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Rev limiter- '93 SC2 DOHC, manual trans

  #1  
Old 07-20-2015, 10:12 AM
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Question Rev limiter- '93 SC2 DOHC, manual trans

HELP.....we just completed an engine/trans swap in a 1993 SC2-DOHC 5 speed manual. Now the 4000 RPM rev limiter which was never noticed before, is kicking in regardless of whether the engine is in gear or neutral, standing still or driving. It kicks in in all gears, regardless of vehicle speed.

FYI, the parking brake has been removed, and there is nothing connected to the e-brake connector wire. We read on the forum that the parking brake might cause the rev limiter to initalize.

We suspect the the VSS or it's connector may be causing it as the trans is different and the connector looks a little sketchy.
This car is used for racing and the instrument cluster has been removed, so we can't see the speedo or MIL.

Any suggestions would be appreciated.

 
  #2  
Old 07-20-2015, 11:56 AM
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Does sound like VSS, as that should only be triggered when speed is <3 mph (when sensor output begins) and in neutral. It transmits 16 pulses per revolution of the differential assembly.

VSS is located on back side of tranny as mounted in the car (side of trans facing back of vehicle) near the bell housing.

VSS resistance should be 700-900 Ohms. If this checks out, you'll want to check out the connector and trace the wiring (yellow and purple) to pins J2A209 (yellow) and J2A10 (purple) at the PCM.

Since you pulled the dash, I'm thinking you also took the diag port with it. If not, you could possibly read real time data through an OBD II scanner w an OBD I adapter.
That way you could verify improper mph signal while driving in real time.

Not sure what you mean by trans looking "different". It should be an MP3 tranny (as are all DOHC M/T cars). ID stamp is on top bell using and should be "MP3" for the 2nd, 3rd, and 4th characters. 1st char is a single digit for the year.

If you find an MP2 in there, all I can say is "go shopping" b/c you're not gonna do well with it---MP2s are for SOHCs and are geared differently. There are no other bolt on M/T s for the S cars.

I deleted your double post.
 

Last edited by derf; 07-20-2015 at 12:08 PM.
  #3  
Old 07-20-2015, 03:11 PM
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Thanks for the reply. What i mean by different trans, it's a later one from 97 with limited slip and better ratios.
 
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Old 07-20-2015, 06:39 PM
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ok, this is how it works.

your team asks a question- 1 person from your team--In 1 location on the forum.
I've already deleted a double post on the subject.

I gave you a lead on the VSS and what the test results should be.
What are the test results?

I don't need Katie pm ing me almost verbatim what's already been posted twice and now a third time to my pm box. Technically not a triple post but mighty close to getting banned.

Keep the questions in the existing thread. I read every post. No tech questions in my pm box period. Anything you need to ask you can ask in front of the others --- they might just know something I don't.......
 
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Old 07-20-2015, 11:09 PM
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oh -- and unfortunately there is no hack for the S series PCMs that I am aware of.

I am more than willing to help you folks out -- I'm normally an easy going guy--let's just keep all the posts/questions in the thread.

Actually, I need to make a correction to what I stated earlier. I have no problem with multiple members of your team posting, as long as it is ALL to this one thread IF it relates to the rev limiter. More heads put together increases chances for success.

Of course if there is a distinctly different issue that needs addressing, just start a new thread.

Sorry but one of my pet peeves is having the same info sprayed across the forum and then into my pm box. That and registering multiple usernames from the same IP---but I'll waive that for you folks since you're all prob sharing a laptop when working on the car.

There is a 10 post/10day minimum to become a permanent member -- so actually I guess it does behoove you to post through the first poster's account so they get to ten in time . You'll get a pm shortly

We want you here if you want to be here.

Just chill a little (and so will I) and it'll all be good.

Peace
Love
Derf
 

Last edited by derf; 07-20-2015 at 11:13 PM.
  #6  
Old 07-21-2015, 07:56 AM
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I had no idea Katherine was posting a pm. Sorry.
 
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Old 07-21-2015, 08:31 AM
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BTW, I posted the same query on Saturn Spot, Saturn Fans and this forum. I assumed they all might have different members and/or expertise.

Have not had a chance to test the VSS nor do I have an OBD adapter yet.
 
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Old 07-21-2015, 08:38 AM
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  #9  
Old 07-21-2015, 09:55 AM
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VSS ohm'd out at ~800.
However, the connector wires are not yellow and purple. They appear to be blue/white stripe and light green/yellow stripe. May have been changed with aftermarket pigtail.
 
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Old 07-21-2015, 11:18 AM
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No worries--it's all good...

Saturnspot has a sordid past which involved moderators who went AWOL, causing the site to be overrun w spam, which led 98% of the membership to go to Saturnfans. So while the Spot may not be terribly active, there is a wealth of info buried from some pretty knowledgeable folks in there waiting to be searched.

Google search on anything saturn related will bring up Saturnfans results first. Why? MASSIVE activity and the sheer number of posts. This is a double edged sword when you post there, as the rate at which questions are posted is so high that any member has so many new posts that you don't know which are getting read......The advice from some of the veteran members is spot on; other replies are questionable.

If none of us here know the answer, one of us will likely mine the 'net for some clues. Or we just say we have no clue. No BS answers here that cost people money for things they don't need. BSers and clueless wonders get a quick exit.
_______________
I think I may have been slightly misleading you on how I got real time data out of the OBD I port with the OBD II scanner
Just to be clear:

My neighbor bought an OBD II code reader w real time data display and the ability to select year and make of the vehicle. That worked fine on my 97, but not on my OBD I 95. So I purchased an ODB I to 15 pin Actron Cable specified for GM (female), connected his 15 pin extension OBD II cable(male), and then to the OBD II scanner with the hopes that it would read real time data from the OBD I port. I got what I believed to be valid data. All readers/scanners/ cables were Actron. They no longer sell them on the website. Unfortunately there is no part number on the OBD I to 15 pin female part --you can contact actron for that. I also do not know the model of my neighbor's scanner but think it was from the Actron CP9100 series

There are oodles of direct conversion connectors for sale (on Amazon for example) but they get **** reviews, and without knowing how the thing is wired (you'd think GM standard would be GM standard), it's a crap shoot.

I would contact the manufacturer of your scan tool to see if they have a converter for your scanner.

I believe my setup worked for 2 reasons:

a) the scan tool I used allowed you to choose the year and make of the car being scanned--even pre 1996 cars
b)all parts of the cabling/connectors were from the same company and thus a known entity

I can't guarantee it'll work with the universal GM ones out there.

Again, contacting your scan tool manufacturer is prob your best bet. Maybe they have some sitting in the warehouse.
 

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