Wow I'm in a pickle. (Broke down truck) and a story.

[Atlas]

Ancillary parts to the lower intake and connections went together without issue.

 

There was a brief pause when I leak-tested the fuel lines and injection system. Fuel was spraying all over. Lovely. O-rings weren't sealing the fuel lines to the spider, and inbound line was leaking at schrader valve, leaks at both flange nuts. It's moments like those when you just want to set fire to the whole shop, and be done with it. I was mostly enjoying the project up until that point, and was tracking to an agenda of having a running Blazer and a cold beverage in hand by dinnertime. 

 

I found some larger Viton o-rings for my spider and some grease to get them to seat. One leak solved. Swapped fuel line Schrader core for old core. Still leaked. Swapped entire valve for old valve. Leak solved. Nudged the flange nuts a little tighter on the connections. Another leak solved. I could cycle the key / prime the pump and the intake was staying dry. 

 

Reassembled the upper intake, with 10,000 vacuum lines, and filled the cooling system with water* (this is temporary, I'm not done with the cooling system yet).

 

Showtime!!

 

Cranked it over and smoke billowed, it was running rough. CEL illuminated and began flashing. P0300 and I somehow tripped a code for the TPS sensor, voltage low. 

 

There's nothing as unrewarding as a vehicle that won't run (and produces the same code/problem) after hours of research and work.

 

Clearly I was in over my head. Was the timing off, did I stab the distributor incorrectly? Is the new distributor bad? With my limited OBD 1.5 data stream I really don't have a lot of parameters to see. The engine was pulling mad timing again (flooding?).
 

Think, Atlas, think.

 

1-6-5-4-3-2. One, six, five.....four, three, ....two. Wait a second. That makes no sense. 1 is the forward cylinder on the driver's side, so 2 should be the forward cylinder on the passenger side, not 6. 

 

I can't believe it, but I'm looking right at it. Swapped 2 and 6 on the distributor and turned the key over, and...

 

It fired, coughed and stumbled, smoked, and then settled into a smooth idle. The scanner showed no codes, no lights on the dash, and the throttle was nice and responsive to gentle revs while it warmed up.

 

It's working!!! IT'S WORKING!!!

 

I paused for a late dinner, no cold beverage yet. I was determined to do my shakedown run. Did a basic safety and fluids check one more time and then went out and put almost 70 miles on it last night. She's a runner, runs good.

 

Came home and did a post-trip, post-mortem. The underside is dry *except* for where the last owner RTV'd the snow out of the intersection of the timing cover and oil pan. He said he had replaced the timing cover seal, but, my dude had clearly done it incorrectly and then tried to hold back fate with black RTV. Never works.

 

Yesterday morning I replaced the broken driver's door mirror. As much as I hate cheap Chinese parts, thank goodness for cheap Chinese parts. I think an entire new power mirror assembly cost me like $30, and it works perfectly. Replacement tail lights (faded, and one was busted) ran me about $12/side. I have a door pin kit ready to go in because the driver's door sags just a little and I want to fix that because there's nothing sadder than a saggy door.

 

I don't know what's next for this rig. Half of me wants to take some nice photos (there's a park nearby with a HUGE American Flag that always seems to be catching wind) and throw it up on CL/Marketplace for a couple grand and see if it flies. The other half of me... I've got a sweet running S10 Blazer that's been keeping my mind off of whatever I'm going through right now, and it's bringing some joy, and is cheaper than therapy. Maybe I'll keep it around for a little while. However, this is my 5th vehicle, just for me. 4 is really my limit, but they are not junk, so need very little attention. I don't know...there's a point where it's just too much and I don't see owning this truck long term. But I solved its major problem, got it running, so I'm going to stick a feather in my cap for now.

 

Sometimes we just need to get our hands dirty and fix something in the physical world to gain some satisfaction.

Edited Saturday at 03:33 PM by Atlas

[Grumpy Bear]

What a wonderful result! Great story telling to. You are quite multifaceted sir.  I'd keep it. Four is my limit too and yet we have five as well. One assigned the 'salt car' to do all those tasks you hate to ask of your 'Save for Good" crowd.  

 

Don't forget the antifreeze. 

 

The Iron 4.3 is a favorite of mine. 

[Atlas]

Fix one problem and find another.

 

Truck didn't have a thermostat in it so I flushed out the system today and refilled with 50/50 Dexcool. This truck is so old (LOL) that it has a sticker under the hood alerting people to the fact that it contains such. There is also an orange supplement with the owner's manual alerting the owner that "Your vehicle is one of a number of late production 1995 General Motors vehicles that use a newly developed engine coolant in the cooling system..."

 

I was still a little flummoxed by what seemed like a rich condition (exhaust smell, and a puff of carbon with a punchy rev). While watching the coolant temperature and testing the thermostat with my scanner, I happened to notice the IAT (incoming air temperature) to the intake was -40F. I know the temp is below average today, but I can still feel my face, and I was wearing shorts.

 

D'oh!! I realized I had never plugged the IAT back in, and the airbox was out while I was doing coolant. So I paused, reinstalled the airbox and plugged in the IAT, and viola. Things cleared right up, and I watched the coolant temp climb to a reported 198 degrees on the scanner (195 thermostat) and then it dropped to 194 (open) and then back up to 198 and held. Let it cool, came back, checked the coolant level and was satisifed.

 

Victory lap?

 

It needed more than the couple of gallons of gas I put in it from almost bone dry, so I ran it up to the gas station. It had earned it, or, at least I was pretty certain I wouldn't be draining or removing the tank anytime soon.

 

CEL popped on just as I was cruising a nice steady 40mph, just after coasting down a slight downhill curve.. Of course, it did, because, why let me enjoy not having dash emojis for a little while.

 

I just happened to have the scanner plugged in. I don't text and drive but I might scan and drive. Don't tell the police.

 

P0401, EGR flow insufficient. 

 

Well, hello, EGR... ...my old friend! Welcome to the party, now that the engine reaches the factory-programmed operating temperature. I'm sure it was gagging on hostile, rich exhaust and carbon this whole time so I'll take it off and look again.

 

At least it's easily accessible, and worst case, about $65 to replace.

 

To keep, or to sell... Hmm. I want it running correctly either way. It's easier to sell when there are no fault codes.

 

It needs tires (they're aged out and cracking)

 

It could probably use an oil pan seal, or maybe the timing cover gasket/ junction with the pan needs redone because I've got an issue there that leaves a drop of oil on the floor.

 

If I do tires I'm sure they'll say the ball joints could use freshening, and, and, and, and.... At some point I'll have to stop. I can't (shouldn't) make it perfect, that's not what this rig is.

[Grumpy Bear]

28 minutes ago, Atlas said:

At some point I'll have to stop. I can't (shouldn't) make it perfect, that's not what this rig is.

 

No, but don't skimp on safe!  

[Atlas]

10 hours ago, Grumpy Bear said:

 

No, but don't skimp on safe!  

 

It's the tires that bother me.

 

If I'm keeping it, obviously it's getting tires. If I'm selling it? Tread is good, and they can be someone else's problem, cracks and all. 

 

Or, do I pay it forward and put a basic set of new tires on ($600). I think I know what I should do, it's just not fun.

[PhilB]

Putting on a basic set of new tires could help seal the sale.  You can always add the cost on to your asking price.

[Atlas]

I think the excitement has run its course. Or, probably need a break from the truck for a few days.

 

Win some, lose some, again. There was still a coolant weep from the front of the engine. This time it was one of those worm-drive hose clamps on the upper hose connecting to the water neck. There's a reason the factory doesn't use those type of clamps; they suck. The hose is all distorted and flared at the end from someone over-tightening it. The water neck just needed to be cleaned, hose seated, and have a *good* hose clamp put on, if the hose wasn't so mangled.

 

Thought I'd kill two birds with one stone and try to diagnose the EGR issue. It's likely a failed EGR but before I spent $85 on the part I wanted to make sure ports weren't clogged or the pintle wasn't stuck. It was kind of a bugger to remove with the upper intake installed. Re-install (because I wanted to drive it) proved more difficult.

 

Per the stack of service paperwork, the EGR has already been replaced 4 times since 1996.

 

It would reason, then, that the EGR flange on the lower intake manifold has had its share of techs trying to work quickly and maybe one of them seated a bolt slightly cross-threaded at one time. The bolt didn't come out without significant effort and tried as I did, it wouldn't go in without significant effort. And then, the mounting ear on the right side of the EGR (lower intake casting) cracked, and crumbled off. $%&@!!!

 

I hate everything. Or, at least, I did in that moment. I was pretty calm, considering. This is what older, junky vehicles do. They nickel and dime their owners, piss them off, and things break that shouldn't break because of shoddy design/workmanship, poorly done repairs.

 

If I want to make it right, I'll need to replace the lower intake manifold and basically re-do everything I spent days doing. At least it should go quicker this time, right?! Looks like a lower intake (used/junk, of course) will run me about $150.

 

Once I get the new EGR, I'll see if I can bolt it up snug enough to verify proper operation, and if it solves the persistent CEL that sets on decel for EGR flow, I'll know I'm back on the right track. And then I can decide how to proceed.

 

Also, an idler pulley has given up. It began squeaking in pain on startup. It's clear this truck hasn't been thoroughly driven in a long, long time as things are just letting go and shaking out. I may have given it the beans once or twice to make sure my intake gaskets were doing their job. Flog an old vehicle, expect what it gives in return.

 

 

[Grumpy Bear]

Hey Atlas, thanks for taking us along. I love this stuff.  

[Atlas]

I don't know if you or anyone enjoys it or not but, why not share it. It's GM "truck" related and we're in the right place to discuss that  I'm also working on some creative writing skills, I'm not quitting my day job to pursue that, either!

 

As I said, I've hit a wall because I'm not making any progress, and the progress is the fun part for me.

 

The idler pulley and EGR valve came in. Against better judgement, I went out there last night and put both of them in. I was able to get a nut on the back of the bolt on the side with the broken flange. There's enough flange still there that I can get that side of the EGR to snug down. It's not perfect, it's not "right", but this is the fix I have for now. If I decide to keep the rig, I talked to a guy locally who will sell me a complete intake for $100. If it's my truck, a broken flange like that would bug me too much. Yes, I'm crazy. But I embrace it.

 

Pulley on, EGR installed, started the truck. Great...still have a pulley squeaking like mad. That was the first disappointment. I thought I had pinpointed the problem. Before I replaced it, I sprayed the back of that pulley with PTFE and it would shut up for about 30 seconds. Is the squeak actually the belt? I'm frustrated.

 

SO then I decided why not disappoint myself twice, so I took it for a spin and sure enough, the CEL set for P0401 insufficient EGR flow again.

 

I had some extra time, so when I arrived home, I decided to ask AI about my EGR code. We had an interesting conversation.

 

I asked how to tell if my MAP sensor is bad and if that could be setting an EGR code since a bad MAP may not be sensing the requisite drop in manifold pressure when the EGR activates. I gave it the MAP value at idle and it told me to blip the throttle hard and watch the MAP reading. It said no, the values appear normal and it's reactive to pressure changes, and then instructed me to test voltage at the harness. I don't think it's the MAP sensor. Interesting, though, I gave it MAP reading values in inHg, and it thought I was using PSI, so I had to correct it. AI is a very dangerous tool if you aren't treating it like the machine that it is.

 

Then it walked me through testing the EGR and harness. It took me down an interesting path. It was referencing a gray wire and a white wire so I told it I can't tell the difference on my harness because it's dirty and old and both could be white or gray, I'm not sure. So it gave me a more accurate description of the ABCDE pins on the connector and started referencing pins instead of colors. Helpful.

 

The EGR harness has 12v power, and it also has 5v reference power from the PCM. What I'm unclear on is there's a ground wire and I thought AI had said that one of my tests revealed the ground in the harness was likely bad and it instructed me to wire a test ground. I got distracted and navigated away from the AI conversation, and when I went back and asked for clarification it said I must have misunderstood. (how rude- next time I'm saving the conversation!)

 

But I think it was onto something. I recall NOT getting 12v when I tested the power wire to the ground wire, but I did when I tested the power wire, grounding the voltmeter to the engine block. AI said no, the ground wire is actually for the PCM, that's how it commands the EGR on by grounding it and so the circuit should be open with the key on (i.e. EGR off). But I think there's also a static/overall ground that should always be grounded, and if that's bad, then the EGR isn't activating when the PCM commands it on, and thus setting the code.

 

There's a bunch of other tests it suggested, back-probing with the EGR plugged in and engine running. I need to get some time to focus, and not just tinkering after a long day.

 

Edited 6 hours ago by Atlas

[asilverblazer]

3 hours ago, Atlas said:

The EGR harness has 12v power, and it also has 5v reference power from the PCM. What I'm unclear on is there's a ground wire and I thought AI had said that one of my tests revealed the ground in the harness was likely bad and it instructed me to wire a test ground. I got distracted and navigated away from the AI conversation, and when I went back and asked for clarification it said I must have misunderstood. (how rude- next time I'm saving the conversation!)

 

But I think it was onto something. I recall NOT getting 12v when I tested the power wire to the ground wire, but I did when I tested the power wire, grounding the voltmeter to the engine block. AI said no, the ground wire is actually for the PCM, that's how it commands the EGR on by grounding it and so the circuit should be open with the key on (i.e. EGR off). But I think there's also a static/overall ground that should always be grounded, and if that's bad, then the EGR isn't activating when the PCM commands it on, and thus setting the code.

Not sure how many wires you've got to play with BUT if there is constant power AND ground at the EGR how is it switching?

 

In other words, the grounding via the PCM to activate it makes sense to me.

[Atlas]

48 minutes ago, asilverblazer said:

Not sure how many wires you've got to play with BUT if there is constant power AND ground at the EGR how is it switching?

 

In other words, the grounding via the PCM to activate it makes sense to me.

 

Wire Pinout and Colors

• Pin A: Brown/White - 5V Reference Signal
• Pin B: Black/White - Sensor Ground
• Pin C: Dark Blue - EGR Position Signal
• Pin D: Pink/Black - 12V Ignition Power
• Pin E: White (or varies) - Ground Control for EGR Solenoid [1, 2]

 

Understanding the Wires

• 5V Reference: A low-power current sent by the Powertrain Control Module (PCM - the car's computer) to the EGR.
• Position Signal: Tells the PCM exactly how far open or closed the valve is.
• Ground Control: The PCM completes the circuit to actually open and close the EGR valve using this wire. [1, 2, 3, 4]

 

 

This is what AI is telling me, in absence of access to a complete service manual for the truck. So there are two grounds and I think I determined one of them is bad. I need to run through the test sequence again to validate what I think might be a bad ground.

 

I'll be honest, electrical isn't my strong suit, but I'm learning.

 

 

[BIGDOGx]

If you keep it, i would just add 4 ball joints, an idler arm and most likely pitman arm to you future list. My 95 s10 zr2 ate 5 sets of ball joints, 4 idler arms and 3 pitman arms in a 100k of use, a glaring weak spot even with the non zr2 variants.

[davester]

maybe get a service manual off ebay?  or check charm.li (website) or subscribe to alldata.com for it?

[newdude]

5 hours ago, Atlas said:

I don't know if you or anyone enjoys it or not but, why not share it. It's GM "truck" related and we're in the right place to discuss that  I'm also working on some creative writing skills, I'm not quitting my day job to pursue that, either!

 

As I said, I've hit a wall because I'm not making any progress, and the progress is the fun part for me.

 

The idler pulley and EGR valve came in. Against better judgement, I went out there last night and put both of them in. I was able to get a nut on the back of the bolt on the side with the broken flange. There's enough flange still there that I can get that side of the EGR to snug down. It's not perfect, it's not "right", but this is the fix I have for now. If I decide to keep the rig, I talked to a guy locally who will sell me a complete intake for $100. If it's my truck, a broken flange like that would bug me too much. Yes, I'm crazy. But I embrace it.

 

Pulley on, EGR installed, started the truck. Great...still have a pulley squeaking like mad. That was the first disappointment. I thought I had pinpointed the problem. Before I replaced it, I sprayed the back of that pulley with PTFE and it would shut up for about 30 seconds. Is the squeak actually the belt? I'm frustrated.

 

SO then I decided why not disappoint myself twice, so I took it for a spin and sure enough, the CEL set for P0401 insufficient EGR flow again.

 

I had some extra time, so when I arrived home, I decided to ask AI about my EGR code. We had an interesting conversation.

 

I asked how to tell if my MAP sensor is bad and if that could be setting an EGR code since a bad MAP may not be sensing the requisite drop in manifold pressure when the EGR activates. I gave it the MAP value at idle and it told me to blip the throttle hard and watch the MAP reading. It said no, the values appear normal and it's reactive to pressure changes, and then instructed me to test voltage at the harness. I don't think it's the MAP sensor. Interesting, though, I gave it MAP reading values in inHg, and it thought I was using PSI, so I had to correct it. AI is a very dangerous tool if you aren't treating it like the machine that it is.

 

Then it walked me through testing the EGR and harness. It took me down an interesting path. It was referencing a gray wire and a white wire so I told it I can't tell the difference on my harness because it's dirty and old and both could be white or gray, I'm not sure. So it gave me a more accurate description of the ABCDE pins on the connector and started referencing pins instead of colors. Helpful.

 

The EGR harness has 12v power, and it also has 5v reference power from the PCM. What I'm unclear on is there's a ground wire and I thought AI had said that one of my tests revealed the ground in the harness was likely bad and it instructed me to wire a test ground. I got distracted and navigated away from the AI conversation, and when I went back and asked for clarification it said I must have misunderstood. (how rude- next time I'm saving the conversation!)

 

But I think it was onto something. I recall NOT getting 12v when I tested the power wire to the ground wire, but I did when I tested the power wire, grounding the voltmeter to the engine block. AI said no, the ground wire is actually for the PCM, that's how it commands the EGR on by grounding it and so the circuit should be open with the key on (i.e. EGR off). But I think there's also a static/overall ground that should always be grounded, and if that's bad, then the EGR isn't activating when the PCM commands it on, and thus setting the code.

 

There's a bunch of other tests it suggested, back-probing with the EGR plugged in and engine running. I need to get some time to focus, and not just tinkering after a long day.

 

 

 

On the PCM side, blue PCM connector, pin 18, solid gray color (no stripe) wire circuit 435.  That is the EGR low circuit which an issue on that line (be it the wiring, the PCM or the EGR valve or system performance) will trigger P0401 when it tests that code.  

 

There is also a VERY old TSB that states to make sure you clear the DTCs ANY time the PCM is unplugged, reprogrammed, or if the EGR valve is unplugged or replaced as the PCM has an auto zero function in the PCM for the EGR pintle data

 

61-65-59: SMU - SECTION 6E - ENGINE CONTROLS - CLEAR DTC'S - (Nov 25, 1996)

 

"CLEAR ANY DTCS FROM THE VCM ANYTIME AFTER DOING VCM REPLACEMENT/ PROGRAMMING, TURNING THE IGNITION ON WHILE THE EGR VALVE IS DISCONNECTED, OR REPLACING THE EGR VALVE."

 

Some diagnostic aid notes in the GM diag on P0401 for a 1995 S10 Blazer:

 

Diagnostic Aids

Notice: In order to prevent further damage if the EGR valve shows signs of excessive heat, check the exhaust system for blockage (possibly a plugged converter) using the procedure found on the restricted exhaust system check. If the exhaust system is restricted, repair the cause; one of which might be an injector which is open due to one of the following reasons:

• Stuck
• Grounded driver circuit

Check the oil for possible fuel contamination if a stuck open fuel injector is found.

• Poor connection or damaged harness - Inspect VCM harness connectors for the following conditions:
  • Backed out terminal BL 18
  • Improper mating
  • Broken locks
  • Improperly formed or damaged terminal
  • Poor terminal to wire connection
  • Damaged harness
• Intermittent test - If connections and harness check OK, monitor a digital voltmeter connected between terminal BL 18 and ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change.