Fuel Injector pressure test

[bytes311]

I was watching a video on YouTube about testing the fuel injectors by pushing down on the plate to produce a spray, seen here: http://youtu.be/V1adoUkH70c

Mine doesn't have any resistance when pushed in, so the method in the video doesn't work. I'm wondering if the spring is stuck in the open position, because my engine has been running rich and terrible for the last week. It seems like it keeps pumping fuel into the cylinders. The engine doesn't idle unless I leave my foot on the pedal.

This started after I cleaned the idle speed regulator and fixed a vacuum leak. It ran perfectly for a couple minutes... it could finally breath! But then it went down hill after that. The Cat got hot and melted the honeycomb.

Through process of elimination, I removed the muffler and the Cat (both were glowing red), bought new spark plugs, cleaned out the idle speed regulator (again), and cleaned the contacts for the ignition coil. The engine still sounds like it's missing, and dies at idle.

I'm at a complete loss here.

Any tips or suggestions would be greatly appreciated.

-Daniel

[David T]

I was watching a video on YouTube about testing the fuel injectors by pushing down on the plate to produce a spray, seen here: http://youtu.be/V1adoUkH70c

Mine doesn't have any resistance when pushed in, so the method in the video doesn't work. I'm wondering if the spring is stuck in the open position, because my engine has been running rich and terrible for the last week. It seems like it keeps pumping fuel into the cylinders. The engine doesn't idle unless I leave my foot on the pedal.

This started after I cleaned the idle speed regulator and fixed a vacuum leak. It ran perfectly for a couple minutes... it could finally breath! But then it went down hill after that. The Cat got hot and melted the honeycomb.

Through process of elimination, I removed the muffler and the Cat (both were glowing red), bought new spark plugs, cleaned out the idle speed regulator (again), and cleaned the contacts for the ignition coil. The engine still sounds like it's missing, and dies at idle.

I'm at a complete loss here.

Any tips or suggestions would be greatly appreciated.

-Daniel
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The plunger is stuck in the mixture unit. It needs to be disassembled, the plunger gently removed, everything cleaned with Acetone till the plunger moves freely, and then reassembled. You may have to replace the cat.

[bytes311]

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The plunger is stuck in the mixture unit. It needs to be disassembled, the plunger gently removed, everything cleaned with Acetone till the plunger moves freely, and then reassembled. You may have to replace the cat.

Aha! I will do that.

[DMCMW Dave]

Yes. The fuel distributor is stuck wide open. Not only are you melting the exhaust you are diluting the engine oil. You are lucky it ran at all. Check the oil level, if it is too high or smells like gas change the oil now. Cams are expensive.

BTW David T does NOT mean to take the fuel distributor apart. Just remove it from the engine, pull the plunger out if you can, clean it, and put it back in. If you separate the two halves of the fuel distributor the odds of getting it back together again and working are somewhere between slim and none.

[bytes311]

Yes. The fuel distributor is stuck wide open. Not only are you melting the exhaust you are diluting the engine oil. You are lucky it ran at all. Check the oil level, if it is too high or smells like gas change the oil now. Cams are expensive.

BTW David T does NOT mean to take the fuel distributor apart. Just remove it from the engine, pull the plunger out if you can, clean it, and put it back in. If you separate the two halves of the fuel distributor the odds of getting it back together again and working are somewhere between slim and none.

Thanks Dave. Yeah, the oil smells of gas and I plan on changing that tomorrow. As for removing the distributor from the engine, I'll have to figure out how that thing is bolted on there. <grin>

- Daniel

[David T]

Thanks Dave. Yeah, the oil smells of gas and I plan on changing that tomorrow. As for removing the distributor from the engine, I'll have to figure out how that thing is bolted on there. <grin>

- Daniel

You take the mixture unit off and separate the two halves of the large aluminum housings. You DO NOT take the metering unit apart. That is the black heavy steel thing with all of the fuel lines attached. Once you have the metering unit apart you can get the plunger out.

[DMC5180]

You take the mixture unit off and separate the two halves of the large aluminum housings. You DO NOT take the metering unit apart. That is the black heavy steel thing with all of the fuel lines attached. Once you have the metering unit apart you can get the plunger out.

David,

I take it your not advocating simply removing the 3 straight slot screws from the metering head and lifting it off the aluminum housing? Have you had bad experiences with this method?

[Bitsyncmaster]

David,

I take it your not advocating simply removing the 3 straight slot screws from the metering head and lifting it off the aluminum housing? Have you had bad experiences with this method?

I had to use an impact "driver" to get those 3 screws out but with that tool it was no problem.

[DMC5180]

I had to use an impact "driver" to get those 3 screws out but with that tool it was no problem.

Yeah an impact driver is mans best friend when it comes breaking loose screws threaded into aluminum. An absolute must have item when working on motorcycle engines too.

[bytes311]

Got it out, but how do I remove the pivet pin to reach the plunger? Took the snap rings off and the ball bearing. I 32880see the pin but which way do I drive it out?

[DMC5180]

I've never had one of these apart before. But what I can see in the picture I'd say the straight slot screws are pinch bolts for the pins your trying to remove. I still think you should remove the 3 screws from the head unit ( they have no effect on holding the head halves together). When you put things back together you'll want to be sure the housing halves are sealed otherwise you'll have a vacuum leak.

[DMCMW Dave]

You take the mixture unit off and separate the two halves of the large aluminum housings. You DO NOT take the metering unit apart. That is the black heavy steel thing with all of the fuel lines attached. Once you have the metering unit apart you can get the plunger out.


Why would you split the aluminum housing? Just take the three screws out and lift off the distributor.

[OverlandMan]

Why would you split the aluminum housing? Just take the three screws out and lift off the distributor.

I have a related question. When you press the plate down and in turn the plunger "open", what makes the plunger "reset" to closed? I may have my open and closed backwards but hopefully that makes sense.

[Bitsyncmaster]

I have a related question. When you press the plate down and in turn the plunger "open", what makes the plunger "reset" to closed? I may have my open and closed backwards but hopefully that makes sense.

There is that large weight that pulls it back if you don't have fuel pressure.

Here is a photo of my impact driver. You just twist CC, hit it with a hammer to remove a screw (or anything your socket is for). You can install twisting it C, but I've never had to use it to install a screw.

[OverlandMan]

There is that large weight that pulls it back if you don't have fuel pressure.

Here is a photo of my impact driver. You just twist CC, hit it with a hammer to remove a screw (or anything your socket is for). You can install twisting it C, but I've never had to use it to install a screw.

Ok gotcha. So if the car is at rest (ie: engine not running) and you depress the plate, it should return itself?

[Bitsyncmaster]

Ok gotcha. So if the car is at rest (ie: engine not running) and you depress the plate, it should return itself?

Yes. If not something is binding or the plunger itself is binding.

[OverlandMan]

Yes. If not something is binding or the plunger itself is binding.

Well crap. Thanks for the info.

[bytes311]

Removed the three screws and carefully lifted off the distributor. Yup, that plunger is stuck! It won't even budge. I'll let it sit in acetone for the night and see if that helps.

[DMCMW Dave]

I have a related question. When you press the plate down and in turn the plunger "open", what makes the plunger "reset" to closed? I may have my open and closed backwards but hopefully that makes sense.

The flap will come back up due to the counterweight at the other end. The plunger is pushed back down due to fuel pressure and gravity. There are no springs anywhere in the mechanism.

[OverlandMan]

The flap will come back up due to the counterweight at the other end. The plunger is pushed back down due to fuel pressure and gravity. There are no springs anywhere in the mechanism.

Ok so to confirm if my car hasn't been run in a long time (over a year) and I push down the plate, while it does return due to the counter weight, when I push again there is little to no resistance, indicating the plunger is still pushed-in. Would turning the car on (or trying to) reset the plunger or is it stuck?

I'm trying to make a prep checklist ahead of trying to fire it up. I rebuilt the fuel system (including a tank cleaning and parts refresh there). I have not put fresh gas in it yet. I want to make sure I don't have another obstacle ahead before I do that. Maybe I'm over-thinking it.

[dn010]

You can try to prime the system or jump the fuel pump through the relay and see if the plunger in the fuel distributor drops - push on the plate while the pump is running or after the you hear the system pressurize - if you get good resistance then you know it worked.

I had the same instance where the plunger was stuck in my FD, but mine was much worse where the O-rings were shot inside the fuel distributor so I had to rebuild the whole thing with new rings - not something you want to do if you don't know what you're doing. Once you get your plunger issue situated and it is still dumping fuel down the intake, you'll need a new fuel distributor.

[DMCMW Dave]

Ok so to confirm if my car hasn't been run in a long time (over a year) and I push down the plate, while it does return due to the counter weight, when I push again there is little to no resistance, indicating the plunger is still pushed-in. Would turning the car on (or trying to) reset the plunger or is it stuck?

I'm trying to make a prep checklist ahead of trying to fire it up. I rebuilt the fuel system (including a tank cleaning and parts refresh there). I have not put fresh gas in it yet. I want to make sure I don't have another obstacle ahead before I do that. Maybe I'm over-thinking it.

At this point yes, turn on the pump (jump RPM relay, don't bother cranking the car) and see if you get resistance on that plate. If not, you're probably flooding the engine so you want to stop right away. To really see what's going on have all 6 injectors in jars. That way you can find and eliminate the bad ones before you try to run a 3-cylinder engine.

[OverlandMan]

At this point yes, turn on the pump (jump RPM relay, don't bother cranking the car) and see if you get resistance on that plate. If not, you're probably flooding the engine so you want to stop right away. To really see what's going on have all 6 injectors in jars. That way you can find and eliminate the bad ones before you try to run a 3-cylinder engine.

I did that a while back and the injectors were ok. I guess if the plate didn't give resistance after that, the plunger is stuck. I can do the flow test again for good measure but I'm thinking I may have a problem here.

What's the best way to unstick the plunger? The OP or someone yesterday mentioned soaking in acetone. Is that the preferred method?

[DMCMW Dave]

I did that a while back and the injectors were ok. I guess if the plate didn't give resistance after that, the plunger is stuck. I can do the flow test again for good measure but I'm thinking I may have a problem here.

What's the best way to unstick the plunger? The OP or someone yesterday mentioned soaking in acetone. Is that the preferred method?

Pull it out with needle-nose vise grips.
I don't like putting acetone anywhere near the fuel distributor.
One last blast attempt is to heat it in an oven to about 150F and then see if that softens it up (it gets hot on top of the engine).
Otherwise it's off to the rebuilder.

[PJ Grady Inc.]

I guess you ran out to the car and removed the metering unit while the other posts were coming in so now you're looking at the inside of the air sensor which won't do you any good. You'll have to put it back together to take the distributor off as it's usually screwed down pretty tight as the later posts mentioned.
Good observation (later post) on the impact driver as it's usually mandatory for distributor screw removal. You could use the opportunity while the sensor housing is apart to lever out the co plug, assuming it's still there, using a cut off nail as suggested in the workshop manual.
Otherwise you just wasted a lot of time unfortunately.
The guru must have forgot to eat his wheaties yesterday morning;)




Got it out, but how do I remove the pivet pin to reach the plunger? Took the snap rings off and the ball bearing. I 32880see the pin but which way do I drive it out?

[bytes311]

I guess you ran out to the car and removed the metering unit while the other posts were coming in so now you're looking at the inside of the air sensor which won't do you any good. You'll have to put it back together to take the distributor off as it's usually screwed down pretty tight as the later posts mentioned.
Good observation (later post) on the impact driver as it's usually mandatory for distributor screw removal. You could use the opportunity while the sensor housing is apart to lever out the co plug, assuming it's still there, using a cut off nail as suggested in the workshop manual.
Otherwise you just wasted a lot of time unfortunately.
The guru must have forgot to eat his wheaties yesterday morning;)

That's exactly what happened. After I realized taking out the unit was getting me nowhere, I took the liberty to clean it out after years of sitting. After I put it back together, I carefully removed the distributor by way of the three screws, soaked the plunger in fluids, and pulled it free with vise grips. It was gummed up bad. I put the distributor back together and now it's running like a champ. Who knows what will go next!

I definitely appreciate everyone's help. You guys rock!

[OverlandMan]

That's exactly what happened. After I realized taking out the unit was getting me nowhere, I took the liberty to clean it out after years of sitting. After I put it back together, I carefully removed the distributor by way of the three screws, soaked the plunger in fluids, and pulled it free with vise grips. It was gummed up bad. I put the distributor back together and now it's running like a champ. Who knows what will go next!

I definitely appreciate everyone's help. You guys rock!

This post gives me inspiration. I'll likely try to get to this sometime this week. Hoping for the same results you got!

[DAP John]

I was watching a video on YouTube about testing the fuel injectors by pushing down on the plate to produce a spray, seen here: http://youtu.be/V1adoUkH70c

Mine doesn't have any resistance when pushed in, so the method in the video doesn't work. I'm wondering if the spring is stuck in the open position, because my engine has been running rich and terrible for the last week. It seems like it keeps pumping fuel into the cylinders. The engine doesn't idle unless I leave my foot on the pedal.

This started after I cleaned the idle speed regulator and fixed a vacuum leak. It ran perfectly for a couple minutes... it could finally breath! But then it went down hill after that. The Cat got hot and melted the honeycomb.

Through process of elimination, I removed the muffler and the Cat (both were glowing red), bought new spark plugs, cleaned out the idle speed regulator (again), and cleaned the contacts for the ignition coil. The engine still sounds like it's missing, and dies at idle.

I'm at a complete loss here.

Any tips or suggestions would be greatly appreciated.

-Daniel

Daniel, The problem is the frequency valve. If it doesn't equalize the pressure in the distributor it will cause exactly what you are describing. Check the wiring. If it isn't making good contact with the plug or it's stopped
then there is your problem.

DAP
John Hervey

[DAP John]

I was watching a video on YouTube about testing the fuel injectors by pushing down on the plate to produce a spray, seen here: http://youtu.be/V1adoUkH70c

Mine doesn't have any resistance when pushed in, so the method in the video doesn't work. I'm wondering if the spring is stuck in the open position, because my engine has been running rich and terrible for the last week. It seems like it keeps pumping fuel into the cylinders. The engine doesn't idle unless I leave my foot on the pedal.

This started after I cleaned the idle speed regulator and fixed a vacuum leak. It ran perfectly for a couple minutes... it could finally breath! But then it went down hill after that. The Cat got hot and melted the honeycomb.

Through process of elimination, I removed the muffler and the Cat (both were glowing red), bought new spark plugs, cleaned out the idle speed regulator (again), and cleaned the contacts for the ignition coil. The engine still sounds like it's missing, and dies at idle.

I'm at a complete loss here.

Any tips or suggestions would be greatly appreciated.

-Daniel

Daniel, I forgot, that happens with age. No fuel pressure after you turn off car is nothing more that leaking fuel / pressure. Injectors, fuel accumulator or my little HOT start 2 O ring kit needs to be replace in the primary pressure regulator in the distributor.

DAP John

[OverlandMan]

I finally got around to this and was able to get the plunger unstuck. When I pulled the distributor off the mixture unit, the plunger had some small gooey fuel deposits around the lip of the area where it slides. I couldn't get it loose without soaking it (just the bottom area) in some parts cleaner. I didn't want to submerge the whole thing in fear of damaging the internal rubber components. Once I let it soak for a couple of hours, I was able to get it out with some needle-nose vice grips.

I put everything back together and should be ready for a test run this week, time permitting.