1995 Sierra runs rough. Needs tune up help

Did a little google of Seafoam. Sounds like good stuff. However, will adding to gas or oil get it into me PCV hose fitting on the carb? And is it good to have the dirty, gritty oil buildup loosen up and travel deeper into the carb and then enter the cylinders...if that is where it would go?
 
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sofasurfer said:
Did a little google of Seafoam. Sounds like good stuff. However, will adding to gas or oil get it into me PCV hose fitting on the carb? And is it good to have the dirty, gritty oil buildup loosen up and travel deeper into the carb and then enter the cylinders...if that is where it would go?
Click to expand...

Follow instructions and the dirt and carbon build up goes right through your engine and out the tail pipe. You can put the Seafoam in your gas tank and engine oil crank case to loosen up the carbon from your upper valve train so be rady to give it an oil change after 250 miles and you can let the vacuum line pull in the Sefoam via through your vacuum boost line and the PVC line to clear out your throttle body and you may also want to buy the Seafoam cleaner in the spray can form to clean out your throttle body. :D

Note, it sound like your engine is really carbonized so your going to need two can's of Seafoam to clean your engine out and your going to have lots of smoke coming from your tail pipe after for about 10 min, just follow the instructions. :rolleyes:
 
I replaced the cracked line from the throttle body to the PCV. But first I connected it to the TB and pointed it straight up. I then filled it with Sea Foam and started the engine. It didn't go down in the tube at all. So I got a wire and pulled as much crude out of the port as I could. Probably got enough to equal the end of my pinky finger. Thick and gummy. Then I reinstalled the new PCV and hooked it up.

I poured a can in my gas and a half can in the crank case. Then sucked the rest into the booster hose. After sitting I let it idle 10 minutes. Then took it on the freeway and had it up to about 85 for a couple miles.

More get up and go then its had in a long time. But I have to admit that a good part of that is probably from replacing the cracked hose...but then again, how can that make a differance when it is sucking NO vacuum. So that could NOT have been the deciding factor.

I'll take the PCV off again and check it for sucion. I don't expect it to clear out for a while though. But then again, what do I know.

They say the blue smoke is from the dirt being expelled from the engine. O come on, isn't that really the color of excessive petroleum distillate burning?
Anyway, the smoke was bad for just about 4 or 5 minutes and after that is wasn't to bad. It went away after 2 miles or so.

It cruises great. Idles really good. Takes off with some sputtering and when its cold it takes off really bad.
Anyway, its a big improvement. I'll give it time and we shall see. I'll keep you posted.

Thanks for your time and patience.
 
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I have checked my vacuum lines for vacuum after every time I take my truck out. So far its been looking pretty hopeless...until today. I am feeling a little vacuum on my PCV line today. I'll be danged!!

There is another little vacuum line attached to the back side of the carb. It comes from an electronic device on the rear, passenger side of the engine. I do not see any other hoses connected to this device. What is it?

I still feel no vacuum on the EGR hose and disconnecting the hose has no noticable effect. The EGR hose hooks to what appears to be an electric selonoid. I will see if I can determine if the selonoid is working.

How much vacuum should I have, if I were to want to check it?

Is it possible to acquire from anyone here, a schematic or exploded view of this throttle body so I can learn whats in it and what things do and what not?
 
sofasurfer said:
I have checked my vacuum lines for vacuum after every time I take my truck out. So far its been looking pretty hopeless...until today. I am feeling a little vacuum on my PCV line today. I'll be danged!!

There is another little vacuum line attached to the back side of the carb. It comes from an electronic device on the rear, passenger side of the engine. I do not see any other hoses connected to this device. What is it?

I still feel no vacuum on the EGR hose and disconnecting the hose has no noticable effect. The EGR hose hooks to what appears to be an electric selonoid. I will see if I can determine if the selonoid is working.

How much vacuum should I have, if I were to want to check it?

Is it possible to acquire from anyone here, a schematic or exploded view of this throttle body so I can learn whats in it and what things do and what not?
Click to expand...

Here you go and keep me posted:eek:

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=03&grouptype=B

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=03&grouptype=B

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=03&grouptype=B
 
I replaced my vacuum control selonoid which applies vacuum to my EGR. The vacuum line going from the TBI to the selonoid had vacuum but the line from the selonoid to the EGR had no vacuum. After I replaced it I still have no vacuum to the EGR. So I bought a multimeter and checked the voltage to the plug for the solenoid. It reads 0.15 volts with the vehicle running.

Does this tell us anything?

It appears that in order to test further to find why the solenoid is not working, I will need to buy or rent a hand held vacuum pump for this test...
http://www.autozone.com/autozone/re...Fig. 5: Negative backpressure EGR system test

or I will have to buy or rent a scan tool (code reader?) for this test...
http://www.autozone.com/autozone/re...=gif&imageName=Fig. 7: Linear EGR system test

OR............?

There are various tests depending on which type of EGR system I have, or at least thats the way I interpret it.

GULP..........!
 
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sofasurfer said:
I replaced my vacuum control selonoid which applies vacuum to my EGR. The vacuum line going from the TBI to the selonoid had vacuum but the line from the selonoid to the EGR had no vacuum. After I replaced it I still have no vacuum to the EGR. So I bought a multimeter and checked the voltage to the plug for the solenoid. It reads 0.15 volts with the vehicle running.

Does this tell us anything?
Click to expand...

The EGR valve for your engine is a negative back pressure EGR valve (working on negative backpressure pulses) and if the catalyist or exhaust has a restriction (partially clogged), it will make the EGR valve malfunction. If the engine is in close loop and when the ECM commanded the EGR circuit to come on, the engine looks like it would choke out.

Verified that the EGR circuit is causing the problem by disabling the EGR circuit (disconnecting the vacuum line between the EGR solenoid and throttle body and capping the port on the throttle body). See if the problem goes away! The EGR may just be opening up too much allowing too much exhaust into the intake port, choking the truck out.:D

Post me back an update on your DTC codes and we can go from there. I have to read back what the issues are with your Sierra again:confused:
 
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I cleared my codes. Drove around the block and checked again...no codes and no engine light.
Truck drove pretty well. Slight hesitation when flooring it from a stop. After it gets rolling it accelerates pretty well. Cruises fine. Rapid deceleration wants to stall. Stopping sometimes wants to stall.

I then drove about 10 miles. Drove as above. Slight hesitation on take off. More hesitation on slow acceleration. I need to feather it else it feels like its flooding. I think exhaust smell increases. Tromping it at higher speed and it takes off good. Cruising at 50 mph and I can feel and barely noticable "pulsing" in the engine. Still no engine light.

After about 5 miles engine light comes on. Take off is rougher. Slow take off has lots of hesitation, surging, lurching. Around 30-45 mph, tromping the gas goes into passing gear and jumps back out quickly. After 50 mph passing gear winds up to 4000 rpm and truck moves out. Quick deceleration wants to stall and a couple times did stall while still moving.

Stopped at a garage sale. When I started up again engine light was off. After some time it came back on. Stopped at a store and the same process was repeated. Got home and checked codes...#44.

I checked solenoid with this test... http://www.autozone.com/autozone/re...Fig. 5: Negative backpressure EGR system test

I was not losing vacuum on the solenoid. Thats as far as I could go because I could not check CKT 439 since I did not know which wire it was...both the same color.

I also applied vacuum to the EGR and it held. I then ran a hose directly from EGR fitting on TBI to the EGR, eliminating the solenoid. The EGR open enough to hear the engine change but not enough to feel the diaphram move with my finger.

Unless you have a better idea I will check the connection on the PCM and if that produces nothing I can get an electrical diagnosis for $50.
 
sofasurfer said:
I cleared my codes. Drove around the block and checked again...no codes and no engine light.
Truck drove pretty well. Slight hesitation when flooring it from a stop. After it gets rolling it accelerates pretty well. Cruises fine. Rapid deceleration wants to stall. Stopping sometimes wants to stall.

I then drove about 10 miles. Drove as above. Slight hesitation on take off. More hesitation on slow acceleration. I need to feather it else it feels like its flooding. I think exhaust smell increases. Tromping it at higher speed and it takes off good. Cruising at 50 mph and I can feel and barely noticable "pulsing" in the engine. Still no engine light.

After about 5 miles engine light comes on. Take off is rougher. Slow take off has lots of hesitation, surging, lurching. Around 30-45 mph, tromping the gas goes into passing gear and jumps back out quickly. After 50 mph passing gear winds up to 4000 rpm and truck moves out. Quick deceleration wants to stall and a couple times did stall while still moving.

Stopped at a garage sale. When I started up again engine light was off. After some time it came back on. Stopped at a store and the same process was repeated. Got home and checked codes...#44.

I checked solenoid with this test... http://www.autozone.com/autozone/re...Fig. 5: Negative backpressure EGR system test

I was not losing vacuum on the solenoid. Thats as far as I could go because I could not check CKT 439 since I did not know which wire it was...both the same color.

I also applied vacuum to the EGR and it held. I then ran a hose directly from EGR fitting on TBI to the EGR, eliminating the solenoid. The EGR open enough to hear the engine change but not enough to feel the diaphram move with my finger.

Unless you have a better idea I will check the connection on the PCM and if that produces nothing I can get an electrical diagnosis for $50.
Click to expand...

Try cleaning out your IAC again or replace it to solve your stalling issues, and inspect or replace your TPS. Check TPS for smooth and linear electrical response over the entire range of motion. If not, replace it. :D

FYI when the EGR is open, it allows the exhaust gas to recirculate in to your intake manifold which will choke the engine causing it to stumble and have ruff idle if it's stick in the open position. :eek:

Other then that keep up the good work and wont hurt to give it another Seafoam treatment paying more attention to your throttle body and upper intake. ;)
 
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