7.3 No start, hard start, runs on one bank, then both banks

blown99 · September 28, 2015

2002 f-350 7.3 auto, 230k on it Towed to me, came from another ford dealer. They installed an IDM. Found it to crank and start, run very poor. I verified the complaint, found about 4 injectors to buzz audibly. Customer runs veggie oil at times. Replaced all 8 injectors, found engine to be harder to start than typical after an injector replacement - found icp sensor biased low. Road test, runs perfect. Long exit ramp off the highway and I have a slight fuel knock noise which goes away after accelerating, decide to run the road test route again, this time it stalls getting off the ramp, I have a crank no start - all pids look good. Eventually it starts back up, coughs and sputters for 2-3 seconds, then runs perfect, get it back to the shop - check over everything - don't find any issues. Drive it around town no stalling. Appears to stall only when rpms drop down to below 625 ish (converter unlocks, then rpm dips for a split second) Ride the throttle pedal and we can't duplicate the problem. I find that in the shop, I can run this at high rpm for a while, get the oil to 190ish and I end up with a very long crank/hard start. It then only runs on the right bank. Run a buzz test OK no codes at all. This then turns into a no start. I check cam sensor air gap, it is out at .050, grind the front cover, set the gap to .020 and tried a new cam sensor- no luck, changed the ipr valve no luck, air check - no leaks in the high pressure oil system. Oil reservoir is full. I have immediate icp that climbs to 2200psi, icp koeo is .24, climbs to 2.2v. Fuel pw climbs to 4.2 when cranking. Crank it long enough, and it starts to spit and sputter (like a flooded gas engine) it will then start and run on the right bank. I removed both valve covers, - little to no oil returning out of return ports, unplug each injector and you can hear the injector coil stop actuating when unplugged. Shut the engine off,restart it, long crank again, but starts up and runs on all 8. A few times, it failed the glow plug lamp output test and I have had quite a few keep alive memory codes pop up. I tried a good test idm, checked fuel pressure, base oil pressure, dead head high pressure pump, leak checked each head for oil leaks, wiggled the harness, inspected pins and connections on what I believe are all the connections for the pcm/idm to engine - 4 connectors on inner fender skirt, idm/pcm conenctions, valve cover gasket connections, engine to chassis connection on the left valve cover. Removed the central junction box, no signs of water. Load tested power and ground s to the pcm and idm with a 55watt head lamp OK. Right now I am leaning towards a pcm because it randomly started failing the glow plug light during the self test and the random keep alive memory codes. Any input is very much appreciated.

8WA Sman · September 28, 2015

Does it stall with the ICP or alternator disconnected? Also check the CJB power wire junction connection at LF inner fender for greenies.

blown99 · September 28, 2015

Yes, it stalls with the icp disconnected. The connector for the cjb is clean as a whistle.

Dual alternator truck, I did not try disconnecting them, but I have the belt off working on the no start/hard start so I should not have an ac voltage issue.

8WA Sman · September 28, 2015

Just to be clear I am talking about the junction block on top of the LF inner fender cover. The main positive cable for the CJB splices @ the inner fender(has a black cover over it)

blown99 · September 28, 2015

Yes, that would be the junction block

Steve Mutter · September 29, 2015

Have you checked fuel pressure at the cylinder heads, maybe the left side is running out of fuel. Had one where the black o-ring was blocking fuel flow to the back of the cylinder head.

blown99 · September 30, 2015

Fuel was checked at the right head as the plug is stripped in the left head. I believe this problem to be a firing issue electronically - when the valve covers are off and you are cranking the engine, it takes a while before you start hearing the injectors pop off, and when it does decide to run on the right bank only, there is very little to no return oil out of the injectors on the left bank. I tried a test pcm, test idm, made a cam sensor overlay harness. At a loss on this one...

Matt Saunoras · September 30, 2015

Just thinking out loud is oil condition okay?

blown99 · October 2, 2015

Fresh oil, made a cam sensor overlay harness, scoped the cam sensor, I can identify the identifier and they are nice and square.

ktmlew · October 2, 2015

Have you checked the fuel to see if it's half gas or something worse?

Kevin_Rymwid · October 30, 2015

Have you checked the large connector on the driver side valve cover?

lmorris · October 30, 2015

Just popped into my head....The high pressure line fittings at the pump have those check valves in them. I remember years ago hearing that if they are put in upside down or left out they will cause starting issues. Just a thought.