Car starts, idles rough and dies, tried coilpack, transistor, CAS, whatnow?

[Verticaljump1]

Turns out the not cranking over problem just needed some battery post cleaning and terminal tightening. Now the car starts, but idles rough as hell, then dies. I have no idea what to do. I replaced the coilpack, power transistor, CAS, and ECU and nothing seems to work for me. The car had a fried wiring harness, I fixed it, but it looks like the CAS burnt back further than I thought, I will try to send a wire straight from the ECU pin to the CAS and see if that helps. The car get's no rpm reading through the tachometer as well, let me know waht I should try guys, thanks~Brandon. By the way, I've got MAF-t. Also, there is no relay for the fuel pump, (not sure if it was a relay, it was a little black box between the hotwire for the fuel pump), I cut that out and wired the wires together, could that be a problem? Thanks for your help dsmtuners.

 

[JLeach50]

I had a very similar prob just a few months ago. My Eclipse would run for awhile then sputter and die. The shop replaced the ECM and checked all the relays and wiring they could think of. Finally, they decided to replace 3 or 4 sensors, including crank position, knock, (not sure exactly what else). Apparently, the signal runs from the ECM through the sensors then to the coil pack. After replacing those sensors, it runs fine. Take a good look at your sensors and replace em all if you don't know which one exactly may be causing problem. Good luck.

 

[versatilx1]

Jleach its not any of his sesnors anyways have you checked for any vacuum leaks or checked your fuel pressure?

 

[Talesin]

Had this happen when I got mine back from a rebuild.

Pull each of your spark wires and put them back in (thump 'em down a couple times to make sure they seated), then clear the ECU by pulling the lower-right fuse in the fusebox next to the clutch (in the cockpit). Let it sit for about two to five minutes, put the fuse back in.

Mine was because the mechanic's assistant forgot to put the #3 wire back on... it was just sitting on top of the plug, with the cap leaning over to the side when I pulled off the spark wire cover. Just putting it in didn't fix it, as the ECU was still trying to compensate for the super-rich reading from the O2.


The mind-trip was realizing that I somehow managed to hit 130 on three cylinders, earlier that evening. Probably what made the ECU spaz out, actually.

 

[92awddsm]

First, pull the ecu out and make sure it has no burnt circuits, no leaking caps, and no corrosion anywhere on the circuit board. If the wiring harness was burnt, it is possible that the ecu was damaged from it.

Also, have you installed a fuel pump lately or even removed and reinstalled the existing pump? If so, pull the pump assembly back out and make sure the oring on the pump is seated properly in the pickup assembly. Ive seen several cases where the oring was either broken or cocked during reassembly and caused similar problems.

Do you get any cel's while the car is running? Go back and double check all your connections under the hood. Specifically the mas harness.

 

[Verticaljump1]

I've tried my spare ecu already. Good thinking talesin! I'll give that a try. What sensors should I try? I know that the TPS sensor does not read ( datalogger), and my engine temp gauge reads all the way to hot as soon as I turn the key over. What else should I check? Do any of you guys know how to pull an engine wiring harness out, I unplugged it from the inside but Idk how to pull it out!

 

[Sharkcus]

instead of pulling the pump, etc, etc, etc, you should start by narrowing it down.

First, get, borrow, steal, etc a fuel pressure gauge. Test for fuel pressure.
Next, make a air leak tester, check the tech guide. $5
Last, make sure all 4 plugs are firing. Quick and easy way, pull the plug wires off the coil. Crank the car for a second and have a friend watch the coil for arcing. 1&2 and 3&4 should be arcing. If only 2 are, it is running on 2 cyl. and it is a REALLY common problem for only 2 cyls to fire when your CAS is bad (or the wiring is bad).

Try those 3 things and you will have a much better idea of what is wrong with your car.

 

[Sharkcus]

Also, I should mention that it is VERY easy to test the connection between the CAS and the ecu. 4 wires: (I can get the colors for you tonight if you need me to...I know this because I just finished my second 2g CAS conversion.)

1 +12
2 negative (ground)
3 should be pulsing (anything above 0 is good)
4 should be pulsing (anything above 0 is good)

If you do not see both pulses on the wire while cranking/running, then the signal isn't being sent. If you feel it is a wiring issue, find the 2 signal wires that go into the ECU and throw a multimeter on them and look for current (pulses) while cranking/running. It is easier to use an analog multimeter so you can see the needle move. If either of those are not pulsing, you will not get all 4 cyl. to fire, just 2.

When my crank sensor died (which is the #3 sensor wire on the CAS on a 1g) I had a steady 4v from the signal wire weather the crank was spinning or not. The signal wires should have no voltage when the cams aren't moving.