Are my plug wires bad and if so would that cause stalling after the car is hot? - Page 9 - Alfa Romeo Bulletin Board & Forums
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post #121 of 302 (permalink) Old 04-03-2017, 05:39 AM
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"Chairman kanga, I admire your perseverance in working on this car. Many a lesser man would have given up and began to read the fire loss provisions of the his home owners policy and the revelant arson laws. However it may be time to seek supernatural assistance.

Don't know how (or if) you roll in spiritual matters, but sacrificing a live chicken in the garage, surrounding the car with a protective line of kosher salt, soldering or brazing St. Christopher's medals to the engine block or other bits, filling the coolant system with holy water are all things I have considered or tried in in the past."


I too, have been that desperate for a solution, on more than one occasion!

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post #122 of 302 (permalink) Old 04-03-2017, 06:40 AM Thread Starter
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The hard plastic injector seals found in the Alfa Spider, are only found in the Spider. They are not used in the GTV6 / Milano. The injector seal in the Milano is a round soft rubber thing more properly described as a square cut O-ring. I've done dozens of these over the years and I've always used the Airtex or Beck Arnley brand.

Smoke testing

I do have the $1,000 smoke test machine (well I have use of it). I always run a smoke test after doing injector seal replacement, and there should be no smoke coming from the intake runners or manifold.

if the system is really tight smoke should come out of the oil filler cap and the oil dipstick. A little should come out throttle body where the shaft passes through body.
The throttle body can be a big source of leaks.
Once worked on a GTV6 that run super well except for a very high idle (1,400 RPM). Big smoke leak through the throttle body. Just replacing the throttle body made the idle drop 600 RPM.
Question - the injector seals you get from Centerline, or even a big box auto parts store, are too tall for the injector well. When I install the injectors, because that lower seal protrudes past the head, they push underneath the O-Ring (using the Bosch terminology) causing them to bulge or tear. Should I be cutting down the injector seal flush with the head? I suppose it would be relatively easy to shave them with a really sharp razor blade.

And on a whim, since I had a few minutes while my daughter was watching Sesame Street, I removed the throttle body form the plenum to look for leaks. There is not gasket in mine. It looks like there's some ancient Permatex or maybe just silicone between the parts. I'll do a *Big Sigh* now assuming this isn't correct. Back to the shop manual.

May this be a lesson to never buy an Italian car from a kid who says he got it because he really loves Mopars, and this car had a hemi, although it wasn't a real Hemi, then after a couple of years decided it was too hard for him to figure out. I feel like 90% of my time with this car is rectifying someone else's quick fix.
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post #123 of 302 (permalink) Old 04-03-2017, 10:11 AM
Del
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Isn't that almost always the case. The dreaded PO is all too common with cars like these, buying them cheap and then at the first sign of trouble or required maintenance, they fiddle with it, bail, leaving the next owner with a potentially stupid mess.
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Del

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1989 Milano, Shankle Sport
1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27

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

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post #124 of 302 (permalink) Old 04-03-2017, 11:42 AM
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Do I remember you saying there was a hiss down around the throttle body? You may have more than one leak. I've seen engines burn valves from localized intake manifold leaks that leaned out just one or two cylinders. Greg's correct in his writeup.

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post #125 of 302 (permalink) Old 04-03-2017, 12:03 PM Thread Starter
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Yes, there is a hiss, although I've been told it's not a leak, just the air being drawn into the throttle body. Although as I mentioned I've discovered there's no gasket between the TB and the plenum. They're on backorder so I'll either try to make one, as the shape isn't especially complicated, or use some RTV until they're available again.

I did go ahead and order more injector seals, along with an AFM gasket, because why not? At this point I'm literally going back through every connection, joint, seal, and removable part.

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post #126 of 302 (permalink) Old 04-03-2017, 01:05 PM
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Suggest you check with DiFatta Brothers (410) 426-7524, Alfa Parts (510) 525-9435, Alfissimo (928) 526-0549 , Spruell (770) 457-2532 and on E bay... somebody will have a TB gasket they'll sell you!

If I had one, I'd give it to you, after what you've been through.

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post #127 of 302 (permalink) Old 04-10-2017, 07:08 PM Thread Starter
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Well, I cut out of work a few hours early today to get some garage time. Installed the new injector seals (at least three of the old ones were badly misshapen) and torqued it down to just 8 ft lbs, as per every other steel-into-aluminum application on this engine.... and only had to Helicoil one! I also installed new gaskets at the throttle body and AFM. Cleaned up those junctions. Tightened everything to spec. Oh, and swapped the fuel pressure gauge with a smaller, lighter one.

Checked fuel pressure. The new gauge read a little high, just a couple of PSI, and the needle flutters, but then I noticed when I switched it off, the needle fell. A lot. I went to get some lawn tools out of the shed and put away the trash cans. When I came back maybe 15 minutes later the gauge was flatlined.

Well, ****.

Swapped the gauge with the old one, and same thing.

**** ****. This is new.

There are no obvious leaks. Maybe I broke an injector in the process, and it's leaking? ? It was groaning and little at one point. Pressure is good as long as I have the AFM flap open. As soon as I release it drops to about 30, then dwindles to 0 over the next 10 minutes or so.

Man, I don't know. I was too frustrated to deal so I built a new swing for my kids, instead. And I won't be surprised one bit if the vacuum issue is now corrected, only to deal with fuel pressure now.
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Last edited by chairmankaga; 04-10-2017 at 07:19 PM.
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post #128 of 302 (permalink) Old 04-10-2017, 08:02 PM
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Ugh, that is frustrating.

It seems like the fuel system's inability to hold residual pressure is a new one, and you are correct that a leaky injector is the most likely cause. There is no check valve at the fuel pump outlet or any other sort of fuel pressure accumulator in the GTV6 fuel system, so the fuel injectors (including the cold start injector) are the likely suspects in the case of fuel pressure bleeding down after engine shutoff . . .

Before pulling the fuel rail, it might be easier to remove all of the spark plugs and then re-pressurize the fuel system by opening the AFM flap with the ignition on. If one of the injectors is leaking, you will likely be able to see/smell the fuel in the offending cylinder due to the central plug location of the GTV6 cylinder head.

If one or more of the injectors is leaking, you will have to decide if you want to order individual replacement injectors (I needed a single injector for my GTV6 due to a broken pintle and found a replacement on EBay) or pull yours and send them to a rebuilder like RC Engineering (which is the most economical option, but means that you cannot commence any further testing until you get the injectors back). You might not know the answer to this until you pull the injectors and closely inspect the pintles . . . .

A leaking injector will also cause engine running issues, but it is also an unfortunate distraction from whatever is causing the long-term stalling issue.

Hang in there, and let us know how it turns out.

Chris

Chris A: '81 GTV6 rescued from junkyard, "GT" car/'86 Porsche 944 Turbo track/street car/'73 BMW 2002tii fun street car/'74 Jensen Healey Lemons Rally car!
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post #129 of 302 (permalink) Old 04-10-2017, 08:51 PM
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It seems like the fuel system's inability to hold residual pressure is a new one, and you are correct that a leaky injector is the most likely cause. There is no check valve at the fuel pump outlet or any other sort of fuel pressure accumulator in the GTV6 fuel system, so the fuel injectors (including the cold start injector) are the likely suspects in the case of fuel pressure bleeding down after engine shutoff . . .
Bosch fuel pumps have a check valve in the outlet. If they didn't, pressure in the rail would just leak backwards through the pump when you switched off the car. That said, if you didn't mess with the fuel pump it's unlikely that has failed.

Leaking injector seems the most likely culprit given that's what you messed with. The only other options are a leaking hose clamp (which I'd assume you'd smell) or a leaking pressure regulator (which, again, I assume you did not mess with so that seems unlikely as a sudden failure mode).

Maybe you could clamp off the injector hoses one at a time to see if you can isolate the leak? Not sure how well that would work but it's all I can come up with.
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post #130 of 302 (permalink) Old 04-10-2017, 08:56 PM Thread Starter
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Hmm. I'll give that a shot.

Still wondering about the regulator. The gauge was bouncing like crazy when the pump was on which is usually a solid sign it's no good, and coupled with the loss of pressure seems to be a solid clue. There's no gas in the vacuum line though or black smoke from the exhaust, but major stumbles on throttle. I wonder if the diaphragm was in fact popped, then maybe that could have been contributing to the vacuum leak? And maybe that was all set off by installing a new pump that was actually flowing as much fuel as it was supposed to just did in the weak regulator? Man, that actually seems plausible. More plausible than a previously FINE injector going bad. It's not like I hammered the rail back into place.

This is like a full blown conspiracy theory, I know.

A friend of mine who has a collection of L-Jet parts for his fleet of junker BMW's actually has a spare 2.5 bar regulator that he thinks will fit my rail, if I want to test it. Thing is, he accidentally reversed the fuel flow in the car it came from and he's pretty sure that's not great for it. Although maybe trying a bum part would be enlightening! At this point...

Or just pull the rail, kick on the pump, and see what happens.
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post #131 of 302 (permalink) Old 04-10-2017, 08:58 PM
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Originally Posted by Gubi View Post
Bosch fuel pumps have a check valve in the outlet. If they didn't, pressure in the rail would just leak backwards through the pump when you switched off the car. That said, if you didn't mess with the fuel pump it's unlikely that has failed.
Good catch, that made me re-read my post! With the Bosch Alfa pumps, there is a built-in check valve in the outlet. Other Bosch pumps have a replaceable screw-in brass outlet fitting that contains the check valve.

It is easy to isolate the issue: simply clamp off the fuel hose the comes out of the outlet: if the system pressure still drops, you know your issue is downstream of the pump.

Chris

Chris A: '81 GTV6 rescued from junkyard, "GT" car/'86 Porsche 944 Turbo track/street car/'73 BMW 2002tii fun street car/'74 Jensen Healey Lemons Rally car!
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post #132 of 302 (permalink) Old 04-10-2017, 09:06 PM
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Yeah, you could theoretically just stick clamps on everything until it stops

You can test the regulator same way: turn off the car, clamp the return line out of the regulator and see if that fixes the issue. Probably also disconnect the regulator vacuum line, make sure there's no fuel spurting out of there.

Tom

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post #133 of 302 (permalink) Old 04-10-2017, 09:18 PM
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Originally Posted by chairmankaga View Post

Still wondering about the regulator. The gauge was bouncing like crazy when the pump was on which is usually a solid sign it's no good, and coupled with the loss of pressure seems to be a solid clue. There's no gas in the vacuum line though or black smoke from the exhaust, but major stumbles on throttle. I wonder if the diaphragm was in fact popped, then maybe that could have been contributing to the vacuum leak? And maybe that was all set off by installing a new pump that was actually flowing as much fuel as it was supposed to just did in the weak regulator? Man, that actually seems plausible. More plausible than a previously FINE injector going bad. It's not like I hammered the rail back into place.

This is like a full blown conspiracy theory, I know.

A friend of mine who has a collection of L-Jet parts for his fleet of junker BMW's actually has a spare 2.5 bar regulator that he thinks will fit my rail, if I want to test it. Thing is, he accidentally reversed the fuel flow in the car it came from and he's pretty sure that's not great for it. Although maybe trying a bum part would be enlightening! At this point...

Or just pull the rail, kick on the pump, and see what happens.
Well, the bouncing gauge needle is new information, and could be a game-changer. If there is no gas coming out of the regulator vacuum port, then a weak or broken spring could cause this . . . . I have only seen a couple of failed Bosch fuel pressure regulators in over a dozen years of working on Porsches and BMWs, but it seems that with this particular car, anything is possible!

Like Gubi said, gradually clamp off the fuel return line and see if the gauge needle stabilizes, while ensuring that fuel pressure climbs accordingly. A hand vacuum pump is also a good tool to have to check if your fuel pressure regulator (or your friend's tester) holds vacuum . . . . .

Chris A: '81 GTV6 rescued from junkyard, "GT" car/'86 Porsche 944 Turbo track/street car/'73 BMW 2002tii fun street car/'74 Jensen Healey Lemons Rally car!
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post #134 of 302 (permalink) Old 04-11-2017, 05:34 AM Thread Starter
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Yeah, it's new information because it just started! I was able to clamp the return line from the FPR and fire up the pump. Pressure shot up to 90 or so immediately, but yes, gradually began to dwindle. I noticed some dampness on the clamp at the gauge this time, which might just be due to the increased pressure in the lines. Not dripping or spurting. Just damp.
I also put a little brake bleed hand pump on the FPR and it seemed to hold pressure when I pulled it down to 21-22.
I'll check the fuel pump next. I'm dressed for work and didn't want to go crawling under the car. Later. I did clamp the send line at the rail (not enough slack to crimp and clamp, so I just stuck two vice clamps on it) and it SEEMED to hold. Didn't have time to wait longer.

EDIT - I don't know if my cheap Harbor Freight vacuum pump is faulty, but I did notice that after maybe 10-15 seconds of the FPR holding vacuum, the needle would plummet. There would be 21-22 psi showing, then it would instantly drop to 0. Could just be a bum valve in the pump. I'm going to borrow my neighbor's AC kit later today.

Checking the cold start injector is easy. That too.


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post #135 of 302 (permalink) Old 04-11-2017, 07:28 AM
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I'll put my money on a faulty regulator...

Has the engine vacuum reading improved after your work on the injectors/seals?

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