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I'm hoping to get some feedback from those of you who are more knowledgeable than me. Car is running rough. Sputters at idle, but never quite dies. Loss of power when driving. Have replaced plugs, dizzy cap, rotor and fuel filter. Even did post mortem on filter to make sure it wasn't full of junk from my fuel tank, which it wasn't. Confirmed fuel pump is running smoothly and not leaking. Plug wires are fairly recent. Coolant temp sensor measures fine. Compression measured OK across all 6 cylinders. Used IR thermometer to measure temps on manifold right next to each injector, which I think has led me to the culprit. During warm up, when 5 of the cylinders were reaching 100 degrees, the 1st/front one was at 80. When the other 5 had reached 180 - 190, the front one was at 120. Pretty good indication that my #1 injector isn't working? Should I pull the plug wire for cylinder #1 to confirm that there's no change in how its running?
If I'm right, I believe you can't pull an individual injector to check it and that you have to pull the entire fuel rail and all 6 injectors to check any of them. Is that correct? Then to check them, just crank the engine with each injector suspended in a jar? When doing this, do I need to make sure I disconnect anything, such as a coil wire, or is this unnecessary?
Thanks for taking the time to read this and any advice is greatly appreciated!
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Probably not helpful. My 1965 164 developed an over-rich condition which got worse rapidly. I checked everything, twice. I lucked out and found a broken valve spring on #1, I had the oil cap off and noticed one of the lifters barely moving.
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Keeping it running is better than buying new
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Before checking injection, check ignition. Before ignition, check mechanical problems.
1st, Set tappets to .022", then do a compression test.
Check ignition timing at idle with no vacuum hoses connected to dizzy, it should be 10°, rev it to 3500rpm and it should be 34°. Put timing light on number 6 and check if it does the same.
Are the plugleads original? Cheap silicon replacements are only good for 2 years, then performance drops markedly.
Pull the plug leads boots back to bare the connection to the spark plug and short them out one at a time with a screwdriver 1st contact the tappet cover, then slide it down to contact plug.
Fit 6 new NGK BP7HS.
With a big screwdriver, check if the idle mixture screw on the ECU does anything to the idle.
Does the car go OK on the road when you run it at cruise speed?
Still driving, slowly squeeze the pedal to the floor, does that cause any problems?
Does the car go OK on the road when you hold it flat?
You should disconnect the vacuum hose to the MPS and suck on it, making sure the hose doesn't have a hidden crack. A leaking MPS should not affect the idle, but affects part throttle performance seriously and will eat a mountain of gas.
The thermostat will have little to do with your problems, EXCEPT, it indicates yours is not closing the bypass properly. The head distributes the cooled water via the brass pipe in it.
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posted by
someone claiming to be blackjackmac
on
Sat Mar 3 04:40 CST 2018 [ RELATED]
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Cold water from radiator goes directly to no1 cylinder which could have a bearing on your temp readings. I have found front cam bearing can wear to the extent that pressure from the helical gears will force camshaft up and close tappet clearances at revs above idle. If you do have No1 missing above idle with lead pulled try opening tappet clearance on that cyl. Just a few options to try. It may be something unrelated.
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The head distributes the cooled water via the brass pipe in it evenly. Cool running on number 1 indictes a poor or incorrect themostat.
Note the location of the water pump on an old Ford, Holden or Valiant six. The pump blasts cold water straight on the front of the bore of number 1 causing it to wear out early. Not so in a Volvo, this is one of the very simple and cheap features of the old Volvo's.
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"Coolant temp sensor measures fine"
How about the ambient air temperature sensor?
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Thank you for the reply!
From everything I've read, it didn't seem like that sensor could cause those symptoms, though my original plan was to test it anyway. Just so happens that my meter is also my IR thermometer, so after measuring the coolant temp sensor, I went right to checking the manifold temps next to each injector. Based on what I found while doing that, it'd didn't feel necessary to check the other sensor. Do you believe it could be causing my problem and is therefore worth measuring, or does it seem that my tests pretty much point to the problem being with my #1 injector either being faulty or having an issue with it's wiring? Note that I'm leaving out the ECU as being a possible culprit, since I'm really hoping that won't be the case and am not sure how I'd even go about checking to see if it is!
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Well, I was thinking that it'd be another thing to check. But true, many times the ambient temp. sensor failure shows us as a rich mixture when warm.
Thinking on it some more though, have you checked that you have a strong spark on that #1 cylinder? Maybe you could swap the plug and / or wires around to see if the failure follows the components.
Not saying it's not what you suspect. Just trying to cover all the cheap bases.
Edit. I'd have no problem pulling the plug wires while running to isolate which cylinder as you asked above.
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Once again, thank you very much for the reply, which was very helpful!
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Stan,
I'm don't know what you've done so far in diagnosing your problem so some thoughts and ideas ....
D-jet CPU's don't fail. Well. OK, it's VERY rarely.
Yes, good idea to pull one plug wire at a time while idling to find which one(s) doesn't (don't) deteriorate the idle much.
You can pull all the plugs, reconnect them to their respective leads, ground the plugs, and crank it over to check for spark. A timing light is nice to use as it allows you to sample each individual plug wire while the engine is running - looking for the spark to "skip a beat" here and there.
Are all of the plugs looking to be burning at about the same color? Or is one of them way sootier or way lighter in color?
You could have a leaking intake manifold gasket or leaking injector seals. You can read up about testing those areas with a unlit propane torch.
If you find three cylinders running well and three sickly, then must likely one of the trigger contacts isn't opening.
As you suspected, a clogged injector is possible. I rigged some clear plastic tubes that fit tightly on the injector tips, were plugged on the opposite ends and had little screws that act as drains.
Once the injector rail was all connected back up to the car, I pulled the distributor out of the engine and removed the cap (left the rotor in place). The trigger contact wiring was still connected to the distributor. I turned the ignition on (the fuel pump will run) and spun the distributor rotor as fast as I could with one finger. The injectors will squirt-squirt-squirt. Since there is no vacuum acting upon the manifold pressure sensor (MPS), you will be simulating a command for a highly rich condition. So the tubes should start filling with fuel, and hopefully at an equal rate. If you connect a long vacuum hose to the MPS and you suck the sensor diaphragm down while spinning the rotor, you "may" be able to detect a reduction in injector flow, but don't worry if you can't - this is a rather crude test. Also, by sucking on the MPS port, you can detect if the diaphragm is shot. If the MPS doesn't hold a vacuum it will cause an extremely rich running condition.
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Very inventive way to check the injectors by spinning the rotor by hand.
Never heard that method.
I like it.
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