I have a '98 Blazer... In cold weather (below 30 degrees), it has trouble starting (firing) if and when it does start, It has load valve chatter and the oil pressure gauge goes to MAX. I saw a couple posts were others have experienced this issue, but saw no solution.

Seems to be two problems. 1st when starting in cold it turns over but does not want to fire ( getting an occasional sneeze), if you keep trying will finaly fire.
Then once it does start, loud valve noise as if oil is not circulating and oil pressure gauge reads almost max... if you accelerate, the oil pressure gauge peaks at max? any ideas?
PS I am useing recommeded oil viscosity

 

It sounds as though you may have a blockage somewhere downstream of your oil filter, a clogged screen on your oil pump, or most likely a plugged or stuck oil pressure relief valve. (cold weather makes the oil thicker and more difficult to push past/around any kind of partial clog.)

It is very dangerous to drive the truck if any of these is the case. I once had a grand am with a completely plugged relief valve that actually ended up blowing the oil filter completely off because the pressure got so high.

On most engines this would not cause a difficulty in cold starting. However on these trucks the oil pressure sensor is one of the components that helps control the fuel pump. Essentially it is reading that something is wrong in the oil system and trying to stop you from starting and possibly destroying your engine.

The best solution is to replace the valve. I have never had to replace one on these engines so I'm afraid I can't be of much help on location and difficulty of replacement information on this one.

You can also do a thorough cleaning of your oil system. This is something that should be done once in a while anyways.

To do this you first need to drain your oil and replace the filter.
Then you need to fill the engine with the cleaning cocktail of your choice. There are many differing opinions on what works best.
I personally use 2 quarts oil, 2 quarts ATF, and 2 cans of seafoam. (adjust the amounts accordingly for an engine that uses 4 quarts of oil instead of 5)

With your cleaning cocktail filling your crank case, start the engine and let it idle for a while. (Do not drive the truck with any kind of oil system cleaner in the crankcase.)

With any luck your oil system blockage isn't total and you should see your oil pressure start to drop back to normal levels as the gunk is dissolved. If it does then problem solved and you can drain out your cleaners and replace the oil and a new filter and your in good shape again.

If it doesn't then you will need to start looking into replacing parts and other possible causes of the problem.

Let us know how it goes.

 

He has a '98 and I think they do not have this feature on the later model engines.

 

I had thought that it was 99 and up when they had stopped doing that.
Thanks for the info. I'll have to go and look up the exact year of the change for future reference.

Either way though the dangerously high oil pressure combined with the valve chatter meaning that the oil is not circulating properly is the problem to correct first.

If it continues to have hard starts after this is fixed then we can go from there to fix the rest of the problem.

 

Thank you for your reply, I have found that one shot of starting fliud gets her to fire up and will restart without problem once warm. So maybe a little bit of a start-up fuel pressure problem ( I will need to check pressure). As for the oil pressure, ( I will flush out system and see if that helps). Just driving the wife's car untill this winter blast passes. Then I will work on the Blazer.