowing description under "hard start cold"

"The common symptom with a bad control pressure regulator is that the engine takes about 20 tries to start, each time idling for a little longer after it starts. Basically, you turn the key, the rpms go up to about 1500 - 2000 when the cold start injector fires, and then the car dies because it is not getting enough fuel after the cold start injector shuts off. Also, a bad control pressure regulator can make the engine almost die when you shift in to neutral (auto trans.) or depress the clutch pedal (manual trans.)"

Sounds about right but my RPM's don't go that high, but this sounds right for all other parts. So on my list of things to do include: Clean the Idle Control Valve, Install new Aux Air Valve, check the cold start injector (thereby checking the thermal time switch) and get a new control pressure regulator.

Sound OK?

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