Tapping

[chris79bronco]

Alright I'll try to explain this as best I can without you actually hearing the truck I know its going to be difficult. This is my first diesel so I dont exactly know what sounds to listen for or what anything sounds like when its going wrong. I bought the truck last wensday and drove it about 75-100 miles no prob, the truck has started to gain a miss at idle more and more frequently, the idle is starting to move around a little too. When its cold it dosnt do this to much. When its cold and I hit 40-45 mph it bucks a little like im on and off the gas. Once its warmed up a little it stops. Here in the last 2 days I have noticed a ticking in the drivers side floor board that has been progressively getting worse, dosnt do it when its cold but warmed up you can def hear it. I took it by a local diesel guy and he drove it and said it might be a exhaust manifold leak, we parked he got under the hood I reved it and he said it was the vacuum pump. Brakes work fine not hard exactly the opposite as a matter of fact. What do you guys think?? Was told the miss could be a cam sensor or the valve cover gaskets, but my main concern now is the ticking, if not the vacuum pump what could it be? Lifter? Rocker? Injector? how do I know. I know this is a lot of reading but I wanted to be very clear in the description of what I'm hearing.

[JD3020]

Pull the valvecovers and watch the engine run, and make sure everything is moving as it should and that every injector is squirting out similar amounts of oil. Also have them run a buzz test and a cylinder contribution test(CCT). This will help to show any issues. Look for soot anywhere on the exhaust/firewall, to find a leak. My truck has horrible manifold and up-pipe leaks, and i mean horrible, and you can hear them very clearly.


Also, have you changed the fluids/filters yet on it? If not, that alone may fix the issues.

[chris79bronco]

Yea Ive changed the fluid/filters, that was the first thing I did. Theres no soot on the firewall or on the manifolds. I got a buddy with a scanner that can do the contribution test so I'll try that.

[chris79bronco]

well did the cylinder balance test and it passed????? Dont know where to go from there lol

[GrizzlyMan660]

6.0 or 7.3? If its a 6.0 check you ficm! I literally just changed my injectors last night cuz it was doing the same thing but to a worse degree good luck buddy

[chris79bronco]

1997 with the 7.3

[chris79bronco]

Alright to follow up a little, I bought the dorman valve cover gaskets and pulled the valve cover on the drivers side and cranked it up. All the rocker arms are moving like there supposed to, they are all spitting the same amount of oil but....... the oil spit looks weak, I dont know if it should be strong but it looks like pouring out of a bottle rather than a strong squirt. And they are not very steady, it will spit 2 or 3 times in a row then skip 2 or 3 on one injector. And I know now the noise is not in that side. The oil pressure guage on the dash is not the one for the HPOP is it? Could the HPOP be weak?

[Haulstroker]

Sounds like the thing to check ASAP.

[chris79bronco]

How do I check the oil pressure coming from the HPOP? Should probably do a compression test also while im in there. theres alot of blow by coming out them oil vents in heads too

[madpogue]

The dash "gauge" is for the lube (low pressure) oil pressure. And it's really just an idiot light with a needle - all the way left at zero pressure, mid-gauge at "enough" pressure.

Injection pressure is monitored by the PCM, so you can read it with a scanner / data reader capable of communicating with our trucks.