First see that there is fuel coming out the fuel return fitting on the injection pump when cranking the engine. If there is close that line off temporarily to verify a weak relief spring is not an issue. It is highly unlikley that a weak relief valve spring would suddenly occur. Although getting some gunk in the relief valve is a possibility somehow holding it open. That is even unusual as well.


Generally though if fuel is coming out the return fitting though most times you will have fuel and at least some fuel pressure in the base of the injection pump. No fuel at all coming out the relief valve and there is a problem. This problem may or may not be the cause of your current issues. This is where I would start probably if it were my car.

As for reading the fuel pressure in the base of the injection pump. This requires a harbour freight 10.00 liquid dampened 0-30 pound gauge. It is too premature to consider it's use at this time.

All you really want to find out is if there is fuel present in enough quantity in that injection pump and it has some pressure. If it is not there change out the secondary fuel filter as it may have almost totally obstructed. This is also a wise thing to do when any form of improper fueling seems present.

You can get a load of dirty fuel at any time. Or a filter just calls it a day. For example I try to only buy diesel fuel at large volume outlets. Things may have improved but I have had my share of issues over the years buying from low volume diesel fuel sales outlets.

If your battery is fundementaly weak you will have to proceed cautiously with the tests. Finding what is the issue is best done with testing rather than guessing is a better way. Many members on site will be here to help.

Another simple test. When you pump your fuel primer pump. Does the effort get harder with pumping? Are you eventually hearing a kind of squeel when the relief valve on the injection pump opens? This has to occur or again something is wrong. Just keep posting the results of the simple tests for help in interpretation of what they may indicate if things are not happening as they should be.

Again in a situation like yours you may save a lot of grief just by changing that secondary fuel filter out as well. Again I may be totally wrong but to me there is a pretty solid indication that you may not have enough fuel available in the injection pump to service the elements properly. Kind of a first things first approach to your problem if nothing else.