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> My 914 Stranded me yesterday, Any ideas?
billd
post Mar 12 2006, 01:23 PM
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After the autocross yesterday my 914 wouldn't start. It turned over just fine but didn't catch. Doug and Dana finally pushed me and I popping the clutch with it rolling in 2nd gear got it to start up after a little hesitation. I unfortunately let it die when I stopped to lock the gate. By this point everyone had left and I waited about an hour before I was able to find someone to help me push start it again. During this wait I swapped the fuel pump and heater motor relay, checked all the lines, wires and hoses, and tried restarting it about once every 10 minutes - without luck.

I drove it home, shut it down, and tried to start it again. It refused to start.

Two hours later when I went out to the garage to debug the problem it started right up with no problem.

What do people think? Could this be a vapor lock issue? A problem with the D-Jet running the fuel pump when the key is turned? Any other ideas.

Here are the facts:

The battery and starter are fine - the engine turns over with no problem.

The ignition is fine. Once it starts it idles and runs well.

The fuel pump is fine once the engine is running - once started it runs fine.

I have a 73 but have a 75-76-type fuel pump relocated up front and stainless steel hard lines from under the tank to just under the MPS.

When I turn the key the pump runs for about 0.5s (I thought it was supposed to run for 1.5s).

My theory is that either the pump is not running (or not running long enough) when the key is turned. This in combination with some mild vapor lock in the fuel lines is preventing fuel from getting to the engine during a hot start. My only other thought is it could be an intermittent ignition switch problem, but that seems unlikely.

I'm not sure what to do to prevent a recurrance. However I now have a piece of wire and my "special" relay in the glove compartment so if this does happen again, I can temporarily jumper the fuel pump to run any time the ignition is on.
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Howard
post Mar 12 2006, 04:09 PM
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When you bridge the pump, does it start OK?
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billd
post Mar 12 2006, 05:01 PM
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The problem has not recurred since I've had my "short-circuit" relay with me, so I'm unable to confirm this.
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SirAndy
post Mar 12 2006, 05:06 PM
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QUOTE (billd @ Mar 12 2006, 11:23 AM)
Could this be a vapor lock issue? A problem with the D-Jet running the fuel pump when the key is turned? Any other ideas.

no on vapor lock. with vapor lock, it wouldn't start when pushed either ...

check the CHT. i have seen them (or the wire) wire come lose. did it feel "rich" after push-starting? black smoke, gas smell?

i have seen the exact same thing at AX and the CHT had un-screwed itself and only made sporadic contact ...

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ejm
post Mar 12 2006, 05:58 PM
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Could be a bad ignition switch.. no power to the ignition/injection while cranking. My '76 had this problem when I bought it... the previous owner had replaced every fuel and igntion component trying to fix it. If he had noticed the gen/oil lights went out when cranking and knew what it meant he could have saved close to $2K throwing parts at it.
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billd
post Mar 12 2006, 07:08 PM
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QUOTE (SirAndy @ Mar 12 2006, 03:06 PM)
check the CHT. i have seen them (or the wire) wire come lose. did it feel "rich" after push-starting? black smoke, gas smell?

I checked the CHT probe. Its in tight and the resistance value reads in an appropriate range for a cold sensor.
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billd
post Mar 12 2006, 07:10 PM
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QUOTE (ejm @ Mar 12 2006, 03:58 PM)
Could be a bad ignition switch.. no power to the ignition/injection while cranking. My '76 had this problem when I bought it... the previous owner had replaced every fuel and igntion component trying to fix it. If he had noticed the gen/oil lights went out when cranking and knew what it meant he could have saved close to $2K throwing parts at it.

Thanks for the advice. This could be it - although its been behaving itself today. I'll keep an eye on the oil and gen lights while cranking from now on.

If the lead to the relay board isn't getting power, however, it still wouldn't push start.
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r_towle
post Mar 12 2006, 09:17 PM
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The car is pissed off.

First you lost the event, that is bad enough,,,but you beat your car up doing it and then you had to stay till the end after everyone left...the car is pissed, it wanted to go home early.

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Howard
post Mar 12 2006, 09:27 PM
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QUOTE (r_towle @ Mar 12 2006, 07:17 PM)
The car is pissed off.

First you lost the event, that is bad enough,,,but you beat your car up doing it and then you had to stay till the end after everyone left...the car is pissed, it wanted to go home early.

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Now you know why we give feminine names our cars.
What's the matter, honey? Uh, nothing, really. (IMG:http://www.914world.com/bbs2/html/emoticons/wub.gif)
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billd
post Mar 12 2006, 10:15 PM
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My car just did it again and I'm now certain that the problem is too rich a starting mixture, not too lean. I was at a friends house and when I went to leave the car wouldn't start. He was standing next to the car and smelled gas, so I opened the throttle and kept cranking and after a while (took longer than I expected) it started up.

I now suspect the AAR is the culprit. Its sticking in the "closed" position and giving insufficient air for a cold start. I'm going to compensate by starting with part throttle for a while.

What a pain. Now I have to grind off the epoxy I used to seal the can the last time I fixed the AAR and open it up again.
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billd
post Mar 12 2006, 10:26 PM
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QUOTE (r_towle @ Mar 12 2006, 07:17 PM)
The car is pissed off.

First you lost the event, that is bad enough,,,but you beat your car up doing it and then you had to stay till the end after everyone left...the car is pissed, it wanted to go home early.

Its probably the AAR, but I like this explanation better. I'll try to win next time, then maybe the car will get me home.
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Dr Evil
post Mar 13 2006, 12:30 AM
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Don't forget that the AAR and the fuel pump share a power circuit and the AAR connecter has a nasty habbit of shorting out against the block. Hardwiring the fuel pump fuse can be a bad thing to do if the AAR is shorted (or the heater fan which is also on the same circuit.)
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SirAndy
post Mar 13 2006, 01:03 AM
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take the hose off the AAR and see if it starts normal ...

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billd
post Mar 15 2006, 12:55 PM
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QUOTE
take the hose off the AAR and see if it starts normal ...


I took the hose off and it starts right up with no problems. I guess that confirms the diagnosis. Now I just need to find a servicable AAR.
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McMark
post Mar 15 2006, 02:24 PM
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Or ditch it. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)
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billd
post Mar 15 2006, 03:37 PM
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QUOTE
Or ditch it.


If I ditch the AAR do you recommend leaving the hose open - in which case I'll run too lean and have too high an idle after warmup - or leaving the hose closed - in which case I'll have to feather the throttle to start and heel and toe until it warms up.
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