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Discussion Starter #1
I have a 1983 Alfa Romeo GTV6 sometimes the car does not want to start up when it's cold and needs extra throttle to start. Sometimes however it will start up on its own, it's kind of hit and miss. But my biggest problem is it'll run fine for the most part when cold, except it will backfire through the intake if it's given too much throttle too quickly. and once it's warmed up it'll seem to idle and rev just fine. But whenever I get out and start to drive it is when more problems start happening. when I drive it it'll be okay for a little bit and then it'll start surging and popping through the intake badly. When it starts doing this I can't give it any throttle at all It only wants to idle. The car will also not drive faster than about 5 mph. I don't know what the problem is I've dug into just about everything I could think of, I changed all the fuel filters fuel pump made sure the tank was venting correctly. Would you guys have any ideas? Could be something just simple?
 

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Joe Elwell
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I agree with @tomhenneka - it's really best to go thru the entire article and check everything.

The article is a priceless piece of GTV6 owner's maintenance documentation, although it is, well, a bit verbose :).

I went thru the whole thing once, and so learned the parts and what they all do. The I just made a nice simple checklist I go thru if there's trouble. It's really a worthwhile investment.
 

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Remove the rubber flex tube from the air flow meter to the throttle body, check for splits and cracks that can open up and cause vacuum leaks. If you find them, use a product called Shoe-Goo to mend the splits. It works great and is available at Wal Mart, etc.
Then, remove any aluminum fuses in the fuse block and install only new copper or brass fuses. Fuses 2, 5 and 8 are critical to start/run functions. Pull the fuses, use a pencil eraser to clean off the brass fuse clips, and reinstall making sure they have enough tension to clamp the fuse securely. Make sure you replace the 8 amp and 16 amp fuses in the right places.
 

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1984 GTV6
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I must support AlfaLoCo, he gave me the same advice a few weeks ago and it is great advice. I just finished going thru Greg with Hiperformace “L-Jetronic” write up on my GTV6. I found quite a few faulty items; the highlights are; numerous broken vacuum system components, my AFM switch was not adjusted properly, throttle position switch was not set, grounds needed maintenance and I had wires shorted to the chassis. He goes thru each component of the fuel system methodically, when your done you can be confident everything is sorted. A word of warning if you go with the shoe Goo option, think it out, it is no longer flexible when done. Also, it’s the definition of sticky and gets everywhere. Like baby pooh and anti-seize. The pics included below are my shoe goo fix for a hole i tore in mine last week. keep going with updates.

IMG_0627.JPG IMG_0628.JPG IMG_0630.JPG
 

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1984 GTV6
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Some other titles of resources I found very useful are included below;
  • Cardisk Deluxe GTV6 Manuals disk
  • Double Relay Demystified
  • BOSCH L-Jetronic Injection Manual
  • Bosch Electronic Fuel Injection ECU Vehicle Component Application
It's better to search the BB with the titles to find the latest versions to work from.
 

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Thank you Sobol... very kind of you. I got a big kick out of your Shoe Goo comparison! I still rely on Alfisti here who are even more experienced and who have more in depth knowledge than I have.
No matter what the car marque, if we don't have 12 volts to start with, troubleshooting won't get us very far. Electric power and grounds are basic.
 

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Discussion Starter #9
Thanks! I will look into the fuses and grounds, and I'll double check my flex hose. I'll try to get back on how it is running soon.
 

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Discussion Starter #10
I checked the flex hose and it seemed a little cracked in one spot but it wasn't all the way through, I went ahead and patched it. I also found out the car was timed incorrectly, I fixed that and it runs way better than it did. But it still doesn't like to drive. After a couple minutes of driving it loses a lot of power and It seems to lurch in gear. is there a chance this could be due to a clogged exhaust or catalytic converter?
 

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Discussion Starter #12
I didn't get under the car to check, I'll have to do that next time, but it does start smoking from the exhaust headers.
 

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Discussion Starter #13
I got under it and it wasn't glowing red, but it was around 320ish degrees, in some spots my thermometer was reading around 350
 

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I got under it and it wasn't glowing red, but it was around 320ish degrees, in some spots my thermometer was reading around 350
That's actually not even fully warmed up, and nothing to worry about. Normal operating temperature of the cat is over 1000 degrees F.
 

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Have you hooked up a fuel pressure gauge? This sounds like a failing fuel pressure regulator or some other issue with the fuel return line.

Get your hands on a fuel pressure gauge, tee it into the fuel pressure circuit using a long hose and see what it does when the symptom occurs. My bet is that it will go sky-high due to a restricted fuel return circuit, which causes the injectors to be unable to open against the fuel pressure and cause the complete lack of power/acceleration. If the fuel pressure regulator is the culprit, rapidly pumping the gas pedal (thus causing the manifold vacuum to fluctuate) will often unstick the diaphragm and temporarily alleviate the issue.

I also wouldn't be surprised if you additionally have vacuum leaks that are causing cold start issues and some of the popping through the intake (that almost always points to lean running conditions). Intake air boot, intake sleeves at manifold, fuel injector seals . . . .

But check the fuel pressure first.
 

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Discussion Starter #16
@cda951 Thanks for the tip! I actually rented one from O'Reilly's but it was broken when I got it, I think I'm going to have to find somewhere else to get one. But I will definitely look into that. What should be the fuel pressure for this car, and where is the regulator? And it actually starts up pretty decent now that I adjusted the timing.
 

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@cda951 Thanks for the tip! I actually rented one from O'Reilly's but it was broken when I got it, I think I'm going to have to find somewhere else to get one. But I will definitely look into that. What should be the fuel pressure for this car, and where is the regulator? And it actually starts up pretty decent now that I adjusted the timing.
I'd have to check the specs in the CarDisc manual (only on my shop computer at the moment), but I believe it's around 28 PSI with the vacuum line connected, ~7 PSI more with the line disconnected, which is in line with other Bosch L-Jetronic systems of the era. A few PSI different won't cause many issues---it would have to be drastically off to cause what you describe.

The fuel pressure regulator is right at the front of the engine, has the rubber fuel hose going to the top and hard line connections at the sides. But the fuel pressure gauge should be teed into the fuel inlet hose at the back of the engine.

Good job getting the ignition timing dialed in, but again ignition timing has to be significantly out of spec to cause drastic running issues, and those issues certainly wouldn't be intermittent if that were the case.
 
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Discussion Starter #18
Thanks man! I'll try to get back and tell you how it goes. And the previous owner timed it of the wrong mark, I believe it was an F mark that they used, and I timed it off the correct mark which I believe was an R. And I am betting that regulator is bad and hopefully getting that fixed should dial the car in.
 

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I had a mysterious problem with my GTV6 when I first started working on it. I could get it to start and it would run fine for 8-10 miles and then it would start bucking and kicking and quit. I would have to sit on the side of the road and let it cool for 15-20 minutes before it would operate again. Needless to say, I started taking a lot of laps around our country block, trying to figure it out. It was quite frustrating. And, the fuel pressure would show up as good when I tested.

It was the fuel pump. It would crap out after it ran for awhile. I figured it out by just letting the car run in my workshop until the symptoms appeared. It took a bit of time as it was just idling. I had been ignoring the pump as the source of the problem given that it had power, and would show that it created the proper pressure at the fuel rail. I was chasing all kinds of what I thought were ignition problems, as it's not uncommon for ignition components to fail once they heat soaked. A buddy and I were going through the ignition system again, after the aforementioned idle session, when I perked up and said, "I don't hear the fuel pump!" Therein was the "Eureka" moment. Swapped to a new pump, never had the problem again.
 

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1986 Alfa Romeo GTV6
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All the symptoms point to air/fuel mixture. The fact that you cant get more than 5mph is a dead ringer. Since you addressed most of the fuel line, time to do the rest.
I saw a video last week that has your problems. and my money is on that other problem with Alfas. ELECTRICITY.
remember, symptons are not a desease.
Check out this video and see if it relates.
read the comments also.
(spoiler, grounding problems with injectors)
what do you guys think!
 
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