Won't start! Will start if I coast down hill and pop clutch! Options

[Ian Stott]

As described! What is up with this situation? Engine runs beautiful when warmed up, will restart no problem if It has been shut off for even a few hours. Kudos to the battery and starter as I have tried to start it normally when it has been sitting for a few days, won't catch, thank goodness I live on a hill, coast down the hill a bit, put her in 3rd gear pop the clutch and vrooom! Have done this 6 times now!

Ian Stott
Moncton
Canada

[wndsrfr]

As described! What is up with this situation? Engine runs beautiful when warmed up, will restart no problem if It has been shut off for even a few hours. Kudos to the battery and starter as I have tried to start it normally when it has been sitting for a few days, won't catch, thank goodness I live on a hill, coast down the hill a bit, put her in 3rd gear pop the clutch and vrooom! Have done this 6 times now!

Ian Stott
Moncton
Canada

I'm guessing too much voltage dip when cranking cold engine....look for corrosion on battery connections & ground strap at top rear of transmission...clean & tighten all of them....age of battery?

[Mark Henry]

So is this the opposite of the hot start issue? Starter works but not firing cold?

[Ian Stott]

So is this the opposite of the hot start issue? Starter works but not firing cold?

Battery is awesome, starter works great, I can crank her over til the battery dies which I don't do! I always try to start it normally, so instead of burning out the starter or draining the battery too much I coast down the hill, put her in 3rd, polo the clutch and vroom! Then I let her warm up, charging system works great by the way, and once she is warmed up easy to restart with a simple turn of the key. Engine runs real nice when warm, so thanks for the choice of battery you chose for me Mark and I am happy with the job you did on my engine. This starting thing has me and my friend who is a mechanic puzzled, any ideas from you will be most helpful.

Ian

[draperjojo]

I used to have to do this with an Opel GT. I rebuilt the engine after I did a wet and dry compression test. The pistons all fell out...lol. Hopefully your engine is in better shape than that one was.

[Krieger]

Is this carbed or injected. If it is injected, I was thinking the cold start valve was not putting fuel in the plenum.

[Mark Henry]

I wonder if the pertronix is crapping out. Check and clean all dizzy connections, ground straps, etc.
I'll have to think on this.

The Battery is a odyssey 925.

[Ian Stott]

I wonder if the pertronix is crapping out. Check and clean all dizzy connections, ground straps, etc.
I'll have to think on this.

The Battery is a odyssey 925.

Batt connections and nice and clean and shiny! My understanding of petronix is you have nothing if it fails, since the engine runs so nice when warmed up and starts with one turn of the key after being warmed up. I did the PCA Acadia region valley tour a couple of weekends ago which was 720 miles, engine performed well, restarted easily after being off for about an hour while we had lunch, which was awesome, best fish and chips I have ever had which is saying a lot for a guy from Atlantic Canada. That is why I didn't suspect the pertronix which has been in the car for about 3 years or more. Ground strap is new, was done after the tranny clinic at your shop, I will check it though.

Ian

[ndfrigi]

If this is F.I., try to push/pump the gas pedal 3 times then push it all down to floor and try starting it. If it start, maybe your cold start valve and CHT sensor need attention.

[Ian Stott]

If this is F.I., try to push/pump the gas pedal 3 times then push it all down to floor and try starting it. If it start, maybe your cold start valve and CHT sensor need attention.

Will try that thanks.

Ian

[Mark Henry]

If this is F.I., try to push/pump the gas pedal 3 times then push it all down to floor and try starting it. If it start, maybe your cold start valve and CHT sensor need attention.

An FYI to others, Ian has a 2.0 L-jet conversion.

[Mark Henry]

Bit more info to help Ian out.

We (and another guru) couldn't get the D-jet to run worth a shit.
I traded him straight up for my known good complete 1.8 914 L-jet system. So his system is all L-jet except for the 2.0 intake runners, all new seals.
Ran perfect except for a minor point, in my 1.8 I never had to touch the gas to start the car, on his you always needed to give it one or two pumps, hot or cold.
I just figured it was the cam. IIRC he has a web73 FI cam.

O2 WB said the AFR was perfect as was the timing. Except for the two pump start it runs like a champ.

Ian a new head temp sensor might help. The one I used, off the L-jet, is 8-9 years old but only had about a year of use.

[Mueller]

Bit more info to help Ian out.

We (and another guru) couldn't get the D-jet to run worth a shit.
I traded him straight up for my known good complete 1.8 914 L-jet system. So his system is all L-jet except for the 2.0 intake runners, all new seals.
Ran perfect except for a minor point, in my 1.8 I never had to touch the gas to start the car, on his you always needed to give it one or two pumps, hot or cold.
I just figured it was the cam. IIRC he has a web73 FI cam.

O2 WB said the AFR was perfect as was the timing. Except for the above it runs like a champ.

Is the flapper moving when trying to cold start? Not enough manifold vacuum due to leak or someone stiffened the spring too much?

[Mark Henry]

Is the flapper moving when trying to cold start? Not enough manifold vacuum due to leak or someone stiffened the spring too much?

I was careful about vac leaks unless it's a new issue,
Spring in the flapper?
I don't think so, off a bone stock 914 that lived a very sheltered life. I think it was driven for 4-5 years then spent decades in dry heated storage till I got it in early 2000's, then again always in dry heated storage.
Except for a re-spray it was a bone stock original cream puff.

[Ian Stott]

Is the flapper moving when trying to cold start? Not enough manifold vacuum due to leak or someone stiffened the spring too much?

I was careful about vac leaks unless it's a new issue,
Spring in the flapper?
I don't think so, off a bone stock 914 that lived a very sheltered life. I think it was driven for 4-5 years then spent decades in dry heated storage till I got it in early 2000's, then again always in dry heated storage.
Except for a re-spray it was a bone stock original cream puff.

Once warmed up runs nice, idle is bang on at around 1100.

Ian

[Ian Stott]

Ok, coasted down the hill at my house, put her in 3rd gear, popped the clutch, vroom! Ran a little rough til warmed up, then ran beautiful all day, did a 300 plus mile tour thru some really nice twisty's, I can pull away from a 944' but the Audi TT can stay with me as she is a good driver, the Honda 2000, can stay with us in the straits but I easily loose them in the switchbacks. Not bragging, just trying to get some feedback on this cold starting thing, we stopped for lunch, we stopped for photo sessions, we stopped for coffee, teener started no problem every time. When I go to use it again, say next weekend for example, I know I will have to coast down the hill and pop the clutch again, but it won't start normally by turning the key. Battery and starter are both in excellent condition, can turn her over like crazy but no go.

Ian Stott
Frustrated in Moncton
Canada

[iankarr]

How long does it take to turn over when going down the hill? Right away?

Since it starts on a hill when cold but not using a starter when cold, there must be something about the momentum of the downhill that's making a difference. Correct me if I'm wrong, but it seems the force of the car rolling downhill in gear is doing a much stronger job of turning over the engine than a starter.

The L-jet gurus will chime in I'm sure, but it sounds to me like your FI brain somehow needs a very strong vacuum/signal to send fuel when cold. After warm up, whatever is sticking gets unstuck.

[type2man]

How about spraying some fuel into the intake when cold

[r_towle]

Vacuum leak

[Spoke]

So it doesn't start when cold but will start if you push/coast start it?

What are the differences in both methods?

Engine speed:
Starter: slow
Coast: slow

Ok, so engine speed should not be the issue.

Extra fuel when cranking:
Starter: YES, the ECU extends the injector pulses to put in more fuel when cranking.
Coast: NO, the ECU sets injector pulse width by temp of engine/ambient/CHT

Here's a difference, pulse width during cranking may be flooding the engine. Maybe not. Does the engine run rich? Have you had the AFR checked?

Voltage at coil:
Starter: Voltage at coil will be lowered by IR drops in the wiring applying less voltage at the coil.
Coast: Voltage should be close to battery voltage since starter is not cranking.

Check the voltage at the coil with a voltmeter when cranking. Measure from coil + wire to engine case ground, not the battery ground. Also, pull a plug wire and install a spare plug on the wire and ground the plug and look for spark when cranking.