Jake Galla

Just got a cam sensor failure code on the OBD reader. I don’t know what it takes to fix the problem or where the sensor is even located.

Any help? Is this a common problem?

Tuned Performance

iTrader: (92)

41 EST Electronic Spark Control circuit
......No distributor reference pulses to the ECM at specified engine vacuum.

sofakingdom

iTrader: (1)

Your car doesn't have a cam sensor. Those codes don't always mean the same thing; different systems use the same code to mean different things. In these cars, the CC Q-Jets, TBI, & TPI all can have different meanings for the same code. The 6-cyl versions probably do too but I don't know anything at all about them except that some people claim they exist.

There's a list of codes on this site. https://www.thirdgen.org/service-eng...t-error-codes/

I strongly recommend NOT using a "code reader" of that sort, but rather, use the paper clip method.

naf

iTrader: (7)

that code will trip if the motor is ever run with the EST wire disconnected, which has to be done to set timing for example.

reset it, see if it stays gone.

GeneralDisorder

iTrader: (1)

Also means the timing is locked out so don't drive it - engine damage can occur.

GD

naf

iTrader: (7)

it's pretty 'safe' to drive with the EST code set.

even if the EST has failed (like in disconnected) the ignition control module has some rudimentary timing advance built in.

this advance can be observed with a timing light. with EST disconnected (such as when setting timing) bump your rpm's up to 1500 or so and you'll see a jump in timing. it's a step increase.

not ideal for the motor but not inherently dangerous. it's a 'limp home' feature.

GeneralDisorder

iTrader: (1)

The engine in my 84 Jimmy came to me with an Edelbrock carb, a large cap distributor with EST, and no computer (removed). It blew the HG's, hydrolocked, and threw a rod through the side of the block. Likely because it was towing a flatbed with improper timing.

GD

naf

iTrader: (7)

or maybe it was the edelbrock carb....

but yes, with the est no longer providing 'proper' timing control you'll eat fuel and likely run hot, especially under load

naf

iTrader: (7)

oh and i had an 85 jimmy at one time, with the 2.8

miss that slow work horse

GeneralDisorder

iTrader: (1)

Wow - a 2.8 in a Jimmy? Never knew such a thing existed. I figured the 305 was the small engine. Crazy.

GD

naf

iTrader: (7)

it was an S15

forgot they were still making the full size jimmies back then!

GeneralDisorder

iTrader: (1)

Oh! That makes more sense. Mine is the K5 Jimmy. They actually made them into the early 90's. Well - the K5 anyway. Not sure about the Jimmy specifically but the K5 Blazer for sure.

GD