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corsepervita HalfDork
2/15/22 3:02 p.m.
Jerry From LA said:

The code is for "too high or too low."  I wonder if you're losing 12 v intermittantly.

Part of why I'm wondering if I'm having an alternator issue, or potentially a harness problem.

My new sensor will arrive today so I'll go do some troubleshooting with a multimeter and see what I can find out.

corsepervita HalfDork
3/17/22 11:26 p.m.

I don't wish to curse myself via the mopar gods, but I think I have found and resolved the issue.

There was a multitude of weird issues.

#1.  The car would intermittently get insane spikes of very very very rich conditions.  The car would basically load up and then backfire like a crazy motherberkeleyer.  If I slammed the gas and opened it up, it'd be fine, and then go back into "LOAD IT UP" mode.  It would then misfire, stall, and do this until the car was restarted.  It would eventually do it again.  It did this starting about 2 miles from home the day I came back from autocross.  What I found is that the original crankshaft sensor was loose, and broken.  On top of this, the harness had no guide for it and the wire was rubbing and touching things.  It seems, as odd as this may be, that it was getting noise being up close to the alternator.  I re-routed, reheatshrinked, and tied it down to ensure it is no longer going anywhere.  No more loading up now, no more spikes, and that was after driving a good hour and a half.

#2.  The map sensor was a noname.  The place I originally bought it from had it labeled as OEM.  However, I bought a new OEM sensor for the car, and not only do they slightly have some quality differences, but they have clear brand names and part numbers stamped on the OEM vs the one I got.  I am thinking I was sold a cheap knockoff and it was dying on me.  I replaced the vacuum elbow as well.

#3.  The harness was pinched.  I noticed that sometimes (but not all the time), if I grabbed the harness or connector while it was still connected and wiggled it, the car would stall, and act as if the map sensor had been briefly disconnected, resulting in the check engine light.  I snipped the connections about halfway down the harness, tested with my multimeter and was able to reproduce wiggling it and moving it and seeing the resistance jump all over, indicating that indeed, they were pinched and broken somewhere.  I added extra wire to extend it to alleviate any stress on the harness.  More heat shrink, a new loom, and it is happy again.

I drove for a good hour and a half after all this.  It's idling perfect, running fantastic, throttle response is out of this world good amounts of snappy, and it has way more power than prior to the rebuild.  So fingers crossed.... i think, for now... I'm done fixing the viper and can go concentrate on the Jalpa again.

TVR Scott
TVR Scott SuperDork
3/18/22 9:53 a.m.

Very cool.  Nice job tracking down the electrical gremlins.

BA5 Reader
3/18/22 10:47 a.m.
corsepervita said:




Forgive me if this isn't a cool thing to say, but I mean it in a good way:

Scrolling past those pictures I thought it was a miata at first.  From certain angles it actually kind of looks like a slightly bigger NB miata.

BA5 said:
corsepervita said:




Forgive me if this isn't a cool thing to say, but I mean it in a good way: Scrolling past those pictures I thought it was a miata at first.  From certain angles it actually kind of looks like a slightly bigger NB miata.

My first post here, sorry if it's a bit of a thread jack...

The reason they look similar is because Ken Saward was on the design team for the Viper concept car and Mazda hired him to help design the second generation Miata.

There are a few pictures online of a nearly matching blue Miata next to a Viper, both have white racing stripes. Image search "Miata Viper". The Miata looks to be a 1999 Special Edition. At one time there was an aftermarket bumper available designed to make the Miata look even more like a mini-Viper. yes

BA5 Reader
3/18/22 7:27 p.m.
corsepervita HalfDork
3/20/22 12:27 a.m.
corsepervita HalfDork
3/21/22 1:03 a.m.

I did a thing.

So I was using a "DSO Shell Kit" Oscilloscope from amazon to troubleshoot these issues.

However, I had no good place to mount it.  So I made a mount that'll fit to gopro and action cams for people who are interested in a cheap, DIY oscilloscope and may want to print their own mount for it.


corsepervita HalfDork
5/16/22 1:40 a.m.

Well, the engine rebuild has been running splendidly.  I finally got out and did autocross.  Unfortunately, a power steering line popped on my way back from lunch.  Good news is, it's a cheap and easy fix but it unfortunately stopped the rest of my day.  My morning sessions got better and better, eventually getting a clean 42.5 for the day.  Definitely feeling much better this time around.

(edit) just looked at the results, I got 3rd today!


Here's all my morning runs


corsepervita HalfDork
6/2/22 2:17 p.m.

Well guys, dunno if I'll make it to the next autocross, we'll just have to see how things go but work is pretty busy.

I did, however, finally take some time to clean the car up after the engine rebuild for the first time.  I actually bothered to detail it.  There's a car show this weekend and all proceeds go to a cancer research center so I entered the viper.  I still have some more work to do but it's lookin' so much better.

I'll post some of the old pics of when I first got it so you can see just how far this car has come.

First... the car today




Here's some early pics:

The paint in the sun which was a dull, swirled mess (which I have since corrected and ceramic coated)

the sanding spots a previous owner put on for tree sap, in this photo i've been wetsanding it down finer and finer as i'm working on getting rid of them in this photo

more nasty up close



engine bay when I got it, which looked like it had sat out in a windy desert for ages as it was covered in dirt/dust/grime

the interior, which you can see, looked to have never been cleaned, along with an autozone shiftlight


Anyway, I don't really expect to win anything at the show with a stock viper.  I think the charity portion in itself is pretty rad so I'm stoked to go.  I am not really a showcar kinda guy but I figure autocross isn't for another couple weeks so... why not.  I'll try to snag some pics at the event.

So far the oil pressure and rest of everything else is absolutely perfect.  Engine is running like a top.  I was beating the piss out of it at autocross and it's running strong as can be.  I do think I should probably invest in some better pushrods so I don't bend any since it did see the rev limiter several times.

The new power steering lines are in so no more fear of fire.  So glad I caught that before it became a fire.

CoolHandMoss Reader
6/2/22 4:02 p.m.

Very cool project. Glad to see it coming together. You are going to cost a lot of people a lot of money if you prove that a viper is the car to have in a-street lol. 

CoolHandMoss Reader
6/7/24 12:25 a.m.

Did you ever get to run in A-street? I've been curious how this went. 

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