OBDII codes 171 and 174 on 99 Blazer

[Nandy]

I have the blazer open up on a different issue but since I have the injectors out I might as well take care of this if possible.
These codes started over a year ago when I replaced the fuel regulator. I know they have to do with the injector banks but that don't tell me much. I checked the injectors and they seemed alright and where secured.
What could be causing this?
What should I check?
I would like to clean the outside of these injectors but I'm not sure which cleaner should I use. Can I use that same cleaner to clean the socket where these injectors connect?
Thanks!

 

[windsors03cobra]

Re: OBDII codes 171 and 174 on 99 Blazer

I would use throttle body cleaner or maybe even gas to clean them if you want too. I know they get filthy but I doubt cleaning them is going to do much but maybe help break a fragile glass slipper.
Are you sure you didnt have any vacuum leaks after you opened the intake to throw those LEAN codes?

Doing some LIM gaskets ?

 

[Nandy]

Re: OBDII codes 171 and 174 on 99 Blazer

Not sure what you mean by the lim gasket...
I only one gasket didn't look right but it could be when I removed the part. Other than gaskets not sealing properly, should I look at anything else?

 

[windsors03cobra]

Re: OBDII codes 171 and 174 on 99 Blazer

It sounds like your doing the old Lower intake manifolds gaskets on that 4.3

Checking fuel pressure and cleaning the mass air flow sensor in the air intake pipe would go some other good things to check. Also check the air intake pipe for leaks/cracks.

What went wrong with it this time ? I think you mentioned bigtime coolant loss in another thread ?

 

[Nandy]

Re: OBDII codes 171 and 174 on 99 Blazer

It got hot suddenly while taking the girlfriend to work then started puttering and loosing power. In short, I let it cool for about 30-40 min and put some water in it to later put the coolant. It started great at usual but in about a couple of miles it started doing the same so I knew it was something larger. I took the air intake hose to the thrortle body and saw a lake of water in the thortle body. Water was coming from the return in the rocker arm cover it seems. It was mixed with oil. Took the oil dip stick out and I could see the water droplets in it and the oil is "mixed" with the water. I hoping it is the head gasket only and not a cracked block/head or warped head. Going to try to take it all apart today and try to fix it. Hope it all work out cus I have to return that rent car tomorrow and after that I have no transportation.

 

[Gary H NC]

Re: OBDII codes 171 and 174 on 99 Blazer

Could it be the intake manifold gasket and coolant is getting into the oil to the point its blowing out the crankcase vent into the air intake?
Is the oil over full or looks like it has coolant in it?
I doubt it is the head gasket....

 

[windsors03cobra]

Re: OBDII codes 171 and 174 on 99 Blazer

No doubt its the LIM gaskets (lower intake manifold gaskets)

Not a whole lot of headgasket problems with the 4.3 tho anything is possible with dexcool and a couple of good overheats ?

Mileage on the truck ? Type of coolant in the truck ?

 

[Nandy]

Re: OBDII codes 171 and 174 on 99 Blazer

The dipstic had water in it Garry and I could see the mixture of water/oil in the dipstick and in the oil cooler lines from at the radiator.
Cobra, it has over 250 miles and the coolant was Preston. It has got real hot about 3 times. Once like 5 years ago and twice this day that it broke. Is there a way to tell if the block is cracked without taking the motor out of the car? I hate to take that monster out to test...
Sounds like you guys are more inclined to the block being cracked. I know my coolant/water mix was about 50/50...

 

[Nandy]

Re: OBDII codes 171 and 174 on 99 Blazer

Stopped for the night. This is crazy, you have to tear the fricking car apart to work in the motor. Hate modern cars... Anyway, I'm having a problem taking the fan off the water pump. I have done this before and even built a tool to hold the pump pulley in place. This time it is not coming loose. The book don't specify it and I have tork this sucker good but no dice. I would have heated the nut but that plastic fan is not taking that heat.
In other issues, I can see the sparks were running hot.
Later!

 

[DECK SWABBER 58]

Re: OBDII codes 171 and 174 on 99 Blazer

That is a cast iron block, the odds of it cracking are low.

With 250k replace the head and l.i.m. gaskets and you will
be good to go for another 250k.

Then.........worry about the codes. Right now they are not
your main issue.

 

[DECK SWABBER 58]

Re: OBDII codes 171 and 174 on 99 Blazer

You need a special tool to take that fan clutch off.

I bet your local autozone will lend you one.

Are you working in a heated garage?

 

[Nandy]

Re: OBDII codes 171 and 174 on 99 Blazer

Ok, looks like the problem was the intake manifold low gasket on the passenger side . That explain why there is such a mess of gooey like grease that is supposed to be oil right under that manifold and everything else had mostly droplets of coolant. Im done cleaning the gasket locations on the motor block. Now I have to start cleaning that gooey thing. Any suggestions? I was planning to use gas to wash whatever down and then empty the oil pan, then I will put new oil in it with that oil treatment, run it for a while then make the last change. Will change the oil filters too of course and clean the oil pump filter or replace it.
I have some photos and will upload later.