Engine RPM's

[littleb]

Im having problems with my car and i hooked it up to the logger today and it wasnt reading any RPM's. How would you check the cam angle sensor?

 

[mistaVR4]

/ubbthreads/images/graemlins/confused.gif So, are you having a problem with the car itself, or is it just the logger not reading the RPM's when the car is running? What seems to be wrong with the car, must know before you can get any help?

 

[littleb]

Theres a lot wrong. Im just trying to get all the sensors and stuff all fixed right now. I bought the car not knowing what ecu was in the car because it ran perfectly fine but then the caps failed so i took it out and found out that it was out of a 1990 talon. Ever since i bought a new ecu/chip the cars been running horribly under boost (no power and egt's were going through the roof) so I put it on the logger to try and see what was going on and there was a bunch of sensors not registering. So I (well my brother worked on it for awhile when i was in school) replaced all the sensors that werent working at the time and then today i noticed RPM's weren't coming up. So I'm just trying to check the CAS as of now. And then im going to worry about the big problem after that. Sorry for not making myself very clear.

 

[cspetros]

What logger setup are you using?

You're saying that the logger doesn't display a value for RPM's, but the engine does run (be it horribly under boost)?

If the engine is running, the CAS is working. The ECU uses it to control the injectors and ignition.

Are those sensors that he replaced now registering on the logger? If not, this might point to an issue with your logger.

 

[littleb]

Im using tmo on a laptop with a cable from ebay. Oh, another issue with the logger that i had, sometimes it disconnects for like 3 seconds and then connects back up. Doesnt do it all the time, just randomly.

And correct, a couple times it registered i think 78 max? or something like that.

And yes, they're registering now.

 

[Rausch]

Quote:
I bought the car not knowing what ecu was in the car because it ran perfectly fine but then the caps failed so i took it out and found out that it was out of a 1990 talon.

This is wired differently than the stock ECU, yes?

 

[littleb]

I figured it would be. But it wasnt. I dont know how it ran right. I forgot to add that it wasnt wired for the 1990. But also, theres no solid green wire on 6 or 14. IIRC 6 was green w/ a dark red tracer and 14 was green with a dark, not light, blue tracer. It made no sense to me at all.

 

[Rausch]

I just now noticed you're local. /ubbthreads/images/graemlins/rofl.gif PM me if I can help, or just want to buy a roller. /ubbthreads/images/graemlins/crazy.gif

 

[littleb]

Haha, help maybe, roller no. Im a kid fresh outta high school, pretty damn broke. Getting this car running good is gonna cost me enough. Thanks though ill keep that in mind.

 

[Rausch]

/ubbthreads/images/graemlins/rofl.gif Shoot me a PM if you need some help. I'm on the near west side, so not far at all.

 

[Hertz]

The CAS is also used on the tachometer. If the tach moves, the CAS is good.

 

[littleb]

So then why the heck would the logger be reading 0 for rpm? Problem with the logger possibly?

 

[CarRacer]

I think I remember Toybreaker telling me there are two phases to the CAS signal. One phase controls the spark and such and the other sends the rpm signal. I'm not 100% on what each phase does, but I do know there are two circuits on the CAS.

Have you messed with any of the wiring? I'd inspect the wiring near the ECU and see if some of the wiring is fubared from a previous owner putting in an AFC or something.

 

[toybreaker]

James, while there is two seperate signals generated in the cas (one that reports #1 tdc every 360* of crank rotation, and a seperate position signal that reports every tdc event at 180* intervals of crank rotation), this doesn't sound like a cas problem.

This sounds more like a problem with ecu/wiring. /ubbthreads/images/graemlins/dunno.gif

Keydiver has a much better understanding of the '90 system, and would be the best source of troubleshooting information on this problem.

If you need some hands on help, I saw Rausch offer some local help. He's pretty good with stuff like this, (and local to boot).

[edit] It would help to know if the tach in the instrument cluster works while this problem with the logger is occuring.

 

I suspect a logger issue, as the car shouldn't even run without the CAS working. The RPM signal in the ECU is generated by the CAS, whereas the dash tach is driven by the output of the ignition coils, and that TACH signal isn't necessary for the RPM to be shown on the logger.
A 1990 ECU isn't going to make any difference either, as the CAS signals are the same. The 1990 ECU is only a problem if you have a bad transistor or coilpack, since you will never get a CEL 44, because the tach pulse polarity is wrong. That still won't keep the car from running right, or the correct RPM from showing on the logger.

 

[littleb]

I would love to have the local help, but im extremely busy for the next week or two because my sisters getting married next week and shes coming in tomorrow so I need to help with all that sort of thing.

I took a look at the wiring for the AFC and it looks like its a pretty shady job. Im gonna take a better look tomorrow when I have more time to actually take a good look at it. Ill also try to try a differnet laptop/logger.

And i dont have a 90 ecu, i bought an eprom ecu from keydiver after the caps issue.