Crank signal trouble? Any one else?

[hellbents10]

Any one have crank signal trouble with these? On the second box and its hit or miss upon start up. The factory ECU works great and the car has always hit right away. Now with the AEM it never wants to run, seeing 0 rpms on crank. Injector tooth counts don't move, there is no spark and no fuel.

Just started tuning another one today on E85, made 709 on the first pull at 8.8psi, fat with no timing.

Last one made 1060/1145 to the tires on E85.

Thanks,

TJ

[John Reed]

Gen 2 or Gen 3?

Gen 3 have a ton of crank sensor problems (and most will run on the stock PCM but not AEM). A new sensor from Dodge has always fixed them up though (don't get a used one, a good used one, a aftermarket good as OEM one, etc). It almost looks like they changed the design a bit, and they are not expensive.

Good luck! Vipers and E85 are fun

[hellbents10]

Thanks for the reply it is a 2nd gen Viper.

Put a brand new Dodge crank sensor in it. Still no dice, well hit and miss anyhow.

Went through the wiring again with a fine tooth comb, as my logic leads me in that direction. Believing it can not be the controller.

It fires up upon actually catching the crank signal.

So I let it warm up on my now fourth tune and make a pull, super clean 730/661 @8.8psi on a stock engine.

Let it sit for a while come back to it and it fires up idles and then starts breaking up, mind you the AFR at idle is sweet at all coolant temps. Then dies, will not start no crank signal again.

I know....I know, it has to be wiring. NOPE. It runs fine on the stock box, check the wring again for trouble, no sig. wire troubles, like ground or power interference, 5v ref good, low ref good.

I think I have reached the end of the road on this one and will have to eat thousands of dollars and put the stock ECU in it and tune with SCT.

[specialed]

What's the serial number of the EMS?

What's the REV/MOD sticker on the EMS say?

[scottie1134]

You should post your map. That way we can check out your settings etc...

[hellbents10]

Here is the MAP.

Upon running the car again I found a weird issue. Mind you it has new crank/cam senors in it now and it shows sync on when running.

It runs great till the coolant fan comes on and the tach sig goes crazy, jumping from idle to 6000+rpms and the car of coarse breaks up and dies some times. fan shuts off when coolant temp comes down and it runs great again.

Attached is the tune that is currently in the car.

[hellbents10]

Well I unplugged the Alt. for grins, and it ran flawless. Fans would go on and off and it would run mint the whole time. This thing is driving me nuts, I wish there was a flow chart for this problem lolz. I pretty fed up now, not sure what direction to go in order to fix this properly. BTW I have changed the alt. too from another Viper with an AEM that runs great. 

[BoostedV10]

Have you checked the battery in the car? I have seen batteries that are able to start an engine fine and still have a bad cell in them that only shows up under high steady load (fans running).  Given your statement about the system acting up under high load, that would lead me to look at your power supply and ground connections as well as the battery. Do not rule out a possibly bad fan motor causing excessive load on the system. I would suggest logging the battery voltage on the internal log at the fastest sample rate and watch what happens when the fan comes on. Is it steady and clean? Or is it noisy and low? If you have an alternator cranking out to compensate for excessive load or a bad battery, the power tends to get noisy and dirty and then causes issues on other electrical components. Does the tach start behaving if you increase the rpm (and increase the available power)? Another quick trick is to listen to an AM radio station and start the car. Is there any more noise running than not?


Do not hesitate to contact me if you have any further issues or need more assistance with these issues.

James Voorhees
281.907.3343
keep us posted on what you find.