Archived Possible vp44 failure but have other concerns

[Magnum Express]

I have a problem with my dads 99 IBS. Truck hard starting, ocassional dead pedal, stalls when putting in gear, lack of power, no smoke, no codes. I don't have a doubt that the vp44 is bad. Problem is when truck stalls and try for restart the lift pump is not running. Just installed new lift pump. Will bad vp44 cause lift pump not to run or do I have other issues. please help. By the way truck is not bombed.

 

[Bob Wagner]

does the lift pump run if you bump the key?

 

[Magnum Express]

Bob, The lift pump will run when tested on Snap-on scanner. but does not run with key cycling. This problem is only there after stall putting in gear. Truck will restart after lots of pampering and after restart the truck will hunt around for a good run. occasional flare in RPM.

 

[Bob Wagner]

does your wait to start light work? You could have an issue with your ecm. If you don't have a wtsl you could try restting your ecm.

 

[Bob Wagner]

and I do have a stock 99/auto/fed ecm that you could try to swap out, if that would help you.

 

[2-ND TIME]

hard starting

By chance do you have a multi- meter with the frequence option??? Check it for frequences. What is the MDH of the truck in the lower left corner of the sticker????

 

[Marco]

Lift pump cycle

Yes, you need to watch out for the Wait To Start Light. It HAS to come on every time you cycle the key. EXCEPT, if you cycle they key too fast on-off-on then the WTSL will not come on AND the lift pump will NOT run.



You have to wait about 10 seconds in the key off position before you turn the key on for the ECM to run it's self test ( WTSL ) and the lift pump to run.



Marco

 

[Magnum Express]

I would like to thank all for the help. I checked fuel pressures yesterday and had 15 psi with engine running. Starts real hard and does not have the good rattle we all come to expect. Have new vp44 ordered, going to install on thursday.



Thanks again



Jeff