New: Hard starting, stumbling just off idle.

John H said:

With no apparent warning, the 164 was hard starting this morning, and ran poorly (missing) just coming off idle. Kind of OK with revs up a little. Did it again when I came back from the grocery a mile away. I let it warm up good, but missing persisted. Weather is fair and no heavy rain. Just this sudden problem with no warning.

The only thing I could think of is sheared Gilmer belt tooth. Maybe plugs, but too sudden feeling, though.

Could be a leaky vacuum hose, I suppose.

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Your 164 is 12v or 24v? CAN'T REMEMBER. Please add car to your signature or in post.

stumble

John, Have you opened the hood to take a look yet? This time of year, depending on your location, when the cooler weather starts to settle in, the clamps on fuel hoses can get loose and result in reduced fuel pressure. If you open the hood before the engine warms up, you will notice fuel dripping if that is the problem. Alfahill

It's a standard 12V.

I'll check for fuel drips in the morning, but weather here has been very mild. We've had a tiny bit of rain, but no deluge.

The 164 did sit unused for about 4 days. Tank is about 1/4 full.

John H said:

With no apparent warning, the 164 was hard starting this morning, and ran poorly (missing) just coming off idle. Kind of OK with revs up a little. Did it again when I came back from the grocery a mile away. I let it warm up good, but missing persisted. Weather is fair and no heavy rain. Just this sudden problem with no warning.

The only thing I could think of is sheared Gilmer belt tooth. Maybe plugs, but too sudden feeling, though.

Could be a leaky vacuum hose, I suppose.

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Check main intake boot (cracks or slipped off AFM or Throttle body), any vacuum line, distributor cap/rotor.

Jason

If your running Bosch +4 plugs, pull one and check. They work well , then go quick.

I don't know what a Gilmer belt is, so I've learned a new term today (presume it is the camshaft drive belt!)

My money would be on HT lead or distributor cap/rotor problems. My previous 164 (also 12V) developed a misfire one day that seemed to go away when driving normally, then rapidly deteriorated to the point where the car couldn't move. I thought it was the crankshaft angle sensor etc. so I had to get a friend to come and recover me. Before we actually towed the car, I discovered the fault. The HT lead into the coil was a loose fit and was only held on by the rubber boot. I pried the end of the lead open and pushed it in properly (before refitting the rubber boot). Never had a problem again. The moral is to check the simple things first

-Alex

Good point. I'll check further in the morning. Usually, mysteries like this are ignition problems. I've got an electronic timing light around here someplace.

Start with an Aspirin before doing brain surgery

AlexGS said:

The moral is to check the simple things first

-Alex

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Hold that thought! Page two story http://www.alfabb.com/bb/forums/447038-post1.html

John H said:

Good point. I'll check further in the morning. Usually, mysteries like this are ignition problems. I've got an electronic timing light around here someplace.

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John, check the hoses on your oil vapour recovery system too - they get ignored behind the rear cylinder bank against the firewall. If the little hose is boogered, you'll get a vacuum leak that will give you a poor throttle response/hesitation and hard starting. It's simple to fix if you can find the right size hose. On my 12V 164, this area was a bit of a mess but just replacing the cracked/hardened/boogered vacuum line fixed it.

Cap and rotor fixed mine when it had the same conditions. Pull the cap and look; if it's like mine you'll know.

John H said:

Good point. I'll check further in the morning. Usually, mysteries like this are ignition problems. I've got an electronic timing light around here someplace.

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Electronic timing light is perhaps most useful these days for checking which spark plug is misfiring...! Just my two cents but I've made several accidental discoveries over the years when I have hooked up the inductive pickup and then noticed 'missed' flashes. I transferred to the other leads and found regular flashes there, so that located a fault in No.1 plug lead.

Alfisto Steve; I didn't quite catch the relevance to your daughter's mishap with the bent track rod end

-Alex

Problem has disappeared, for now anyway. Maybe it was a bit of debris or water in the gas. We will see what the future brings.

Check distributor first

Sounds like exactly the same symptoms I had. Mine even went away for a while. But then returned suddenly. Eventually the car stopped completely - had to get towed. Distributor contacts inside were all eroded/corroded.

luxinator said:

Sounds like exactly the same symptoms I had. Mine even went away for a while. But then returned suddenly. Eventually the car stopped completely - had to get towed. Distributor contacts inside were all eroded/corroded.

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"Distributor contacts "? Does the alfa have contacts? I thought cars all had magnetic pickups.

What they mean is the distributor cap and rotor. The ignition and fuel is triggered magnetically via the crank angle sensor. I changed mine out and my car ran way smoother, and probably prevented future issues.

Sorry, this was a strange duplicate post of my edited post below: tried to delete but cannot.

jontg428 said:

What they mean is the distributor cap and rotor. The ignition and fuel is triggered magnetically via the crank angle sensor. I changed mine out and my car ran way smoother, and probably prevented future issues.

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Sorry to be pedantic but... did you mean you changed out your crank angle sensor? I suspect you meant that you changed out your cap and rotor, but just wanted to check.

JohnH, 'Distributor contacts' I take to mean the six brass stepped-posts moulded into the distributor cap. It's usual for there to be some erosion but if the flatness of the face is completely gone, the cap life is probably over The last car I know of that had contact breaker points was my 1988 Bertone X1/9 (all other Italian models had breakerless designs by that time!)

-Alex

Well, rockauto.com shows both a cap and rotor for the 91 164L for $60 and $20. I'll pop the cap and see what it looks like.

Just changed///

AlexGS said:

Sorry to be pedantic but... did you mean you changed out your crank angle sensor? I suspect you meant that you changed out your cap and rotor, but just wanted to check.

JohnH, 'Distributor contacts' I take to mean the six brass stepped-posts moulded into the distributor cap. It's usual for there to be some erosion but if the flatness of the face is completely gone, the cap life is probably over The last car I know of that had contact breaker points was my 1988 Bertone X1/9 (all other Italian models had breakerless designs by that time!)

-Alex

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The cap and rotor after hearing stories on the BB from people, figured it was a safe bet to change before things went bad