Old, New guy, with Old Problems

[Ripsaw]

They sold me a tube at the auto parts and got that done.

Replaced the badly leaking power steering pump. Wish I could get my hands on the research and developement team for Chevy that designed that, so I could choke them to death.....

Reset the timing right this time at 0 degrees and idling with wire off, then hooked it back up and it runs and idles well.

Took it half mile up the road, and now it stumbles and is rough at low rpm's and when I call for fuel. Got it to 45 finally and sped up, and it seems to have power now at higher rpm's. Exact opposite of yesterday.... Good a low, bad at high speed.

When I hooked the set timing wire back up, it advanced about a 1/2'' above the 12 degree mark.....you think I need to just fiddle with the timing some more and double check it, or run it awhile and let the computer reset or something ? I have a lot of patience, but it is starting to get on my nerves. I think tomorrow morning, I will seafoam it like you said, ...I bought a can of it today and have it ready. Ohh, the intermitent miss is gone now too. But stumbles and bogs on take off in normal stop and go driving. I don't think it is a fuel problem though, acts like a timing problem.....but then, what do I know...

One more question if you please...when doing the timing, and hooking and unhooking the set timing wire, should the engine be running or off ? Reason I asked is I didn't want to do any damage to the circuits. I had it running, and unhooked it to set timing, and it popped fire to the other side of the lead. Is that normal or am I messing up again ? Again, many thanks for any help in this matter....best regards...rip.

[ChevyTech]

I agree with you one the power steering pump. Another GM design disaster. And the pump failure rate is to high.

You should not have to move the timing once it is set right. The electronic spark control system will move the timing where it determines is best.

I have always disconnected the timing wire with the engine off thinking it is safer for the electronics.

Run the Seafoam through it, and drive it a bit, before you change anything else. The computer has some relearning to do.

With the key OFF if you unplug the ECM fuse/fuses the trouble code should be cleared in ten seconds. Disconnecting the battery is how many people clear the memory.

If the stumble does not go away, you can try disconnecting the vacuum hose to the EGR valve, and take it for a test drive.

Fuel pressure could still be a issue.

[Ripsaw]

Ok, that's the plan for tomorrow, thanks bud !

Will keep you posted of developements. Keep your fingers crossed for me, and I will buy a fuel pressure gauge.

Don't be at all surprised, if after I shoot in the Nationals at Camp Perry in Ohio in the summer, I show up on a road trip to Minnesota to throw you party ! ......wintertime, no way......heh heh heh.... all the best.....rip.

[Ripsaw]

Boy, this just keep getting better and better. I foamed it half can, let sit, finished it, went around the block, acting starved for fuel on take-off, still stumbling, got code 34
MAP sensor(voltage low)
MAF sensor

Then the battery light came on, checked voltage output from alternator, zip, zero, nada. The bearing was sounding off a little, then nothing. I guess all the time that power steering pump was slinging fluid, it messed it up internally, or the bearing just gave way. Off to get another one. I guess the alternator not working would make it code 34 for low voltage to map sensor ?
From my reading, I also take it the map sensor is a must for proper fuel and air and pressure to ebe right for the computer to run it all correctly ? Thanks...

[ChevyTech]

Fix the alternator issue, clear the code, and see if it get set again.

You can do a little testing of the MAP sensor voltage.

A normal Map sensor reading on the wire that connects to terminal “B” (possibly Lt green) would be 1 to 2 volts at idle. With no vacuum to the MAP sensor the voltage should go to at least 4 volts.

A low voltage on the MAP sensor reading would indicate to the ECM that the engine has high vacuum.

This would cause the mixture to be go lean.

[Ripsaw]

Originally Posted by ChevyTech

Fix the alternator issue, clear the code, and see if it get set again.

You can do a little testing of the MAP sensor voltage.

A normal Map sensor reading on the wire that connects to terminal “B” (possibly Lt green) would be 1 to 2 volts at idle. With no vacuum to the MAP sensor the voltage should go to at least 4 volts.

A low voltage on the MAP sensor reading would indicate to the ECM that the engine has high vacuum.

This would cause the mixture to be go lean.

Well,... replaced the alternator, code set 34 again, replaced the map sensor and code cleared, and went cruising. It took a couple miles to start acting right, then it seemed to clear up and do well. Then I got to higher RPM's around 45mph when it went in high gear, and it started pulling left real hard, and the engine seemed to struggle with power.

I thought the old dry rot tire was going down, but of course it couldn't be that simple. The truck has set up for a while and the hose to the left front caliper was dissentigrating or collapsed, and locked the caliper up. I smelled burning and felt heat at the wheel, had a little smoke as I pulled over. In the middle of nowhere, just like everywhere around here is. The truck sat and idled perfect at 600rpm's while I waited for the rotor to cool some. Had a smoke and decided to crawl under there and break the fitting loose so the pressure would release, or try too. It worked and I sat a while longer and eased home without using any brakes.

Just the way it's always been with me, fix one, and another goes. I will fix that tomorrow and get back with you when I have had time to give it a good road test for a few days. Many thanks again,... and for the map voltage and test info. It is good to know so when my 89' 4x4 starts falling apart too. The 91' has 211K, and the 89' has 202K on it.....only a matter of time......best regards...rip.

[Ripsaw]

Hey ChevyTech and guys, I just wanted to report, I rechecked the timing, and I guess that dual roller racing chain and gears I installed, had some stretch in it from the factory. After running 12 miles, it was off 2 degrees.

As you may remember, first I timed it with 1200 rpm's, then I re-did it right, at first it had all kinds of power from 0-45, and a dog any higher, after re-doing it, it had no power 0-45 and all kinds of scat at high rpm's.

I checked it again out of curiosity and it had moved 2 degrees. I reset it, and all is well. Stretch is all I can think of it was. Anyway, it runs fine now, thanks to your help. She still bogs when I call for fuel when cold or first starting up, but clears up quickly in about 20 seconds. I think it hasn't been driven enough yet and still has some questionable gas in the tank. Mixed 20 gallons of fresh with it to help that. Maybe the computer is still relearning how to run it all after how screwed up everything was. I have only driven it 21 miles to date, and only gotten up to 60mph once so far. Still haven't gotten a fuel pressure gauge yet, but do intend to do so. Hope everyone has a happy holiday......regards, ...rip.

[ChevyTech]

A double roller timing chain should not be stretching.

I hope you soaked it in oil before you installed it.

The base timing on these engines usually stays where it is set and does not need to be adjusted again.

[Ripsaw]

Originally Posted by ChevyTech

A double roller timing chain should not be stretching.

I hope you soaked it in oil before you installed it.

The base timing on these engines usually stays where it is set and does not need to be adjusted again.

I did soak it overnight in a pan. It may have been my mistake when originally setting the timing too. I marked the notch on the harmonic balancer with a white paint pen, and it got a little wide when it ran some. I wiped it with a rag and it smeared pretty wide. When I did it the last time, I sanded off the paint to a thin line and reset timing, so that was probably it.

As an aside, I went out this morning and cranked it up, and she fired right off, but still wants to stumble and faulter and not idle when cold starting. After a few minutes as temperature climbs, she idles perfect. I can idle it up and perfect while not in gear. When I drop her in gear to go, and dod not push the throttle, she pulls away at idle perfect. When I push the gas pedal to go, she bogs.

This thing is driving me nuts. No codes at all now. I have a new throttle positioning sensor, and will get the pressure gauge for the fuel and check the hose in the tank for cracks and replace it first. I am really at a loss here now over this truck and the way it acts. The test drive the other day went fine. I am beginning to think it is something internal. The intermitent miss was back this morning when cold starting, but went away after a few minutes.

I fear a valve in number 3 is bad, and heard a tap going on before changing the oil. Either that or the cam has a worn lobe on it. Sometimes at about 45mph when I call for gas, she stumbles and acts like she wants to backfire, then catches up and is fine. Had a bad cam that acted like that one time....heck I don't know anymore...I swear.

[ChevyTech]

Definitely check the fuel pressure.

Take a test drive with the EGR disconnected.

When a cam lobe is going flat it is hard to diagnose until the lobe has a lot of damage.

If an exhaust lobe gets flat, it will pop back through the intake when the throttle is cracked wide open for a split second, while in neutral, with the air cleaner removed.

I had a friend that asked for some ideas on his truck after he did a full tune up replacing all ignition parts. After I heard it run, I told him to remove the air cleaner and start it. The popping out the intake was extreme. He had not run it with the air cleaner off to notice the popping. One of his exhaust lobes was so flat the rocker arm had almost no movement.

If an intake lobe is getting flat it is not as easy to find and a flat lobe does not show up well when doing a compression test.

It is so easy to take the rocker covers off on these TBI trucks, to me the easiest way to check for a flat cam lobe is to remove the rocker cover and check the rocker movement. You can disconnect the ignition coil primary wires and unplug the injectors so it does not start and squirt oil everywhere or supply fuel.

If there is valve-train noise, the knock sensor can detect this a pinging, and cause the timing to retard.
Something loose rattling on, or in, the engine, like lifters, cam, rod, crank and piston noises all have the potential for causing false knock signals to be produced.

When these truck have head gasket failure, a compression test shows the problem. Usually these trucks ping, when the engine is hot, when the head gasket fails between the center cylinders.

[Ripsaw]

Originally Posted by ChevyTech

Definitely check the fuel pressure.

Take a test drive with the EGR disconnected.
I did, it knocked and clattered like crazy, had to hook it back up ?????

When a cam lobe is going flat it is hard to diagnose until the lobe has a lot of damage.

If an exhaust lobe gets flat, it will pop back through the intake when the throttle is cracked wide open for a split second, while in neutral, with the air cleaner removed.

It did pop back through originally, and the whole reason I replaced the timing chain originally. I thought it was a timing problem. That and the incessant surging up and down when idling. Incidently, it is still doing that surging up and down in idling when cold start, then subsides when it warms. ???

I had a friend that asked for some ideas on his truck after he did a full tune up replacing all ignition parts. After I heard it run, I told him to remove the air cleaner and start it. The popping out the intake was extreme. He had not run it with the air cleaner off to notice the popping. One of his exhaust lobes was so flat the rocker arm had almost no movement.

If an intake lobe is getting flat it is not as easy to find and a flat lobe does not show up well when doing a compression test.

It is so easy to take the rocker covers off on these TBI trucks, to me the easiest way to check for a flat cam lobe is to remove the rocker cover and check the rocker movement. You can disconnect the ignition coil primary wires and unplug the injectors so it does not start and squirt oil everywhere or supply fuel.

I will do this after fuel pressure check and hose replacement in the tank.

If there is valve-train noise, the knock sensor can detect this a pinging, and cause the timing to retard.
Something loose rattling on, or in, the engine, like lifters, cam, rod, crank and piston noises all have the potential for causing false knock signals to be produced.

Yep, I read that in your post on other threads. And number three definately had a lifter tapping previously. Maybe it is still happening and I just cannot hear it with fresh, thicker, clean oil in it now. Old Indian trick taught me by my Father, I listened with an old cut-off broom handle on the valve cover at each piston location to find which one it was.

When these truck have head gasket failure, a compression test shows the problem. Usually these trucks ping, when the engine is hot, when the head gasket fails between the center cylinders.

Ohh Lordy, don't even go there. I have a sneaking suspicion I will be going through this engine entirely before this is all over. I refuse to let this thing whip me. Been thinking about a 454 in it anyway.

Thanks for all the latest info and tips. Will keep you posted of what I find.
Merry Christmas to all......rip.

[LynnJr]

RipSaw
I just read your post above were you are going to Camp Perry.In 2010 I was the nbrsa 1000 yard national champion who got cheated by the leadership do to the errant rain call.
Lynn

[Ripsaw]

Originally Posted by LynnJr

RipSaw
I just read your post above were you are going to Camp Perry.In 2010 I was the nbrsa 1000 yard national champion who got cheated by the leadership do to the errant rain call.
Lynn

Yeah, it happens. I have many issues with the CMP and the NRA because of antiquated rules and nonsense. Congrats anyway on a heck of a title. That's tough to do. I regularly shoot at 600 and 800 yds. and am working on loads for 1000 yds. with my M14. Hard to do as well. The 155 palmas caught my attention for awhile and I juiced them up mucho hot, but the big Bergers will be the ticket.

I was the one that put the M14 back on the line for the first time since the 60's. I assembled and sent two six man fire teams to compete in the National Trophy Infantry Team (rattle battle) with the M14's. Last year was the third year in a row. The Marine teams are now talking about fielding a team of M14's, and the Army Marksmanship Unit too, in the rattle battle. It originally started as a way to get some attention about our guys getting whacked in Afghanistan and Iraq because the M16 wasn't cutting it at extended ranges. The M14 fixed that problem when they started re-issueing them. Hajji keeps his head down now......best regards....rip.