Faulty Fuel Injector causing mis at startup?

[rusty ol ranger]

I took it out to lay in the sound absorption material you see there in pic. It’s annoying enough of a project that I’m tempted to just replace it if I’m already opening it up haha. Oh the fun world this is.

They arnt hard to open and put back togther. 4 screws the case slides right off

 

[rubydist]

Just because the oxy sensor is only a year old does not mean its good.

 

[eightynine4x4]

True. But which part to throw at it first? Haha.

Here’s a short vid. First part is idle from inside cab, second is idle in engine bay. Third is shut down, then startup. After that it’s unsteady and bumpy for a bit. Not a clear distinct miss, just very imbalanced. Watch how far the rpm’s dip though. Pretty weird. Truck shakes a little. Then I give it some throttle and the issue clears up.

Good news is this the quietest the engine has ever been. New injectors starting to work out? Seems like it. In fact I took it on two more short drives and it felt great this time. But still getting this new check engine light.

The wobble and low idle feels similar to when I had fuel delivery issues when I first got the truck. To solve that I replaced the pump and also regulator, and of course the filter.

So I went to test fuel pressure and couldn’t find the damn shrader adapter for the kit. Gotta track one down now and run fuel pressure tests.

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[eightynine4x4]

Adding another video that demonstrates the wandering RPMs and also the difference of engine sound from warmup to post-drive hot startup.

After all this work, the most promising thing is that the engine sounds quite a lot smoother and quieter than it ever has, when it’s not ticking. This is heard in first part of video. So I know it has the ability to be smooth mechanically. The second half it sounds like a diesel. This comes and goes.

But the idle/RPMs still waver a lot no matter what. One time after a hot startup it swayed back and forth from 1K to 2K, every second. I kid you not! But below, in both the first part and second part, I’m holding the throttle perfectly steady at 2K and it still wavers up there. Then I drop it down to idle which also wavers a little.

I think at this point that i have checked every vacuum line/connection and tested with the mighty vac and I’ve replaced a few slightly leaky connectors but it hasn’t made any diffence. I also put a new hose from the plenum to the back of the fuel regulator.

I could see the short jitteryness at low idle being fuel/pressure related. But I just filled the tank before the second half of this video and drove it around before recording that part, so it doesn’t seem like air being pulled from fuel / tank is the direct cause of steady back and forth wandering RPMs. So at this point I don’t what else to attribute this to other than the ECM just running the RPM’s up and down for some reason. It’s not usually 1K to 2K, it’s usually only a difference of 200-300. But it hasn’t gotten better after like ten short trips of driving.

Next up.. opening up ECM and taking a look. Maybe it needs new capacitors somewhere?

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[rusty ol ranger]

Adding another video that demonstrates the wandering RPMs and also the difference of engine sound from warmup to post-drive hot startup.

After all this work, the most promising thing is that the engine sounds quite a lot smoother and quieter than it ever has, when it’s not ticking. This is heard in first part of video. So I know it has the ability to be smooth mechanically. The second half it sounds like a diesel. This comes and goes.

But the idle/RPMs still waver a lot no matter what. One time after a hot startup it swayed back and forth from 1K to 2K, every second. I kid you not! But below, in both the first part and second part, I’m holding the throttle perfectly steady at 2K and it still wavers up there. Then I drop it down to idle which also wavers a little.

I think at this point that i have checked every vacuum line/connection and tested with the mighty vac and I’ve replaced a few slightly leaky connectors but it hasn’t made any diffence. I also put a new hose from the plenum to the back of the fuel regulator.

I could see the short jitteryness at low idle being fuel/pressure related. But I just filled the tank before the second half of this video and drove it around before recording that part, so it doesn’t seem like air being pulled from fuel / tank is the direct cause of steady back and forth wandering RPMs. So at this point I don’t what else to attribute this to other than the ECM just running the RPM’s up and down for some reason. It’s not usually 1K to 2K, it’s usually only a difference of 200-300. But it hasn’t gotten better after like ten short trips of driving.

Next up.. opening up ECM and taking a look. Maybe it needs new capacitors somewhere?

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Have you checked your oil pressure?

That thing sounds sick. Real sick. I know you said that noise comes and goes....but im wondering if you got oiling issues causing this.

Possibly from the lifters losing pressure or something. Thats not the usual 2.9 tick.

 

[eightynine4x4]

Have you checked your oil pressure?

That thing sounds sick. Real sick. I know you said that noise comes and goes....but im wondering if you got oiling issues causing this.

Possibly from the lifters losing pressure or something. Thats not the usual 2.9 tick.

Have the kit but haven’t tested yet. My dashboard gauge always appears good. I know it’s just a crappy switch gauge or whatever.
Yeah I also wanted to post this sound for others to hear. This really sickly sound only occurs after a hot startup and I can get it to go away with some revving. Doesn’t do that when on a drive. It has a lighter tick.
It does do it on cold startup and then fades away as engines warms and gets nice and quiet as you can hear in first part of vid.
I’m running 15W40 Rotella like some other do, and am thinking of going back to the lower viscosity 5W30 or whatever the engine calls for. It seems like maybe the oil is getting too thin, and then it drips down when even thinner/hot, so hot startups are noisy as hell for a bit until I drive again and slosh oil around. That’s my best guess.

None of this seems to relate to the wild RPMs though right?

 

[rusty ol ranger]

That gauge will show pressure as long as its over 3psi. Which is about enough pressure to keep a sewing machine lubed. My 97 460 had mains knocking and the gauge showed normal pressure

Im not sure, but if the lifters are collapsing due to low oil pressure it could very well affect RPM.

I think you need to verify oil pressure. It maybe worn cam bearings, when the oil is cold and thick it can hit the top of the engine, but when its hot it cant get enough up there. Could also possibly be a failing oil pump.

If you do have oiling issues going back to 5w30 would make things worse.

I would verify pressure before i went any further with it.

 

[eightynine4x4]

That gauge will show pressure as long as its over 3psi. Which is about enough pressure to keep a sewing machine lubed. My 97 460 had mains knocking and the gauge showed normal pressure

Im not sure, but if the lifters are collapsing due to low oil pressure it could very well affect RPM.

I think you need to verify oil pressure. It maybe worn cam bearings, when the oil is cold and thick it can hit the top of the engine, but when its hot it cant get enough up there. Could also possibly be a failing oil pump.

If you do have oiling issues going back to 5w30 would make things worse.

I would verify pressure before i went any further with it.

Is this my oil pressure sending unit/switch? This is on drivers side.
Any pointers as to what the threading is? I assume I’ll need to quick swap the test gauge connector on so as to avoid losing lots of oil quickly.

I‘m considering just leaving a test gauge hooked up temporarily and running a line to the cab so I can watch it and note symptoms. Maybe it’s a risk of oil busting out in cab but it’d be worth the risk to learn something accurate here.

And I’m just assuming I’m about to find out that the engine needs to be rebuilt.

 

[rusty ol ranger]

Yes thats the sender.

Im not sure on thread size...but if you buy a sunpro kit for a mechanical gauge i believe they come with different fittings.

Use copper line though, not the crappy plastic line that pry comes with the kit.

2.9's are pretty resiliant. If you have run it a whole lot like this you might be able to save it if its the oil pump. If its the cam bearings or something you pry should plan on tearing it down completly then you know everythings good.

 

[eightynine4x4]

Yes thats the sender.

Im not sure on thread size...but if you buy a sunpro kit for a mechanical gauge i believe they come with different fittings.

Use copper line though, not the crappy plastic line that pry comes with the kit.

2.9's are pretty resiliant. If you have run it a whole lot like this you might be able to save it if its the oil pump. If its the cam bearings or something you pry should plan on tearing it down completly then you know everythings good.

This is the kit I have. Seems rugged enough to run into cab and leave in place for a while.

Engine and Transmission Oil Pressure Test Kit

Amazing deals on this Engine Oil Pressure Test Kit at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

The engine doesn’t sound like this except for specific conditions and I can get passed it with some throttle or by driving briefly. Usually when there are any sounds while driving I’m getting lightweight sounding ticking/tapping, and when it’s at its quietest it sounds like the other stuff I’ve posted here. I’d say it’s like 50/50 between those two.

I wouldn’t be upset if I find out the oil pump is failing and i need to replace it. I’ve had my eye on one of those nice high volume ones by Mellings. I know I’d need to lift the engine a little bit to get under there but that a pump swap can be done.

How does one determine if it’s the pump failing though? As opposed to determining it’s the cams?

 

[rusty ol ranger]

This is the kit I have. Seems rugged enough to run into cab and leave in place for a while.

Engine and Transmission Oil Pressure Test Kit

Amazing deals on this Engine Oil Pressure Test Kit at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

The engine doesn’t sound like this except for specific conditions and I can get passed it with some throttle or by driving briefly. Usually when there are any sounds while driving I’m getting lightweight sounding ticking/tapping, and when it’s at its quietest it sounds like the other stuff I’ve posted here. I’d say it’s like 50/50 between those two.

I wouldn’t be upset if I find out the oil pump is failing and i need to replace it. I’ve had my eye on one of those nice high volume ones by Mellings. I know I’d need to lift the engine a little bit to get under there but that a pump swap can be done.

How does one determine if it’s the pump failing though? As opposed to determining it’s the cams?

That i really dont know, if you pull the pump and its sloppy that would be a clue, but im not sure how youd check the cam bearings without dissasembly.

Whatever kit you use just keep an eye on the hoses.

The only other thing i could think of that might cause a sound like that would be the ECM pulling timing big time.

My phone speaker aint the best.

Check the oil pressure and go from there.

 

[eightynine4x4]

That i really dont know, if you pull the pump and its sloppy that would be a clue, but im not sure how youd check the cam bearings without dissasembly.

Whatever kit you use just keep an eye on the hoses.

The only other thing i could think of that might cause a sound like that would be the ECM pulling timing big time.

My phone speaker aint the best.

Check the oil pressure and go from there.

Here’s the results, and the video is below.

During warmup I was in the middle of the 40-60 range when revving to 2K RPMs but once temp was in middle of Normal the PSI would only reach 38 at 2K. And at this temp, idle is around 15.

I’m sure that if I ran the truck hotter, say up hills, the 2K PSI would creep down further.

Does this seem like the pump is on its way out? Do pumps tend to slowly weaken, or do they suddenly just crap out?

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[rusty ol ranger]

Here’s the results, and the video is below.

During warmup I was in the middle of the 40-60 range when revving to 2K RPMs but once temp was in middle of Normal the PSI would only reach 38 at 2K. And at this temp, idle is around 15.

I’m sure that if I ran the truck hotter, say up hills, the 2K PSI would creep down further.

Does this seem like the pump is on its way out? Do pumps tend to slowly weaken, or do they suddenly just crap out?

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Video keeps freezing halfway through.

Either way...i do think its possible you got a pump going.

Spec is 55psi@2000rpm (warm) and 20psi on a hot idle.

Oil pumps usually wear out, they dont just grenade, they get weaker overtime.

I wouldnt run the truck much more untill you get this sorted out.

The old addage was 10psi per 1000rpm...so assuming its just the pump (which, im not sure but seeing as how the oil pressure sender is close to the pump, top end noise with good pressure i would think would be more likely cam bearings), but it could be rods/mains...which is rare on a 2.9.

Either way...get your wrenches ready.

 

[eightynine4x4]

Video keeps freezing halfway through.

Either way...i do think its possible you got a pump going.

Spec is 55psi@2000rpm (warm) and 20psi on a hot idle.

Oil pumps usually wear out, they dont just grenade, they get weaker overtime.

I wouldnt run the truck much more untill you get this sorted out.

The old addage was 10psi per 1000rpm...so assuming its just the pump (which, im not sure but seeing as how the oil pressure sender is close to the pump, top end noise with good pressure i would think would be more likely cam bearings), but it could be rods/mains...which is rare on a 2.9.

Either way...get your wrenches ready.

Ever done the pump replacement? Any advice? If i can lift the engine a little without a huge fuss, I’m not weary of the project.

 

[rusty ol ranger]

Ever done the pump replacement? Any advice? If i can lift the engine a little without a huge fuss, I’m not weary of the project.

Not on a 2.9 no.

But i believe its pretty straight forward.