Unusual starting problem.

[91417nut]

1973 914 1.7, fuel injected. pump relocated to front.
Ok I pulled my 914 out of its winter nap. I had it running just fine in January before I put it back in the garage with all winter crap in front. about 2 weeks later i remembered I forgot to attach the battery tender with no way to get access to it, swore quit a bit. So last weekend I try and start, barely turns over. Crap. So I drag the car out, throw the tender on let it sit overnight. I throw a few gallons of fresh gas in. Next day I try and start it again, turns over with full vigor, can hear fuel pump go "vert" but no start. An occasional "putt" but not running at all. Can smell gas in exhaust. Being Easter I had about 30 min to slip away and had to go back in.

So back to it this weekend...
Pop distributor cap, sand points/rotor, re-gap Pertronix ignitor. Check coil 3.4ohms. Check battery, fully charged. Pull spark plug wire and put on old spark plug, have assistant turn in engine and have a spark. So I pull the plugs and check the gaps. @.024+/-.001. Can smell fuel in oil and at exhaust. Pull out the fuel pump relay can hear injectors click and fuel pump go "vert". Drain fuel @ 1 gallon of fuel from engine end of tunnel (fuel pump relocated to front) just to make sure fuel hadn't gone bad. I even resorted to spraying some starting fluid in the intake and nothing.

Going nuts. I have fuel, spark and it turns over. Any tips?
Do Pertronix ignitors just go bad?

[beatnavy]

It sounds like you have fuel and spark, and you didn't mess with the timing or anything when you put it away? I'm guessing it's flooding due to my favorite foil, the CHT. One way to check if it's flooding: after trying to start it a couple of times, pull the trigger points from the back of the dizzy. Then crank again. If it tries to fire and almost starts, you're way too rich. Happened to me this weekend. Check the MPS connector and the CHT circuit.

[John Rogers]

You did not mention if it was started at all during the winter down time? The lesson here since you said it was fine when you stored it, the only think that can change is the gas that was in it and it has turned to something between paint remover and gorilla snot. I would suggest opening a fuel line at the engine and run the pump until the old gas has just about all gone out into buckets or other containers, getting 5 or more gallons of fresh gas in it, then pump a bit more, hook up the line(s) and then try it. The gas we have everywhere in the country is terrible and even race gas such as VP or Sunoco will go bad and putting new gas in on top of the old just dilutes the crap you have.

In the future, a product such as Stabil will help but it best to start and warm up the car at least weekly during down times.

[91417nut]

Originally Posted by beatnavy

It sounds like you have fuel and spark, and you didn't mess with the timing or anything when you put it away? I'm guessing it's flooding due to my favorite foil, the CHT. One way to check if it's flooding: after trying to start it a couple of times, pull the trigger points from the back of the dizzy. Then crank again. If it tries to fire and almost starts, you're way too rich. Happened to me this weekend. Check the MPS connector and the CHT circuit.

I'll have to check the cht. I made sure the MPS was plugged in. Can the CHT suddenly fail?

[91417nut]

Originally Posted by john rogers

You did not mention if it was started at all during the winter down time? The lesson here since you said it was fine when you stored it, the only think that can change is the gas that was in it and it has turned to something between paint remover and gorilla snot. I would suggest opening a fuel line at the engine and run the pump until the old gas has just about all gone out into buckets or other containers, getting 5 or more gallons of fresh gas in it, then pump a bit more, hook up the line(s) and then try it. The gas we have everywhere in the country is terrible and even race gas such as VP or Sunoco will go bad and putting new gas in on top of the old just dilutes the crap you have.

In the future, a product such as Stabil will help but it best to start and warm up the car at least weekly during down times.

I had it run for about 30 minutes back at the end of Jan.till it was just about down to R. before parking it again. I added 3 gallons. After it didn't start this weekend, I drained out the fuel from the engine, and had an assistant hit the key to accessories to purge the gas from the pump.

[Dave at Pelican Parts]

Originally Posted by 91417nut

I'll have to check the cht. I made sure the MPS was plugged in. Can the CHT suddenly fail?

If the MPS is not plugged in, no fuel will be injected. If the hose is disconnected, the mixture will be very rich. Ditto if the internal diaphragm ruptures.

CHTs can suddenly fail, but it seems more common for them to suddenly get disconnected. If they are unplugged the mixture will go very rich as well.

How's the fuel pressure? A blocked return line will send the pressure sky-high and give you a rich mixture as well.

--DD

[beatnavy]

I agree with Dave. The circuit can go bad (disconnected) or frayed wire on that circuit. Try starting it a couple of times then disconnect the trigger points. If it tries to fire/start then you're definitely way too rich.

[91417nut]

Originally Posted by Dave at Pelican Parts

If the MPS is not plugged in, no fuel will be injected. If the hose is disconnected, the mixture will be very rich. Ditto if the internal diaphragm ruptures.

CHTs can suddenly fail, but it seems more common for them to suddenly get disconnected. If they are unplugged the mixture will go very rich as well.

How's the fuel pressure? A blocked return line will send the pressure sky-high and give you a rich mixture as well.

--DD

I was able to disconnect the fuel lines and fuel flowed right out of both the intake and return lines. So I doubt there is a blockage. (could be wrong) I also turned had an assistant turn the key, priming the pump and fuel would spit out.
I checked that everything was plugged in.
When I pulled the plugs they were pretty soaked. I'm thinking off trying some brake cleaner and cleaning them to make sure the are getting a decent spark. See if I can get it to fire before replacing them.
Going to do a zealous wiring check this weekend.

[Dave at Pelican Parts]

Fuel flow is not fuel pressure. The spec pressure is 29 PSI in the high-pressure loop. It might be a good idea to verify that...

--DD

[91417nut]

Thank you all for the help.
CHT sensor. Luckily I had accidentally bought a second one years ago. Checked the new one 2.7k ohms. good. Pull out the old one 6.5-7k ohms. Plugged the new one in, cleaned the gas off the plugs and it started right up perfectly.
Thank you again.

[beatnavy]

Awesome. Glad you figured it out! My personal sample size is 2, and I've had 2 CHT issues. Wish there was a better failure mode on that thing...