Jump to content

Another Toy MH - 1991 Winnebago


quasi-moto

Recommended Posts

Recently purchased a Micro Minnie Winnie. I used to own an 1986 Dolphin that was awful, as had been lived in by some goofball so it was in need of rehab. My new 1991 has a beautiful house area, and a rebuilt v6 with about 20,000 miles.

Drove the rig back from Montana to So. Cal after purchase and was surprised at how utterly gutless it was over all the many mountain passes. It performed about as badly as my 86 4 cyl, when it was loaded with 4 people and all suppl for two week trip to Wash and back to So. Calif. I expected that an empty six cyl. would do better.

The check engine light indicator is on and it shows knock sensor alert. Mechanic said it was fine and the sensor is an expensive fix.

Any input?

Link to comment
Share on other sites

Well you are moving over 6000 lbs with less than 200 HP.  If you want to go faster you will have to buy a rig with a higher HP to weight ratio.

I did a trip through the mountains out west and rarely was under 35 MPH which I consider very respectable. Plus around town I consider the V6 peppy.     HTH  JIm

 

Link to comment
Share on other sites

I'd suggest you start by diagnosing your codes and try to determine if you actually have a faulty knock sensor. If it's working properly, try to figure out why it's sensing a knock. I'm not sure with our vintage OBD, but the knock sensor might be trying to adjust your timing to make the knock go away. This could be what's hurting your performance.

Link to comment
Share on other sites

Well I'm assuming he had the codes checked cause we don't have an instrument panel knock sensor alert. Only way is to check the codes. Did he tell you the number? It would have been a code 52. I would try cleaning the throttle position sensor first. Delayed timing can make it knock and maybe throw a code. Have the codes checked again or check them yourself. Lots of places online with instructions. No reader needed, just count blinking lights

Linda S

Link to comment
Share on other sites

IF the CEL has a 52 (knock sensor)  the computer will put the engine into "limp" mode.   Performance will be terrible as will gas mileage.

I overheated 2 summers ago and got that code. I made a work around (you can not just "unplug" the knock sensor to "fix" the problem) and limped home.  Replacing the KS is a big job -involves removing intake manifold. The manual says the front of the engine has to come off (timing belt) but there is a way to avoid that. 

BTW< several toy mechanics familiar with the VZ3E engine have told me the issue is usually the wiring harness that goes to the KS - less then $20.  When I got into mine I bit the bullet & replace the KS too - I did not want to go back in there.

Wonder if the person who rebuilt the engine changed the KS wire harness - that is SOP for a seasoned toy mechanic. In my case, I adjusted valves due to mileage (90K) and how hot the engine was. My exhaust valves were way out of adjustment. 

 

 

 

Edited by DanAatTheCape
Link to comment
Share on other sites

  • 1 month later...

Took it for a look-see with a Toy mechanic. He felt there was no problem with the engine and that the cost to replace is not worth the sensor reset. I had to unplug/replug the check engine sensor in the parking lot of the smog check station to reset. Luckily, the rig passed and the check engine light did not come back on until I drove home, with my CA smog cert passing score. 

With my cert in hand, I registered vehicle.

The overheating was likely situational, as many other cars were overheating on the I-5 outside of Vegas.  Around town it is functioning just fine, except for a new problem. :\

Twice my Toy failed to start in the Disneyland parking lot, after a few hours in the park. It never failed to start on the trip back from Montana, even when it was really hot from hours of driving or close to freezing.

Eventually, after about an hour of waiting, praying, and trying the ignition, it restarted. Called AAA for a tow and twice cancelled. This happened in the same row of the lot and at night, but not when I parked in other rows. Hmmmmm...

Beware!  Bad JuJu in the Disneyland Pinnochio Lot, in the row right next to the parking structure. LOL!

 

Link to comment
Share on other sites

On 12/18/2016 at 0:16 PM, linda s said:

Well I'm assuming he had the codes checked cause we don't have an instrument panel knock sensor alert. Only way is to check the codes. Did he tell you the number? It would have been a code 52. I would try cleaning the throttle position sensor first. Delayed timing can make it knock and maybe throw a code. Have the codes checked again or check them yourself. Lots of places online with instructions. No reader needed, just count blinking lights

Linda S

Good suggestion about throttle pos sensor.

I own a code book and plug in that a mechanic used while I counted the number of flashes. That is how we knew Knock Sensor.

Link to comment
Share on other sites

On 12/18/2016 at 2:05 PM, DanAatTheCape said:

IF the CEL has a 52 (knock sensor)  the computer will put the engine into "limp" mode.   Performance will be terrible as will gas mileage.

I overheated 2 summers ago and got that code. I made a work around (you can not just "unplug" the knock sensor to "fix" the problem) and limped home.  Replacing the KS is a big job -involves removing intake manifold. The manual says the front of the engine has to come off (timing belt) but there is a way to avoid that. 

BTW< several toy mechanics familiar with the VZ3E engine have told me the issue is usually the wiring harness that goes to the KS - less then $20.  When I got into mine I bit the bullet & replace the KS too - I did not want to go back in there.

Wonder if the person who rebuilt the engine changed the KS wire harness - that is SOP for a seasoned toy mechanic. In my case, I adjusted valves due to mileage (90K) and how hot the engine was. My exhaust valves were way out of adjustment. 

 

 

 

Knock sensor was on when it was not overheated. 

This 91 year does not put the truck in limp home mode. It drives normally and goes through all appropriate gears.

Unfortunately, previous owner did not surrender any receipts for repairs. The mechanics shop was a Ford Dealership, which is all that's available in that area. He told me the mechanic checked it out, and found no knocking. I presume the sensor harness failed after the rebuild warranty expired and was cost prohibitive to repair.

I have that limp-home problem with my 2000 Volvo V70. It has a quirky problem in the gear shift that gets sticky in hot weather and trips a check engine/limp home mode putting me in perpetual 3rd gear. Luckily there is a tricky fix I found on a Volvo boards. 

Link to comment
Share on other sites

19 minutes ago, quasi-moto said:

Knock sensor was on when it was not overheated. 

This 91 year does not put the truck in limp home mode. It drives normally and goes through all appropriate gears.

Unfortunately, previous owner did not surrender any receipts for repairs. The mechanics shop was a Ford Dealership, which is all that's available in that area. He told me the mechanic checked it out, and found no knocking. I presume the sensor harness failed after the rebuild warranty expired and was cost prohibitive to repair.

I have that limp-home problem with my 2000 Volvo V70. It has a quirky problem in the gear shift that gets sticky in hot weather and trips a check engine/limp home mode putting me in perpetual 3rd gear. Luckily there is a tricky fix I found on a Volvo boards. 

not sure what you are saying?   my understanding of toyota limp mode for code 52 does not affect the tranny.  It retard timing so as to prevent detonation, which robs power and fuel mileage.

Link to comment
Share on other sites

Many times you can reproduce spark knock with a hammer start the engine and watch the timing give the block a good tap and see if it retards. The biggest failure with the 3L was the wire harness. To properly check it you will need a oscilloscope to look at the wave form if you get nothing it most likely will be the harness. 

Link to comment
Share on other sites

8 hours ago, Maineah said:

Many times you can reproduce spark knock with a hammer start the engine and watch the timing give the block a good tap and see if it retards. The biggest failure with the 3L was the wire harness. To properly check it you will need a oscilloscope to look at the wave form if you get nothing it most likely will be the harness. 

I think you are describing a way to verify knock sensor AFTER achieving access.   I have read accounts (google it) on how to test a KS - using an impact hammer (like some use to remove lug nuts) to create a steady bam bam bam  --then something to measure output  -a KS is a piezzo - transducer. (generate electricity under impact).  

The poor performance described is consistent with bad KS induced limp mode.

Link to comment
Share on other sites

16 hours ago, DanAatTheCape said:

I think you are describing a way to verify knock sensor AFTER achieving access.   I have read accounts (google it) on how to test a KS - using an impact hammer (like some use to remove lug nuts) to create a steady bam bam bam  --then something to measure output  -a KS is a piezzo - transducer. (generate electricity under impact).  

The poor performance described is consistent with bad KS induced limp mode.

Nope all it needs is a sound that mimics a knock it will not work on every thing with a knock sensor but it will work on many. It would be very hard to read voltage as a transducer it is pretty wide banded as far as noise and very easy to see a wave form spike and that is Toyota's preferred method. Yes if it fails it will limp. In the case of the 3L the highest failure seems to be the harness from the sensor to the loom.

Link to comment
Share on other sites

Found a good discussion on a Toyota boards about this. Lots of folks replace the pigtail k.s. wire assembly and it does not solve the problem. It really can be so many things or a combination of several. 

https://www.yotatech.com/f116/3vze-code-52-knock-sensor-184480/

 

Link to comment
Share on other sites

If it won't start in Park. Try starting in Neutral.

If the starter is marginal, a tap with a tire tool can revive it.

If the fuel pump is marginal, whacking the fuel tank with your palm may revive it.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...