Originally Posted by INVESTIGATING GM'S COMPRESSION SENSE IGNITION by Jim Garrido

This combustion chamber detective uses ignition signatures to deduce engine phasing and cam position. We'll show you how it gathers the clues.

Several General Motors vehicles are equipped with a 2.2L engine called IiCOTEC. This four-cylinder, fourvalves-per-cylinder, all-aluminum power plant was first installed in some Saturn models, beginning with the 2000 L-series. Saturn VUE and ION models followed. It was the optional engine in the 2002 Pontiac Sunfire and Grand Am, Oldsmobile Alero and Chevrolet Cavalier and MaIibu, and standard equipment stalling in 2003. The ECOTEC is also used in the Saab 9.3.

The ECOTEC engine uses a speed density-based fuel injection system, along with a waste-spark electronic ignition system. The waste-spark ignition is part of a unique Compression Sense Ignition (CSI) system that allows the powertrain control module (PCM) to determine proper engine phasing (cam position) without the use of a separate camshaft position sensor mounted near a rotating engine member. This article will explain how the CSI system operates. We'll also document new misfire diagnostic techniques that are made possible by die system s unique design.

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Originally Posted by alleycat58

That's pretty cool. It's not 2.2 specific, all Ecotecs have the same ignition system.

Originally Posted by alleycat58

I can see where you got that it sounded 2.2-specific because at first they were listing off the 2.2L applications, but then when it got down to the nitty gritty of it, they were talking about the Ecotec line of engines in general.

Originally Posted by red_wing_2121

I have a 2.2L, so I guess I was just thinking of my engine when I first titled it.

Originally Posted by avro206

The 2.4L ignition is some what different and better then 2.2--just an updated one I guess.

Originally Posted by justin_k

Is there a simple way to sum that up for someone who lacks engine knowledge?

Originally Posted by alleycat58

That's pretty cool. It's not 2.2 specific, all Ecotecs have the same ignition system.

Originally Posted by Novajoe

basically we have the same ignition system as every other car 03 and newer. Waste spark has been around for a while. Basically all it does is fire off an extra time on the exhaust stroke for emissions purposes. The ignition isn't anything special, every car on the market today with electronic ignition runs the timing off the cam sensor and crank sensor output signals.

Originally Posted by WopOnTour

Actually, the 2.2 is the only engine in the ECOTEC family that uses "Compression Sense" the 2.0L and 2.4L varients both have a cam sensor for event cylinder identification.
WopOnTour

Originally Posted by hypsy

Wow man. Apparently you didn't read anything I typed before you responded. MOST cars have CMP and CKP sensors. The Ecotec family doesn't have a camshaft position sensor though. Try reading the RIGHT info before you give WRONG info please. Thanks.


BTW...This system is also why it makes installing a MSD ignition a little more involved.

Originally Posted by hypsy

Yes indeed there is. On most cars there is a camshaft position sensor and a corresponding "device" on the cam to create a signal to tell the ECU what the valves are doing in relation to the crankshaft so it can detect what cylinder to put spark to properly. On the Ecotec there is no sensor. It is done through electrical feedback. There are sensors built into the IDI unit that take readings for cylinders 1 and 3 to detect which one has fired on it's compression stroke. It then matches the fuel injection up to the proper cylinder in the sequence.

Page 6-477 in the GM Service Manual, if you have access, describes the setup in detail in realtion to DTC P0340. Any other particulars you need let me know.

Originally Posted by Suprsky

The problem I have is I'm running comp cams with no cam sensors. I've been told the only way to make it start normally without cranking on it for about 10 seconds is to go to a stand alone ECM (engine managing computer). Other then starting it seems to run ok but doesn't like to idle below like 1200 RPMs. Will this hurt the engine and is there anything I can do about it without buying s stand alone ecm?
thanks

Originally Posted by alleycat58

That's pretty cool. It's not 2.2 specific, all Ecotecs have the same ignition system.