Engine/Transmission (1994 - 1998) Finding Top Dead Center With Truck that has been torn apart!

[edgeman]

Well now I am having a hard time finding tdc on the truck. The timing pin will not push all the way in on my truck so I am just guessing on where tdc is. Is there anyway that anybody could help me with this to locate tdc so I can time my pump and adjust the valves right so the truck will start. This is really starting to get on my nerves. #@$%!

 

[snappy]

Pull number one injector. Use a wire (coat hanger) to find tdc. Watch the valves as you rotate the motor over.

 

[The patriot]

I saw where someone used a plug in the fuel pump.
Search youtube for "40 minute cummins timing" or similar.
I also believe you can unscrew the plactic pin assy and visually look at the hole.
Between that and watching the valve train it'll get you close enough.

 

[WDixon27]

how i marked my balancer for tdc was by using the dropped valve method, if adjusting valves too get all the valve covers off (otherwise just #1 and #6) and watch for both rockers to be in motion on #6, using a magnetic base/dial indicator and over the top spring compressor you can pull a rocker and compress a spring on #1 and let the valve drop enough to sit on the piston (i left the compressor on the spring and let it ride the valve) find the spot where the valve is at the highest point and that is pretty much tdc but not good enough for timing, to capture a better measurement make a pointer for the harmonic balancer (piece of coat hanger will do if permanent is not desired), zero the dial indicator then back up the engine till the valve drops a certain amount say . 050, mark the balancer and advance the engine till you get to zero and then back to . 050 and mark again, split the difference of the two marks should be perfect TDC, you may want to measure a couple times to verify just because... .



another way is to adjust a valve on #1 till it hits a piston mark then back up a full rotation till it hits again and mark



keep in mind if you remove the balancer your TDC mark will no longer be true as the holes are slotted, a couple alignment marks for the balancer help for that



valve adjustment, do the companion cylinder to the one that both valves are in motion to 1/6 2/5 3/4



this info is verifiable with a search of TDR and has been used a a few times by me on 1st and 2nd gen 12v's with success

 

[Dieseldemon]

Your timing pin is probably broken pull it and replace with a new one

 

[edgeman]

Your timing pin is probably broken pull it and replace with a new one

I thought this also, but when I put a new one in I thoroughly inspected the pin and it did not seem broke. Alright boys here is the scoop. I got the truck to run for about 30 seconds to bleed the injectors off. It ran off straight diesel too, which is a huge improvement. But now I am getting great fuel pressure at random times. I checked the Timing again on the pump and it is right:-laf. But when I crack the bleeder screw on the top of the filter I am not getting any bubbles and no fuel coming out of it. When I prime the lift pump I then get bubbles and can get the truck to fire. But then nothing. Could this be the lift pump or bad fuel lines. If it is bad fuel lines, could it be the rubber lines behind the engine? Please help, I just want to get the truck running!!!:{ Oo.

 

[Dieseldemon]

Then roll the engine around until you can see the hole in the gear If you turn the engine over until #2 ex valve is open all the way then look for the hole in the gear that will be TDC

 

[Vaughn MacKenzie]

edgeman if the fuel line was really drained of fuel it can take a while to prime it. I usually open the drain valve and pump the primer button until I get a good flow.

Fuel lines have been known to split inside the fuel tank. Also the metal lines back by the tank area have been know to rust through. If that were the case there should be good evidence of leaking fuel back there. If it's split inside the tank it will run fine on a full tank then have problems once the fuel level drops.

On occasion the fuel pickup screen in the tank gets plugged with algae/bacterial growth but that doesn't commonly happen, and is generally preceded by reduced power problems.

When you push on the primer button does it feel like it's working and moving fuel or does it feel soft and easy to push? Maybe unscrew the "cap" on the end of it and take the plunger piece & spring out and make sure everything looks OK and the plunger isn't sticking. Inspect the check valve/diaphragm piece for damage or debris.

 

[edgeman]

When I push the primer it seems to have great pressure. I can get great fuel flow out of the bleader hole and out of the inlet on the injection pump from the fuel filter housing. I don't think it is that. I wanna say there is just that much air in the system but at the same time I have never had a truck this hard to start after bleeding the entire system!

 

[The patriot]

Did you crack loose the lines on the injectors to prime them?

From what I understand some injectors are self bleeding and some are not.

 

[edgeman]

I did and I get fuel flow at the injectors. I have always been able to bleed the injectors with the truck running after three cylinders were good but I think that there is just that much air in the system to make it fire and then not fire and then run and not run!

 

[hsmith]

Hope you didn't leave the intake blocked with a shop rag or something.

 

[edgeman]

No I did not leave a shop rag in there lol. Although I know of people that have! But it sounds like it is just air!

 

[edgeman]

Well here is what I found out with my truck. I pulled the lift pump and the rubber lines behind the engine off. The rubber lines are deffinitly dry rotted but I don't think that they are bad enough to the point that they are leaking air, but I am going to change them anyways seeing how they are off of the truck. I pulled the lift pump off and inspected it real well to notice that some one had been in it before. I pulled it apart and I noticed some blue silicone type stuff that was in the plastic cap. I don't know if that is what is supposed to be in it but it is. That was just torn apart. So needless to say my lift pump was definitly leaking air and pressurizing the tank. So it looks like I will be ordering a new lift pump from geno's and the lines from Larry B's. Thanks for all your help I will post pics of what I found so you guys can look.

 

[SRadke]

Pull the timing pin out and stock your finger in the hole.

 

[CharlieFoxtrot]

I've adjusted valves on hundreds of gas engines without having a timing pin; at my first diesel valve adjustment I couldn't get the timing pin to work on my 96. I was concerned that this was a problem, but several experts told me that as long as you know what you're looking at and the valve is closed (rocker arm loose, etc), you're fine without the pin... . Just pick a method that works for you from the many listed on this site, follow it, and be confident your valves are adjusted right.