The Diesel Stop banner
1 - 14 of 14 Posts

·
Registered
Joined
·
204 Posts
Discussion Starter · #1 · (Edited)
Colder weather is coming my way summer starts were so simple no problems. I totally forgot about last winter...some how. Well I want to try to figure it out before really cold weather comes.

I have a 2002 f250 7.3 my oil was 55 late this afternoon, and I had a hard start. Last winter it was hard starting at 45-50 and under. What it does is strange to me. I sit there start it after cycling gp and it's cranking strong then few second it almost feels like it give up I could hold it there for a day and it won't fire, so I have to re cycle after few seconds. It'll do that 2-5 times then start just fine, runs strong. White cloud smells like pure fuel puffs and clears up and no smoke after the first puff of smoke. Strange part is this, plugging it in had zero problems to start. Start instant. After I get it running I could shut it off and it will fire right back up instantly. Wondering if it's my gp or gpr? While cranking it does not change, it's a steady crank.

Also I should add it doesn't act like it's about to turn over and start during this it just cranks.
 

·
Registered
Joined
·
585 Posts
Sounds like a glow plug problem. The block heater is probably getting enough heat into the engine so that the there is enough compression heat to ignite the fuel. The smell of fuel at the tailpipe confirms that the engine is getting fuel.

Glow plug relays have to switch a lot of current, and they are known to fail. I replaced my stock GPR with a super heavy duty Stancor relay. The GPR has four terminals. The 2 small terminals are the control power for the relay. The large terminals are for the main power. One side goes to the battery and the other goes to the glow plugs. Grab a multimeter or a test light and check the large terminals. Once of them should always show battery voltage, the other should show nothing when the relay is off. Now connect the multimeter or test light to the terminal that is normally off and turn the key to the RUN position - this should energize the relay. You should now see 12V on the terminal. If you don't see voltage, you either have no control power or a bad relay.
 

·
Registered
Joined
·
68 Posts
If you use a voltmeter to check your gpr, make sure that you get a strong voltage. After getting my work done on my truck (truck sat for most of summer with 5 year old batteries) my batteries had enough power to run the starter but not enough for the glow plugs (measured 7 volts on GPR). It sounds weird but I am just saying that if you get a low voltage when your gpr is engaged you may want to check your batteries and wiring because your gpr may be fine like mine was. Once I got new batteries and cleaned all the terminals my truck fires up within a touch of the key regardless of temperature.

Just thought I would throw out the possibility of chaffed or messy wiring.
 

·
Registered
Joined
·
628 Posts
I second checking ALL connections. Battery and at starter and everywhere else you can find! Just because it sounds like it's turning good doesn't mean it's turning good enough!
 

·
Registered
Joined
·
204 Posts
Discussion Starter · #5 ·
I'll have to check that when I get someone to hold the volt meter for me. But isn't it not normal for the engine to not try to turn over at all at a very good pace of cranking? It cranks at the speed it normally starts right up at.
 

·
Registered
Joined
·
628 Posts
Your ears won't hear the difference between 90 rpm and 100 rpm... and yes, that's enough to cause a no fire...
 

·
Registered
Joined
·
3,553 Posts
With good batteries, clean/tight terminals, the GP's will pull 290 Amps for a second or two then drop down to 130 Amps for the duration of the cycle, the voltage will drop to ~9 VDC and level out to ~10.5 VDC for the cycle. The GPR can ON/OFF cycle for up to 2 minutes depending on ambient temp. If your WTS does not stay on for 4-5 seconds at 50*F, you may have bad GP's. Use only Motorcraft/Beru to replace them, proven to be the best. If after a GP cycle, the battery voltage recovers to only 11 VDC, you probable need new ones, engine won't crank fast enough to start.

To save a little battery power, unplug the fuel filter heater, it's useless anyhow.
 

·
Registered
Joined
·
204 Posts
Discussion Starter · #8 ·
After they cycle my battery is still at like 10.4 10.5 while cranking so it wouldn't be weak battery. Guessing ok gp and or relay then?
 

·
Registered
Joined
·
585 Posts
Battery voltages are good, and a healthy fast crank also means good batteries. I would go after the GPR first. If that's good, you can check the individual glow plug resistances to see if you have bad glow plugs.
 

·
Registered
Joined
·
204 Posts
Discussion Starter · #11 ·
Man I just hate taking those valve cover off.... hoping to god its my gpr, just for the sake of time and anger that will be causes from thay back bolt haha
 

·
Registered
Joined
·
1,809 Posts
Make sure that the wires are tight on the GPR and that the GPR is good and passing all the current to the plugs. It has been proven that a GPR can go bad and have burnt spots that lose the power in Never Never land , the plugs do not get the power to heat thus good batteries and over night engine heater will start the engine no problem but the GPR could be the weak link in the chain.
I had that going on for awhile, and in the van it is really a pain.
 

·
Registered
Joined
·
1,243 Posts
I got the california model....lucky me, well sort of. When a GP goes bad it tells me which one it is. I had the dreaded loose under valve cover connector problem. GP failed on that side of the motor as a result.

I'd put money on GP relay. If it was a problem with even half the glow plugs it would eventually fire albeit reluctantly.

Also for sh**s and giggles, put a good battery charger on the truck for 15-20mins and keep it connected while cranking just to double check those batteries. You say 14.6v, you mean 12.6v after a cranking attempt? You won't see 14.6 unless truck is running.
 

·
Registered
Joined
·
11 Posts
Im having the same problem right now with my 03 but I have new gp gpr starter and batteries. I need help find the ground location. If mine isn't plugged in when I go to start my gauges will dim instantly and it will crank fast for just a moment then it will want to kill my batteries. Im under the impression that I have a bad ground some were. Please give me some information on the grounds cause my truck sits at work and I cant plug it in so I have been running into this problem a lot lately.
 
1 - 14 of 14 Posts
Top