0 Tach/bucking/CEL

[ctwrench]

My '92 has started an intermittent problem of running rough at idle, bucking at cruising speed and during acceleration. The tach will sometimes drop to 0 even though the car is running fine. If the tach isn't at 0, it either reads fine or follows the roughness of the idle. Sometimes the CEL will come on during these events, but not all the time. I haven't had a chance to get any codes, yet, but figured I would see what I could find from here. I'm thinking it may be the cam or crank sensor. Which one operates the tach, crank? Thanks in advance for the help.
:thankyou:

 

[encryptshun]

cam sensor i believe?

 

[SuperHO]

correct you are, sir. you are now the proud owner of a faulty cam position sensor! you've won a non expenses paid trip to the parts store, where you'll be ***** on the price only to get home and tear open three knuckles getting in there to replace it!

 

[92MTX]

Pulling the intake will save you some skin...
I can do it in well under 30 minutes now.. lol
undo the T.B., and leave it in the car, that saves time..
Make sure you put the coolant lines back on on.
Or, this is the time to do the coolant bypass for the T.B. (We don't need it here in TX..)
And don't drop the cam sensor screws!
I use a magnetic nut driver so I don't lose them..

 

[St Louis SHO]

Dont pull the intake, thats dumb. Pull the crossover tube maybe. I usually remove the engine support shock and PS reservior and move that stuff to the side for a direct shot.

Yes, your Cam sensor is faulty, a $30 or less part.

- James

 

[ctwrench]

I've already got the new sensor. $29 at the Zone. I've read something about using a synchro positioning tool or else there can be damage to the fuel system. Any thoughts?

 

[St Louis SHO]

It's clocked on the head, no need for that...

 

[92MTX]

Yes, you can do it by pulling the cross over tube..
But pulling the intake will allow you to do the plugs and wires, with ease..
Look for vertical cracks in the plastic part of the boots..
4 of the 6 had cracks on mine..
That is if you havent done the plugs and wires yet.
They are a real ***** to do with the intake on..
YES, I know it can be done, but it IS EASIER with it off.. IMO
Vato-zone has some pretty good wires for 44 dollars??

 

[Huntervf]

Did I miss something? I thought the OP was just replacing the cam sensor

No need at all to remove the intake for that. Plugs and wires yes, but not the cam sensor.

 

[SHOCH]

How many SHO mechanics does it take to change a cam sensor?
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Six
One to do it and 5 to ask, "Why did you do it like that?
Yea I know REPOST

 

[hawkeye18]

One to do it and 5 to ask, "Why did you do it like that?
Yea I know REPOST

Yet, somehow, still timely - especially given this thread. FWIW, I tend to agree with the others on additional maintenance - if you don't know when the last time the plugs and wires were changed, it certainly couldn't hurt to change them (except your wallet).

It is, of course, entirely up to you.

For me, a cam sensor is about a 15 minute job (to be fair, I have piano hands) and not really worth all the added effort of changing other stuff, but generally I like to keep the 'Things I replace/fix/change' to 'Times Into the Deep Dark Abyss' ratio pretty high.

 

[mattsho1993]

been there done that i just took off the damper and moved the power steering res out of the way but yeah deff strip knuckles

 

[The Grand Pooba]

Hello, I'm new to this forum mainly for this reason. I have the same issues as the original poster. I was looking through an unrelated repair manual I had laying around and it said that the CRANK position sensor was tied in with engine rpm and spark timing. I am just checking to make sure that I really do have to change the cam sensor and not the crank sensor.
-thank you

 

[randy'sho]

I had the same symptoms as the OP when my cam sensor was going south!

 

[SuperHO]

9 times outta 10, crank sensor failure is closely followed by a trip on the back of a tow truck due to the engine's inability to start. the symptoms described in the original post are classic cam sensor failure signs. now...who ya gonna believe, some repair manual that probably lists changing the supercharger oil as regular maintenance or a couple of guys who've been around the block a time or two with these hookers?

 

[The Grand Pooba]

Well I'm on a tight budget, and that's why I came to the forum that has people who know the SHO. Thanks for the clarification