MattB Posted August 30, 2010 Share Posted August 30, 2010 We've got a 2001 E350 in the shop that will run rough and stall at cruise or accel. Runs great at idle and seems to do so indefinately. Sounds like fuel knock when it starts to go. It will always restart, but has a long crank. Will consistantly act up in the shop by redlining, stalls within a minute or two. Fuel filter is new motorcraft. Fuel supply is verified. Measured 70 PSI at the pump and 65 at the rear of the heads. Inlet restriction at WOT is a max of 5"hg. Also tried sucking straight out of a fuel can with known good fuel. No fuel aeration was noted when sample was taken at the rear of the heads, even when it was acting up. ICP voltage KOEO is .23V. Passes oil aeration test, IPR never exceeds 65%. Oil looks good, customer states it was replaced recently. ICP reads 1500 PSI when van stalls. What else are we missing? Something else I'll mention. We have alot of needle fluctuation (bounce) when measuring fuel pressure at the heads. Not sure if it's normal or not, can anyone confirm? Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 30, 2010 Share Posted August 30, 2010 Does the ICP ramp up slow after it quits? Why is it long cranking, I mean. What isn't there when you're trying to start it? ICP, Fuel, ETC.? Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 30, 2010 Share Posted August 30, 2010 How many miles on it, and what's it used for? Ambulance, delivery van, etc? Maintenance history OK? Fuel in the oil? Maybe some crappy injector o-rings? Quote Link to comment Share on other sites More sharing options...
MattB Posted August 30, 2010 Author Share Posted August 30, 2010 about 130k. Has 4x4 conversion, its a material services truck traveling into mines. It's an 11 passenger wagon. The van is really rough, but fluids and filters look maintained. Has almost 2000 PSI ICP within 2 seconds of cranking. Sometimes takes 30 sec of cranking to fire. Also has full fuel pressure when key is turned on. No sign of fuel in oil, no sign of oil in fuel. Injectors were all just removed and resealed. It's got a new IPR valve. It had ICP circuit codes also and a wire fault was found and repaired. It's not road worthy, so we can't take it out on the public hwy to drive it. I will talk to the guy tomorrow and get more info to post up. It had a long list of DTC's originally, now it passes koeo/koer/injector/contribution, no dtc's stored. All injectors buzz loudly. We're kinda lost on this one. It appears to have air, fuel, and compression available. Shouldn't be a problem, right? The only other thing I can think of is maybe a very brief VREF short to ground. It has a fuel knock as it starts to run rough, and we can pull full fuel flow out of the rear of the heads as it's running rough and stalling. So mechanically it seems to have everything it needs to run, it would almost have to be something shutting down the injectors. Any idea how the IDS reacts to a VREF short on a 7.3? I guess it'd be easy enough to figure out. Thanks for the reply, let me know if you have any ideas for us to try. Otherwise I think we'll try shorting it out tomorrow to see how it reacts. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 30, 2010 Share Posted August 30, 2010 Don't look at ICP pressure, look at ICPV, which should be about .17-.24v KOEO and ramp up to 1.5V quickly cranking. ICP is a calculated number and ICPV is a factual number. What is IPR doing when this happens? Ramping up? With this being repeatable at WOT I'm thinking oil starvation on the LPOP side causing the HPOP to starve. I'd do a physical check of LPOP with a gauge and oil aeration tests. Pull a sample from the OPS while the motor is at high RPM, there's a TSB on it. I have checked FP at the heads on an E-van and don't remember any bounce in the gauge. Is it both heads? I remember a shorted ICP pulling VREF to ground on a 7.3 that caused no communication. Good Luck! Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 31, 2010 Share Posted August 31, 2010 VREF shorts usually react in a PCM reset... like someone shuts the key off... Usually they don't run like shit, do they? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 31, 2010 Share Posted August 31, 2010 VREF shorts usually react in a PCM reset... Intermittent short, yes. The one I remember was a dead shorted ICP sensor and it came in on a hook. The reason I remember it so clearly was it stalled while at the fuel island getting fuel- now what's the odds that it's NOT a fuel problem on that one? like someone shuts the key off... Usually they don't run like shit, do they? Correct, but Matt asked.... Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted September 5, 2010 Share Posted September 5, 2010 "Usually" is an intriguing word. Rates right up there with "always" and "never". While we suffer through "pattern" failures and TSB driven "streamlined diagnosis", it is important to remember that each and every customer concern might fall outside that "box" that we trap ourselves into. I don't know what I'm looking for... but when I find it, I'll know it. Quote Link to comment Share on other sites More sharing options...
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