TheSamba.com :: View topic - new plugs,injectors,temp sensor, still hard to start

Tue Dec 20, 2005 11:35 am

Help!

I have 82 westy, with new air flow meter,injectors,plugs,air flow meter, temp sensor II and still hard to start in the cold mornings, after its warm runs like a champ. Any clues? The Bentley only goes so far as the cold start injector and temp sensor.

Thanks, Mike

Tue Dec 20, 2005 11:56 am

You checked the thermot-time switch that hooks up to the cold start valve?

Tue Dec 20, 2005 12:06 pm

And the fuel pressure upon start up?

Tue Dec 20, 2005 12:59 pm

No, didnt check either of those. I suspect it is the fuel pump. I will check the thermo time switch 1st. Let ya know what I find out.

Thanks, Mike

Tue Dec 20, 2005 1:07 pm

If I push the pedal down about a quarter of the way down at 1st morning/night start up it fires right away but then I have to sit for quite a few minutes to warm up or it will roll and die! Then its a real !)@$% to start up.

Tue Dec 20, 2005 2:12 pm

You know, mine kind of does the same thing. I've got an 83 aircooled with fuel injection. I've got to give the accelerator a little push to get the engine started in the morning, which I shouldn't have to. I haven't had time to check the cold start vavle and thermo-time switch yet, but that is what I suspect the problem to be.

If I don't get it to start the first time, it's a pain in the A#@ to start up after that. I have to sit there cranking for a few minutes to get her started after that.

Tue Dec 20, 2005 4:34 pm

lilweasel wrote:

If I don't get it to start the first time, it's a pain in the A#@ to start up after that. I have to sit there cranking for a few minutes to get her started after that.

I am still trying to understand the fuel injection system . Would this be because the cylinders are flooded or perhaps because the ECU has accepted incorrect information ?

Tue Dec 20, 2005 5:33 pm

Colin explains it so well...

Iggi was explaining how he turns the key to the "on" position 4 times before he tries to start the car....

Amskeptic wrote: iggi wrote: ratwell wrote: What's that doing? Warming up the coil?

heck if I know... but it works. :?: :?:
However, I think it more likely that I'm cycling the cold start valve than warming up the coil. Or it could just be a weird bit of voodoo that shouldn't work but does. :wink:

If this were a self-priming fuel pump circuit, like on many CIS FI cars, that cycling you speak of would be pressurizing the fuel rail to your advantage, the pump is designed to run for like three seconds every time you switch the ignition on. But our lowly L-Jet tells the pump not to do anything until the starter #50 circuit is energized, or the AFM tells the pump to get going.
Your best bet with L-Jet on any extremely cold morning is to press the accelerator halfway down during cranking, which will provide only a nominal increase in fuel. If it does not start within ten seconds, repeat after a minute or so wait. You will then get another cold start squirt (whose maximum time is like ten seconds). Try again as necessary with the accelerator to the floor under prolonged cranking because that gives you more air, somewhere in between those two is the optimal mixture that will fire up the engine. (this is assuming that the thermo-time switch, cold start injector, and aux air regulator are all up to snuff)
Colin

Thu Dec 29, 2005 5:46 am

So I took it to bugformance in Sunnyvale and they checked the compression and fuel pressure, adjusted the air flow meter and said it was the culprit. Then they said if it doesnt start right away to push the pedal down a couple inches, even though they say you shouldnt have to either. So sure enough im in their parking lot and I turn the keyt and nothing till I push in the gas on the 2nd try. Seems like im going to wear out the starter. I can see it now im somewhere in California on a sunday morning ready to go home and my wife is looking at me while im cranking away. Yikes! What next?

Thu Dec 29, 2005 8:02 am

Your cold start mixture is off, that's why you have to press the gas.
How cold is it in the morning where you are?
The sad thing about these old cars is very few people will work on them much anymore, and or don't want to.
Cold starting is the hardest thing your engine can do, having all good working parts helps, sounds like your adjustments are just off somewhere. What did they adjust on The AFM?
After I replaced my head I had to go though and set everything again.
The last thing I adjusted was the Idle bypass screw on the AFM (CO adjustment). The closer I got it the correct setting the better it cold started.
Here in Texas it got down to 20 not to long ago, she started right up.
When I start mine I do slowly press the accelerator till it fires, this introduces a bit more air to the mix.
I have an 81 aircooled just like yours and it ran like crap when I bought it.
Remember when your van was new it had no problems with this, time and friction have had their way.
As much as we like to give our vans personality it is still a machine, it worked right once it can be made to work right again, don't let anybody tell you different.

Thu Dec 29, 2005 12:55 pm

Sounds like a defective or maladjusted auxiliary air regulator. The auxair reg allows extra air to bypass the idle screw when cold to compensate for the extra fuel supplied by the cold start valve. On a carbed engine, you have a "step" at the idle set screw to make the engine idle higher with the choke on so it won't flood. The cold start valve/ aux air reg work together to achieve the same result. Get it? They MUST work hand- in- hand, or the engine will run like garbage until warm. If you have to goose the throttle when you first start it, that can only mean that the auxair reg is not letting sufficient air in to allow it to fire. Most likely it runs like crap in the warmup because it's trying to flood.
A bad fuel pump will either be bad ALL the time, or it will tend to heat up and fail the longer it runs. The airflow metre also tends to be more troublesome when warm than when cold.
There are other considerations here but, with the info you've given, I have to say that the auxair is the most likely suspect, as its job is to do EXACTLY what your foot is doing when you have to goose the throttle to make it start or keep it running when cold. :wink:

Thu Dec 29, 2005 1:36 pm

Tram has a very good point, I have a used aux regulator on mine that I don't trust much, it's a very overlooked part and it's easy to check (with the Bentley).

Fri Dec 30, 2005 8:19 pm

Hi,

Thanx for the pep talk. I will try the auxiliary air regulator and report back.

Thanks, Mike

Fri Jan 06, 2006 3:03 pm

What did they adjust on The AFM?

So Im still stuck with a cold start problem. I did find out that the air flow meter was making the fuel pump all the time so it was readjusted.