[BustedKnuckles00]

95 blazer, truck and engine have under 100k, when at a stop the rpms bounce around the 500 mark and the truck feels like it's on the verge of stalling... sometimes when it's cold it'll run perfect at around 850 rpms for a minute or two. Any clue what this is? I'm looking to clean or replace the egr valve because it stalled once with an egr valve code, heard it could also be fuel pressure or spyder injectors? Any and all help is welcomed!!!

 

[Cowboytrukr]

Start by checking the fuel pressure. Test first before spending.

 

[JTward1]

Idle Control Valve, sits on the passengers side TBI unit. Need BIG wrench and compress it pin-tel till it's an inch from the body. Easy install part is cheap. But check fuel pressure first like Cowboytrukr stated above.

 

[BustedKnuckles00]

The fuel pressure is fine, the egr looks brand new, would it be possible to adjust the idle stop on the throttle body? If I can get it to run 200 rpm higher it runs 100x better... my dad wants to check the timing to see if it's off

 

[JTward1]

NO, the idle control valve works off the coolant temperature sensor and oxygen sensor. These two sensors convey their info to the PCM and the PCM sends a signal to the Idle control Valve and the throttle position now comes into play as it tell the PCM that the engine speed has increased. Once the engine gets to 195 degrees, then the PCM settles back and the engine to run normal. Now this is how OBD-I works. I'm pretty sure you truck is still a OBD-I equipped engine, other wise you are going to need an OBD-II reader and diagnostic tool. Their cheap, I bouth on for $17.00. Good luck !

 

[BustedKnuckles00]

The truck is OBD-II

 

[ThundahBeagle]

Wasn't '95 the odd OBD 1.5 year? Or is that only on the big Blazer?

Also, any thought this could be the MAF?

 

[BustedKnuckles00]

I'll try to check on the MAF this weekend, I guess I should also state that the truck is running really rich, you can smell it in the exhaust

 

[xPosTech]

Then it should tell you it's rich via the DTC codes. Unless it thinks the engine hasn't warmed up yet. You should have 2 temperature sensors. A 2 pin sensor near the thermostat that tells the PCM it's up to temp and go to closed loop. A single pin sensor between cyls 1 and 3 on the driver's side head.

Another cause is the MAF like ThundahBeagle pointed out. If it reads more air than actual it would run rich but should flag it from the O2 sensors.

Check/clean the temperature sensor and connector at the thermostat.

Ted

 

[BustedKnuckles00]

The 95 blazer doesn't have a MAF... there is a plug that goes into the air intake right near the throttle body... is this a type of maf?

 

[Cowboytrukr]

Close. It’s an intake air temp sensor which is the forerunner to the MAF.

 

[BustedKnuckles00]

Would cleaning it help the idle? I cleaned the air filter and it runs almost to where it should...

 

[Cowboytrukr]

It might, but they’re less than 10 bucks at Rock Auto

 

[BustedKnuckles00]

After driving to work and back the truck is running back how it was. I cleaned the intake air temp sensor,and that didnt help at all... trying to check the timing but cant find that tan wire with the black stripe under the glove box...

 

[BustedKnuckles00]

Aaaand just read that via the distributor that the truck has the wire I was hunting for is non existent....

 

[JTward1]

After driving to work and back the truck is running back how it was. I cleaned the intake air temp sensor,and that didnt help at all... trying to check the timing but cant find that tan wire with the black stripe under the glove box...

OK, we're back to step 1. I thought 1996 was the date were the GM trucks went from GMT400 to GMT800 and for that you need a cheap OBD-II scanner. But I read all of the posts and to me you don't have and ignition problem so much as you have a fuel problem. Why don't you check the fuel pressure at the injectors. And if it is a OBD-I diagnostic system, something will leave a code. If it's a OBD-I then you have a Manifold Absolute Pressure sensor. Both the sensor, and the valve are behind the Throttle Body on the passengers side of the blazer. Maybe I'm wrong here but it sounds like there is too much fuel, then too little fuel. I believe that would be the MAP sensor. But instead of swapping parts, we need a hint of where the problem. If you use a steel paper clip and short out the top two ports on the diagnostic port under the dash. If you do that but the "Service Engine Soon' like does not flash on and off, then you have a OBD-II and it will need a scanner and it would give you a stored PO-xxxx code. But without a diagnostic code, we're now here.

 

[BustedKnuckles00]

While driving the truck around during timing "adjustment", the service engine light was flashing. Which when we looked into meant that fuel was getting into the cat. Side note~ The truck is an obd-II

 

[xPosTech]

Post the actual codes you're getting. You're running rich like I said before. Just saying gas is getting in the cat doesn't help. The truck is trying to tell you where it hurts. Post the codes not your interpretation of them.

And when you were asked about fuel pressure you just said it was fine. What is the fuel pressure?

Ted

 

[BustedKnuckles00]

The flashing ses light was because we pulled an injector and forgot to reinstall it. Fuel pressure was at 60 and didn't drop more then 5 during leak down test. There are no codes currently, only got codes while attempting to adjust the timing and had forgotten some things

 

[JTward1]

OK, Can you post a picture of the fuel injection system ? See without a diagnostic system I have no idea what I'm talking about. If I'm not wrong you should have a OB-I system but you say it's not Throttle body in the truck, if that is the case then you should be able to do a system check while sitting in the drivers side. . . Or then I believe you would have 'Tuned-Port injection" system. But without a idea I can't be of any help, but it is a OBD-II system then you need a cheap code reader, and it will a "PO" code displayed trouble code. Then you will a code. This is what the OBD-I PCM coolant sensor.