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Discussion Starter · #1 ·
I recently replaced a new fuel pump, cleaned the fuel lines and verified that fuel is being pumped like Old Faithful, but the car idles roughs and backfires and does not stay idling for long before it dies. I have posted a video of the experience here: https://www.dropbox.com/home/1973 Volvo 164?preview=MOV_0463.mp4

I would appreciate any inputs on what is ailing my ride. Please let me know if you have any trouble linking the site. Thanks.

Svens.
 

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I recently replaced a new fuel pump, cleaned the fuel lines and verified that fuel is being pumped like Old Faithful, but the car idles roughs and backfires and does not stay idling for long before it dies. I have posted a video of the experience here: https://www.dropbox.com/home/1973 Volvo 164?preview=MOV_0463.mp4

I would appreciate any inputs on what is ailing my ride. Please let me know if you have any trouble linking the site. Thanks.

Svens.
I couldn't view the video (asks for a user name and password). What kind of fuel system are we talking about? D jet or Stromberg / SU?

If it is Djet, I would suggest that one of the first thins you should check is the fuel rail pressure. Lean backfire could be caused by a lack of fuel pressure. On a B20E it would be 28 - 30 psi. I am not sure about the B30. If the fuel pressure is OK, then there are other things to check.

As I recall, you had rust issues. If you have D jet and you have crud in the injectors, it could be impeding fuel flow which would also cause lean misfires.
 

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Discussion Starter · #3 ·
I couldn't view the video (asks for a user name and password). What kind of fuel system are we talking about? D jet or Stromberg / SU?

If it is Djet, I would suggest that one of the first thins you should check is the fuel rail pressure. Lean backfire could be caused by a lack of fuel pressure. On a B20E it would be 28 - 30 psi. I am not sure about the B30. If the fuel pressure is OK, then there are other things to check.

As I recall, you had rust issues. If you have D jet and you have crud in the injectors, it could be impeding fuel flow which would also cause lean misfires.
The link is set for anyone with the link should be able to see it. If you send me an email address, I can add you tot he link and see if that works.

Yes, it is D jet, and I have rust issues. I have a Moeller glass filter and have cleaned the filter regularly, but no doubt rust has made its way to the injectors. Besides replacing the injectors, is it possible to clean the injectors?
 

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Besides replacing the injectors, is it possible to clean the injectors?
Not if they are fouled with rust. Injector cleaners are organic solvents and are for gum and carbon deposits.

Have you checked the coil?

I can't see the video either. I think "everyone" means "everyone with a dropbox account".
 

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The Dropbox page still presents a login with no way to X it away.

Question about your "backfires" comment. Does it do this at idle? Not to suggest the obvious, but any chance someone switched a plug wire? :)
 

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Discussion Starter · #11 · (Edited)
The Dropbox page still presents a login with no way to X it away.

Question about your "backfires" comment. Does it do this at idle? Not to suggest the obvious, but any chance someone switched a plug wire? :)
It backfires when accelerating. No chance a plug was switched. Haven't touched them. I wish it was that easy.

Here is a new link on YouTube. https://youtu.be/mr6PXPHjiSk

Please let me know if you can access it. Thanks.
 

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That video works. As you said, fuel pressure looks OK.

There is a procedure on the Djet where you can cause the injectors to fire by operating the throttle switch with a non running engine; but, the key in the run position. If you pull the injectors out of their holders and have six containers to catch the fuel, you could do this test fire and get an idea as to whether the injectors are non working / plugged up. I do not like this kind of test because, particularly on a B30, its hard to keep 6 injectors in place and avoid spraying atomized gasoline all over the place - great potential for a fire or explosion. You could do the test on an injector by injector basis by sequentially unplugging and reconnecting the six injectors. Much easier to manage one injector at a time than six; but, more hassle! The better and safer solution would be to pull the injectors and send them to an injector testing & cleaning service.

Even if you don't pull the injectors to check for flow, do the throttle switch test and carefully listen to the injectors. You should hear them clicking. If you don't hear clicks from all of them, you have a faulty injector(s) or a wiring problem.

Before you consider pulling the injectors, pull the sparkplugs and have a look at the insulators. Are they white as can be (probably running lean) or are they dark brown to black? If its lean then you likely have a fuel delivery problem and injector testing and cleaning (or at least confirming that they are operating) would be a good idea. If you pull the injectors for testing or cleaning, plan to replace the rubber ring seals around the injector pintle as a minimum. These get hard with age and probably will not reseal when you stick the injector back in to its holder. Also, before you pull the injectors:

- make sure the throttle position switch is set up accurately (there is a link to an on-line copy of the set up procedure for the D jet on the 1800 forum)
- make sure your ignition timing is set correctly. Your engine is running so rough that I don't think you will be able to use a timing light; however, you should be able to check the static timing of the points. Unfortunately, I don't know what the static timing is for a B30. Should be in the service manual if you have or can find a copy.
 

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Discussion Starter · #13 ·
Not if they are fouled with rust. Injector cleaners are organic solvents and are for gum and carbon deposits.

Have you checked the coil?

I can't see the video either. I think "everyone" means "everyone with a dropbox account".
Ok, the coil readings are primary 1.4 ohms and the secondary is 10.6 ohms. I have a pertonix flame thrower 40k volts coil which shows the primary as 1.5 ohms and the secondary as 9.0 ohms. From what I have read and seen on youtube, these readings are within standards. What do you think?

Steve
 

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Seems reasonable, and if the coil isn't overheating it is probably ok. The more I think about the backfiring comment the less I think it's the spark itself. But it might be worth peeking under the distributor cap for rotor damage or crossfiring.

Two questions:
1) do you literally mean it's backfiring, i.e. detonation back into the intake? Or is the car bucking and/or detonating out the tailpipe?
2) did this come on all of a sudden?
 

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Discussion Starter · #16 ·
The answers to your questions:
1. Both, but mostly from the tailpipe
2. Yes. I was driving the car when I noticed the usual signs of fuel pump issues of low power. I drove back by mashing the heck out of the gas pedal and managed to get it very close to home. I changed out fuel pumps and drove it well enough back tot he house. I then drained the fuel tank, flushed it with apple vinegar and then fill it back with gasoline and now am at the issue I have now.
 

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In my first response I referred to lean backfire, I should have said lean misfire.

Misfire, which is a failure of the fuel mix to ignite usually manifests itself as a noise out the tail pipe. It may pop if the fuel mix subsequently ignites in the exhaust manifold. It can be a fuel mix problem or a failure of the ignition to ignite the mixture. Backfire is as tmtalpey implies, firing back through the intake manifold, usually because there is an ignition timing problem or a valve timing problem. Valve timing is usually an assembly problem and doesn't just show up.

Flushing with apple vinegar is a new one for me. Sounds kind of expensive and I wonder about its effectiveness. The acetic acid content of vinegar tends to be pretty low and I expect may not be that effective at rust removal.
 

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Yow. Well, it does seem like a fuel issue. Did you replace the fuel filter after the salad dressing treatment? Maybe disconnect the fuel supply and return lines, route them to a large fuel can, and see how it runs with no tank and no filter in the loop. If it still misfires, then I'd pull the injectors and test them in a bottle as mentioned below.
 

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Discussion Starter · #19 ·
Yow. Well, it does seem like a fuel issue. Did you replace the fuel filter after the salad dressing treatment? Maybe disconnect the fuel supply and return lines, route them to a large fuel can, and see how it runs with no tank and no filter in the loop. If it still misfires, then I'd pull the injectors and test them in a bottle as mentioned below.
I plan on doing that, but I am waiting for replacement injectors to arrive first. My best guess is like you said, after the salad dressing treatment, there must have been way more loosened rust than I realized, and some of it quickly worked its way into the injectors.
 

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It is really hard to get all the residual debris out of a fuel tank. Generally it's best to take it to a specialist who can tank the entire thing, flush it thoroughly and test for leaks while they're at it. Still, it's possible the fuel filter caught it, and is just constricted even though the flow appears ok. I've done test drives with a pressure gauge sticking out from behind the hood, visible from the driver's seat. Might be a fun thing to try while you wait for the parts. :beer:
 
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