Hello everyone, I just want to say thanks for taking the time to read my post. Also thanks in advance to anyone who offers advice. Here goes.

I have a 92 s-10 blazer that has a had a recent engine rebuild. Were talking all new inner parts and resurfaced heads, new crankshaft, rings, valves, new cam, etc the whole deal. I have also recently replaced the IAC valve, MAP sensor, EGR valve, Plugs/Wires, CTS, and battery. Before the engine was rebuilt, about 1 year ago the fuel pump was replaced. Other small non-running parts have been replaced. Even with all these parts replaced, I am getting a check engine light after running for some time. The light will only come on after driving for some time, then in Drive, the car will start to stutter and want to die (it sometimes does) and then it revs up and the check engine light comes on. After driving it around for a few minutes the check engine light will turn off and occasionally flicker. The codes my mechanic (my uncle as well) retrieved were code, 32, 33 and 45. For the code 45 we found that the EGR Solenoid vacuum line to the EGR was not connected, so we fixed that issue but it still stutters and stalls occasionally. I think the code 33 was High Voltage for the MAP sensor but don't recall what code 32 was. I apologize for the long description but I felt it necessary. Again, thanks for any help in advance.

Please note: The blazer also runs out of gas at 1/4 of a tank and will die out if I take a sharp right turn when near the 1/4 tank marker. I have been told it is the Fuel Sending Unit. Will the new float resolve the misleading gas gauge reading? Lastly could this be part of the issue? Thanks again.

 

I'll answer that last part.

Depends on if it doesnt seem to go very far after a fillup, but the problem is probably not with your fuel sender but with the fuel pickup. It's all the same, really, as you will have to pull the assy to fix it..

In the 80's some {Ford} FP assemblies had a piece of fuel line in the assembly. They were prone to crack after about 15 years. Also the connection from pump to pickup may have broken. I'd suggest replacing pump while you have it out, anyway.
As said elsewhere dont go cheap unless you want to do it again cause you like dropping the gas tank so much. AC Delco or Bosch if available.

 

Is your engine a TBI (round air cleaner on top of the engine) or CPI (air cleaner located over on the driver side front corner of the engine compartment?

 

Yes its TBI, forgot to mention a vital detail, my bad.

 

Here are the code descriptions for your truck:
32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas.
33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%.
45 Oxygen sensor voltage was over 0.7 volts for 70 seconds after engine had been running for 1 minute with a throttle angle between 2 and 20 percent.

A vacuum leak or EGR leak/stuck open can cause a high MAP reading (low vacuum). The MAP sensor can be tested by back probing the output wire. There should be a +5V reference from the ECU, a ground, and then the sensor return. Run a search for "MAP+voltage+altitude" with an author of "swartlkk" and you should find the voltages for various altitudes.

If the O2 voltage is high, that means the O2 content of the exhaust is low which is a rich condition.

If the EGR valve were stuck open, this would cause less combustion supporting air to be pulled into the combustion chambers and could cause a rich reading from the O2 sensors as well as a high MAP reading at idle. It all kinda fits together.

 

From what I can tell from your post, I must check the EGR valve for functionality before I do anything else. I will replace the whole fuel pump and sending unit. The pump I can get at the moment is dorman and the FSU is ac delco. Any suggestions? I know the prior post referred to use only AC DELCO or Bosch but I have not found any parts (yet) that I can use.

 

Hello, my 1997 4/4 Blazer is idling down until it dies at traffic lights. WHY? This started very recently. It always starts again but really shouldn't do this! Can someone help figure this problem out? THANKS

 

I said 'if you can find them'.
The CFI should not have the same failure issues as the 2nd gen system has. Besides, there may not be anything wrong with your sender, I tried to make that clear. If you find a crack or break between your pump and the pickup you dont have a sender problem.
- to put a point on it: when you run out of gas at 1/4 tank, how many gallons does it take to fill it up? vs what is tank capacity.
Just not Airtex assembly you wont be happy.

 

I don't know if the O2 sensor has even been replaced, so I may want to replace it anyhow. How do I check for the stuck/open EGR valve? I will run a search as suggested and verify that the MAP sensor is operating as it should be. Lastly I notice that when I do stall or have issues, I will smell a strong has odor if I pass towards the rear of the vehicle. I am assuming the fuel mixture is too rich as suggested, correct?