PowerSToKed Posted October 26, 2012 Share Posted October 26, 2012 All glow plugs check good, glow plug relay is bad but can jump power across relay and still no start, icp jumps right up during cranking 1200 psi plus, if you plug in block heater for 4 hours engine starts and runs a little rough then clears up, customer says it has sat a while, fuel is red but good and good fuel pressure, fuel filter is clean, truck runs ok after it has started, puffs a little out of oil fill tube but i have seen alot worse without cold cranking issues, changed oil and filter still having cold cranking issues (and its not that cold hear, will not crank on a 50 degree day if it has not been plugged in, truck has 150000 miles on it Quote Link to comment Share on other sites More sharing options...
lmorris Posted October 26, 2012 Share Posted October 26, 2012 How long have you driven it since getting it started? Sometimes you need to give them a good 20 minutes of hard driving to get them back to normal after sitting for awhile. Quote Link to comment Share on other sites More sharing options...
PowerSToKed Posted October 26, 2012 Author Share Posted October 26, 2012 The truck was driven to me from 45 miles away, could it be stiction in the injectors like we see in the 6.0s?, low miles on this truck but not sure how its been maintained and then sat for who knows how long Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted October 27, 2012 Share Posted October 27, 2012 1. The ONLY way to check glow plugs on a 7.3 is to test amperage. As you know the relays go bad very frequently, the amperage should be 190ish, dropping to 120 after 30 seconds. If you don't have an amp clamp do a voltage drop test across the relay, it should be 12.6 open and under .5 closed. 2. Cranking RPM is also critical, check it with a scan tool as your ear is not good enough. It should be 150+ cold, at 130 they will start hard or not start and it might "sound" like it's cranking normally. Many times guys get beat up by bad batteries. 3. Use ICPV, not ICP on a no start, as the PCM will substitute a known good value when the ICP is low, ICPV should be about .24 KOEO and quickly rise past 1.5v cranking. If the PCM is pissed off, it will show 1200PSI but actually have zero ICP pressure with ICPV staying low near .24v. BTDTGTTS, and I've seen guys burned by this many times. If all of this is good, commonly your injectors have a poor spray pattern/atomization or your compression is low. Good Luck! Quote Link to comment Share on other sites More sharing options...
lmorris Posted October 27, 2012 Share Posted October 27, 2012 The truck was driven to me from 45 miles away, could it be stiction in the injectors like we see in the 6.0s?, low miles on this truck but not sure how its been maintained and then sat for who knows how long I am meaning after you changed the oil and got it running, not by the customer. Typically the customer won't drive it hard enough. If glowplugs, batteries, starter and ICP voltage all checks, go bag the piss out of it. I only suggest this because we had in 3 trucks in the past 2 weeks from an aircraft fuelling company that sat for a long time and this is what we had to do to get them to start normal. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted October 28, 2012 Share Posted October 28, 2012 If it starts fine after being plugged in, then I wouldn't stray to far from the glow plug system before ruling it out for sure. Quote Link to comment Share on other sites More sharing options...
lmorris Posted October 29, 2012 Share Posted October 29, 2012 What is the EOT reading when cold? Quote Link to comment Share on other sites More sharing options...
mrbudge Posted October 29, 2012 Share Posted October 29, 2012 Simple test, does it smoke white while cranking but not starting? If you have smoke you have fuel. No smoke, no fuel. Quote Link to comment Share on other sites More sharing options...
PowerSToKed Posted November 3, 2012 Author Share Posted November 3, 2012 I replaced #1,3,5 and 8 injectors do to it running rough while driving (replaced those four do to contribution test, buzz test, injector cut out test and perdel readings... i felt they were the worst), checked injector harness and ohm'd all glow plugs and replaced the glow plug relay, still will not start, truck does not have a lot of white smoke while cranking and sounds like its starving for fuel (fuel knock while cranking) which leads me to a fuel delivery problem, but why does it start after being plugged in, Quote Link to comment Share on other sites More sharing options...
ktmlew Posted November 3, 2012 Share Posted November 3, 2012 Compression test? Quote Link to comment Share on other sites More sharing options...
PowerSToKed Posted November 4, 2012 Author Share Posted November 4, 2012 I know, just not what I wanna hear - nore does the customer, also would low compression allow one to crank after being plugged in, Is it possible I have 4 more bad injectors not firing (stiction) when cold and start firing after warming the engine, I have not driven the truck or had it cranked since I replaced the injectors (tomorrow I will plug it in and drive it and see if the run rough concern is repaired then see if it will crank cold after that (doubt it will cause i cranked the crap out of it - icp is up and will run on starting fluid) but while cranking sounds like its starving for fuel - but after being plugged in starts good (STICTING??????) Quote Link to comment Share on other sites More sharing options...
Aaron Posted November 4, 2012 Share Posted November 4, 2012 In my opinion I would have changed all 8 sticks while both rocker covers were off. Same labor to do one in each side as it is to do a set. Quote Link to comment Share on other sites More sharing options...
PowerSToKed Posted November 4, 2012 Author Share Posted November 4, 2012 The customer had to "scrape" up the $ for the 4 already installed, I strongly recomended all 8 but could not guarntee the fix, I will plug it up today and put some miles on it, does anyone have any other ideas about this one other than the other four injectors being that it will start and run after being plugged in and the glow plug system is in tip top shape Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted November 4, 2012 Share Posted November 4, 2012 You workin' on Sunday???? Quote Link to comment Share on other sites More sharing options...
PowerSToKed Posted November 5, 2012 Author Share Posted November 5, 2012 10-4 buddy, got mouths to feed and bills to pay, 14 hours a day 5 days a week (10 hours at dealer and 4+ at home) and a little less than that on the weekends. gotter cranked but no time today for road test, more info tomorrow, seems to be running better though Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted November 5, 2012 Share Posted November 5, 2012 Used to be in the same boat your in, those days are long behind me now. I used to come home for dinner and tuck the kids in to bed and then go right back to the shop til midnight or later and then rinse and repeat. Wrenching has gotten my family through some tough times but workin' like that is tough on the 'ol constitution. Quote Link to comment Share on other sites More sharing options...
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