CK5
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1989 K5 - Gradual Learning

First 4x4 - learning basic maintenance / upkeep and maybe some small mods.
Yeah Tech 1 is the best scan tool for your truck.
If the booster is leaking there might be a whistle or whooshing when you step on the break. Memory may be wrong didn't you a booster on 1 of the 2 trucks recently ?
Vacuum leaks are always at the top of list for drivability symptoms.
 
Yeah Tech 1 is the best scan tool for your truck.
If the booster is leaking there might be a whistle or whooshing when you step on the break. Memory may be wrong didn't you a booster on 1 of the 2 trucks recently ?
Vacuum leaks are always at the top of list for drivability symptoms.

Yeah, I just did the booster on my K5. It's good to go.

I hung out with @ZooMad75 yesterday and we hooked up the Tech 1. Everything seemed to be reading fairly normal (O2 sensors, TPS, etc). We checked the readings while in Park and also took it for a short rip around his neighborhood.

We were able to reproduce the issue that I encountered a few days ago. The Blazer was parked out front of his house, and it was idling in Park for a while. We dropped it into Drive and it started stumbling badly. It died on us after perhaps 5-10 seconds.

While that was happening, Rob was monitoring the Idle Air Control via the Tech 1 tool. It was showing that the voltage readings were changing, as if the computer was instructing the IAC to give the engine more air. However it was clear that the engine was not receiving any air... it kept stumbling until it died.

So now I have a couple of to do items:
  1. Pop off the IAC and check to see whether it is gummed up. The IAC itself is fairly new, so it should be clean. While it is off, I also need to check the passage inside the throttle body that the IAC goes into. I am going to clean both of them and probably will just replace the IAC unless I find that it and the passage are really gummed up.
  2. Unplug the EGR vacuum line and plug it up with a screw or bolt. I am going to make sure that it is closed first and then just disable that thing. I'll hook it back up before I go to the emissions testing facility next time.
Big thanks to Rob for hanging out with me and helping me with the Blazer. I am optimistic that this issue is IAC or EGR and that these steps will take care of it for me. As always I'll keep you all updated on what shakes out. I should be able to get into the garage tonight.
 
Golf tee's make great vacuum hose plugs. When you remove the iac put a light machine oil on the threads, similar to what and how much you'd use on electric hair trimmer.
 
I plugged the EGR last night and took a peek at the IAC.

IAC:

PXL_20230707_011758045.MP.jpg

Throttle Body Port:

PXL_20230707_012017407.jpg

The IAC itself wasn't too dirty, which is expected because I replaced it about 3 years / 7k miles ago. The port was a little dirty so I wiped it out with a shop rag that had carb cleaner on it.

I am going to run it like this for a while. If the stumbling returns, I'll just replace the IAC.
 
Regarding buying a full-size spare...

The tires on my K5 are Hercules Terra Trac T/G Max (35X12.50R15LT). I really like them overall although they're a bit noisy. Unfortunately, it doesn't look like Hercules makes them for a 15" wheel anymore.

If you guys were in my shoes, would you just pick up the cheapest 35X12.50R15 used tire you could find? The idea being that you would just use it in emergency situations...

Then when I buy new tires for the K5, I can either get five matching tires or I could save some money and buy four and just resign myself to not having a matching spare.

These two tires are close to home, comparatively cheap, and are "new". Might just go pick them up but wanted to hear your guys' opinions.
 
I’d rather have a matching size spare. That way you don’t have to swap from one axle or the other to address a flat.
 
I’d rather have a matching size spare. That way you don’t have to swap from one axle or the other to address a flat.

Definitely gonna get a spare that is the right size. Really would love to get a matching brand / model spare... I could even swap it in regularly so that the wear on all five tires matches. But looking like I should just get a cheap used 35X12.50R15. There is a spot off of Federal and I-70 that sells used tires, might give them a call to see.
 
Definitely gonna get a spare that is the right size. Really would love to get a matching brand / model spare... I could even swap it in regularly so that the wear on all five tires matches. But looking like I should just get a cheap used 35X12.50R15. There is a spot off of Federal and I-70 that sells used tires, might give them a call to see.
It’s nice to have them match for rotation purposes, but looks like that’s not possible with what you have. Just get the the right size and go.
 
The correct size is better than the wrong size, and the wrong size is better than none.
I am using an old, best tire for a spare. Nothing wrong with that.
 
I picked up a beat 35x12.50R15 tire mounted on an old 70's ford wheel for $50. Gonna swing by Costco and have them mount it on the factory spare. Will probably toss the Ford wheel or give it away here on the forums.

I drove up to Broomfield (~22 miles away) to pick up the spare, and the Blazer was fine on the way there for the most part. I felt it shudder at stop lights but perhaps it wasn't as bad as before. On the way home however... I got gas at Costco and had to sit in a line. It was having real trouble. Even in Park it was shuddering and I was thinking it was gonna die. I feathered the gas pedal in Park and kept it going.

While driving home on I-25, I was cruising at a good pace... call it 70 mph. I would play around with it a little bit by letting off the gas pedal a bit (but not entirely)... then I'd hit the throttle hard. It would stumble and take a second before it was able to accelerate. It stumbled so bad a couple times that I got into the far right lane in case I had to pull off the road.

When I got home, I read the codes just to see whether I found anything new. 32 was there, which was expected because I plugged the EGR a while ago. 43 was also there, which is electronic spark control / timing. Over the years, this code has shown up every once in a while. Then it goes away for a while, then it comes back up. It's back again and I'm going to give a real shot at figuring it out.

I am gonna pick up a test light and try the diagnostic procedure that is in the PDF file @dyeager535 added to the "TBI Trouble Codes" eagle mark thread back in 2008. Wish me luck.
 
If that old Ford wheel is 5 lug I'll take it. If someone can bring it to Bb23
 
It's all yours. In theory I can bring it to BB23. If something happens and I'm not able to come then I can hand it off to Rob or Ron.
 
Thanks

Yeah I have 2 dodge wheels on 1 of my E200s they work but the center hub is big on the wheel. The ford stuff is harder to find.
 
is an on going process. with this egr. While it may never be correct with the choices of replacement egr valves these days. It is plug at the moment to see if stalling under decel and stops goes away. It is my suspicion that the egr is sticking and creating a vacuum leak at low rpm/speeds. Stalling and or poor idle.
 

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