Why are PSD's so slow to start?
03-01-2005, 09:03 PM
#1
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Why are PSD's so slow to start?
I was sitting in Sonic eating supper when a Ford PSD next to me started up. I notice that they always seem to crank for a couple of seconds before they catch. My CTD starts after just rolling it through the first compression stroke, even when it's cold and the block heater wasn't plugged in.
Is there some fundamental difference in these engines or do their computers keep them from starting quickly? I would think they go through starters more often also.
How do the GM diesels compare?
Edwin
Is there some fundamental difference in these engines or do their computers keep them from starting quickly? I would think they go through starters more often also.
How do the GM diesels compare?
Edwin
03-01-2005, 09:12 PM
#2
Registered User
On the 7.3 ps, I believe the injectors are, at least in part, operated with engine oil pressure. There may be something built into the injector pump to compensate for oil pressure coming up before firing off. Just a half shot in the dark on that one. When I hear them turn over, I just hope they start, cause I've heard a lot of them just crank and crank...
If I had to guess, I'd say my starter has been around one quarter turn for every time it's ever been started---still makes me grin every time it fires off
If I had to guess, I'd say my starter has been around one quarter turn for every time it's ever been started---still makes me grin every time it fires off
03-01-2005, 09:33 PM
#4
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Mine starts right up on the first crank.
Has since day one.
Only time it cranked more than once was after my first fuel filter change.
It cranked and cranked and cranked and rested and cranked and cranked and cranked.
Now I know better.
phox
Has since day one.
Only time it cranked more than once was after my first fuel filter change.
It cranked and cranked and cranked and rested and cranked and cranked and cranked.
Now I know better.
phox
03-01-2005, 09:52 PM
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Originally posted by 3KrackerRacing
(IM A FORD GUY)
Its because it has so much power it needs alot to crank over.
(IM A FORD GUY)
Its because it has so much power it needs alot to crank over.
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03-01-2005, 11:47 PM
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It's the oil rail pressure building up in the "High Pressure" oil system (about 2-3000psi, up to 5000 on 6.0's) under the valve covers. Yes, it actuates the injectors, which are electronically controlled NOT to begin squirting fuel until adequate pressure is built up. The 6.0's are even more so due to higher rail pressure, what's odd about them is they crank and give no indication they are close to starting, all the sudden it just---happens. Really odd.
03-02-2005, 12:13 AM
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Isn't it great to have a 12 valver??? My old 95 PSD cranks a bit before starting too. It's the oil pressure in the injector rails that has to come up, then cam sensor, and if the cranking voltage holds out long enough, the injectors will finally fire, if the glow plugs still work the engine might start.
03-02-2005, 01:20 AM
#12
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Originally posted by 96_12V
It's the oil rail pressure building up in the "High Pressure" oil system (about 2-3000psi, up to 5000 on 6.0's) under the valve covers. Yes, it actuates the injectors, which are electronically controlled NOT to begin squirting fuel until adequate pressure is built up. The 6.0's are even more so due to higher rail pressure, what's odd about them is they crank and give no indication they are close to starting, all the sudden it just---happens. Really odd.
It's the oil rail pressure building up in the "High Pressure" oil system (about 2-3000psi, up to 5000 on 6.0's) under the valve covers. Yes, it actuates the injectors, which are electronically controlled NOT to begin squirting fuel until adequate pressure is built up. The 6.0's are even more so due to higher rail pressure, what's odd about them is they crank and give no indication they are close to starting, all the sudden it just---happens. Really odd.
BTW, have you guys noticed that dealer parts have gone through the roof! I bought 4 plastic bushings to fix my wiper linkage. They were $3.00 EACH!
Edwin
03-02-2005, 04:19 AM
#13
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Plastic thingys
Originally posted by edwinsmith
OK, now I understand. It makes sense if the high pressure pump runs off the engine it would have to crank a lot to build up sufficent pressure. The engine doesn't have a timed pump like the CTD which gives instant pressure to the injectors. I'd sure hate it if I had one of those and the computer messed up. I bet it's a lot more than an injector pump.
BTW, have you guys noticed that dealer parts have gone through the roof! I bought 4 plastic bushings to fix my wiper linkage. They were $3.00 EACH!
Edwin
OK, now I understand. It makes sense if the high pressure pump runs off the engine it would have to crank a lot to build up sufficent pressure. The engine doesn't have a timed pump like the CTD which gives instant pressure to the injectors. I'd sure hate it if I had one of those and the computer messed up. I bet it's a lot more than an injector pump.
BTW, have you guys noticed that dealer parts have gone through the roof! I bought 4 plastic bushings to fix my wiper linkage. They were $3.00 EACH!
Edwin
**BTW, have you guys noticed that dealer parts have gone through the roof! I bought 4 plastic bushings to fix my wiper linkage. They were $3.00 EACH!
Hey mine broke during the last big rain we were having, I heard a snap sound and the wiper arms were locked solid in the center of the windshield. Going 60 MPH and couldn't see a thing. The linkage got stuck on the motor crank. I got the bushings at PepBoys "Help" asile for a few bucks and I have spares. I ran in at 8:55 P.M. and grabbed them.
Jim.
