Are my plug wires bad and if so would that cause stalling after the car is hot? - Page 4 - Alfa Romeo Bulletin Board & Forums
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post #46 of 251 (permalink) Old 02-20-2017, 08:06 PM
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Here's the link for the fuel tank and venting:

Fuel Line Routing (GTV6/Milano)

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post #47 of 251 (permalink) Old 02-21-2017, 06:22 AM Thread Starter
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I replaced the vent valve with Greg Gordon's kit 4 or 5 years ago. The fuel pressure regulator was changed maybe 3 years ago when I had the injectors shipped off for testing and cleaning. Last year I replaced ALL of the fuel hose and clamps. Pulled the sock, inspected the tank for corrosion and buildup. No issues. Fuel pressure has always been correct.

I have read of some guys drilling through the gas cap to improve pressure equalization. While not technically legal, it seems to help?

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post #48 of 251 (permalink) Old 02-21-2017, 06:33 AM
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Just loosen the cap... see how it goes.
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post #49 of 251 (permalink) Old 02-21-2017, 07:29 AM Thread Starter
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I tried that yesterday. No indication of any related issues.

as good as a car can be... briefly.
'82 GTV6
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post #50 of 251 (permalink) Old 03-20-2017, 07:30 AM Thread Starter
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Well, I got new plug wires in. The car still stalls out.

I don't get it.

I'm going to start over from square 1. Drain the gas, pull every sensor, test continuity of every circuit, etc.

The problem is, sometimes it runs fine, sometimes it dies. Sometimes it starts first try, sometimes it won't start at all. Sometimes it runs like it's running a race, sometimes it's choking for breath just cruising. Sometimes it'll idle for hours smoothly and quietly, sometimes it'll sputter, chug and cough before dying, then refuse to restart for minutes or even hours. There's zero predictability or reliability, and it's making me nuts. The car has been doing this for years and I (or my mechanic, or the other guys who have come by to help) have never been able to resolve the issue.

I'm at a total loss. I think this engine might be haunted.

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post #51 of 251 (permalink) Old 03-20-2017, 08:11 AM
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Mr. Chairman, forgive me if I'm plowing old ground, but are the original plastic hard fuel lines still on the car? Have you blown them out with compressed air?

I worked on an MGB decades ago, installed a new SU fuel pump, filters, cleaned the carbs, dropped the tank, etc. ... finally I removed the old steel fuel lines and there was a stringy goo clogging them up. The car would idle, but not start or run well.

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post #52 of 251 (permalink) Old 03-20-2017, 08:17 AM Thread Starter
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No, actually, not the steel lines. While I was replacing the hoses I flushed them with carb cleaner, and I've never had any issues with fuel pressure, so I reasoned they couldn't be the problem. At this point, I can't assume anything. I was under the impression replacing them means having new lines bent to match original spec?
I'm also planning to get the fuel tank back out and have it cleaned and sealed. Why not.

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Last edited by chairmankaga; 03-20-2017 at 08:20 AM.
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post #53 of 251 (permalink) Old 03-20-2017, 08:23 AM
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Not necessarily... I was suggesting simply disconnecting the hoses at each end of each tube, and blowing them out with compressed air. That would confirm there's no obstructions in any of them, the main supply line, the vent line, and the return line from the pressure regulator.

I admit it's a long shot...

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post #54 of 251 (permalink) Old 03-20-2017, 08:53 AM Thread Starter
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I'll definitely check out the hard lines, too. I'll drain the tank and reinspect it, although the baffles might be the reason I haven't seen if there is actually a problem. Maybe better to clean it, or have it cleaned.
Like I said, Square 1. Start at where the fuel goes in, work my way forward!

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post #55 of 251 (permalink) Old 03-20-2017, 09:01 AM
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You sir, are a very persistent and determined man! Anyone shipwrecked with you on a deserted island would be in good hands, and would likely survive!

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post #56 of 251 (permalink) Old 03-20-2017, 09:07 AM Thread Starter
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I'm also suspecting the fuel pump wiring. I redid the power and ground wires when I replaced the pump last year. Maybe run some test leads to the driver's seat so I can monitor the meter while I'm driving. I've swapped the combo-relay around with no change in behavior, of course. That's not the issue, unless all three relays have the exact same fault!

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post #57 of 251 (permalink) Old 03-20-2017, 09:51 PM
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Quote:
Originally Posted by chairmankaga View Post
Well, I got new plug wires in. The car still stalls out.

I don't get it.

I'm going to start over from square 1. Drain the gas, pull every sensor, test continuity of every circuit, etc.

The problem is, sometimes it runs fine, sometimes it dies. Sometimes it starts first try, sometimes it won't start at all. Sometimes it runs like it's running a race, sometimes it's choking for breath just cruising. Sometimes it'll idle for hours smoothly and quietly, sometimes it'll sputter, chug and cough before dying, then refuse to restart for minutes or even hours. There's zero predictability or reliability, and it's making me nuts. The car has been doing this for years and I (or my mechanic, or the other guys who have come by to help) have never been able to resolve the issue.

I'm at a total loss. I think this engine might be haunted.
Man, this sounds frustrating.

It sounds like your symptom occurs randomly, but it seems duplicable enough that if you had some strategic equipment hooked up, you could at least isolate the problem next time it happens. Based on my reading of this thread, it seems like you have replaced a lot of parts in an attempt to solve the problem, but not much actual diagnostic work has been done (though I could be wrong). Do you have any idea if it is lack of fuel or lack of spark that is causing the stalling/no start? Next time it acts up, hook up a timing light to one of the spark plug wires. If it still flashes while cranking the engine, you probably have enough spark for the engine to run.

As I have posted before, have you ever actually kept a fuel pressure gauge hooked up to the system? Have you ever pulled the fuel level sender from the tank and looked inside to make sure that the tank isn't full of rust that is intermittently clogging the pickup screen?

Check the basics before tearing everything apart!

Chris A.

'81 GTV6 rescued from junkyard, "GT" car
'86 Porsche 944 Turbo track/street car
'73 BMW 2002tii fun street car
'87 Porsche 944 race car project (stalled)
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post #58 of 251 (permalink) Old 03-21-2017, 07:10 AM Thread Starter
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I did know I was having spark issues. The coil was overheating and cutting out. I went ahead and replaced the amp too. I'd been meaning to replace the plug wires for years as they're original and depending on how they twisted, were either in spec, or totally out. I know I'm at least getting clean spark, even when the thing starts to stall. Previously it would just shut off, like a switch had been hit.
I also had a bad coolant temp sensor, which would cause the car to run rich before flooding out. That was pretty easy to diagnose and repair.

So this almost has to be fuel related, right?

I know I have good pressure, at least usually. I've tested it MANY times at the cold start injector. The problem is they have to be quick readings, as my gauge doesn't really fit the hose and leaks gas. I'll figure out how I can leave the gauge installed to gen continuous readings during the stall.

My pump seized last year so I replaced it. While I was under there I also replaced the pump wiring and fuel hoses, and also inspected the tank. The vent valve was replaced a few years prior (and it did fix the issues with the vapor smell inside the car), FYI. As I mentioned I didn't try to replace the hard lines, but I did flush them with carb cleaner and dry then with shop air. No blockages. No rust.

But the fact that the problem is intermittent and more or less random seems to indicate some sort of "floating blockage", maybe some sludge that is somewhat mobile and is either blocking the send or return lines. Just a hunch, but I planned to drain the gas, pull the tank out and REALLY inspect it.

I do think I've had a confluence of issues that are slowly being resolved by replacement of parts that needed to be replaced anyway, like plug wires, wiring and sensors. But this one is increasingly frustrating because while one repair fixes one specific issue, it still won't run (for long).

I suppose it could also be the ecu getting the mix wrong? The plugs are a little damp with gas after a stall.
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post #59 of 251 (permalink) Old 03-21-2017, 10:20 AM
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I owned a 86 GTV6 which had some driveability problems kinda like this, similar. Was frustrating. Turned out the car had two problems.

One was that a main ground for the engine, to the firewall I think, was not tight and would get hot after a while and evidently start to build resistance, affecting how the engine ran, rough, and perhaps quitting, not restarting. Cleaned and tightened, that fixed that problem.

The other, at another later time, was the multiconnector to the AFM being very dirty, and after the engine and bay warmed up, would start acting up, sometimes not conducting properly on one or more of it's connections, engine running rough and sometimes quitting. Cleaning with electronic spray and using dielectric grease solved that problem.

Car ran like a dream after fixing those two poor/dirty connections.

In a sense, it was a similar problem, dirty electrical connections, with my 94LS, where the ignition modules under the air filter box were dirty and sometimes would not conduct on several cylinders, engine running rough and sometimes quitting after a while. Cleaning those multiconnectors and using dielectric grease cured that problem.

Alfa did reimburse Alfa mechanics on warranty for cleaning and using dielectric grease on engine bay electrical connections in many of these cars, including the 164s, to solve persistent driveabililty problems. Not saying the above are your problems with the car, and you may have already checked them, but checking and cleaning those cured similar problems with my GTV6, so thought I would offer them.

good luck.
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Del

Seattle

89 Milano (wife's daily driver since 1989, Shankle Sport)
91 164S (my daily driver since 1994)
94 164LS (~Q) (trip Alfa since 2000)
72 Morgan 27 (water time since 1976)

previously owned since 1964:

62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6

Last edited by Del; 03-21-2017 at 10:34 AM.
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post #60 of 251 (permalink) Old 03-21-2017, 01:21 PM Thread Starter
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So I redid a couple of the ground wires, replaces bad terminals, several years ago. I'll be sure to recheck those. Maybe a bad crimp, maybe a loose terminal, maybe a bad connection.

And I cleaned and greased the AFM harness recently during some regular maintenance, but maybe the heat is causing issues, like with yours? Except it doesn't always have to be hot - sometimes it runs poorly within seconds of starting. Sometimes it's fine. A few weeks ago I ran it for several hours with no issues. This past Saturday it started stalling in less than 5 minutes. Stalled out. Parked for about 2 hours, refused to start the first three tries waiting about 15-20 seconds between cranks, but the fourth it fired right up and had no more problems. I even drove around the neighborhood for about 15 minutes to see if it would stall out, and it ran like a top.

I guess that's what's so frustrating - sometimes it's perfect, sometimes it simply refuses to run at all.

as good as a car can be... briefly.
'82 GTV6
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