Posted February 27, 20169 yr Lost lift pump and this morning I have the p1689 code. Truck still starts but guess the airdog took out the injection pump also. I think that it is just barely under warranty. Ill have to check.
February 28, 20169 yr Owner P1689 code is more of alternator issues than a lift pump. I would test the alternator for excessive AC noise first. Then dive into the P1689 code article and do a bit of bench testing.
February 28, 20169 yr Author Thank you Mike. I have been thinking that I should do that anyhow. The lift pump failed and I was driving in very heavy traffic in Phoenix, AZ pulling a car I just picked up. it was at slower speeds so I didn't notice it for a long time. I think I drove about 80 miles or so without it. I am sure it didn't do the injection pump any good but it will still start and run. The lift pump is an Airdog FRRP and is under warranty so I am waiting to hear from them while working on my new (to me) SUV.
February 28, 20169 yr Owner No worse that the truck sitting in my yard with a dead lift pump ZERO fuel pressure and it was driven from east side of Wyoming to west central Idaho with zero fuel pressure. Still starts a runs fine so far, no codes, no problems but really does need a good lift pump. The owner is going to be getting a FASS 150. Just waiting...
February 28, 20169 yr Author That does make me feel a good bit better. The truck isn't going to move though until a new lift pump arrives. Not taking any more chances. Back to work on the Isuzu Trooper for now. Thanks
February 28, 20169 yr FWIW I lost my oe lift pump at 150k. Truck just died. I had no gauge to even no how low the pressure was. I ran that pump another 70k before replacing it. It had not died but went thru another bout of low fuel pressure with the in tank pump dodge gave me. I had extra money then and just replaced it not wanting to get stranded somewhere. All this was before finding Mike's farm here. Knowing what I know today I dont think I would have replaced when I did. But you really never know, I have seen folks loose both at the same time and others such as myself loose one and not the other. Kind of a crap shoot. Good luck with yours.
February 28, 20169 yr Author Thanks. I will talk with Pureflow tomorrow and see about getting a warranty replacement on the way. For some reason the lift pump just quit. I went out this morning and unplugged the pump and then made a direct connection to the battery to verify that it wasn't in the truck wiring and the pump wouldn't make a sound so its definitely DOA. It'll be running by next weekend.
March 10, 20169 yr Author Got the replacement Airdog from Pureflow and it is running great again. Thanks for all the advice. I have not tried the alternator AC check yet. I do not know if my meter is sensitive enough. And it has not thrown another P1689 code. As soon I Pureflow the serial of the failed lift pump the sent one right. I had to pay the extra $68 to get it second day delivery though. They didn't even ask for the old one to be returned.
Lost lift pump and this morning I have the p1689 code. Truck still starts but guess the airdog took out the injection pump also. I think that it is just barely under warranty. Ill have to check.