Daox's 1997 Paseo Build Thread

[hackish]

No, not really. The cam(s) rotate at 1/2 the speed of the crank. A complete engine cycle is 720 crank degrees or 360 cam degrees. The crank pattern will therefore repeat twice for each engine cycle and the ECU needs to see the cam pattern to discern whether the engine is on the 0-360 or 360-720 phase. If it doesn't know this then it might be shooting fuel at a closed intake valve which is not very good for economy and emissions.

The majority of OEMs will not fire injectors until it gets this sync. Spark doesn't matter because the plugs won't do anything on the exhaust stroke because there isn't much left to burn in there. This also explains the observed behaviour and incorrect assumption that the injection timing comes directly from the cam. My subaru for example uses the cam sensor to start. After that you can unplug the cam sensor and it will happily run all day long. Won't start unless it gets that signal.

-Michael

[Christ]

My Civic (OBD-0 MPFI) would start and run w/o the CPS (Cylinder position sensor)... not sure how the injector signal is timed on those... the CPS on that particular engine is in the distributor, which is cam-driven (the DOHC engines from that family had the CPS on the opposite cam from the distributor, same electronics, though.)



I guess we're a little OT here, though.

[hackish]

Most hondas up to around 1998 or so used only the distributor so you're already running at 1/2 the engine speed. Later models added a crank speed variation sensor that bolts to the oil pump and triggers off a toothed wheel behind the crank pulley.

Also, limp home features are very important to carmakers so they can do lots of things to get you home if a sensor fails. Some cars just drop down to batch injection when one of the rotational sensors fail. In theory you could run an engine off a single sync pulse on the crank or cam. It just wouldn't work that well.

-Michael

[Daox]

Yeah that makes complete sense. The cam sensor only has one trigger point where as the crank sensor has many trigger points for improved resolution. Thanks Hackish.

[Daox]

I had some trouble on the way home last night. The car started missing when I was pulsing, at idle it was fine. So, I let up and just drove a steady speed. By the time I had gotten to my house, it was even starting to miss at steady speed.

Once home, I started taking things apart. First thought was the coil packs. I replaced them with ones from the other Paseo I have sitting in the garage. No difference there. Then, I removed the plugs and noticed one was darker than the rest. Bingo. One of the Pulstar plugs that I had gotten from a test on CleanMPG had gone bad on me. I replaced them all with Bosch platinum plugs from the other Paseo and it drove smooth again.

I mention this only really because I've only been running the Pulstars since 8/08, roughly 1.5 years, and only 8,400 miles. These things were supposed to last, and had I actually paid for them I would be very upset. They cost a small fortune if I remember correctly. BTW, I saw no noticeable increase in mileage when I installed them.

BTW, I almost thought the Bosch platinum plugs were bad too. Its a weird looking design. I pulled them out and was like... aw crap, theres no electrode left! But, apparently thats the way they're supposed to be. Mine look just like this, but have only two grounding straps on the side.

[Christ]

Bosch Platinums are exactly the same as other plugs for electrode design.

Platinum +2 are what you have, and they're cut back so the flame kernel propagates to the center of the electrodes.

Platinum +4 are what you've pictured here, same idea.

Platinum +2 and +4 plugs have been shown (somewhere) to increase spark advance due to lower signal latency (I believe that's the correct term). In some people's engines, this has caused problems, and in severe cases, engine failure.

Best to check and adjust, if you have a way to adjust for it. Might even get an extra .00002 MPG out of it. LOL.

[Daox]

I just got a notice from USPS, my adjustable cam timing pulley is on its way! I got a grey one pictured below.




I'm curious if there is enough adjust ability in this pulley to get something like a Prius/Atkinson like effect going on.

I have started a new thread to discuss this mod:
http://ecomodder.com/forum/showthrea...-fe-12488.html

[Daox]

Well, it was impromptu mod time tonight. On the way home I decided I had enough keying off and decided it was time for a kill switch. When I got home, I grabbed my electrical diagrams and found the crankshaft position sensor wire off the ECU.





I snipped it and soldered on wires.




Brought the wires up through the shifter boot and soldered on a normally closed momentary switch that interrupts the crankshaft position sensor signal.




For now, I just taped it on. I'm not sure where I really want it yet, but this looks like a good spot. I can reach it with my thumb, but its not really in the way if I grab the shifter.




I tried it out a few times in the driveway. It works great. I do think I want to put another switch in parallel with it to make an override for when other people drive the car so they don't have to worry about killing the engine.

[Christ]

Originally Posted by Daox

Well, it was impromptu mod time tonight. On the way home I decided I had enough keying off and decided it was time for a kill switch. When I got home, I grabbed my electrical diagrams and found the crankshaft position sensor wire off the ECU.





I snipped it and soldered on wires.




Brought the wires up through the shifter boot and soldered on a normally closed momentary switch that interrupts the crankshaft position sensor signal.




For now, I just taped it on. I'm not sure where I really want it yet, but this looks like a good spot. I can reach it with my thumb, but its not really in the way if I grab the shifter.




I tried it out a few times in the driveway. It works great. I do think I want to put another switch in parallel with it to make an override for when other people drive the car so they don't have to worry about killing the engine.

So, I see this becoming more and more of a concern with people who have kill switches... why not just mount it somewhere near the key?

It's a place that only you would ever reach while driving, so no chance of someone else knocking/using it, or damaging anything, etc.

Those plastic pieces around your steering column come off fairly easily, usually, and it'd be a great place to mount it where it won't get bumped/used accidentally.

[jedi_sol]

Originally Posted by daox

on the way home i decided i had enough keying off and decided it was time for a kill switch.

finally. Oh, btw, why the crankshaft positioning sensor? What are the benefits? Sorry im not that mechanically inclined.