miss at light cruise or steady state

[JHILL]

I have a miss ? that has shown up recently after changing oil.
Have had an issue all along @ 2300 rpm in a steady state throttle position which I have assumed was a tuning issue. After oil change, at light cruise cut's in and out with no change in pedal position. Under load do not notice and makes good power, starts fine, DC, and peak ICP #'s seem normal ,@ Idle 17% cold, 9-10% warm, 2950psi @ WOT @39% DC. On the scanner I am seeing a 150-200 psi ICP drop when it acts up.


Buzz test - all 8 buzzed with 1 sounding slightly weaker, Cylinder Cont. #1 and #8- balance fault.

Compression test over the winter was good ,390 psi low with 2 holes that were high 430 and 450( possible oil /fuel seepage causing the high reading's?), the other 5- 400psi or slightly higher IIRC.


345k miles, no excessive blow by,fuel mileage seems normal, not that I check

ICP sensor is dry. Dirty IPR? I have tried 2 different TPS and recently swapped back to the original ford TPS

edit: Delo 400 with 2 bottles of Rev-x previously, Valvoline 15-40 with 1 bottle Rev x on this oil change The Rev x seem's to smooth out the idle nicely.

 

[Fordcowboy]

Seems pretty similar to something I had going on years ago. I really don't remember exactly what it was doing or numbers like ICP and such, but cleaning the IPR helped, and I ended up getting a new one and haven't had the problem since. So I would say looking into the IPR would be worth a shot.

 

[golfer]

I have never seen an IPR cause a misfire...the IPR sends equal pressure to all 8 injectors...

JHill~ I would re run the compression test. a brand new engine won't have more than ~425psi of compression...

if compression is good, then check rockers/valvetrain...and inj(s).

the quiet buzz indicates that there's a problem with that injectors' armature to solenoid clearance...and a poppet valve that was hanging open would cause an intermittent misfire, as well as a very quick drop in pressure when that poppet hangs.

 

[JHILL]

Dave, Thanks for the input. Other thing's I forgot to mention, ticking noise that has been present for months. Hard to isolate, Drivers side,thinking exhaust manifold leak but no evidence of soot. Has seen 4k + more than a few times. no codes that aren't expected with mods. did throw a 1298 code IDM fault on contribution test, have read a modded IDM will always show up. Time to pull the valve covers and have a look.
Thanks, Jeff

 

[littleredstroker]

Subed

Sent from my HTC PH39100 using Tapatalk 2

 

[golfer]

..... did throw a 1298 code IDM fault on contribution test, have read a modded IDM will always show up.
Thanks, Jeff

if there isn't a CEL/SES light on...and it passes a buzz test (regardless of how it/they sound)...then the wiring & IDM is fine.

also, IDM codes are expected with modified IDMs

 

[JHILL]

Found a couple things yesterday, exhaust leak is the source of the ticking noise, soot on drivers side #8 on manifold. borrowed a break out box looks like 2 injectors have issues. same 2 holes that had high compression readings- Carbon build up possibly?

 

[golfer]

carbon build up on what?

 

[JHILL]

Assuming the piston/combustion chamber IDK. with the egt's this motor has seen I wouldn't think it would be carbon'd up. Although I drive it like a grandpa most of the time. I do know what happens when you ASSume things though
Appreciate the help Dave.

 

[JHILL]

Well, went to the beach today, truck ran like it has been as mentioned previous.
went to head home, maybe a mile on the sand back to pavement, truck runs like a** , has a dead miss.
get to within 5 miles of home, oil pressure drops(factory gauge) and light comes on ,shut it down.

Oil level -Full on dipstick (maybe 1000 miles since changed) no foaming or bubbles . restart same thing, except over 1500 rpm pressure builds. going to throw the scanner on it and pull codes, will put a mechanical gauge on to verify actual psi.

We were thinking LPOP, but it builds HPO and starts. Did some reading
will a bad injector bleed enough oil to cause this issue? IPR/Oil cooler relief valve stuck open?

 

[JHILL]

no unusual codes, until we ran a buzz test all 8 buzzed -ok but all 8 cylinders came up as high/low open circuit and a 1298 for the IDM -not unusual for a modded IDM. swapped IDM's for the heck of it, cleared all codes no codes other than usual for given mods.

Put a mechanical gauge on at oil filter port, when first started up at Idle, 20psi mechanical, dash in the normal range, no oil light. 1500 rpm 50psi .
Decided to try and drive it home. 1 mile down the road same issue as last night ,under 1300rpm's dash pressure drop's with oil light on.

Confirmed on Mechanical gauge back at the shop,Lube oil pressure drops,
ICP / DC on scanner are normal values when Dash light comes on and pressure drops. Did not run it very long with 0 psi on the dash to see how long it would take to see a HPO drop. IDK what direction to go next, leaning towards a LPOP. Have read about oil cooler relief valve's that stuck open. Can an injector pass enough oil to cause this issue? Still runs rough, starts up fine.

 

[JHILL]

Melling 208 LPOP Installed. Picked up 10psi cold start settled to 20 after 5 or so minutes idling ..

Still runs rough ,starts fine. hope to find the cause of rough running condition before I drive it and see if oil pressure issue is gone.

Running drivers valve cover off,no major oil difference out of injector spouts, #8 a little more than others, found a rocker arm issue on # 4 exhaust, replaced with a used replacement, all seems well now. check other side in am.

 

[JHILL]

#7 cylinder both rocker towers broken , 1 bent push rod. should be out and head off in the am.

 

[mattman347]

Good luck Jeff!! Tell jake to get his dang hands dirty for once!!

 

[JHILL]

LOL Thanks Matt, He did get a little dirt under his fingernails. All but ready to pull it out in the morning. waiting on a trans jack. Depending on what we find, may have some injectors headed your way. :toast:

 

[JHILL]

Motors back in and running fine,

Another set of heads went to the machine shop, mine were cracked between the valves in a couple of places as well as most of the exhaust seats. middle's seem to be worse.

Surfaced Head, Injector cups, ex.valves and seats, new valve guides & seals, rockers,springs.

Injectors flow checked thanks Full Force Diesel.

Bearings looked great. Fixed dipstick tube leak.

couple hundred miles on it so far :thumbsup:

Special thanks to -Irate Jake for the shop use and storage, now just get my water pump here :blah:

 

[mattman347]

Good to hear its running again Jeff!!