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Username Post: Code 44 HELP        (Topic#174515)
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-11-07 10:29 PM - Post#1294004    

I need help ruleing out issues.

The only code the van reads is a code 44..... lean condition........ resetting and driving it again.............. it comes back reading a code 44 again.

It's about driveability problems on a Chevy van. It has a 350, not sure of the year, but it has a TBI on it........ late 80's early 90's???

Unfortunately, I cannot easily communicate with the owner............. she has no phone and she must call me.

It runs ruff when driving and accellerating.
When I first started the cold engine today, the idle was wandering on a regular basis....... up down up down up down up down and finally steadying out at around 15 inches of vacuum a few minutes later as the engine warmed up.
At this point, the engine was steady as a rock on the vacuum guage 15 inches. I figure for a stock engine it ought to be closer to 18 or so. It never got to that point.

After warming up a little more, the idle became more erradic............. up and down, up and down, up and down. At this point, the vacuum guage was wandering from 12 to 15 inches, maybe 11 to 16.
We went for a ride........ engine cover off, and vacuum guage still attached.
It was very hard to get to 35 mph. I feathered the gas pedal as if it was a carbureted engine to get the speed up. Got it up to 45 or so before I came to a stop sign................ we went back to the house from there and it ran 10% better........... very crappy.
Once fully warmed up, she said it will gradually make it to 55 MPH so she can make it 10 miles to work driving on the highway.

OK, not being on the highway during my testing, the vaccuum reading ranged no more than 10 inches, even on flat ground at a steady 35 mph. I bet the vacuum on this stock van should be at 20 inches or more under this condition.
On very light accelleration at low speeds, (10 to 30mph) the vacuum reading was extremely low..... between 1 and 4 inches.......... steady cruising on flat groud at 3 to 4 inches of vacuum is just unreal............. it should be at 20 or more with such a light load. I am baffled.

Air cleaner, plugs, wires, cap and rotor, O2 sensor and fuel filter have been replaced. With a week of highway driving, the new plugs do not look overly lean...... they look pretty good..... Meaning not carboned up, nor blistering white. Mostly white with the usual dark patch on ones side of the ceramic............ Like I said... they look right for a 7 day old plugs.

I could find no vacuum leaks including the manifold or hoses.
Upon checking the rocker arm cover holes where the PCV and breather are, I could actually see a slight pressure build up when I temporarily plugged them both.............. indicating to me, a normal condition for a engine with over 100,000 miles on it........... this meant no internal vacuum leak.


The engine never runs completely normal........... once warmed up, it can run crappy, or it can run much better than crappy.................... the engine runs better or worse depending on it's "mood", not the actual driving conditions. Never does it run "normal"
........... it takes a while to get it up to highway speed................. and once at highway speed, the gas pedal seems to be the ticket to maintaining that speed.............. keeping it steady or even feathering it lightly so it will remain cruising steadily.

It's not always predictable how it will idle, or how it will run.............. she crosses her fingers every day............. and I am not much help because of my lack of knowledge of computers, sniffers and TBI systems.

I was thinking a timing chain jump............. If so, could it idle at 15" of vacuum .....steady as a rock?
If so, why the fluctuating idle and backfiring at times once warmed up and driven?

I have not checked the fuel presure, tho she says the fuel shows a nice "umbrella" shape exiting the TBI injectors when running.

Timing chain?
TBI injectors need cleaning?
Bad computer?
I think the EGR is OK............. it functions fine under idle conditions.
Can the fuel pump cause these irregular symptoms?


I probably don't have enough info for you guys yet, but this is a start.

Like I said, I don't know the year of the van. She said the plug gap is supposed to be .035 according to the Haynes manual........ if that helps identify the year.

Any feed back at all will be appreciated. I am lost on this one.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


Edited by ranman on 11-11-07 10:45 PM. Reason for edit: No reason given.

 
55chevy383 
Silver Supporting Member
Posts: 1306
55chevy383
Age: 46
Loc: Noble, Ok.
Reg: 12-08-05
11-11-07 10:53 PM - Post#1294014    
    In response to ranman

I'm thinking bad injector, or the fuel pump is going out and not yet completely gone. Just my guess.

Phil
11.66 @ 115 N/A.
Phil's '55


 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-12-07 12:30 AM - Post#1294058    
    In response to 55chevy383

She said the spray pattern looks good....... but that's only by eyeballing it at idle............. not very safe way to anylize the injectors either.

Injector screws are buggered up, so we need a couple new screws before the injectors are taken out and cleaned.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


 
sgian 
Valued Contributor
Posts: 4551
sgian
Loc: MO
Reg: 12-25-03
11-12-07 09:34 AM - Post#1294233    
    In response to ranman

If you haven't already done so, you might try some fuel injector cleaner in the gas tank and some good quality gas brand like chevron at next fillup. I've noticed a big difference at times between gas brands (especially when it is a brand that adds ethanol or something to the gas). I had one FI Mazda that would do something similar, I had to add a bottle of techron to the tank every couple months.
90 C1500, 05 Tahoe 4WD


 
IgnitionMan 
Valued Contributor
Posts: 2664

Reg: 04-15-05
11-12-07 10:36 AM - Post#1294275    
    In response to sgian

If the engine has a large number of miles on it, then, code 44 is indicating the O2 sensor is seeing massive lean. It may or may not be a one part physical issue. some code books will tell you the part that is reporting, but not the cause of the report, as in code 44, leak someplace else other than the O2 sensor.

I'd check for any and all air leaks, including at every rubber line and the plastic hard lines, as heat will make them break easily. And, take a close look at the EGR valve, it can have just enough carbon buildup to cause the valcv itself to not completely seat, not blocking the vacuum off correctly.

My 1982 2.8 V6 S10 had a serious miss at cylinder 6 one year while waiting for its California smog check. I thought wire/plug, intake/exhaust valve leaking badly, and it had a code 44. It turned out to be the EGR valve not seating, new valve, blasted right through the smog inspection, miss gone.

 
Vaughn 
"12th Year" Gold Supporting Member
Posts: 15387

Loc: Colorado Springs, CO
Reg: 08-08-04
11-12-07 12:32 PM - Post#1294343    
    In response to IgnitionMan

Probably a bad EGR valve or vacuum leak.

Also check/replace MAP sensor.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-12-07 03:31 PM - Post#1294460    
    In response to Vaughn

Can the EGR be temporarily blocked off? She has spent a lot so far and can't afford to keep replacing parts.
I really appreciate the info guys.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


 
The_Hunter 
Contributor
Posts: 983
The_Hunter
Loc: Manitoba, Canada
Reg: 02-14-05
11-12-07 05:04 PM - Post#1294515    
    In response to ranman

EGR can be disconnected, the check engine light will turn on after about 5-10 minutes of steady driving.

I disconnect the vacuum source to the EGR solenoid.
86 C10 Short Box

Computers are like air conditioners - They can't do their job properly if you open windows.


 
fritz1990 
Senior Member
Posts: 6397
fritz1990
Age: 52
Loc: Kansas
Reg: 02-16-03
11-12-07 05:06 PM - Post#1294517    
    In response to The_Hunter

Yea but if there is carbon etc. under the valve it will still cause a leak.

Regards, Jeff
1998 K1500 6.5 Coal burner
1965 C10 with 498 BBC AFR Heads
1964 C10 Ran 348W for 6 years, now SBC.

Corvettes owned: '74 '77 '78 L82 Silver Anniversary, 2002 LS1

Don't have a nervous come together!

http://picasaweb.google.com/fritz199090


 
IgnitionMan 
Valued Contributor
Posts: 2664

Reg: 04-15-05
11-12-07 07:18 PM - Post#1294610    
    In response to fritz1990

Pull the valve off the engine and take a look at the plunger and seat. It's only a gasket if the valve isn't bad. If it is, block it until the lady can afford one. EGR valves usually don't cost the National Debt of some small country, they are relatively inexpensive.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-12-07 09:06 PM - Post#1294705    
    In response to IgnitionMan

It's about 45 to 60 bucks for an egr here........ not sure which one of those models she needs.
To a single working mom, that's a chunk of change............. especially considering all the other fixes she has done in the past month ......... with zero results.
Air filter, pcv valve, fuel filter,
cap, rotor, wires, plugs, O2 sensor.... I know I am missing a few things.
Worst probem is she lives 15 miles away and has no phone. If she lived next door, I could experiment with it when I get home from work each night.
Once again.............. I am absorbing the info, and more is better...................... because ecventualy, I will look like I am smart!
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


 
IgnitionMan 
Valued Contributor
Posts: 2664

Reg: 04-15-05
11-13-07 11:31 AM - Post#1295029    
    In response to ranman

OK, to check the EGR valve for leaks, pull the vacuum hose off it and with the engine just fired up, reach under the diaphragm and lift it upwards in its body. If the engine performance DOESN'T change, valve is bad and leaking, does change, the engine should stall or come close to stalling, valve is OK as far as the diaphragm and seat.

The lady would need to have a friend do this, wearing a glove. Although I have cleaned EGR valves with bead blasting, some may not like that.

On later GM vehicles (my '82 carb'd S10 V6 had one), there is also a valve on the manifold that controls vacuum to the EGR valve, with electronics activating it, could be bad. I think some of the earlier TBI systems used this EGR solenoid as well. I can't remember the exact procedure to check the solenoid, but I seem to think it is to activate the electrical part, and see if vacuum passes through the valve, disconnect, no vacuum.

Edited by IgnitionMan on 11-13-07 11:32 AM. Reason for edit: No reason given.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-13-07 09:29 PM - Post#1295389    
    In response to IgnitionMan

  • IgnitionMan Said:
OK, to check the EGR valve for leaks, pull the vacuum hose off it and with the engine just fired up, reach under the diaphragm and lift it upwards in its body. If the engine performance DOESN'T change, valve is bad and leaking, does change, the engine should stall or come close to stalling, valve is OK as far as the diaphragm and seat.

The lady would need to have a friend do this, wearing a glove. Although I have cleaned EGR valves with bead blasting, some may not like that.

On later GM vehicles (my '82 carb'd S10 V6 had one), there is also a valve on the manifold that controls vacuum to the EGR valve, with electronics activating it, could be bad. I think some of the earlier TBI systems used this EGR solenoid as well. I can't remember the exact procedure to check the solenoid, but I seem to think it is to activate the electrical part, and see if vacuum passes through the valve, disconnect, no vacuum.




With the vacuum line hooked up, I did reach under the valve with one hand and pull upwards a tad, the idle got slightly worse. I did not use both hands, nor did I apply a lot of pressure. The idle was runnning at a very steady 15 inches, and the engine was still warming up............Being a stock engine, I think it should have run closer to 18 or 20 inches even with just 4 or 5 minutes of run time from a cold start. It was a good 60 degrees outside, so cold weather was not an issue.

There is a restriction type valve in the line going to the EGR. It is brand new. I assume it is a restricted orifice of some kind for delaying the vacuum signal. I didn't see a solenoid type valve like you mentioned.

If this engine jumped a tooth on the timing gear, could it act this way? .......... or would it simply not run? Like I said, the engine at idle ran a very steady 15 inches............ only after after warming up did the vacuum start to alternately rise and fall. (from 16 to 12 or so)
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


Edited by ranman on 11-13-07 09:31 PM. Reason for edit: No reason given.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-13-07 10:54 PM - Post#1295442    
    In response to ranman

Pinto Ho............
Um.... I mean "this lady I know"

Called me tonight. ....... and I need your help more than ever.
She called me to say that the van runs fantastic. She had not started the rig since we messed with it on Sunday. It was running crappy as ever when we shut it down.

Here's what we know.

The van runs perfectly fine now .......providing the heater fan switch is in the off position, and the vent selector to the heat/defrost is in the off (closed) position, and the temp control is also in the closed (left) position.

Got that?
Heater fan switch off
Temp control and heat/defrost control arms slid to the left, or closed positions.

WHAT HAPPENED HERE?????? It runs fine now, and not only that, but the horn now works! It didn't work before. She even thinks the transmission shifts better.

She told me tonight that on Sunday as we were messing aroud, that I slid the heater and vent controls closed.
I don't recall doing that, but if I did, I am a freekin genious.

What could those switches have done? I am guessing a grounding issue which still needs fixing.
Also, do the heater switches use a vacuum diaphram to open and close vents? I am still wondering about vacuum leaks being an issue.

At the moment this is a happy day.......... but somthin' still needs to get figured out here. We don't need this problem re occuring on a cold rainy night 10 miles from home.





~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


Edited by ranman on 11-13-07 11:00 PM. Reason for edit: No reason given.

 
IgnitionMan 
Valued Contributor
Posts: 2664

Reg: 04-15-05
11-13-07 10:56 PM - Post#1295443    
    In response to ranman

That makes no sense. Unless the heater controls electrically alter the computer, and/or moved a wiring harness under the dash, not likely.

Edited by IgnitionMan on 11-13-07 10:58 PM. Reason for edit: No reason given.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-13-07 11:03 PM - Post#1295448    
    In response to IgnitionMan

Yer darn tootin it makes no sense.......... that's why I am askin'
The van had barely run for a few weeks now.

The only thing she did after I left was to re install the engine cover.

It sat all day Monday, then today it ran like a fine Swiss watch. I recall the her saying that the mud on the mud flaps looking to be in the shape of Jesus. I made that part up.........
This is quite baffling.

The van, by the way is an '88 1/2 ton.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


Edited by ranman on 11-13-07 11:14 PM. Reason for edit: No reason given.

 
55chevy383 
Silver Supporting Member
Posts: 1306
55chevy383
Age: 46
Loc: Noble, Ok.
Reg: 12-08-05
11-14-07 06:52 AM - Post#1295551    
    In response to ranman

This is a long shot, but maybe a short somewhere with the heater fan effecting another circuit?

Phil
11.66 @ 115 N/A.
Phil's '55


 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-14-07 09:02 AM - Post#1295620    
    In response to 55chevy383

Hey guys, I just thought of one more thing.

She did, during all her attempts to fix the problem, install a new cap and rotor. It made no difference.

Last thing during our testing, was for me to take a peek inside the cap. I had never seen the insides of a distributor like this. I am only familiar with points and HEI distributors.
Once more, the van is an '88
Anyway, I removed the cap and rotor to see if this funky distributor had some kind of mechanical advance. All I saw was a big brass ring or collar inside. It was movable, but you could rotate it clockwise or counterclockwise..... I'd guess about 10 or 20 degrees.

Once moved, he ring did not spring back into any particular position when I twisted it and let go............ it feels kind of gummed up inside. It did not take a lot of force to move it, but it looks as if it would hold itself in whatever position I left it in.

What does this collar do? ...... and how should it behave when I manually twist it one way or the other?
The repair manual did not mention or tell the function of this collar.
What is the name of this kind of distributor?

If messing with this collar was part of the fix, it doesn't explain why the horn now works.
The van is posessed I think.

She is going to play with the heater controls on the way home tonight just to see what happens.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


 
55chevy383 
Silver Supporting Member
Posts: 1306
55chevy383
Age: 46
Loc: Noble, Ok.
Reg: 12-08-05
11-14-07 09:54 AM - Post#1295649    
    In response to ranman

Is this kind of what it looked like?

Dist. Pic

I searched an '88 C10 Chevy 1/2 ton 5.7 ltr. van.



Phil
11.66 @ 115 N/A.
Phil's '55


 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-14-07 10:19 AM - Post#1295665    
    In response to 55chevy383

Looks different without the brass collar thingy on it. It looks similar, but not quite sure.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


Edited by ranman on 11-14-07 10:23 AM. Reason for edit: No reason given.

 
IgnitionMan 
Valued Contributor
Posts: 2664

Reg: 04-15-05
11-14-07 10:42 AM - Post#1295684    
    In response to ranman

If I am right, the "brass collar" is a shield for the magnetic pickup, below the rotor. It shouldn't interfere with regular operation. It does have a bit of movement in it, though, no problem unless it has cut the magnetic pickup wires.

 
Vaughn 
"12th Year" Gold Supporting Member
Posts: 15387

Loc: Colorado Springs, CO
Reg: 08-08-04
11-14-07 12:12 PM - Post#1295734    
    In response to IgnitionMan

Changing the heater controls would have activated or shut off various vacuum valves - affecting the amount of vacuum in the vacuum reservoir(s). It may have caused the vacuum to the EGR to be disrupted, or disruption of another control.

If shutting off the heater made that much difference - it could possibly affected the map sensor on the TBI unit. Since it no longer was drawing vacuum from the reservoir, there may have been sufficient vacuum to the MAP to make it run properly. This assumes that there would be a vacuum leak somewhere in the heater system.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-14-07 09:18 PM - Post#1296052    
    In response to Vaughn

  • Vaughn Said:
Changing the heater controls would have activated or shut off various vacuum valves - affecting the amount of vacuum in the vacuum reservoir(s). It may have caused the vacuum to the EGR to be disrupted, or disruption of another control.

If shutting off the heater made that much difference - it could possibly affected the map sensor on the TBI unit. Since it no longer was drawing vacuum from the reservoir, there may have been sufficient vacuum to the MAP to make it run properly. This assumes that there would be a vacuum leak somewhere in the heater system.



She said that't she'd probably call tonight and that she was going to play with the controls when she got close to home after work. If she calls, I'll update with new info.
She did mention a hiss sound when the heater control was in a certain position. I can't imagine a line that small making such a difference in the way it runs, but then again, I never though cows could fall from the sky either.


Ignitionman, that helps. I was thinking there might be some kind of a mechanical advance hidden under that collar. I still can't figure out why it has about 20 degrees of play built into it.............. that's why I thought it might have an advance mechanism inside it.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


Edited by ranman on 11-14-07 09:24 PM. Reason for edit: No reason given.

 
IgnitionMan 
Valued Contributor
Posts: 2664

Reg: 04-15-05
11-15-07 12:07 PM - Post#1296443    
    In response to ranman

Heater valves are vacuum operated, so...look there.

 
ranman 
"2nd Year" Silver Supporting Member
Posts: 10697
ranman
Loc: The cold wet and windy O...
Reg: 03-10-01
11-15-07 10:29 PM - Post#1296903    
    In response to IgnitionMan

Thanks for all the input guys. She hasn't called back, so I will update when I hear from her.
I assume the van is stil running better than ever.
~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
If plants ruled the world, would they regulate oxygen?


 
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