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OBD1 Issues-HELP PLEASE!!!

2500HD4X

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2500HD4X Enthusiast

2500HD4X

Posted
Posted

VEHICLE- 88 K5 Blazer. 350TBI, VIN K.

PROBLEM- CODE 43- Knock sensor....

THE STORY.....

I bought the Blazer at the beginning of last month. It had been sitting up for a few years. Drove it home, the SES light was on, rough idle, etc. I put some injector cleaner in and drove it almost empty to purge the old gas. Refueled (~ 12 gallons) with fresh gas (87 Octane) and another bottle of injector cleaner. Pulled the codes (32-EGR, 43 Knock Sensor). Reset the codes and did a basic tune up (Air filter, oil change/filter, PCV, Plugs, Cap, Rotor) and drove it around a few days. EGR tripped the SES again on the way home from work one day and it started running really badly (rough idle, stuttering/surging). Pulled the EGR valve out, cleaned it and the passage, it improved for a few days then tripped the SES again, so I replaced the EGR valve.

 

Everything was great-ran strong, but now that the EGR valve is no longer an issue-Every time I run at or near full throttle, it sets a code 43. I have replaced the knock sensor, ESC module, verified the continuity of the blue wire between the knock sensor and terminal "E", replaced the fuel filter (lean condition at WOT maybe??), dumped two bottles of super-duper octane boost on top of 10 gallons of gas left in the tank, repaired an exhaust leak, verified I am getting 12V to the ESC module, checked and cleaned the connections between the ECM and ESC module, cleaned and verified grounds all over the engine, reset timing to zero BTDC (with the tan/black timing wire disconnected), and it is still doing the same crap. :) There is no mechanical noise that I can hear coming from the engine or driveline. It has a stock style (BIG) muffler with single outlet and still has the catalytic converter on it so it runs pretty quiet. Sorry for the long post- Some of its venting, as well as letting y'all know what I have already tried. Right now it takes off like a rocket, until the SES light trips then it pulls timing and falls flat like you threw out an anchor. Any ideas/input/suggestions/sympathy/empathy or other stuff is appreciated.

 

EDIT: Meant this for general engine tech...Oh well...

2500HD4X Enthusiast

2500HD4X

Posted
  • Author
Posted
Since I can't help much with your actual problem :(

 

I'll move it for you :cheers:

 

 

 

Thanks Wingnut!! :puke:

Drove it to work this morning....Ran fine, but I didn't romp on it. We'll see how it does today.... :)

Wingnut Senior Enthusiast

Wingnut

Posted
Posted

For what it's worth...It's doing EXACTLY what my '92 K1500 Blazer was doing when that knock sensor failed.

 

So I'd say that (even though you've been all through it) that's where your problem still lies. Bum new sensor maybe?

 

But things like this are hard enough to figure out when you're right in front of it... Uber-hard to figure out without being there.

 

So I'll just say this....Nice CJ :)

2500HD4X Enthusiast

2500HD4X

Posted
  • Author
Posted
So I'll just say this....Nice CJ :)

 

 

 

 

Thanks- :puke: Its going to the Jeep Jamboree at Tellico next month w/new tires (swamper 33's) and a locker, thats my other ongoing project. Its funny, I have the Jeep as my avatar here and my truck as my avatar @ JU... My log in everywhere is 2500hd4x....

 

For what it's worth...It's doing EXACTLY what my '92 K1500 Blazer was doing when that knock sensor failed.

 

So I'd say that (even though you've been all through it) that's where your problem still lies. Bum new sensor maybe?

 

But things like this are hard enough to figure out when you're right in front of it... Uber-hard to figure out without being there

 

Maybe it is the knock sensor, although it is putting back the correct voltage at idle. I don't know. False knock (maybe) is a booger to track down. I've got a friend with a laptop, been thinking about downloading WINALDL, building up a cable and seeing just what is tripping it, it takes time to learn that stuff (what you are looking at in the tables) though and I've never done it. Suppose I could learn. I had an 87K5 I built up a few years ago, I got so frustrated with the TBI I just ripped it all off and put a 600Holley on it. TBI is supposed to be simple!!

I eventually want to put a carbed 383 in this one, but this engine still runs pretty strong and has strong compression etc, I wanted to run it till I was ready to swap in the 383/TH400/205. I have 4 small blocks in the shop in various states of repair that I could put in there but I need a few more months to get what I want ready. Machine work, etc....Too much going on at once, too many projects+not enough time.

Wingnut Senior Enthusiast

Wingnut

Posted
Posted

I'm trying to talk a guy at work out of his '88 YJ with a burnt up engine and grenaded tranny...If I can get it on the cheap, I've got a buddy with an LS1 w/trans and harness just begging me to buy it off of him. I'm thinking I can build a badass river rat for under 5k. Problem is, I don't know a whole heck of a lot about Jeeps...Other than the few lift kits I've done on them. I need something to beat on :)

2500HD4X Enthusiast

2500HD4X

Posted
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Posted

This is Jeep #4 for me. I've almost got it right this time...but 88 Wrangler with an LS1 sounds like it would be more fun. You would definitely have to upgrade the running gear. Dana 35's are boat anchors. My first Jeep I blew out several D35's with just 32" tires in mud, not rocks. D35's have this need habit of spitting out a wheel during a turn when you abuse them-or as my friend put it "theres a pole with gears on it sticking way out on my side." I did beat on it pretty hard though. (Drove that heep from 15-23 when I got out of college)

 

Thats what this K5 is supposed to be (a beater). I have a 79K20 I am pulling the 14BFF, 8 Lug outers and TH400/203 out of to beef this one up for mud racing. This will be the 3rd K5 I've built up, but the first that is absolutely rust free. The sheetmetal is immaculate other than the clear coat peeling. I've been trying to DD it while I wrench on the Jeep the next few weeks to get it ready for the Jamboree. It did pretty well when I went to lunch, but I'm still driving it like Ms Daisy is in the back. Maybe the octane boost is mixing in and doing its thing. It still gets better mileage than my 2500 so far.....but that ain't saying much. :)

OnyxMAX Enthusiast

OnyxMAX

Posted
Posted

might try seafoam could have a small chunk of carbon setting up a second wave front in the cylinder. 2nd bottle of boster doesn't help.

 

humm ar the engine mounts good it might be just bad enough that at full throttle it's twisting and touching something it's not supposed to.

2500HD4X Enthusiast

2500HD4X

Posted
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Engine/tranny mounts are in good shape, been over the whole underside and looked for cracks, creaks, improper contact etc. The only thing I have found thats in bad shape is a bushing on the left rear spring/shackle. Its not really that bad though, doesn't creak/squeak yet. When I swap the rear axle all thats getting replaced with poly bushings anyway.

 

It pulled a code 43 on the way home from work yesterday....55 down a flat stretch of highway, in O/D with no load on it all, just buzzing along....first time its done that. I didn't mess with it all last night. :) I've been fiddling with this thing for a week daily, the thing that kills me is that it had the code when I first picked it up, then when the EGR was messing up, it didn't, now that the EGR is fixed, its doing it all the time. Maybe I broke a bunch of carbon loose when I was cleaning the passage or something-I don't know.

 

I haven't tried seafoam yet....Never used it before- I am gonna talk to my buddy at work tomorrow about using his laptop/fabbing up a cable to really get into the computer (ECM) and see whats causing it to flag/trip the code..

 

Maybe after I get done mowing today I'll hit it with the seafoam. The other thing I am going to try is pulling out the new sensor, maybe isolating it somehow-wrapping it in rubber and running a ground wire back to the block so it takes the knock sensor out of the system and I can figure out if its really knock or a glitch in the ECM (yes I'll plug the hole on the block with the old one).

OnyxMAX Enthusiast

OnyxMAX

Posted
Posted

humm, next thing i would do is break out the wrenches and give all the bolts a twist for stuff mounted to the engine all the brackets ect. assumeing were chasing a false knock. especialy the a/c and air pump if it has one.

 

did you check the advance on the distributer make sure it wasn't stacking? do 88 still have vacumme or were they electronic?

2500HD4X Enthusiast

2500HD4X

Posted
  • Author
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88 is electronic, I went back the other night and rechecked the timing....Its right where its supposed to be. It runs pretty well, between the tuneup etc. It just won't take full throttle. I am sick of messing with it, so I am just going to run it till it pukes and replace it with a rebuilt engine (383 w/carb most likely) in a few months. It may be knocking internally and I just cant hear it. I know the knock sensor is working, if you smack the engine with a hammer, it trips as well......

OnyxMAX Enthusiast

OnyxMAX

Posted
Posted

yea after all you have done i would suspect low compression in a cylinder, or a stupid computer they sometimes get that way.

 

time to run the piss out of it.

  • 6 months later...
csucsi Enthusiast

csucsi

Posted
Posted
VEHICLE- 88 K5 Blazer. 350TBI, VIN K.

PROBLEM- CODE 43- Knock sensor....

THE STORY.....

I bought the Blazer at the beginning of last month. It had been sitting up for a few years. Drove it home, the SES light was on, rough idle, etc. I put some injector cleaner in and drove it almost empty to purge the old gas. Refueled (~ 12 gallons) with fresh gas (87 Octane) and another bottle of injector cleaner. Pulled the codes (32-EGR, 43 Knock Sensor). Reset the codes and did a basic tune up (Air filter, oil change/filter, PCV, Plugs, Cap, Rotor) and drove it around a few days. EGR tripped the SES again on the way home from work one day and it started running really badly (rough idle, stuttering/surging). Pulled the EGR valve out, cleaned it and the passage, it improved for a few days then tripped the SES again, so I replaced the EGR valve.

 

Everything was great-ran strong, but now that the EGR valve is no longer an issue-Every time I run at or near full throttle, it sets a code 43. I have replaced the knock sensor, ESC module, verified the continuity of the blue wire between the knock sensor and terminal "E", replaced the fuel filter (lean condition at WOT maybe??), dumped two bottles of super-duper octane boost on top of 10 gallons of gas left in the tank, repaired an exhaust leak, verified I am getting 12V to the ESC module, checked and cleaned the connections between the ECM and ESC module, cleaned and verified grounds all over the engine, reset timing to zero BTDC (with the tan/black timing wire disconnected), and it is still doing the same crap. banghead.gif There is no mechanical noise that I can hear coming from the engine or driveline. It has a stock style (BIG) muffler with single outlet and still has the catalytic converter on it so it runs pretty quiet. Sorry for the long post- Some of its venting, as well as letting y'all know what I have already tried. Right now it takes off like a rocket, until the SES light trips then it pulls timing and falls flat like you threw out an anchor. Any ideas/input/suggestions/sympathy/empathy or other stuff is appreciated.

 

EDIT: Meant this for general engine tech...Oh well...

 

my post is coming ...same problem....starting to really dislike "the heartbeat of mexico"

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