View Full Version : st185/205 swap starts then dies

11-02-2011, 05:39 PM
Hey celicatech! So I just finished my build in my st165. I swapped in a 185 block with a 205 top end. I'm using a 165 harness that has been modded to run a 185. And has been further modded to accomodate for the 205 head. I wired in resistors to all the plugs that aren't used because I'm using a 165 ecu and its still checking for things that aren't there on the 205 head. Like Tvsv and Tvis, Egr, etc. So my problem is, that the car starts, runs for 2-3 seconds then sputters out. I was told to check my arm readings with the key on and the engine off. Here's what they read. From right to left. (Because I took the readings from the front of the car)

1st 1.57
2nd 3.95
3rd 0.01
4th 0.02
5th 0
6th 0.01
7th 0

Also, I'm using a 165 ecu. But I do also have a jumper harness to hook up my jdm 185 ecu. I'm using the 165 ecu because its usdm and doesnt have a speed limiter for the track.

And the only codes that I'm pulling are 22 and 54. And when I get it to start, sometimes I can mess with the throttle and get it to idle only if I hold it. But sometimes I can't even do that, where I can start it and manually make it idle because its idled so low I can't get anywhere. Other than that, it runs fine and sounds smooth through every rpm. I just can't get it to idle. And yes, the car is timed. Not with a timing gun, but I put piston 1 to TDC and when I put the distributor in, it was pointing to number one on the cap. And the distributor irks clocked perfectly center. But I have better luck getting it to start when I clock it all the way to the right

Also, here's a video of what's happening.


11-03-2011, 03:23 PM
well your frist problem is the 165 ECU. if you have a 205 top end its got a totally different type of signals. if you are running a 205 top end then you should run a 205 ECU

11-03-2011, 04:20 PM
True. But I've already wired the harness to work with the 165/185 ecus. The 205 top end doesn't have Tvsv, Tvis, and am Egr. So, on my Tvis plus I used 2 10k ohm resistors, Tvsv I used 10k+4.7k ohm resistors, Egr solenoid 10k+10k ohms, and Egr temp got 1k ohm resistor. This is to make the ecu think those 4 plugs are doing their jobs so the check engine light doesn't come on. Only reason why I'm not using my 185 ecu is because its a jdm and I don't want the speed limiter to limit me at the track.

11-03-2011, 06:04 PM
Odd, my JDM 185 ECU doesn't limit my speed at all.

11-03-2011, 06:23 PM
You don't.get cut off around 120mph? I did when I had my 185 swap.

11-03-2011, 06:39 PM
Nope. I've gone 145mph before backing off the throttle. It was still pulling hard at 145.

11-03-2011, 06:57 PM
I've heard some people say they have a speed limiter and others don't. I know that the ecu uses the speed sensor for cruise control. It keeps you from setting cruise past 120mph. This same function may also control speed limit. If you wanted to bypass that you could just cut the SPD wire to the ECU or wire in a toggle switch on the circuit. You would likely get a CEL. There's also a speed cut defender that you could make.

11-06-2011, 04:46 AM
You don't need all those resistors. In fact, the only one you do need is the EGR temp [your harness should have had a resistor already plugged into the harness connector unless it's a CA spec car]. Assuming you're using your AFM for an airflow signal it sounds to me like a vacuum leak or your AFM is bad.

The speed signal for the ECU comes from the speedometer [at least in the 5th gens]. No speed signal will eliminate speed cut but will set a speed sensor code. I don't know if some JDM ECUs didn't have speed cut or not though.

well your frist problem is the 165 ECU. if you have a 205 top end its got a totally different type of signals. if you are running a 205 top end then you should run a 205 ECU
The signals aren't different. You should have no problem running a 205 head with 165 electronics [assuming everything is wired right].