derceg

My 01 truck starts perfect in the morning and drives fine, but when it gets warmed up it takesa long crank to start. It has no stored codes either. Where do i need to start?

johnh

fuel system

BigIron70

I would first load test power and ground at injection pump using headlight as a load. Then do a fuel pressure test if that checks good and 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.

derceg

I've got 31 pounds of pressure at the pump according to edge. The IP can be bad with it running right and cold start good?

BigIron70

This site has the best information on no start or long crank that I have found for the VP44, I suggest you read it first before replacing any parts, especially no start test 3
http://www.bluechipdiesel.com/vp44diagnostichelp.html

johnh

too much pressure is the cause for hard starts when warm...the vp 44 is designed to operate at no more than 15 psi.

http://articles.mopar1973man.com/2nd...njection-pumps

derceg

Crap, I haven't heard that one. I've got stacked pumps (running lift pump and fass.) Been running it that way for 6 years with no issues.

johnh

get your pressure down and i'll bet the hard start will go away....maybe the relief/bypass valve is bad

Dieselbuilder

Try to park your truck nose down on a hill and see if it starts, that will tell you if you have a fuel problem its a place to start?

derceg

My mechanic thinks the IP is shot. The start problems are worse now, but it's not throwing and codes. Is it possible me edge is causing issues?

derceg

I've been looking for new IP's. What have you guys used that you'd recommend?

Lary Ellis (Top)

Shied diesel or Bluechip is who I would use.....

KATOOM

For some reason these topics always resort to everyone saying the VP is bad.....

If your truck ONLY hard starts when the engine is warm.....and doesnt want to restart very easily after sitting for a short time then there can be a few reasons for this problem. Again, this is for ONLY if the hard start is when the engine is at full operating temperature and not when the engine is cold or when the trucks been sitting at least overnight.

1) The batteries are weak and the heat is taking a toll on voltage/amperage output when they get hot. Usually this is only a problem in hot weather. Load testing them separate from each other and the truck will detect a bad cell which can cause starting problems.

2) The starter is weak or dragging. This is usually only a problem if the OEM starter contacts went out and someone replaced it with a cheapo over the counter "lifetime replacement" unit. Those are garbage starters and will never hold up for very long. OEM starters are very strong units and will last a long time.

3) If the VP is the original factory unit and there's many miles on the odometer then the VP computer has been subject to a number of heat cycles over time and is letting you know that the Pb free solder has crystallized and the connections are becoming intermittent. If this is the case then pouring cold water directly on top of the VP will cool the PSG and the truck should start better. Obviously a new VP is going to be needed soon as it will eventually fail completely.

4) If the VP is a rebuilt unit and you have installed or currently have a new higher volume/pressure fuel pump then the cranking pressure while trying to start the truck is too great and locking the internal function of the VP. This happens because the internal tolerances change as the VP heats up and even though the ECM is trying to reduce the fuel pressure by only sending alternating 12 volts to the fuel pump, the pressure is still too great. Bosch says no more than 7 psi during cranking but in reality the VP prefers no head pressure as long as there is fuel in the lines and the prime is maintained. If this is the problem then completely disabling the fuel pump during engine cranking will result in the truck starting completely normal. You can either install a manual switch to shut the fuel pump off during cranking or install a delay relay which does that automatically.

And just to point out.....there is NO high pressure limit for the VP. Why?.....because Bosch doesnt say there is and no one has ever found a connection to pressures over 20-30 psi and any VP problems. That said, is it necessary to run fuel pressure over 20 psi?.....no, because all you want is to maintain no less than 15 psi at WOT. And whatever idle and cruise psi you need to achieve that 15 psi at WOT is where you set the pressure. But if that pressure difference from idle to WOT is greater than around 10 psi then you probably have the wrong fuel pump or immense amounts of fueling.

You mentioned an Edge too. When you experience strange issues that have no codes stored in the OBDII system then disconnecting any electrical add on devices like that is a way to rule them out as the problem.

high bid

I'd begin with the simple test by lowering fuel psi to 15 thru a regulator, test, then disconnect the edge and test again. Check the simple stuff first.