Meet Tatanka, my 99 Suburban K1500

[tedly]

Dizzy is back together, now might as well check the crank sensor. So I crawl my tubby butt under the truck and pull it out. There's an oil leak at the front of the engine, so everything up there is oil soaked. Not good, but not a lot I can do about it right now. Crank sensor is behind the harmonic balancer on the bottom of the engine. Can't see the damn thing when I have the tools and my hands up there to pull it, but easy enough to do by feel. Pop the electric connector, pull out the retaining bolt, and... It doesn't want to come out. Wedged in there tight as can be. Try rotating it to break it loose. No dice. Break out a small pry bar and pop it out in a few seconds.

Well, pop most of it out. The other piece comes out with some needle nose pliers. Crank sensors are supposed to be one piece, right?



Dammit.

Guess I'm putting in the new one after all.

It was a pain in the ass getting the new one in, but finally got it installed.

[tedly]

Before installing the new crank sensor, I did clean it up, look it over, and compare it to the new one. The cap showed a wear pattern, but there was no sign of contact with the reluctor wheel. Surface was smooth as can be even with the difference in coloration, running my fingernail over it with my eyes closed I could feel no ridge at all. So no end play on the crank, which would have brought the reluctor in contact with the sensor. Good news there.



New part is a different design, so I wanted to make sure it fit in the same spot. No difference in depth, they just changed the design. Good news there.

[tedly]

Drop the distributor back in, position the housing as close as I can to what it was when I pulled it (the computer adjusts the timing on these, you don't have to turn the dizzy for that). The mark and the rotor don't line up.

No problem, I'm a tooth off, just adjust. Pull it just enough to move it a tooth and drop it again. Mark is in between the first time I dropped it and now. Move it back where it was to check, sure enough. nothing lines up.

I made the mark when it was out of synch because the gear was worn.

Dammit.

OK, leave it here, put everything back together and start it up. If it doesn't start or runs like shit, just move it a tooth again. No biggie.

Got everything put back together and buttoned up. Crossed my fingers and crank it.

Spins and spins without even trying to catch. OK, no problem. Try it again just to be sure. Same thing.

Hop out, remove the intake, cap, and wires, pull the dizzy and advance it a tooth, reassemble and try again.

Same thing.

Great.

What did I f*#k up now? It ran when I pulled it in so it must be something I messed with.

With the time constraints it took another week before I could get back to it. Meantime I would research the hell out of everything.

[tedly]

One thing I did notice was no fuel smell from the throttle body when I took the intake off. Stuck a screwdriver in the #1 plug wire and held it 1/4 inch from a bolt, then had Keni turn it over. No spark at all.

No fuel, no spark, that means a computer kill code. I don't have a scanner and don't have the $140 to put as a deposit at a parts store rental program. Put out a call to my friends looking for a scanner.

Werner's got one. He can be here the next day. Sweet! We can hang out and screw around while being productive!

Next day he gets here early afternoon and we pull the codes. Crank sensor circuit. That would certainly send a kill code and not allow the engine to start. Brand new part, so why is it sending that code??? Pulled the sensor and made sure it didn't get gunk on it during install. Clean as a whistle. Was a pain in the ass getting it back in again.

Front of the engine is oil soaked, including the connector for the sensor. Maybe the connector is bad. Might be a short in the wiring harness as well. Pulled the connector and harness back to the main harness and split it open to inspect the wiring. No issues there, but the connector looks sketchy as hell with all the oil sludge on it. Lets replace that. 30 minute drive to the parts store, 30 minute drive back home and we swap the connector. $33 added, so total now is $1906.

Crank it again and...

Nothing.

This is really pissing me off.

OK, what haven't we checked? Lets make sure power is getting to the sensor. Bust out the voltmeter, and sure enough, everything is right in specs that we found digging around online.

That leaves one thing.

The sensor was bad right out of the box.

Take it out, 30 minute drive to the parts store, 30 minute drive back, install new one and it plops right in, no issues whatsoever.

Turn key on, let the fuel pump prime, and it actually does. We can hear it this time. Crank it for a few seconds, nothing. Then just as I'm walking over to grab the sledgehammer, it fires off and settles into a smooth idle.

I'd like to say that at this point I let out a barbaric roar of triumph that could be heard for miles, but in reality I probably shrieked like a schoolgirl and giggled like a lunatic for a few minutes.

[tedly]

Took it out for a test drive, and the old girl runs beautifully. No hiccups, no sputters, no misfire whatsoever. I floor it at 50 and we get pushed back in our seats as we hit 90 in no time and it was still pulling strong. Do an oil change and flush the next day to get as much metal out as I can.

I've had no issues with misfires since.

That problem is solved. Now on to the next.

[tedly]

while you're at it, pull the distributor and physically check for play - they're super cheap to replace, my rule of thumb, if something is super cheap to replace - it means it's been a problem. those plastic housings are not resilient. Also, you can have oil pressure issues if the housing is starting to go.

SBG, you are right on the money and looking in all the right places. This truck is becoming an exercise in frugality and a test of my diagnostic capabilities. If it works, I don't want to replace it until I have to. The $110 difference between the gear and whole distributor can go a long way to fixing other things right now. I'm taking the risk of the dizzy breaking soon, but I'm comfortable with how it was functioning when I pulled it. With a little luck it will last long enough.

[STINEY]

Thanks for documenting this adventure Tedly. Our '90 4.3 manual shift 1/2 ton 2wd has taken to hiccups (or lean mis-fires?) on occasion with no apparent pattern. Although lugging the engine by an early shift you can get it going almost every time, and if it does it once it will do it worse and worse once it starts.

And other times it never does it at all, on the same drive to work.

You have given me a place to start. Have already done the fuel inj cleaner and new filter, no permanent change although I did think there was a brief improvement after the filter. Might have been my imagination.



Your property is really cool....though I sympathize with your driveway. I grew up back a 1/4 mile drive - they definitely have their good and bad points.

[tedly]

Thanks for documenting this adventure Tedly. Our '90 4.3 manual shift 1/2 ton 2wd has taken to hiccups (or lean mis-fires?) on occasion with no apparent pattern. Although lugging the engine by an early shift you can get it going almost every time, and if it does it once it will do it worse and worse once it starts.

And other times it never does it at all, on the same drive to work.

You have given me a place to start. Have already done the fuel inj cleaner and new filter, no permanent change although I did think there was a brief improvement after the filter. Might have been my imagination.



Your property is really cool....though I sympathize with your driveway. I grew up back a 1/4 mile drive - they definitely have their good and bad points.

That sounds real familiar. Pop the cap and wires off and turn the crank at the pulley. Go back and forth. If there's a dead spot, you know what to do. For a long time the misfire was intermittent and showed no real pattern other than flooring it for a few seconds would often clear it up. The closest thing to a pattern was it got steadily worse until it was constant. It was infuriating.

[tedly]

I live on the end of a 1/8th mile private road. There are 8 houses on our road and my house has 100% of the 4x4s. I also have a tractor - I like most of my neighbors (and I like getting the mail when it snows) so I plow our road.... that said, it would need to be a pretty rough situation if I couldn't get out.

I'm at the point in my existence where, if the plugs are missing, I won't buy the motor. A bit of coolant isn't really a big deal but flushing the rearmost cylinders could really keep it going for a lot longer. Really that motor isn't in terrible shape, but the days of garden-variety gas in it is over. I also would consider running several injector cleaner bottles through it. Around here, a 6 pack of Chevron injector cleaner is 12 bux at Costco - I'd run them all through, maybe even doubling up after the first bottle/tank. Don't double the first one, if there's big stuff in the system, it will mess things up.... by the second tank, the big stuff is gone and what's left needs soaking to get loose.

Perfect plugs - should be a light tan color.

And to help you read what you have, consider:

Tan is perfect
Grey means light oil getting into the motor (including from a bad PCV)
Grey speckled means knocking (all of this is on the white part) - and this is, literally, aluminum being blown off the piston...
black means soot - running rich
shiney black means you're laying down a smoke screen
Red/Rust means water is getting into the cylinder
missing tip means lean
white means excess antifreeze/water (also white built up like a calcium deposit)

there's a lot more but those are the majors - you can tell how a motor is running by how the color changes from the tip to the base of the insulator. A proper running Vortec will have tan on one side and white on the other.... because it burns the mixture so well that the flame path doesn't make it all the back around the cylinder... pretty cool, huh?

Thank you for the info on plug reading! That is massively helpful!

As for the fuel system, funny you should mention that... It's had a couple cleaners run through it in the last year, and the next installment involves the fuel system.

[tedly]

On my way to work a few weeks ago, I stopped at the local gas station to get some caffeine. Jumped back in the truck, cranked it and nothing. It turned over but not even close to catching.

Dammit.

Tried it again. Tatanka has always fired off right away, no hesitation. Same thing. OK... Is the pump working? Turn key on engine off, and nothing.



Son of a...

OK, lets look under the hood. Coil wire is still attached solid. Nothing has worked itself loose. Nothing unplugged. Fuel pump relay is not the same as any other relay in the fuse box, so no swapping it out to check that. Oh this is going to be fun. After about 15 minutes it just randomly starts on the first crank, like nothing ever happened.

Great. Fuel pump or the relay is going.

[tedly]

Spend some time looking into the fuel system specs. Key on engine off prime should be 60psi minimum, idle should be 50-55psi. I get hold of a fuel pressure gauge a day or two later. Prime is difficult to get accurate because I can't see the gauge from inside the truck and it's falling by the time I get over to it. No way it can be higher than 58 though. Start it up, 48psi at idle. The computer can shut things off if pressure is below 50 from what I've read.

Wonderful.

OK, lets look around, see it there's any pinched lines or anything. Get to the fuel filter and the connections are rusted all to hell.



I guess it's been awhile since it's been changed. Probably clogged up. I wonder if it's 2psi worth of clogged?

Go out, grab a new filter, $14. Those lines are not going to come off there, so I might as well get the fuel line repair kits for them, $16 each. I'm probably going to lose one of the ferrules from the splice, so better pick one up as well, $4. Get the relay as well, $25. $75 total, so I'm into it for $1981 at this point. Picked up a mini tubing cutter for $11 as well, but that's a tool and doesn't count toward total for the car.



The filter is in an awkward location, and it took about 2 hours for me to cut through the old lines, splice in the new ones, and install the filter. It wasn't that terribly difficult, just took a lot of patience. It took a couple times of starting the truck, checking the connections, turning it off, then tightening the splices to get all them leak free, but it got done.

Put the gauge back on, primed it, 60psi. Cranked it up and got just under 50psi at idle. Like not even halfway to 49, but just a hair shy of 50. Close enough for me. Swapped the relays for added insurance and called it a day.

Runs beautifully and no more issues starting. I know I'm going to have to change the pump out soon because it is getting week, but this bought me some time and needed to be done anyway.

[STINEY]

Where are you tapping in to check fuel pressure? Our ‘90 doesn’t seem to have a schrader valve anywhere. Fuel filter looks identical to your setup, and it actually came apart and went back together without leaking or breaking.

[SuperBuickGuy]

Where are you tapping in to check fuel pressure? Our ‘90 doesn’t seem to have a schrader valve anywhere. Fuel filter looks identical to your setup, and it actually came apart and went back together without leaking or breaking.

his is a 99, totally different fuel system. Your 90 has 11 psi, the 99 has 45-60..... vortec baby.

[tedly]

Where are you tapping in to check fuel pressure? Our ‘90 doesn’t seem to have a schrader valve anywhere. Fuel filter looks identical to your setup, and it actually came apart and went back together without leaking or breaking.

Schrader valve is at the back of the intake on the driver's side on mine. The Vortec motors have a lot of differences from the small block before it. Heads, intake, injection system, and a lot more.

I tried getting the lines out the easy way first. The connector just disintegrated with any kind of torque. It wasn't coming off without a fight.

[tedly]

Since we've made it a week or two without any major car related emergencies, I thought I'd address some of the comfort and aesthetic issues on Tatanka. One of the things that has been driving me nuts but is not necessary for the truck to function was the ac/heater fan switch and blower motor resistor. The fan switch was just worn out and only worked on high. If I hit a bump, there was a 50/50 shot the fan would cut out. Hell, touching the selector knob would often be enough to cause it to go out. Putting sideways torque or pressure on the switch would normally (not always) get it to work again, but I just left the damn fan on high and would usually crack the window to regulate the temperature rather than risk pissing off the fan when adjusting the temp knob. It was serviceable, and I developed a light enough touch to adjust the temp without tripping the fan, but fiddling with that stupid switch while in rush hour traffic is not fun.

Initial searching around yielded only the whole control unit at $185 new and $80ish used from a scrapyard. No way I can justify $185 right now since it does still function, and getting a used one might mean I get the same problems.