Checking LP or IP While On A Test Drive

Tejas TJ

Tejas TJ

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I'm in the market to purchase my first diesel truck. I'm going to be looking at a couple of trucks this weekend. One of the trucks is a very clean '99 auto 4x4.

1. Is there a way to check the LP or IP without a fuel pressure guage, and if so how do you do it?

2. I need to know exactly where (pics help) of where to look to know if the truck is a "53" block.
 
There should be a shrader (sp?) valve on the bango bolt where the fuel line goes into the injection pump. If you had a mechanical gauge, I think you can just pop it on there and read the lift pump pressure. I don't know if you are able to hook like a Snap-On Modis or other type scanner and monitor the LP pressure. I think if that info was available electronically, Edge and others wouldn't have to have us put a pressure reader on the spot where I told you the shader valve is to monitor pressure. Does this help? I tried.
 
Kinda, is there a way when I turn the key or anything like, something easier. I wouldn't like it if some one who came to look at my vehicle was hooking a bunch of stuff up to it you know.
 
Well, you can look at it two ways. You can't test IP pressure without equipment. You can test the LP doing that I mentioned above if the owner would let you "check out a few vital questions you have" before the purchase; However, if the pump is bad or weak, it will only cost you a hundred and change to put a new stock pump on it. I can point you to a good source if you like. So, if you don't ask, and don't check it, you are gamblin' with about a $100 or so. Not that big of deal when you consider that the tranny and other systems are a bigger risk.

As far as the tractor, I think it fell off a trailer. :hehe: Very bad juju. :D
 
You can "bump start" the truck to see if you can hear the LP running. Try and start the truck but dont let it turn over. thats one way to check it without equipment. Harbor freight sells a "Injection pump test kit" for $15-$20 that includes a FP gauge and the hookups you will need to test at idle. Buy a longer hose and connections and you can hold the Gauge and go on a drive to check pressure before you buy.
 
Thanks for all of the advice guys, I really appreciate it.

So, turn the ket to bump start it and there should be a sound like a fuel pump turning on, correct? About how long does the sound occur?
 
It should run about thirty seconds or less. You actually turn the starter over but dont start the truck. The sound should be originating on the drivers side of the block near the back end of the engine.
 
The pump can run all day long, and not produce any pressure, if you want to check it out, take a gauge along.
 
I was advised at a site I was frequenting at the time to buy a fuel pressure test gauge when I went truck huntin'.
Connected it to the Schrader Valve on the side of the VP, turned the keyswitch just enough to bump the starter then released...the lift pump started and ran for 25 seconds...showed 10 psi so I bought it after the test drive went well....5 years ago this month!
Ya gotta watch those used truck dealers...they're cheap and will run one outta cooling/lubricating fuel and kill a VP.
 
Any fuel pressure gauge that is set up to check fuel rail pressure on an EFI car should be able to screw on to the schrader valve that has already been mentioned. Just take a gauge with you and check it.

If you are buying this off of a car lot I would just request that the lift pump fuel pressure is tested and that you want a report about the pump's condition. If they refuse to give you one just walk IMHO. They should be more than willing to provide you with that info if they want to sell you a truck.
 
It's a private seller. I'm a little scared buying a 24V from a dealer, because they don't know when and what was replaced on the truck. I'm going to look at the white truck this weekend. He said the IP and LP were repalced two years ago.
 
cummins4408 said:
Have you used this kit before. The description says fits most injection systems (except Bosch, xxx, etc.). Just curious. I was at Harbor Freight yesterday. Had I seen it and known it would work, I'd definately bought it as I'm looking for a second VP truck right now.
Click to expand...

Yes I have used it before my uncle has a kit, we used to troubleshoot my last LP failure. It has hookups for the schrader valve hookup.
 
Awesome, Alright some has to show me pics of exactly where to hook this bad boy up to. Words really don't help because I know nothing about diesel truck right now. Thanks in advance. I'm going to look at the truck tomorrow around noon.
 
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