cwert87

I have 2000 Dodge w/ 289,000 miles. New Vp 1 1/2 ago. New Air dog2 100 I put on last week. In the morning I jump in the truck turn the key on and wait for the wait to start to go off and start the truck. Then i go somewhere and the engine gets warm,shut it off and sometimes doesnt start back up on first try,even w/ the new fuel pump. Checked the truck w/ scanner,no codes. checked pin #7on vp for correct volts, good there. Dropped the fuel tank to see anything was broken o something in the tank causing to not have enough fuel press. nothing wrong there.took the fuel sending unit apart piece by piece and cleaned the bottom screens and put back together.does anybody know the volts to the sending unit should be?How do u know when the fuel sending unit is bad?nd no it is not the in tank pump. When i turn the key to start the truck, if it doesnt fire it will throw the check engine light on and then it will go off,when it does start the engine light sometimes comes on nd goes right back off.checked fuses and wires.any body w/ any suggestions or tips will help thanks

BigIron70

IF THE CONCERN IS A HARD START/LONG CRANK TIME AFTER A 10 - 60 MINUTE HOT SOAK, there are NO CODES and fuel supply pressure is good, problem is probably a defective injection pump. A way to confirm this is to duplicate the hard start condition, then (with the engine not running) cool the injection pump with a large quantity of water (e.g. use a garden hose). If the engine start better after cooling the injection pump, the pump needs to be replaced.

cwert87

Thanks big iron.now to decide to get a new vp44 save up and p-pump my truck and do away w/ the electronic pumps.makes me sick.i should have taken it back 6months after having it on when it first acted up again.any suggestions abt p-pump

BigIron70

When you check power and ground to injection pump use a headlight bulb that way the circuit is put under a load when checking for power.

Dane

The symptom you describe is exactly what my 2001 acted like before the vp44 pump died completely. When it finally died (would not start even when cold) there were no OBDII codes in the computer.

KATOOM

Dont worry..... Your VP and everything else is perfectly fine. This is a common cause which is a result of your new aftermarket fuel pump. The fuel pump is placing to much pressure on the VP's pintle valve during engine cranking when the engine is at full operating temp. Actually I'm surprised more people haven't understood this as an issue yet given how many threads there are regarding the problem after someone installs their new Airdog, Raptor, or FASS. To prove this is truly the cause, when you experience the hard hot start issue, simply pull the fuse for your Airdog and try starting again. It will start like normal. Just make sure you immediately put the fuse back or shut the engine down so as to not run with no fuel pressure. If this works (which is will) then you have to install a relay which disables the fuel pump during engine cranking. Here's a diagram.

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Silver_Ram

Another way to cure hard start hot after installing a new high pressure lift pump, is to get the last flash Dodge has for the 24v. During cranking, the lift pump circuit is disabled until the engine starts.

You can get the flash from the dealer or if you know someone with an up to date smarty, load the smarty in & then unload it. The smarty leaves the newest ecm flash in the ecm when returned to stock.

KATOOM

True but finding a dealer that will do it.....or even knows what you're talking about. A Smarty or the relay would probably be the easiest. I chose the relay because I dont care to chance causing an issue with the ECM for any reason.

Silver_Ram

As far as the dealer is concerned, all you need is an ecm update. This is the only flash you can get through the dealer, because they as flashes are updated, the old ones become un-available. The last update release for 24v truck was in 2004 & this is the same update that gets left on your ecm by the Smarty.

I didn't need it, but I tested it out on my 02 & it works right. The lift pump stops pumping while you are cranking & the lift pump starts pumping when you let go of the key.

swordfish

^^^+1 I did the relay and haven't had the problem since. Its pretty simple to implement and works well.