Still Stumbling ?

[luminaapv3]

Ok, I'm back. My other topic was getting too long, so I'm starting this one. I finally got the truck back together and I'm still having the same problem! If you want to read my last topic and look at the responses the topic is called "stumbles a little, but no stall" sub topic is "running out of money".

Anyways I still have the same problem; When I hook up the egr valve it stumbles like it wants to stall around 1000 to 2000 RPMS (truck doesn't have a tach). Unplug the egr and the truck runs fine

Below is a recap of all the things done to this truck:

 

My truck:

93 Chevy Suburban 5.7 Liter K1500 4WD automatic

 

Replaced the following with New parts:

EGR valve

EGR soleniod

Spark plugs and wires

Right side exhaust manifold gaskets (they were shot and causing a lot of noise)

Intake manifold gasket

Rocker arm gaskets

Temp sensors (2 of them, one on top and one on the side of the engine)

TPS (throttle position sensor)

Air filter

Oil & filter

Fuel filter

Oxygen sensor (in exhaust manifold, one wire type)

PCV valve

PCV valve vacumm line

PCV valve grommet

Thermostat

Fuel pump relay (located on the firewall)

MAP sensor

Distibutor cap and rotor (wire brushed as much rust from these parts as i could)

Negative battery cable

Replaced the ground wire from the engine to the chassis, but had to do so towards the front of the engine.

Replaced the ground wire from the engine to the fire wall

Replaced the ground wire from the gas line to the chassis (at the rear of the truck, yes there is one back there!)

 

Cleaned, checked or repaired:

IAC sensor (pulled, cleaned, new gasket, put back on)

Regrounded every visible ground I could find (down to the metal)

Ran seafoam through the pcv vaccumm line

Checked all vacuum lines,they seem good

Ran a bottle of fuel system cleaner called "Guaranteed to Pass" (in gas tank)

Alternator was checked at autozone, that came back OK

Fuel pump replaced too according to prev owner.

Checked the fuses, all look good (haven't light tested them yet, kids broke it

Cleaned all electrical connections for all the things I listed here.

TBI (Dismantled the entire throttle body and cleaned it out)

Intake manifold (dismantled and cleaned out the entire thing)

Every vacuum line, hose, etc. that was on the intake manifold was cleaned

Got a new light tester and checked all fuses, all are good.

 

Other things about my truck:

Aftermarket auto start/door opener (no alarm) installed (not factory)

Trans was rebuilt about 3500 miles ago according to prev owner, got papers to show it, although the crapy tech they used forgot to hook up the ground wires, which I did manage to do.

The electric mirrors don't work (don't know why)

Wires near the right side exhaust were laying on the exhaust, didn't see any exposed wires though, looks like mostly the outer plastic was melted, but not positive, can't get to it really good.

The PCV valve is also clicking away once it warms up, don't know why, there is a very strong suction coming from this line, don't know if that is normal.

 

My last post was with this statement here:

I checked to see if i had vacuum in the line from the egr solenoid to the egr valve before and there was none at idle like it should be, but tonight i unpluged the line, put my finger on it, CAREFULLY streched over the engine and slowly reved the engine and wouldntcha know it, just as it hit somewhere around 1000 to 1500 rpms (I don't have a tach) the line filled with vacuum (sucking)!!!! and then stopped as I reved it higher. It only lasted for a few seconds, but I'm guessing in those few seconds and when I hold it around that rpm it is opening up the egr valve and letting in exhaust to be reburned, hence the stumble!

 

So after tearing apart the top part of my engine and cleaning, painting and putting it all back together I'm still stuck with the same boat rocking stumbling problem I started with!!!!

Although the intake manifold gasket and TBI did need cleaning (it was all clogged) it still didn't solve my problem, so I'm back to

 

One other thing, the truck is running really hot, floating somewhere around 250 degrees, is this because there is air still in the system? I'm gonna check the radiator tomorrow morning, just want to know if this is normal after draining the coolant.

 

I have until 10-19-07 before the suspend my registration

Anybody have a clue , feel free to share.

[ChevyTech007]

Sounds like a restricted catalytic converter. Use a back pressure to verify. I have seen it before. When the EGR opens, too much exhaust goes in if the pressure is too high.

[luminaapv3]

I've heard of doing this, but am not sure exactly how! Is this done by hooking up a presure guage to one of the throttle body vacuum lines? or am I way off?

[ChevyTech007]

You can buy a gauge that screws in place of the O2 sensors. Just make sure you test in front of the converters.

[luminaapv3]

You can buy a gauge that screws in place of the O2 sensors. Just make sure you test in front of the converters.

 

 

I hooked a pressure guage up to the PCV port on the throttle body, heres the results:

(This is with the egr valve unhooked at the valve)

Idle: 20 in-hg (holding pretty steady)

about 2000 RPM's: approx.22 in-hg

released and it jump to 25 then to 20 again

 

(This is with the egr valve hooked up)

Idle: 20 in-hg (holding pretty steady)

2000 RPM's: somewhere around 10-15 in-hg (fluctuates a lot when truck is doing its boat motion on the way up to 2000 RPM's, goes from 5-15 in-hg)

released and it will go back to 20

 

From what I read this means I have a restriction in my exhaust somewhere, which I'm assuming is the catalytic converter, because the rest of the exhaust from the cat back looks fairly new.

 

Also my truck is running HOT!

 

What do you all think?

[Draenor]

If the cat is clogged, the EGR is recirculating extra hot gasses, which could be why your running hotter than normal.

 

 

 

 

 

 

....You must love this burb, to be doing all this. I give you credit, and some tylonal for the headache you must have.....

[luminaapv3]

If the cat is clogged, the EGR is recirculating extra hot gasses, which could be why your running hotter than normal.

 

 

 

 

 

 

....You must love this burb, to be doing all this. I give you credit, and some tylonal for the headache you must have.....

 

I do like this burb a lot, I bought it for $1,100 bucks, figured if I put a grand into it over time it will be worth it.

I want to be able to take my family on vacations, like camping, without being all squeezed together and no room for supplies (I have 4 kids plus the wifey), I have a dodge durango, but it's too small for all of us to go comfortably!

 

Anyways I think it's the cat too, do you know of any other ways of testing this thing, I don't have anything to screw into a oxygen sensor port.

I was thinking the same thing with the egr recirculating hot gases, but the strange thing is that it didn't do this before the intake manifold gasket change! I started questioning my work until I took a look at a new gasket from autozone and compared it to the parts of the gasket I could see showing from underneath the manifold and it looks good to me.

One other thing is now the top radiator hose doesn't become hot until the truck is ready to blow (red zone on temp guage).

Water pump go out on me during the change? Too much air in the system? I've been bleeding it for two days and it seems ok. I did notice the antifreeze reserve filling up, but assumed that was because engine was too hot.

As for the aspiran I just until it goes away! Although I am close to putting it on Craig's list if it doesn't start acting right!

O'well any more advice will be appreciated.

[luminaapv3]

By the way does anyone know what temp these trucks should be running at? What reading on the temp gauge in the cluster.

[luminaapv3]

s**t, I almost forgot, the truck gets hot when the egr is plugged in or not plugged in.

[496 XL]

By the way does anyone know what temp these trucks should be running at? What reading on the temp gauge in the cluster.

 

This depends on what temp thermostat you installed,(usually around 180-190). I think I would put another new name brand thermostat

in,sounds like it's stuck closed,or remove the old one and put it in a pot and bring it up to around 200-220 degrees(you have to have a good oven temp gauge) to verify that it is open or closed.Thats the first thing I would start with pryor to diggin deeper.

 

Hope this helps,

rgds,

Perry

[luminaapv3]

By the way does anyone know what temp these trucks should be running at? What reading on the temp gauge in the cluster.

 

This depends on what temp thermostat you installed,(usually around 180-190). I think I would put another new name brand thermostat

in,sounds like it's stuck closed,or remove the old one and put it in a pot and bring it up to around 200-220 degrees(you have to have a good oven temp gauge) to verify that it is open or closed.Thats the first thing I would start with pryor to diggin deeper.

 

Hope this helps,

rgds,

Perry

 

 

I'm already on my second brand new thermostat. I changed out the new one, even though I knew it wasn't the problem, but just to make sure it didn't get damaged while I was repairing the intake manifold i changed it anyways, only a couple of bucks. This one was rated at 193 degrees.

I was wondering if anybodys truck ran in the 200's or does the needle point straight up to the 210 mark, or just before it?, just after it?????

A general reference is what i'm looking for.

And does anyone know how to test if your water pump is dead?

[atboley]

You gotta buy an adapter to screw into one of th o2 sensor holes, you should have little to no restriction b4 the cats... that will tell you right away a cat is plugged... you could get a gage with adapters for cheap, after all you have done, you might as well try it...

[496 XL]

Other than a possible plugged exhaust,hows your timing and have you checked to see if the distributor bearing is worn,this could cause your timing to be thrown of causing the stumbling and heat.Just a thought.

 

rgds,

Perry

[496 XL]

Other than a possible plugged exhaust,hows your timing and have you checked to see if the distributor bearing is worn,this could cause your timing to be thrown off causing the stumbling and heat.Just a thought.

 

rgds,

Perry

[luminaapv3]

Other than a possible plugged exhaust,hows your timing and have you checked to see if the distributor bearing is worn,this could cause your timing to be thrown of causing the stumbling and heat.Just a thought.

 

rgds,

Perry

 

 

I checked the distibutor bearings when I pulled it and they look good, as for the timing I hooked a timing light up to it before and I think it was fine, I'm gonna check it again just to make sure though.

If it is off how do you correct it?

As for the adapter I'm gonna see if I can find one that will hook up to the vacuum gauge I have now, I don't want to buy a whole new setup, I really don't have the loot for it right now. Is there an adapter or am I shot up?

I can fix anything if I know what's wrong, but testing is my weak point.

thanks for all the help.