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Discussion Starter #1
My '84 has developed a weird starting issue. When it is hot, the engine will not start, or catch, until the ignition key is released and then it coughs a time or two and then it starts up as normal.

When it is cold, it will start normally, that is, while the engine is cranking with the key still on.

I recently repaired and replaced cracked airflow meter and plenum hoses, but that didn't solve the problem.

Timing issue? Vacuum leak? Any ideas where I should start my search?

Thanks in advance,

David
 

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See the link in my signature to a page of info about the L-jet system.

My first thought is to check system voltage during cranking. If the starter is drawing a lot of current then system voltage could drop below the computer's wake up threshold. As you release the key the starter's draw ceases and perhaps that allows voltage to get up to the needed level? Check voltage by attaching a voltmeter to the battery (if your car ahs one don't use a dash gauge for this test). With everything off system voltage should be ~ 12.6V. Then see what it reads during cranking. Our '84 Spider reads about 11.4-11.8V during cranking. If it drops below 10.5V the computers will not power up to send the make spark/squirt fuel signals.

If you find marginal voltage then have the battery load tested. And clean all electrical connections in the battery to starter circuit.
 

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My '84 has developed a weird starting issue. When it is hot, the engine will not start, or catch, until the ignition key is released and then it coughs a time or two and then it starts up as normal.

When it is cold, it will start normally, that is, while the engine is cranking with the key still on.

I recently repaired and replaced cracked airflow meter and plenum hoses, but that didn't solve the problem.

Timing issue? Vacuum leak? Any ideas where I should start my search?

Thanks in advance,

David
Hi David,

Eric gives good advice there to follow up on.

Are you saying that when the engine is hot, you turn the key, the starter cranks, but the motor doesn't start? Or is your issue that when you turn the key nothing happens, then when you turn it again the starter turns the motor and she starts as normal?

I've had both symptoms in the last year. The second scenario was fixed with a starter relay (see faq). The first situation turned out to be a combination of a weak coil, fouled spark plugs, and fouled contacts in the distributor cap.

Other possible causes suggested when I was searching included leaky injectors or a bad fuel pressure regulator (both of which I had recently serviced and bench tested good by OK injectors).

There are other possibilities... good luck in figuring it out.
 

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I'm voting for a battery/low voltage situation.

Just as you stop cranking, but before the engine stops turning, system voltage rises above the threshold necessary to bring essential electronics to life, hence the brief effort at starting.

The "OK cold start" is a bit of a puzzlement but perhaps the cold start injector and other engine enhancements during cold start are assisting. It would be interesting to know when a battery works hardest (other than sub-zero conditions, of course). Does a warmed-up engine have higher compression?

I used to encourage survival of old batteries with chargers and jumpers but now, at first sign of an issue on over 3-5 year old batts, they are replaced.

And thanks for being reasonably clear on your problem's description. I luv the "it won't turn over" attempt to enlighten readers :(.
 

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Discussion Starter #5
Hi Eric, Phil, and Steve,

Thanks for the info and tips. I notice that my alternator light is on constantly, at least with a faint glow and a brighter glow when headlights are on, so it sounds like a ground/battery issue. It is confusing that it only happens when the car is hot, but it could be that the drain is building up as the car runs with more and more accessories on.

Phil, what happens when the engine is hot is that I turn on the key, the engine turns over normally (doesn't sound slower than normal), but it will not 'fire' while the key is on. I have to release the key for the engine to run, and when I release the key, the engine coughs a few times and then starts (or doesn't).

I could never get the fuel injection to run properly on my '58 Corvette and ended up removing it and putting on a regular 4 barrel carburetor, so I have been reluctant to tear into the fuel injection on my Alfa. Looks like it's time to give it a shot, though.

Thanks again,

David
 

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with alternator light constantly on, maybe remove the connections at the back of the alternator, clean and re-attach. Of the two screws on the regulator/brush bit that fits into the back of the alt, one of the screws acts as a ground...clean.

At the same time (I am presuming your spider has an internal regulator) I would remove the regulator out from the back of the alt. and check the condition of the brushes. There are ways of testing these internal bosch regulators (seen it on youtube, can't remember how it went now), but if regulator/brushes look worn down or worn uneven then I would simply replace it....not expensive and easy to do (2 screws, once the air filter is out of the way)

Also remove lid of the main electrical connector on the left inner fender, and clean all those big red (starter) wires and the green (alternator) one.

Have you checked/cleaned connections on ignition switch and starter/solenoid itself?
Maybe hit the ignition switch with some contact spray.
 

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Hi Eric, Phil, and Steve,

Thanks for the info and tips. I notice that my alternator light is on constantly, at least with a faint glow and a brighter glow when headlights are on, so it sounds like a ground/battery issue. It is confusing that it only happens when the car is hot, but it could be that the drain is building up as the car runs with more and more accessories on.

Phil, what happens when the engine is hot is that I turn on the key, the engine turns over normally (doesn't sound slower than normal), but it will not 'fire' while the key is on. I have to release the key for the engine to run, and when I release the key, the engine coughs a few times and then starts (or doesn't).
My 84 also did the faint glow thing. I worried about the battery draining, but it never did even when running at night with AC on. I added an extra wire between the alt and the junction box on the driver's fender. I think that is a common issue and may or may not be related to your hot start issue.

A quick thing that may reveal if low voltage is playing a role due to increased resistance after warm-up is to jump it when you get the symptom--even though it seems its turning over fast enough. The extra juice should increase above the minimum for the computers to start-er-up.

Another thing to try is when its cranking but not starting, push the accelerator to the floor and hold it for a few seconds during cranking to see if it catches, that would indicate a different issue than voltage loss I think.

FInally, before you tear into the FI, it may be worth a routine tune-up to include plugs, cap and rotor... maybe wires and coil too. If they havent been done/tested in recent history, they're relatively cheap and easy things that are good to do anyway and may help.

That's all from me, hope to see you at Viva Alfa in a few weeks.
 
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