What the heck did my car just do?

[Alley]

So I was having some fun with the car and basicly did a 1/4 mile run at WOT. In 3rd gear I felt a slight hesitation at like 5k rpm. Went into 4th and again at like 5k rpm had a huge hesitation, felt like the car fell on its face. So I put in the clutch and went to nuetral and come to a stop. Car was running really hot after this run. Then I start going again driving normal. I notice that my speedo is no longer working! My tach is fine, but my speedo reads 0. And I go to shift into 5th and I get nothing but grinding. Coasting along, I try clutching again a couple times but it just grinds when I try to put it into 5th.

So I stop the car and shut it off for a few min. Turn it on and start moving and my speedo works again! And it goes into 5th gear just fine! What the heck happened?

I do have gears and have one of those boxes thats wired in to make the speedo correct. But I didn't touch it when the car was off.

It was also about 90 degrees outside and I havn't really got on it in that kind of heat since I did my ported heads and tuned it and added 2 degrees of timing. Don't know if that could have something to do with the hesitation?

Whole thing just seems bizare. Any ideas?

 

[plumcrazy]

i take that back. i have no idea.

 

[dave6666]

I you get your car hot in a 1/4 mile in Nebraska you have a cooling problem or a tuning problem. And don't give a sermon about 90 degrees I live where it gets to 110 and have never gotten "hot".

Is it safe to assume all other gears were functioning correctly during the time that 5th was not? Did you try 6th?

 

[Bird325]

90 degrees? ... THAT kind of heat? Try running your Snake with our 110 degree days! I'm just glad that it doesn't shut down completely. Sounds like your PCM took over to keep you from messing something up ... these Vipers are pretty smart sometimes.

 

[Alley]

Since the ported heads and raised compression I have been running hotter on a regular basis. Even just regular driving in stop and go traffic. I may need to revisit the cooling system. Car was dyno tuned and just 2 degrees of timing added.

I forgot to try 6th, but all other gears worked.

 

[Alley]

Could there be some sort of wierd overdrive lockout that kicked in with the speedo at 0?

 

[dave6666]

Yes the overdrive speedo lockout at 0 mph was mandated by the EPA as it was determined that when you are not moving you don't save any gas by utilizing overdrive. To my knowledge they only installed it on one car before the engineers starting fighting over exactly how many decimal places there are in zero. Congrats on getting that 1 of 1 car.

 

[PhoenixGTS]

With no direct knowledge, but having monitored this forum for the last six years, I beleive that sounds like a weak spark plug wire issue. Tons of load, at high heat = miss = sounds like plug wires. Try searching that topic - specifically with user ab.

 

[dave6666]

With your smorgasbord of issues I think half of all the bolts on your car are loose. Just tighten everything and motor on!

 

[Alley]

With no direct knowledge, but having monitored this forum for the last six years, I beleive that sounds like a weak spark plug wire issue. Tons of load, at high heat = miss = sounds like plug wires. Try searching that topic - specifically with user ab.

That's not a bad suggestion. My wires got at least 6k miles on them. Same ones from when I bought the car.

 

[RTTTTed]

Thought the engine shutdown a couple times, now it just missed?

Don't think that the spark plug wires would shut off the speedo.

 

[Alley]

No the engine never shut off. It was a couple hesitations is the best way to describe it so maybe it was a miss. But your right that doesn't explain the speedo.

 

[REDBLACK]

Yes the overdrive speedo lockout at 0 mph was mandated by the EPA as it was determined that when you are not moving you don't save any gas by utilizing overdrive. To my knowledge they only installed it on one car before the engineers starting fighting over exactly how many decimal places there are in zero. Congrats on getting that 1 of 1 car.

stupid ****.

 

[RTTTTed]

Box for the speedo - was it wired incorrectly? If the computer thought you were tryiong to shift into second gear at low speed the solenoid would be activated to push the shifter out of the 1-2 gate and push your shifter into the 3-4 gate. If you were in fourth I don't know what would happen, but the skip shift solenoid is the only thing that the computer could activate that could possibly stop 5th gear shifting. Only other computer controlled solenoid is the reverse lockout and I doubt that would do anything except lock out reverse.

There could be a hundred or so things causing an engine "hesitation" or "rev limiter" action, one of them being the computer.

Most likely cause of speedo stopping would be the added box, connections or computer.

Common element in all symptoms is the computer. Could be the new box shorting out or no signal. Computer could do strange things like adjust rev limit because it thinks your car is stopped (as the speedo is telling you).

Computers do weird stuff when they think you're stopped. I always look to new things I've added to the car when there is a new problem as that's new stuff is usually the cause of new problems ( when you add stuff anyway).

Suggest removing box and run with no boxes in the wiring and see if the problem goes away.

Ted

 

[Alley]

Sorry I should have been more clear. The box isn't new. Had it on there for 2 years with no issues. I just wanted to make sure I was giving as much info as possible. But that doesn't mean that might not still be the issue. Since this is the first time this has happened I'll be watching to see if it happens again. And I'll check all my connections tomorrow.

 

[HOLLYWOOD1]

Smart ass Dave. A guy asks a serious question and the clown responds with an answer like that....there's another website for this garbage so go over there....

 

[Twister]

Good luck for a smooth easy fix

 

[dave6666]

stupid ****.

Smart ass Dave. A guy asks a serious question and the clown responds with an answer like that....there's another website for this garbage so go over there....

Morons of the day... Tough choice ladies.

I've probably forgotten more about cars then there are spokes on your Big Wheels

Just to let you know you've not imfluenced anything but your power bill. Congrats.

 

[Chuck 98 RT/10]

stupid ****.

Smart ass Dave. A guy asks a serious question and the clown responds with an answer like that....there's another website for this garbage so go over there....

Jeeze, what's the big deal? Dave's just having a little harmless fun. Lighten up.

 

[dave6666]

When you say your car got hot do you remember what the temp was? And how long you sat there as you said you pulled over for a few minutes? Time frames can become distorted when having car trouble. And do you recall if what your temps were when you got going again?

Like I said before with the smorgasbord comment, it almost sounds like 3 problems.

-> Engine
-> Clutch/driveline
-> Cooling

The engine and cooling can be related but I would solve them both by whatever means is needed. Adjust the tune or get the cooling up to *****. But the T56 electrical mechanisms are reverse lockout and skip shift. None of those match the symptom you describe. Did your clutch feel normal throughout this episode?

 

[InjectTheVenom]

I did not catch what year Viper we are talking about?

 

[RevHeat]

I did not catch what year Viper we are talking about?

Looking at his signature, its a 1995.

Rev

 

[Asp Man]

With what you've said about it not going into gear I'd guess clutch. Makes sense when you think about the "hesitation", probably just slipping under load. Cools down and it's OK again. Have you ever changed the stock clutch?

 

[rocknroll]

93' - Since the dyno in Lincoln a few weeks ago and the trip to Hastings, I also have an intermitent speedometer. It starts to act up only on the interstate in 4th/5th and 6th and I also get a shift light in 5th and 6th. I was ASSUMING hot tranny and I'm replacing the magnetic speedo pickup on the tail shaft this week. I'll let you know if it helps.

Max

 

[Alley]

After the run the car was at the nearing the 3/4 temp dash, so like 225. When I started again it was back to normal 190. Like 20 minutes later.

Clutch felt normal. Previous owner had the entire tranny replaced at 30k miles. I got 50k on the car now.

 

[eucharistos]

Smart ass Dave. A guy asks a serious question and the clown responds with an answer like that....there's another website for this garbage so go over there....

must also be joking ......

stupid ****.

or noob....

Jeeze, what's the big deal? Dave's just having a little harmless fun. Lighten up.

or, if not, chuck is right



i for one hope it is just your wires, but some other good things to check in this thread, pls post up what solution you find

 

[InjectTheVenom]

Looking at his signature, its a 1995.

Rev

Whops my bad, my cellphone doesn't show signatures

 

[dave6666]

225 is definitely not hot, esp around these parts. And thanks for clarifying "a few minutes". 20 minutes, or 1/3 of an hour, better explains how pulling over might have let things cool off versus the 2 to 3 minutes I expected from your original statement.

BTW, 20K on a clutch or slave can be worn out depending on how you drive.

 

[InjectTheVenom]

With what you've said about it not going into gear I'd guess clutch. Makes sense when you think about the "hesitation", probably just slipping under load. Cools down and it's OK again. Have you ever changed the stock clutch?

Sounds familiar.. but my maintenance guy keeps saying my clutch is ok As soon as I had replaced some vacuum hoses and went WOT white stinking smoke came from under my hood.
What could the cause be, pressure group or plates? Can't seem to recall if Viper's flywheel is solid or multipiece.

 

[Alley]

I would of thought a slipping clutch would of caused the engine to rev higher, not hesitate? No clutch smell was apparent either.

I just took the car out for a couple runs and everything seemed fine.

Going to order new wires today. They need to be replaced anyway. No idea how old they are.

But the speedo failing and 5th grinding still puzzles me.