'95 Stalling out

[gluciano]

I am not sure what or where to go for this stalling issue that I am having. I bought a scanner and have found no codes. I have done seafoam, plugs/wires, IAC, TB cleaned, fuel pump relay, air filter and a fuel filter.

It seems that when it is warm and I drive it around for a bit, come to a stop light the truck will stall out. I am able to avoid this if I feel it's about to stall by holding my foot on the brake and giving it gas up to about 1100-1500 rpm. If I let it stall out it seems to start sometimes right after it stalls, other times you either have to floor it while you're starting or wait about 5 minutes before it will start. Once it starts after you floor it it bogs down a lot for a few seconds until it can spit whatever is in the engine out. Usually some black smoke will come out for a bit. I just have no idea what else I should be looking at. My options were to replace the coil pack along with fuel pump.

Anyone have any advice or suggestions?

Thanks!

 

[Dilbert5]

You have a scanner, see what the short, and long term fuel trims are. Also check what the coolant temp is reading. From the sound of it you are running rich. The next thing to do would be clean the MAF sensor, purchase the correct cleaner for this from a auto parts store. I would hold off on the coil pack for the time being. It does not sound like the problem to me.

When it is driving, does it feel like it has decent power / acceleration?

 

[gluciano]

You have a scanner, see what the short, and long term fuel trims are. Also check what the coolant temp is reading. From the sound of it you are running rich. The next thing to do would be clean the MAF sensor, purchase the correct cleaner for this from a auto parts store.

Running rich ran though my mind as I get horrible gas millage out of it. I just did a water pump as well as thermostat last month. The gauge usually sits in the middle or slightly lower. To replace the MAF how do I do that? It seems that is inside and attached to the air housing box right after the air filter. Is this replaced as a whole unit?

Also while driving it runs strong, it does sometime under WOT while in 2nd gear seem to bog down slightly. Another thing I want to add is that sometimes after it is started up from the stall it seems to have a very high idle, around 2k. It will return to idle after a while.

 

[Joe Dirt]

Define horrible gas mileage...

 

[gluciano]

Define horrible gas mileage...

Full tank only getting around 200 or less miles under normal and highway driving.

 

[Dilbert5]

I suggest cleaning the MAF before replacing it. But first what you just wrote brings up another possibility.

Check the coolant temp sensor, most cars have two sensors. One is for the gauge on the dash. The other is for the PCM, use your scanner and read the temp. The fact that you recently replaced the water pump makes this much more likely. It is possible that you knocked the connector loose. The PCM adds extra fuel while the engine is warming up, so that would explain the poor mileage.

 

[gluciano]

I suggest cleaning the MAF before replacing it. But first what you just wrote brings up another possibility.

Check the coolant temp sensor, most cars have two sensors. One is for the gauge on the dash. The other is for the PCM, use your scanner and read the temp. The fact that you recently replaced the water pump makes this much more likely. It is possible that you knocked the connector loose. The PCM adds extra fuel while the engine is warming up, so that would explain the poor mileage.

It stalled out before I had replaced the WP and thermostat. After I replaced the theromostat the gauge would dance around a little. Thought it was because of air in the system which worked its way out.

I'll have to see if my scanner can read temps and such. It's one of those cheap 30 dollar ones that shows the CEL codes.

How do you remove the MAF from the plastic housing? It seems to be built into it..

 

[gluciano]

I want to add that I drove it around today and it was again doing the same thing. I did notice that the temp gauge is showing that it looks like it is running cold but I can't tell. The needle usually seemed to be below the thermometer that is on the gauge, it would level out at the thermometer but then drop down lower.
Is that normal?

I don't think I can test to see if it's going into CL on my scanner, it doesn't look like it has that function. Here's a picture of the users manual as I don't have the scanner with me at this moment.

Here is a link to it as well. http://www.amazon.com/gp/product/B000HI6OXM/ref=ox_ya_oh_product

I unplugged the MAF sensor, drove it around and it didn't seem like the conditions got any better and seemed as if they remained the same.

 

[Dilbert5]

the temp gauge response does not sound normal to me, You may want to consider replacing it again. I would suggest a different brand thermostat. Make sure that it is 195deg (stock) do not ask for a lower temp.

Technically you have a code reader, not a scanner. I don't know if you have heard about the USB scanners that they have. You can pick them up on ebay for less than $60 these give you Much more information. IE such as this case, you would just look up the coolant temp sensor, and it would tell you the temp in deg.

Anyway I looked up the location of the temp sensor you your car (I believe 4.0, ) it shows the sensor as being to the left of the throttle body. It should have two wires on the connector. 1) light green/red 2) gray/red at 80 deg you should measure app 16 k ohms resistance.

hope this helps a little.

 

[gluciano]

the temp gauge response does not sound normal to me, You may want to consider replacing it again. I would suggest a different brand thermostat. Make sure that it is 195deg (stock) do not ask for a lower temp.

Technically you have a code reader, not a scanner. I don't know if you have heard about the USB scanners that they have. You can pick them up on ebay for less than $60 these give you Much more information. IE such as this case, you would just look up the coolant temp sensor, and it would tell you the temp in deg.

Anyway I looked up the location of the temp sensor you your car (I believe 4.0, ) it shows the sensor as being to the left of the throttle body. It should have two wires on the connector. 1) light green/red 2) gray/red at 80 deg you should measure app 16 k ohms resistance.

hope this helps a little.

Got a new thermostat and a temp sensor, I'm going to replace those when I get sometime to do it. I'll update when it's done and let you know the results. Thanks.

 

[gluciano]

I want to follow up with this as it seems that the problem is fixed. I replaced the ECM which turned out to not fix the problem. I was just about to replace the O2's when I figured I'd replace the coolant temp sensor since I got a code for it. I put it in today and it seems to have fixed the running rich/stalling out when warm condition. I figure that it was no good and that it was sending bad signals to the ECM causing it to think it is cold. I drove it about 5 miles today and had no issues, runs good. I'm going to take it to work tomorrow which is about 20 miles away; I hope the problem is fixed as I don't want to get stuck on my way to work lol..

One thing though which is odd, the sensor seems to be from an earlier model X, like a 94. The one that calls for my 95 was a different connector which has thin leads on it, mine are round. Is it odd that the sensor is an earlier model in a vehicle that was made in 6/95?

 

[Texan01]

I had something similar happen, mine would randomly stall out for no apparent reason. I borrowed a scan-tool that could observe the parameters and found out the coolant temp sensor was going nuts.

Dropped 15 bucks on a new one and it was all good after that.

If the computer gets the wrong temperature value it, it really does mess up quite a bit of readings.

Mine is a 3/95 build and it has the round pin. the 1995 model year is an odd duck in that it's the last of the obd-i and first year for the 2nd gen body style, sometimes I've had to call it a 94 or a 96 to get the right parts.

 

[gluciano]

Yeah 15 bucks seemed to have fixed it. I drove it to work this morning and had no issues, it ran fine. I'm still keeping my fingers crossed!

That make sense about the sensor then being that it's the odd year OB1/OB2, I'll keep that in mind when I get parts for it!