2000 3.0 has vibration/lugging between 1200-1500 RPM in gear and out of gear

[fij]

I've done a ton of work to bring this ranger back. Replaced head gasket, timing chain, water pump, spark plugs and bunch of interior stuff. I got it all back together. it start fine, coming up to speed is fine. but if the engine sits around 12-1500 RPM in any gear i get some odd engine vibration. It might be missing during this time but it seem like a bad vibration to be caused by missfire. I did have a pending code for misfire on cylinder 1. I'm going to check the spark plug later today but i expect it to be fine. I did have the harmonic balancer off for the timing chain change. could the harmonic balancer be going bad. i've heard coil packs go bad on these. i'm not getting a pending code anymore. I've cleaned MAF and IAC. I have a fuel filter i'll probably put in the next couple days. That was $8 so it just seemed prudent. I don't have problems getting up to speed with engine calculated load in the 80% so I wasn't to worried about fuel pressure or the injectors. next steps I was thinking was coild pack or harmonic balancer. coil pack is $25 and harmonic balancer is $65. I've heard some say the coild packs go bad so maybe its worth it to change it for the price. Anything else i'm missing?

 

[RonD]

Coil packs can crack but not at all common

Cold engine
Take the fan belt off the crank pulley
Start engine, you can only run it 60-90 seconds with no water pump, but that's a lot of time, and you can repeat this test any time engine is cold again
Battery light will stay on, no alternator
Engine bay will be DEAD QUIET with no fan
Raise RPMs to the "vibration" zone, see if its there or gone
If its gone then most likely the fan clutch or fan blades are bad

If vibration is still there then its in the engine and most likely a misfire or partial fire
Shut engine off and put fan belt back on

When each cylinder fires it adds the same power to the crank, if a cylinder doesn't fire at all then no power added, if a cylinder fires but has lower compression or poor fuel mix then not as much power is added to the crank
These can cause vibrations

Best place to start is a compression test just to rule it out
Remove all 6 spark plugs first
Test each cylinder and write down results
3.0l runs 9.3:1 compression ratio so should be 165-170psi brand new
155-160psi would be OK, but its not about a high number

Point of a compression test is to test all cylinders that day with that gauge and that battery
If you have 5 cylinders at 150 and one at 130 then there is an issue, on a 3.0l its usually a burnt exhaust valve
But better to find out now than to waste time and money on spark and fuel
Compress is black and white no grey area, its mechanical, so once its off the table misfires are spark or fuel related

 

[fij]

i've done compression test and leak down test. that was two weeks ago and before i took it for long drives so maybe I can check again. i was getting 150# on compression but it was a weak battery. its a free test(excluding time). I hadn't considered the fan and fan clutch being a culprit. The fan is always running. I just assumed if it failed that it would just run all the time and a cooler engine probably wouldn't be that catastrophic. the belt removal test is probably worth it(free).

 

[fij]

checked engine without belt on and vibration is still there.

 

[RonD]

So its a misfire
Its possible harmonic balance is failing but vibrations should increase with RPMs, wouldn't be a "range"

Misfires can be in a "range" depending on the cause

 

[fij]

i ordered a coil pack. it will be here tomorrow. i'll give you an update then. if its not the coil pack. then i'm thinking harmonic balancer and ignition synchro. both are a bit more work to change. any thoughts on doing a test where engine running in vibration zone and removing spark plug wire from oil? maybe thats a bad idea. i'm struggling on what tests I can do to help narrow it down before buying more expensive parts.

 

[pjtoledo]

have access to an infra red thermometer??? they can read the temperature on an individual cylinder revealing which one is not firing properly.

double check the plug wire order too.
did you pull the cam sync unit for inspection?
a few drops of oil on it's top bushing won't hurt anything and may prolong it's life.

 

[fij]

I don't have an infra red thermometer. I replaced coil and no change. I called my brother to bounce some ideas. i'll probably try wires next. but i'm going to check that the balancer has the accessory drive with the 4 bolts fully seated. maybe I didn't get one or more of the bolts all the way driven in. they were really tight threads and I used and impact to drive them in. so i'll check that tonight. Still leaning towards balancer.

 

[fij]

Also spark plug on cylinder 1 looked fine. checked spark wires to correct cylinders.

 

[fij]

checked pulley bolts for the harmonic balancer and those looked seated well. replaced fuel filter. about 20% clogged. looked to be original filter. no change in vibration. I ordered a set of wires. If wires doesn't help at all, i'm left with balancer(which i'll go to next). After that cam synchro. I haven't messed with a cam syncrho ever. looks to be straigtht forward though. I figure I need to change wires anyways.

 

[bills4065]

I know you said pending code, has it set a code yet? have you happened to look at your fuel trims at idle and say 2500 rpm? Thanks

 

[fij]

no set in codes. i'm not even sure the misfire on cylinder 1 was associated with this. I had a leaking injector on cylinder 1 and replaced the injector(no more gas leaking out) so code could have been pending for that. i've driven about 20-30 miles and haven't got another pending code or set in code. thats why i was leaning towards mechanical(harmonic balancer). it seems to run really good except for that couple 100 rpms. unfortunatly that is nice cruising speed at 45 and in overdrive at 65ish. what would the fuel trims be called on the obd2. I also have a forscan. I just have to dig it out of a box. haha

 

[fij]

I know you said pending code, has it set a code yet? have you happened to look at your fuel trims at idle and say 2500 rpm? Thanks

idle 967rpm(still warming up, drops to 850 after warm)
shrtft1 0-1
longft1 5.5

shrtft2 0.8
longft2 -6.3

2500 rpm
shrtft1 0-2
longft1 10.2

shrtft2 0-3
longft2 -0.8

 

[bills4065]

@fij I think we are both saying the same thing only differently, lol Remove pcv valve and block off that hole. cover opposite valve cover hole at same time. Remove oil dipstick and put vacuum gauge rubber hose over top of dipstick tube and take a reading with engine idling. You should not see any vacuum reading in crankcase doing this. Thanks

 

[fij]

Check for internal vacuum leak. disconnect pcv valve fresh air in and the pcv valve. Plug both of those so you have totally isolated the pcv system. Then put a vacuum gauge hose over the oil level dipstick and see your reading. you should not see any vacuum in the crankcase. only reason I mention this you said replaced head gasket . This test eliminates lots. Thanks.

Well i'm not sure if i did exactly what you mean. I removed the small plastic Pcv valve. I felt vacuum from the hard plastic pcv valve. I covered the whole in the valve cover. and the PCV with vauum at the same time. i also had somone else cover opposite valve cover hose that goes into intake hose. i tried to draw vacuum manually from hand pump that was connected to oil dipstic. I couldn't draw a vacuum. I started engine and no vacuum built up on the guage either. I'm a little confused on the PCV valve fresh air in