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04:29:55 - 04/28/2024
General Dakota Board
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TexasTodd
Dodge Dakota
JOIN HERE
2/04/2008
17:12:52
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 Subject: 4.7, Rarely starts on first crank.
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2001, 4.7, manual, yadda, yadda......
For months now, my 4.7 won't start on the first crank. It cranks over just fine, runs fine too.
But it rarely ever starts on the first crank anymore. I crank it for 10+ seconds. NOthing. Then as soon as I crank it again, starts right up, runs fine.
Runs excellent, no Codes, etc.
If you KNOW what causes this, great.
Tell me.
PS- the plugs, etc. are pretty new.
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Kowalski
GenIII
2/04/2008
17:48:55
|  RE: 4.7, Rarely starts on first crank.
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I KNOW one thing that could cause that - having the fuel pressure bleed down. Once the fuel pressure is built up and you start it, if you turn it off and then try to start it again right away - will it start right up like that ?
Lead, follow, or get out of the way
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1hotkadota
Dodge Dakota
JOIN HERE
2/04/2008
18:58:04
|  RE: 4.7, Rarely starts on first crank.
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It happens to me sometimes too and I believe Kowalski is correct. Hell, even my wife's 06 GLi has the problem.
What has helped me so far is to put the key in and turn it forward to the point that all of your lights come on, there is also that little chime your truck makes when the key is in but not turned on, let it ding twice and then start it. I've been doing that since I got the truck just to let the fuel pump prime up and then its easy starting. And I'm up to 135k miles.
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TexasTodd
Dodge Dakota
JOIN HERE
2/04/2008
20:07:32
| RE: 4.7, Rarely starts on first crank.
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1hot, and Kow...,
I agree this could fo it. However, when I try the key on trick first as you 1 hot, it still RARELY cranks first time. I leave the key on for 10+ seconds.
One day I tried the valve on the fuel rail when it was cold, and no pressure came out, which I know it should. Even off this engineis suppose to keep pressure in the fuel rail.
However, when I get on it, only once EVER did it starve for gas, and I've never been able to reproduce it. My truck is fun trying though.
AND strangely enough, on a real cold morning here (which is rare), it will fire off right away first crank like it always did before.
And it usually won't start right backup again, if it's just been running, don't think so anyway, I'll check that again and get back to you Kow...
any other ideas?
Thanks guys
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TexasTurd
Dodge Dakota
JOIN HERE
2/04/2008
20:14:09
| RE: 4.7, Rarely starts on first crank.
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Its just been used and abused by you racing down the road. What do you expect. Quit driving it like a race car and it will treat you with reliability. You just need to mature.
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miltonwaddums
Dodge Dakota
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2/05/2008
09:08:07
| RE: 4.7, Rarely starts on first crank.
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I'm not familiar enough with the fuel systems in these engines, but it sounds definitely like a fuel pressure problem. It sounds like your truck is just bleeding off pressure when the enigne is off. My first guess is of course the Fuel Pressure Regulator. But heck, you aren't dumping fuel on the ground are you? (A slow drip may evaporate before you see a puddle on the ground.) After that many miles, a fitting could have rattled loose, a hose may have a slight hole or crack in it, etc.
If you turn the ignition "on" with the door open, how long do you hear the fuel pump pressurize? Mine is only maybe 1 or 2 seconds. Any longer than that and your fuel system is probably dry. If it doesnt "pre-pressurize" (for lack of a better word) at all, then your pump isn't getting the proper signal. How old is your battery? I've heard that old batteries can cause odd startup behavior. Good luck and keep us posted.
TexasTurd, STFU or post something useful.
Jay
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TexasTodd
Dodge Dakota
JOIN HERE
2/05/2008
10:01:27
| RE: 4.7, Rarely starts on first crank.
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Thanks again guys,
I suspected the fuel pressure problem as well many weeks ago. Especially since when it was cold, there seemed to be no pressure in the fuel rail when I tried the valve.
Thinking it my be the relay, I swapped out a different Relay, since they're all the same, and it did the same thing.
I keep it in the my garage at home at all times when I'm home, and never smell any gas vapors.
There is never ANY stains on the concrete under my truck either. I've been getting very good MPG's, so a leak is lower on my 'Differential Diagnosis' (medical terminology).
When I stopped at our centrally located mailbox in our neighborhood last night. Shut it off and it started right back up as soon as you turn the key. Got out, got my mail, without opening any on the street, gave it a quick look over and got back in. Maybe 1-2 minutes, and it did NOT start right up again. Until the second crank.
What's puzzling is, that sometimes on the first crank, I can let it go for 10 seconds, no fire over. Turn the key again, and it usually starts right up then. If it were the fuel pressure problem, why wouldn't it fire over after it cranked for 5-10 seconds?
Keep up the excellent suggestions, I agree with what's been stated so far.
What's nice is, it always DOES start, and it runs great.
But it's embarrasing sometimes, like when dropping my son off at his school and having to crank it 2 or 3 times to get it to start in the drive thru line. (Sometimes I wait 5+ minutes before the line is open)
Todd
01 SLT QC, two tone paint,
OEM fender flares
Cab high Leer cap w/ double slider window,
Infinity sound,
Tire and handling pack,
Trailer towing pack,
4.7 manual,
HO cams,
HO intake,
Ported the stock 68mm TB,
Homebrew 'true' CAI, w/ K&N
No belt driven clutch or cooling fan
No third cat.
SuperChips Tuner
Max dyno, NO short belts, etc.
227 RW HP
300 RW TQ
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TexasTodd
Dodge Dakota
JOIN HERE
2/05/2008
10:13:22
| RE: 4.7, Rarely starts on first crank.
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Also,
I did get a code, AFTER it did this for months, about the gas cap (P0445?), or something like that. The light whet out without clearing the codes. I just did the key trick, and there are NO stored codes, and I didn't clear any.
The battery seems fine, cranks over great, each time, and my gauge is always in the middle. I too thought of the battery issue. But it cranks so well, I don't want to get a new battery- yet.
Please, keep up the suggestions, we'll find it yet! (remember when this board worked so well to diagnose a problem someone was having, and how much we learned about our Daks?), kinda like this thread.
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1hotkadota
Dodge Dakota
JOIN HERE
2/05/2008
11:12:15
| RE: 4.7, Rarely starts on first crank.
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There could be an evap leak coming from that damn box under the truck. Usually a cracked hose on the box. I have code P0456 right now on my truck. Had it before but just taped up the crack in the hose. Completely forgot about it and now it's back.
Check the box, located under the truck basically where your seat is.
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miltonwaddums
Dodge Dakota
JOIN HERE
2/05/2008
11:16:17
| RE: 4.7, Rarely starts on first crank.
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TexasTodd,
I too like this thread. I wish there were more like it.
It sounds more and more like a fuel pressure regulator or some type of check valve (this is a total guess on the valve, I dont know even if there IS one). If you lose pressure that fast, you definitely have fuel leaking back to the tank somewhere (since its not on the ground).
Also, (and let me reiterate my lack of familiarity with the system), it may be leaking the fuel through the vacuum lines connected to the fuel pressure regulator. I've seen that before on a sportbike motor (60 psi system). Replaced the FPR and all was well (after we drained the cylinders of fuel).
The only piece of information you didnt give was how long the fuel pump pressurizes the system before cranking. That can be a good indicator. I doubt it has much to do with the battery since you stated the lines were completely drained when you checked for pressure. As for relays, I doubt it, since the FPR is more than likely mechanically controlled and if it starts (eventually) the pump IS turning on.
Do you have a security system? I know I posted this in another thread, but sometimes they can disable fuel systems as a security feature. Maybe its screwy and not letting the fuel pump kick in until AFTER you turn the key to the start position. I don't know, I'm just throwing out ideas.
Jay
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TexasTodd
Dodge Dakota
JOIN HERE
2/05/2008
11:17:18
| RE: 4.7, Rarely starts on first crank.
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Sure,
I'll try that and check all the hoses, but would that depressurize the fuel rail?
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TexasTodd
Dodge Dakota
JOIN HERE
2/05/2008
11:21:12
| RE: 4.7, Rarely starts on first crank.
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One Diffential diagnosis (medical term), is that the TPS doesn't give the signal for any fuel, as in to idle at start up on the first crank.
See this thread:
http://www.dodgedakota.net/boards/v8/11079.html
My idle has varied some, but it has only done that a few times, in YEARS.
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Kowalski
GenIII
2/05/2008
13:11:42
|  RE: 4.7, Rarely starts on first crank.
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Why don't you think you've already found the problem ? The check valve is not holding pressure. As you crank, you are also bleeding off some pressure through the injectors - that's why it starts better after you turn it off. Gives it a chance to pressurize, I think. Gas cap code is likely unrelated, may have just been loose. I don't think you have another mystery problem you seem to be looking for. The best way to tell would be to fix the problem you already know you have - my belief is that will be the end of the problem.
Lead, follow, or get out of the way
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TexasTodd
Dodge Dakota
JOIN HERE
2/05/2008
13:33:08
| RE: 4.7, Rarely starts on first crank.
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milt...,
I have the factory security system.
I have an 01 SLT, with the under the cab insulation, and can't hear any fuel pump noise in my Quad cab drivers seat. I'll try it with the door opened. If that don't work, I'll lean down outside shile someone else turns the key.
Kow..,
If it is the 'check valve', where and what is that?
Why does it crank the second key turn, no matter how long I crank it on the first turn? Sometimes, it will crank on the first turn, after a LONG cranking.
Thanks,
I/m bored at work and would like to solve this for good, without trying the wrong solution.
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miltonwaddums
Dodge Dakota
JOIN HERE
2/05/2008
13:53:11
| RE: 4.7, Rarely starts on first crank.
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That makes two of us bored at work. ;-)
A chiltons or haynes manual should locate the check valve no problem. Or just follow the fuel line from the tank to the rails. I'm sure it is a relatively cheap part (maybe).
You should be able to hear the fuel pump pressurize with the door open. On my old RC V6, it was loud as hell with the door open, I've never really paid attention in my 03 QC 4.7. You've probably heard before and never really realized it.
As for the security system, I really dont think that would do it, I'm just throwing out ideas if all else fails.
Jay
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1hotkadota
Dodge Dakota
JOIN HERE
2/05/2008
17:23:51
| RE: 4.7, Rarely starts on first crank.
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If anyone wants it, I have the FSM for a 2002 Dakota. WAY better than chiltons or haynes.
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Kowalski
GenIII
2/05/2008
17:30:12
| RE: 4.7, Rarely starts on first crank.
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The check valve is part of the fuel pump assembly. About the only other thing that could release the pressure would be an injector sticking open. I suspect the pump over that because I think when you stop cranking, the injectors that open as you crank will be closed, allowing the pressure to come up to spec. Then it starts for you. Could be injector though.
Still have your factory manual ?
Lead, follow, or get out of the way
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TexasTodd
Dodge Dakota
JOIN HERE
2/05/2008
17:52:33
| RE: 4.7, Rarely starts on first crank.
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Kow...,
You mean the factory manual I have on CD?
Didn't I send you a copy when I was giving them away?
I'll read the section about the fuel system tonight.
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Kowalski
GenIII
2/05/2008
18:02:32
| RE: 4.7, Rarely starts on first crank.
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Absolutely; and thanks again - that's why I figured you might still have a copy.
Gave me good kharma, I think - since I've had it, I haven't needed it...
Good luck with your problem !
Lead, follow, or get out of the way
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DSW
Dodge Dakota
JOIN HERE
2/06/2008
05:19:48
| RE: 4.7, Rarely starts on first crank.
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Pop a fuel pressure gauge on the rail and see if it's bleeding down.
If an injector is leaking, I'd think the engine would run rough until all the raw fuel was cleared out of the offending cylinder, still a possibility though?
I've heard (no experience) the Dak fuel pumps are a complete unit, pump/filter/regulator and it's a PITA to replace because you either have to drop the tank or pull the bed,,, with pulling the bed the preferred method.
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TexasTodd
Dodge Dakota
JOIN HERE
2/06/2008
12:11:41
| RE: 4.7, Rarely starts on first crank.
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DSW,
Good idea.
When I had a bad 02 sensor, I also had a code about the #5 injector stuck open.
After I replaced the 02sensor, no codes since.
Thus far, I've tried, and can't seem to hear the fuel pump whine at key on.
I think this is the probable cause, and if so, the right solution. I'm just not too eager since it always starts, and runs fine.
Thanks to everyone,
Todd
01 SLT QC, two tone paint,
OEM fender flares
Cab high Leer cap w/ double slider window,
Infinity sound,
Tire and handling pack,
Trailer towing pack,
4.7 manual,
HO cams,
HO intake,
Ported the stock 68mm TB,
Homebrew 'true' CAI, w/ K&N
No belt driven clutch or cooling fan
No third cat.
SuperChips Tuner
Max dyno, NO short belts, etc.
227 RW HP
300 RW TQ
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