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Discussion Starter · #1 ·
After sitting for more than a day or two, the engine cranks over just fine, but takes a while to fire up. Starts immediately on restart. Just started doing this. Haven't noticed any other problems.. 160K miles 318 TBI. Haven't checked anything yet. Acts as though its waiting for fuel pressure to build.

Is there a check valve in the pump (original as far as I know) to prevent drain back?

Is the pump supposed to cycle on then you turn on the key? Can't hear anything over the buzzer etc. I suppose a fuel filter would be in order, but figure if it was plugged up, the engine wouldn't be so quick to restart after the initial cold start.

I have a fuel pressure tester, but no time at the moment. Any suggestions would be appreciated.... even to get off my ass and hook up the FP gauge.
 

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both = the fuel pump and the fuel pressure Reg have check valves to hold pressure , so either one is bad or you have a leak
 

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agreed , test ? after sitting turn key on wait 2 seconds , turn key off and back on wait 2 seconds then crank , start faster ?  check valve system loosing pressure over time ... ( puter will activate fuel pump ONLY twice with out cranking doing it 3-4-5th  times has no additional effect on the fuel )  no better?  after sitting turn key on depress gas pedal to FLOOR , crank ( LET OFF when it starts !LOL ) dripping injectors or injectors seals , cracked throttle body , engine flooding after you shut it off because residual fuel pressure is leaking off into intake .  (depressing throttle all the way on a start up tells puter your clearing a flooded condition , and it shuts OFF the injectors ....) 
 

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Discussion Starter · #4 ·
Thanks for the replies. I assumed the pump would cycle when the key was switched on, so tried that last evening. Good to know the computer only allows that twice. I had tried holding it to the floor, but still no joy and the long crank time turned into "no start". I went out there this AM and tried again. Looked at the TB and no sign of leakage...cycled the key twice and cranked. Cranked over for a while and then it made a very feeble attempt to catch, maybe 4 or 5 cylinders fired once each. Held it to the floor... no go. Had another look at the TB and still no signs of fuel and couldn't smell any.
Once I finish another cup of coffee, I'll feed it some gas or propane through the TB.

I bought this truck for $500 about 15 yrs ago. Did front brakes, EGR, balanced rear driveshaft, and a timing chain when I first got it. It doesn't owe me anything and I'd just shove it off a cliff if it wasn't a Ramcharger. I've been able to remain blissfuly ignorant of its TBI and don't even own a service manual. I'm just guessing at this point that because those bastards didn't put an access panel in the floor, that I will eventually have to drop the tank to get to the pump.

If anyone has a link to a manual, that would be nice. Hoping this will be simple and can avoid buying a manual for another 15 yrs....
 

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Discussion Starter · #5 ·
Poured a bit of gas in the TB and it fired right up and ran just fine. Shut it off and it restarted ok.

Left it for a while, then hooked up a FP gauge. Cycled the key twice and the FP went to 10 psi. Cranked the engine over and psi dropped to 0.
Tried more gas down the TB and it fired for a second, but FP stayed at 0.

I'm assuming the next step is to check for battery voltage at the pump when the key is cycled on.
Anything else I should check? I'm not sure what the 10 psi tells me..... pump is knackered, pressure regulator is off, or the never before used Chinese FP gauge is off. Maybe it would have gone higher if I could have got the pump to cycle more than twice. What is the best way to convince the ECU to forget the two cycle limit? Just disconnect the battery?

Looks like I may be shopping for a pump.
 

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there is a fuel return on the regulator , you pinch off and pressure will rize if the regulator is at fault , if not pump is. 10 is not enough .
 

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Discussion Starter · #7 ·
Thanks....
I couldn't do that yesterday because the pressure dropped to 0 PSI and engine wouldn't start, plus cycling the key didn't make any difference. Assumed I used up my two cycles of the key.

Went out there this AM. Turned the key on and got 10 PSI. Cycled the key again and got about 12 PSI, Then I was able to start the engine and it ran fine, but still only 12 PSI. Pinched off the hose and no difference. Pressure did not rise.
I suppose the filter could be badly plugged, but assume even with a plugged filter, the pressure would eventually rise above the 12 PSI at idle.

Any recommendations for what brand of pump to put in there.... and where to buy? Don't want to drop the tank once never mind twice.

 

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look forward to better mileage with higher fuel pressure ... yeah 2 times UNLESS you crank it again , then ya get 2 more times ... ( if it has a crank signal , which yours does...)
 

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Discussion Starter · #9 ·
Tried it again, and it started right away.....So it turns out I'm a bit of a dummy. I was pinching off the wrong line. When the actual return line is pinched off the pressure went up to about 30psi and I released the hose when the engine started to run rough. So I'm still not sure exactly what is causing the intermittent long crank time and now intermittent no start. Still leaning towards the fuel pump, but just to try and verify that... I'll leave the fuel pressure gauge on there for a few days and hopefully I'll get another no start situation.

This happened yesterday as per the previous post Left it for a while, then hooked up a FP gauge. Cycled the key twice and the FP went to 10 psi. Cranked the engine over and psi dropped to 0.
Tried more gas down the TB and it fired for a second, but FP stayed at 0.


I'm trying to figure out what that means. It would likely take the two cycles of the key to fill the lines and FP gauge and get 10 PSI... Cranked it over dropped to 0 and didn't fire at all. I tried some gas down the TB, but it stayed at 0. I can only assume my helper turned the key off, so should have got another cycle of the pump when the key was turned back on, but pressure remained a 0. Sounds like there could be a dead spot in the pump? Maybe the pressure regulator is off a bit, but shouldn't cause a long crank time or no start if its at 10. Actually today it looked closer to 12.
 

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pinching off return makes the system charge to what ever pressure the pump can make , with the regulator working the psi should be over 10 , and not drop to 0 even running , let alone cranking .. I might check to see that the fuel pump is getting power when the gauge drops to 0 .  the lines should HOLD pressure after it has run , if the pressure drops as soon as the motor is shut off ... my bet would be the regulator/check valve system . If when its running you get only 10 psi the regulator is not working properly , OR the pumps volume is VERY low , ( clogged filter ?) leaking injectors would likely NOT dump fuel/pressure as quickly .

pressure / volume .... produced / used  .... effect
 

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Discussion Starter · #11 ·
It only dropped to 0 that one time. When I left it last night the 10 psi had been holding for a few hours, but it was almost 0  this AM. One cycle of the key and it went to 11... started engine and it stayed at 11 PSI.
The filter is pretty old, so will try a new one and see what that does to Pressure/volume. I have no doubts that it will help, but obviously won't cure the intermittent no start.

The problem now is getting it to do its no start thing while I have the gauge hooked up. Can you tell me where the most convenient place is to tap into the fuel pump circuit and test the voltage (without dropping the tank). Please and thank you. Backside of auto shutdown relay?

In anticipation of dropping the tank, I made a deep socket to get the nuts off the J hooks.
 

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this IS a tbi  and NOT a efi correct ? makes a diff in required fuel pressure tbi is 14.5 , yeah the asd would give you something , but there is a ground wire ( OR 2 ) for the pump and gauge , should be near the tank , bolted to the frame ( screwed) and then there's 1 OR 2 connectors before the pump , and a few feet of wire ... so how accurate pulling a voltage at the asd would be ??? at the pump ...  asd is 2 hots IN  1 "load side " out and 1 ground to operate the asd ON/OFF by the pcm . so key ON gives you 3 hots for about 1-2 seconds ONLY , then the pcm shuts OFF the ground and your "load out " goes dead , its why the pump only runs zzzippp when you turn key ON , but runs all the time when engine is running .... the pcm says it IS using fuel , keep pumping .. so testing at the asd with engine off ,,, don't work well .. 
 

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Discussion Starter · #14 ·
Yes its TBI. I thought about the distance from that relay to the pump and or a festering ground. Just trying delay the inevitable jacking the thing up and crawling around under there. Thinking of adding some line to the gauge, so I can set it up along side a voltmeter and be able to watch while I'm in the cab turning the key. Might prevent a divorce.
As for putting a pump in... I'll most likely get to that point eventually just because I want this thing to be reliable and its probably the original pump and the tank could use a cleaning. Both the filters will likely be toast too. I just have this thing about knowing exactly what it needs and why before I replace things. And the lines.... true, but when I get to that point, that gets me closer to the crossroad. Do I just go through the truck and fix everything along with the rust. Not much rust, but needs to be dealt with. What I need is a good Cummins donor truck, but my back and neck are not going to like another major project and they are voting for a newer truck.

I assume the pressure regulator is on its way out, given the pump did go to 30 with the hose pinched off. Yes the filter is probably limiting volume, but even so, I would think when idling, the pump/volume would eventually catch up and the PSI would go to 14.5. speaking of assuming... I'm still assuming the Chinese gauge is reasonably accurate. I do have another one that max's out at 15 PSI, so could try that.

I did find a factory manual, but gotta say the wiring diagrams make my head hurt.
 

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THE thing to remember when looking at the wire diagrams , the pcm switches grounds ON / OFF not power , the key and / or relays do that . I'm voting the regulator is going bad , sticking open sometimes ( 0 psi ) . Like you say the pump DID make 30 psi , 2 x's the 14.5 , you could do a flow/ volume test but ... at some point the hassle / danger playing with gas isn't worth the cost of a "new" try it    part ...  I added up a years worth of parts bills for 1 old truck I had .... " hot rod", after complaints I was "spending TOO much"  on MY truck ... LOL it wasn't 1/2 of the payments on HER new Jeep .......  ::)    some folks find it easier to raise the bed up rather than drop the tank ... I have NO GOOD way here to do that myself ...
 

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Discussion Starter · #16 ·
Its a Ramcharger, so can't lift the box. I'd actually like to lift the body off anyway and transplant it onto that Cummins donor chassis that is on my wish list. The place I'm in now does't have any suitable trees, so would have to invest in two more 4 ft jacks.
I can't understand why they didn't put an access panel in the floor. Friend who ran a repair shop (mostly domestic stuff) was cursing about dropping the tank on an old Accord to replace the pump. Didn't have the heart to tell him it's much easier to pop it out through the access panel.

Anyway... ordered a FPR and filter last night. The regulator is made by Herko... never heard of them.. hopefully ok.

And hopefully the regulator also explains the leak down. It was at 0 again last night.. cycled it twice to 10 psi and it was at 0 again this morning. Both times I opened the butterflies and didn't see or smell any raw gas.

Still a little unclear on the 0 psi while cranking and when I tried putting gas down the TB. As in... was it because the FPR was stuck open... or all of the pressure from the two cycles of the key was used up just filling the newly installed gauge and lines.  Will the pump run while the engine is just cranking over or does it actually need a signal that the engine is up to idle speed.... or whatever signal or circuit the ECU uses to determine its running.





With the wiring diagram thing, its mostly because I spent a lot of time working on Honda Motorcycles and familiar with their layout and colour codes etc.
 

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yeah the ignition sensors ( crank and cam efi or dizzy pick-up tbi ) tell the pcm , o.k. we're cranking pump fuel , so it should be pumping , your test light on load side of asd would show the pump still powered up , OR if it shuts off after the same 1-2 seconds like if its was JUST key "on" I never checked that to see ...  overnite may not be too bad you might expect it to leak down after that long , but 10 - 11 is low running , and 0 could well be the valve stuck , dumping pressure . It don't take alot of fuel to loose pressure in the lines , the fuel its self cannot be squashed and spring back like air can so its pressure releases quickly .. ( there is no accumulator like the abs brakes have ) 
 

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Discussion Starter · #18 ·
It'll be a few days before the FPR arrives, so will shelve the thing until then. A few years back I bought a 81 Porsche 911SC for $1,000. It had been sitting outside for 13 years. Obviously needed a tank flush, filter etc. When I went to crank the line, I jokingly said to myself I should hold a rag over it just in case. To my amazement the accumulator was still holding pressure. Geepers the gas stinks after that long.

Thanks again for your help BTW.
 

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Discussion Starter · #19 ·
So installed the new fuel filter and FPR. Cycled the key a few times and the pressure went to about 12 psi. Started engine and FP stayed at 12. Pinched off the return hose and at first it didn't make an difference. Tried it again and it went to about 30 psi. Maybe hose wasn't completely closed off the first time. Seems like my new never been used before Chinese FP gauge is crap? Think I'll just try driving it and see what happens. If it screws up again. I'll hook up the other FP gauge. It only goes to 15 PSI, but I have a little more faith in it.
 

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cyborg said:
So installed the new fuel filter and FPR. Cycled the key a few times and the pressure went to about 12 psi. Started engine and FP stayed at 12. Pinched off the return hose and at first it didn't make an difference. Tried it again and it went to about 30 psi. Maybe hose wasn't completely closed off the first time. Seems like my new never been used before Chinese FP gauge is crap? Think I'll just try driving it and see what happens. If it screws up again. I'll hook up the other FP gauge. It only goes to 15 PSI, but I have a little more faith in it.
Alternatively, you could just drive your truck periodically and see if the problem is fixed (no more long cranking times)
 
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