Tack droped to 0 and car started cutting out bad.

[t5535]

Ok first of all I got to say thanks to all you pros for all the help. But I got 1 more prob. Got the car running and driving great yesterday!!!!!!!!! today I was driving it and the tach droped to 0 and the car started cutting out real bad. I shut it off for a min and started it back up and everything started working again. what may have caused that because I am sure it will happen again?

 

[zach44102]

Cam sensor

 

[rubydist]

normally, if the cam sensor is bad, the tach will drop to zero and the car will run normally - but it will be hard to start as the dis will not know how to time the spark.

a sick cam sensor could cause the symptoms you describe, but also a sick dis can do the same thing.

you can check the cam sensor by unplugging it (may take several tries to get the engine started) but if it runs well, then the cam sensor needs replaced. if it has the same symptoms then I would replace the dis.

 

[Denny]

I don't see how a cam sensor would have anything to do with the tach. The tach signal comes off of the crank sensor. I had a similiar issue recently and while I truly didn't find the cause; either a bad coil pack or the connection itself. Here is what you should check. First, check the battery and the connections. Then check your grounds(one behind the intake by firewall on the intake manifold mounting arm. The bolts that connect the crossover tube to the manifold. The small bolts for the DIS to the crossover tube.) Check your crank sensor, is it wet because the waterpump is leaking on it?

This is a tough one to validate, but something electrical is at fault. Good luck and report back because I always have this on the back of my mind now.

 

[zach44102]

Denny, IIRC your tach signal goes from the cam sensor and then through the DIS.

 

[t5535]

I checked for water leaks. there are none. gonna check the cam pos sensor next.

 

[t5535]

I checked the grounds they look good. the motor was just put in the car. it has been running for 2 days. this is discouraging. gotta check the cam pos sensor next but its running fine right now. should I start it then un plug it or unplug it then start it?

 

[t5535]

Denny, IIRC your tach signal goes from the cam sensor and then through the DIS.

is that the stig from top gear that you have for you picture?? love it.

 

[t5535]

normally, if the cam sensor is bad, the tach will drop to zero and the car will run normally - but it will be hard to start as the dis will not know how to time the spark.

a sick cam sensor could cause the symptoms you describe, but also a sick dis can do the same thing.

you can check the cam sensor by unplugging it (may take several tries to get the engine started) but if it runs well, then the cam sensor needs replaced. if it has the same symptoms then I would replace the dis.

Stupid question what is dis short for?

 

[Toolman]

Distributorless Ignition System

 

[SVOFANATIC]

I personally know it to be your cam sensor. Before my motor blew mine was going bad. It would cause the tach to go to 0 and would run like crap until I shut it off and started it up again it would run good just without a tach. Try wiggling the plug while its running that's a good way to tell.

 

[t5535]

I personally know it to be your cam sensor. Before my motor blew mine was going bad. It would cause the tach to go to 0 and would run like crap until I shut it off and started it up again it would run good just without a tach. Try wiggling the plug while its running that's a good way to tell.

will try that now.

 

[t5535]

Ok heres what I did. I unpluged it while it was running and it died. I left it unpluged and started the car and it started fine but no tack. sounds like this is what is causing the problem. when it went nuts I was driving the car so I dont think it would die that easy like it did at idle. when I restarted the car (on the side of the road) it ran fine but no tach then eventualy the tach came back on. I cant rember if I shut the car off then back on for the tack to come back on (while on the road)

 

[Denny]

Anybody got a wiring diagram?

A cam sensor is in charge of fuel delivery, the PCM needs to know which valves are open and which are closed to deliver fuel.

The crank sensor measures how fast the engine is spinning.

OP. I'd check your connection at the coilpack and the coilpack as well. I swapped mine and my erratic tach and stalling concern that plagued my fairly recent motor swapped ride were resolved when I replaced the coilpack. However, when I went to disconnect the coilpack, I found the orange isolator in the connection to be bunched up...so maybe the issue was that the connection was spread apart because of that.

 

[llamaking122]

crank sensor also controls fuel delivery. it times the injectors. ask me how i know..... its most likely cam sensor or DIS pack.

 

[lowc]

replace the cam sensor and your problems will go away

 

[rubydist]

reading this thread makes me angry. if you guys don't know wtf you are talking about then shut up and learn something.

the op was told in post #3 exactly what to do to confirm whether it was the cam sensor or the dis that was causing his problem.

then in post #4 he was given information that was completely wrong - no wonder the guy is confused!!!!

op - if you unplug the cam sensor, you will get no tach reading (whether the cam sensor is good or bad!) - what you need to determine is if you get the same running poorly condition with the cam sensor unplugged or not. if you do, then its not the cam sensor that is causing your problem. if the problem goes away, then changing the cam sensor should solve the problem (unless its a wiring issue.)

 

[220ksho]

Sounds to me like a bad crank sensor. Here's why.

Going down the road and the tach drops to zero. Actually, the engine stalled momentarily. And since it's a manual trans, it started itself back up again once the crank signal was acheived again.

You should have a stored code for an erratic ignition signal.

 

[SHOtimer]

Sounds to me like a bad crank sensor. Here's why.

Going down the road and the tach drops to zero. Actually, the engine stalled momentarily. And since it's a manual trans, it started itself back up again once the crank signal was acheived again.

You should have a stored code for an erratic ignition signal.

Not necessarily. When my cam sensor went bad the tach would drop to zero '0'...and the motor would keep running like normal.

The cam sensor is going bad and part of that is that it is dropping it's signal for the tach.

To echo Rudydist, the answer to this thread was given in post #2.

Doug

 

[SHOtime2511]

1. Check the ground strap on the rear passenger side of the intake manifold.
2. If the ground is properly connected,replace the cam sensor.