Old Blue - 1984 XL Flareside

[ckuske]

Just putting my recent thread here in here so I can look through this all later, or others can laugh ;)

In other news, tried to start the truck after finishing the wiring and clean KOEO. Wouldn't start... started for a second, died. Start for a second, died. Repeatedly. It was acting like it was starved for fuel. It finally started after my battery was almost dead. When it did start and stay running, it had a serious miss and RPMs were wondering all over the place. I was afraid I had munged something in the wiring work.

I ran code reader again - KOEO still clean, but continuous memory now says MAP sensor is bad... (Code 31). Probed the connector. Power is good (5v), ground is good - no pulses coming out of signal wire (0 Hz, should be around 150 Hz with normal atmospheric pressure). Signal wire is outputting 2.5 volts. I assume this sensor uses pulse code modulation... It *was* working...

Ordered a new one, hopefully that gets it running smoothly. Will check signals again (and vacuum line to be sure) before I even try to start it...

Got my new MAP sensor in the mail (2 days early!).

I plugged it into the harness, tested with a vacuum pump. My meter immediately started recording a signal (~150 Hz). Old (barely used) MAP didn't report any signal on the green wire at all. Ran KOEO - Code 11. Cool, let's proceed.

Started the truck - started with about 3 seconds of cranking. So much better than the last time I tried! Let it run until it got warm. There is still an occasional stumble/miss, it "feels" fuel related still but nothing like it was before. It only does it on higher RPMs (like high idle). When I kick the idle down, it is diminished. That makes me think fuel delivery, but??? I think the truck needs to take a trip to the carb shop again.

Turned the truck off, hooked up the EEC reader. KOEO still 11 (yay), Continuous codes also 11 (Double yay). I'll run the KOER in the next couple days but I'm feeling good at the moment! If I get the "miss" diagnosed, I'm ready to shut the hood and move on to the rest of the truck finally.

[ArdWrknTrk]

Got my new MAP sensor in the mail (2 days early!).

I plugged it into the harness, tested with a vacuum pump. My meter immediately started recording a signal (~150 Hz). Old (barely used) MAP didn't report any signal on the green wire at all. Ran KOEO - Code 11. Cool, let's proceed.

Started the truck - started with about 3 seconds of cranking. So much better than the last time I tried! Let it run until it got warm. There is still an occasional stumble/miss, it "feels" fuel related still but nothing like it was before. It only does it on higher RPMs (like high idle). When I kick the idle down, it is diminished. That makes me think fuel delivery, but??? I think the truck needs to take a trip to the carb shop again.

Turned the truck off, hooked up the EEC reader. KOEO still 11 (yay), Continuous codes also 11 (Double yay). I'll run the KOER in the next couple days but I'm feeling good at the moment! If I get the "miss" diagnosed, I'm ready to shut the hood and move on to the rest of the truck finally.

Congratulations Chris!

Hopefully you can put the engine issues to bed

[ckuske]

Congratulations Chris!

Hopefully you can put the engine issues to bed

Thanks Jim! I couldn't take it, so I ran the KOER. Not great results:

43, 72, 73, 73, 42, 83

When I try to run the Dynamic Response test, my truck died three times before I got it to stay running through it (and I didn't give it as much throttle which caused its own problems, see below), and I got the codes above.

Most of these (especially 72 and 73) I can chalk up to the dynamic response test not being run properly.

Awhile back the accelerator pump started leaking - I replaced it myself and I'm pretty sure I ordered the correct one but I am wondering if I need to take that back apart and look again? It wouldn't address my "miss" issue, but could address the truck dying when I pour a good amount of throttle on...

[ArdWrknTrk]

Thanks Jim! I couldn't take it, so I ran the KOER. Not great results:

43, 72, 73, 73, 42, 83

When I try to run the Dynamic Response test, my truck died three times before I got it to stay running through it (and I didn't give it as much throttle which caused its own problems, see below), and I got the codes above.

Most of these (especially 72 and 73) I can chalk up to the dynamic response test not being run properly.

Awhile back the accelerator pump started leaking - I replaced it myself and I'm pretty sure I ordered the correct one but I am wondering if I need to take that back apart and look again? It wouldn't address my "miss" issue, but could address the truck dying when I pour a good amount of throttle on...

Remember, when troubleshooting to always start with the lowest number first.

It's easy enough to see if the pump is dribbling with the engine running.

Definitely something to check if you feel unsure about your previous repair.

[ckuske]

Remember, when troubleshooting to always start with the lowest number first.

It's easy enough to see if the pump is dribbling with the engine running.

Definitely something to check if you feel unsure about your previous repair.

Thanks for the tip on the lowest number!

After I replaced the accelerator pump, the leak stopped so I felt good about it. But, the throttle response seemed to be worse. That could just be my association of when it got worse, but it may be coincidental and there is something else at play. I remember having a hard time holding the housing to the carb body while trying to get the screws started - maybe the spring isn't seated right against the diaphragm???

[ArdWrknTrk]

Thanks for the tip on the lowest number!

After I replaced the accelerator pump, the leak stopped so I felt good about it. But, the throttle response seemed to be worse. That could just be my association of when it got worse, but it may be coincidental and there is something else at play. I remember having a hard time holding the housing to the carb body while trying to get the screws started - maybe the spring isn't seated right against the diaphragm???

If the spring we're not returning the diaphragm and pump arm properly you should be able to see that, right?

I'm not entirely familiar with how the pump's check ball and weight load into a 2150.

Does the lever have the correct gap, and is the cam screwed in the proper position?

[ckuske]

If the spring we're not returning the diaphragm and pump arm properly you should be able to see that, right?

I'm not entirely familiar with how the pump's check ball and weight load into a 2150.

Does the lever have the correct gap, and is the cam screwed in the proper position?

Right, it appears to work fine. When I replaced it, I just removed the four screws on the housing, removed the old pump, replaced it, then put the four screws back in to secure the housing to the carb again. The plunger returns properly when pressing down on it. I think all is well, but I am grasping at straws.

I'm going to try and run the KOER again today and let it warm up a bit longer and try the WOT test by going from idle to WOT a bit slower (not a jab, maybe try over two seconds or so and see if that computer is still OK with that, and see if some codes go away)

Either way, there is still some work to be done.

[ckuske]

Right, it appears to work fine. When I replaced it, I just removed the four screws on the housing, removed the old pump, replaced it, then put the four screws back in to secure the housing to the carb again. The plunger returns properly when pressing down on it. I think all is well, but I am grasping at straws.

I'm going to try and run the KOER again today and let it warm up a bit longer and try the WOT test by going from idle to WOT a bit slower (not a jab, maybe try over two seconds or so and see if that computer is still OK with that, and see if some codes go away)

Either way, there is still some work to be done.

I got the KOER test to run. The latest codes are:

20, 83, 93, 3, 4

I'm a bit stumped on the 3 and 4!

I called the carb shop that got the truck fixed about four years ago. Described the symptoms. Bill (the owner) was gracious enough to give me some things to try. He thinks the diaphragm on the carb may be leaking fuel into the intake. The carb was rebuilt ~4 years ago, and hasn't been used much. He thinks ethanol has probably eaten the rubber away in the diaphragm and other bits of the carb etc.

This would explain the O2 rich from the HO2S, the low idle, and stumbling.

He said as a test to try clamping off the vacuum hose from the power valve to the EGR - I did that and saw some improvement. So, the carb may be at fault.

He said I can either bring the carb to him, or bring the truck. To save labor $, how hard is it to remove/reinstall? There are lot of linkages etc and I'm a bit nervous I'd break something or not reattach properly. Any special tools needed?

Or, I may just chicken out and have the truck towed to him (it's currently registered as PNO, and I need my brakes done also...)

[ckuske]

I got the KOER test to run. The latest codes are:

20, 83, 93, 3, 4

I'm a bit stumped on the 3 and 4!

I called the carb shop that got the truck fixed about four years ago. Described the symptoms. Bill (the owner) was gracious enough to give me some things to try. He thinks the diaphragm on the carb may be leaking fuel into the intake. The carb was rebuilt ~4 years ago, and hasn't been used much. He thinks ethanol has probably eaten the rubber away in the diaphragm and other bits of the carb etc.

This would explain the O2 rich from the HO2S, the low idle, and stumbling.

He said as a test to try clamping off the vacuum hose from the power valve to the EGR - I did that and saw some improvement. So, the carb may be at fault.

He said I can either bring the carb to him, or bring the truck. To save labor $, how hard is it to remove/reinstall? There are lot of linkages etc and I'm a bit nervous I'd break something or not reattach properly. Any special tools needed?

Or, I may just chicken out and have the truck towed to him (it's currently registered as PNO, and I need my brakes done also...)

A little update:

Last time I ran the truck to temperature, the oil smoke coming from around the valve gaskets had gotten worse... noticeable for sure now. I retorqued the bolts to ~50 in/lb, tried again. Still smoking. Geez!

I got frustrated, and ordered some Fel-Pro PermaDryPlus gaskets. Put those on, did the whole procedure. Still smoking. Now I am just getting plain mad... lol. I took a walk, calmed down, and started it one more time and really paid very close attention to the area the smoke seemed to be emanating from. ("Above" the last bolt on the exhaust manifold, passenger side. I started recording video, sticking my phone down there to get as good as video as I could without burning myself. Then while recording, I saw a clue. I noticed a teeny tiny air bubble coming and going between the bolt, the washer on it, and the manifold.

I did some Googling and confirmed my basic understanding of engines (which is still nil compared to most in this forum). It seems like 90% of valve cover leak issues are due from debris on the gasket, overtorqued covers becoming warped, etc. But, there are a few issues on forums where the gasket is dry and there is still smoke coming out.

I got my torque wrench out and tightened the exhaust bolts. The suspicious bolt turned about half a turn before it even felt snug, then maybe a 1/4 turn to hit 24 ft/lb. Two other bolts turned a bit also.

All of that narrative to say... the smoke is much much reduced. There is still a whiff sometimes but it is hard to pinpoint and I am hoping it is residual that will go away.

Besides that, I'm trying to save some money up for the brake job. I'm not going to bother chasing the carb issue now, as the truck will just sit and get the carb damaged again while waiting for the brakes to get done before I can get it back on the road.

[ArdWrknTrk]

A little update:

Last time I ran the truck to temperature, the oil smoke coming from around the valve gaskets had gotten worse... noticeable for sure now. I retorqued the bolts to ~50 in/lb, tried again. Still smoking. Geez!

I got frustrated, and ordered some Fel-Pro PermaDryPlus gaskets. Put those on, did the whole procedure. Still smoking. Now I am just getting plain mad... lol. I took a walk, calmed down, and started it one more time and really paid very close attention to the area the smoke seemed to be emanating from. ("Above" the last bolt on the exhaust manifold, passenger side. I started recording video, sticking my phone down there to get as good as video as I could without burning myself. Then while recording, I saw a clue. I noticed a teeny tiny air bubble coming and going between the bolt, the washer on it, and the manifold.

I did some Googling and confirmed my basic understanding of engines (which is still nil compared to most in this forum). It seems like 90% of valve cover leak issues are due from debris on the gasket, overtorqued covers becoming warped, etc. But, there are a few issues on forums where the gasket is dry and there is still smoke coming out.

I got my torque wrench out and tightened the exhaust bolts. The suspicious bolt turned about half a turn before it even felt snug, then maybe a 1/4 turn to hit 24 ft/lb. Two other bolts turned a bit also.

All of that narrative to say... the smoke is much much reduced. There is still a whiff sometimes but it is hard to pinpoint and I am hoping it is residual that will go away.

Besides that, I'm trying to save some money up for the brake job. I'm not going to bother chasing the carb issue now, as the truck will just sit and get the carb damaged again while waiting for the brakes to get done before I can get it back on the road.

Be sure to check your PCV system all the way to the intake manifold.

If you see "bubbles" I suspect the crankcase is being pressurized.

It's possible the valve itself is free and the tube between valve and intake is clogged. 💡

The other possibility is that your rings are completely shot, but let's not go there yet...

A leak down test would show for sure, but not everyone has the tool and checking the external PCV components is quick, simple and inexpensive to replace.

Did you ensure the valve cover flange was flat before changing the gasket?

A lot of times people really overtighten the valve cover bolts and dimple the cover.

It will never seal properly if that's the case.