View Full Version : ST205 troubleshooting

01-25-2012, 01:05 AM
Hi guys,
I have a 1994 ST205 WRC.
The car developed a weird problem. It cuts fuel really violently at about 8psi.
At least I think it is fuel cut as it feels like fuel cut on overboost.
No Check Engine.
I am puzzled...
I have already replaced the turbo pressure sensor (MAP?) as I had aspare from my now retired ST185 with ST205 swap.
Any suggestions?
I need some help! Please!



01-25-2012, 11:27 PM
Does your CEL even work? If you bridge TE1 and E1 do you get constant flashing or nothing?

Have you troubleshot the map sensor at all? It sounds to me like you are having an ignition problem to be honest. But there are so many things that can cause your troubles, we need a bit more info.

01-26-2012, 06:32 PM
Check engine light is working. I just checked the error codes and all I have is a 34 and 54 stored.
54 is the IC and its not a biggie, I did have to fill it a month ago. The 34 is more like it but there is an exlonation for this too.
When I did play with the turbo pressures last time i did hit the fuel cut and that is just stored as i didn't disconnect the battery for at least a year.
34 will light up the CEL when the error is active but I don't have a check engine when the above problem occurs.
I will reset the ECU codes and try boosting again later tonight.
I just hate testing this problem as the rear diff mount is shot and everytime i get this "fuel cut" the car sounds like it just hit a tree :(

I am also contemplating changing the ECUs around.
Does any one see a problem with replacing a '94 ST205 WRC ECU with a '98 ST205 (non WRC)?

Please if you have any suggestions as to where to start checking for problems let me know!!

Thanks again

01-27-2012, 01:46 PM
I reset the old codes, tried boosting and the car does the same fuel cut.
I didn't get any new codes....

01-28-2012, 05:45 AM
So, are you still pulling a code 34?

01-28-2012, 08:37 AM
No. There are no codes and the fuel cut persists. I am really puzzled.
What else (other than over boost) can cause a fuel cut with the 3rd gens?

01-28-2012, 09:45 PM
Faulty ECU/wiring/map sensor.

01-28-2012, 10:00 PM
that's nice....
I did exchange the MAP, so i know it's not that.
I will try the "98 ECU tomorrow and cross my fingers i don't have to screw around with wiring <- that could become a nightmare.
Thanx for your suggestions Luni!

01-29-2012, 05:10 PM
Well, I replaced the ECU and same thing, fuel cut at ~10psi...
As far as wiring - do you mean the MAP circuit or are there other circuits also that could cause it?

01-29-2012, 11:12 PM
MAP circuit or wrong MAP sensor. Is there a sticker on your MAP sensor? Is it purple?

01-30-2012, 12:29 AM
I just checked the MAP circuit according to the engine manual and everything looks ok.
2.2v at atmospheric pressure all the way up to 20psi with 4.9v. Vacuum looks like its working too.
the sensor has thee original purple sticker.
So I guess that eliminates the MAP circuit...

01-30-2012, 07:06 PM
Then Im getting to the point where Im running out of stuff to tell you to try. I have to assume youve checked all the basic stuff, but your issue could be ignition based. I mentioned that above and you never touched on that.

When was the last time you changed your plugs? How many miles are on them? What plugs are they? What are they gapped to?

How about your cap, rotor, and wires? Any idea?

01-30-2012, 07:11 PM
i just did a 205 in my 185 and after two weeks had the same problem...i put new plugs...gapped at .28 ngk number 7, took the distribtor cap off and lightly sanded the contacts and did the same for the rotor inside...my problem went away....also try changing your water temp sensor bro!!!

01-30-2012, 07:16 PM
and try and get a HKS FCD...only like 160 and u can boost 17-19 psi all day....

01-30-2012, 07:58 PM
A FCD wouldn't help his problem at 10psi. Also, that is a bit dangerous to use on a MAP based ECU.

There's no chance the hose to the boost gauge isn't leaking? Do you have anything aftermarket on the engine that might impact anything relevant? When was the last time you refreshed the ignition components?

01-30-2012, 11:39 PM
I'd do a run with a known accurate gauge plumbed into the intake somewhere as well.

02-01-2012, 03:01 AM
Thanks guys for all the suggestions!
Sorry I haven't responded earlier, working late everyday...
I will look into the ignition components next.
The boost gauge was one of the first things I verified and it works.
Thanks again!

02-02-2012, 09:52 PM
Also, the water temp sensor for the intercooler can limit the boost if you are using the stock TVSV system, but I don't know if it will actually lower the boost cut when the IC water temp is high. I would check it anyways, and check the intake air temp sensor while you are at it.

03-13-2012, 01:26 AM
Well, I finally got around to fix the problem...
It was as suspected by Luni and others (thanks for the pointers) the rotor.
It was arching to the ground. It was not apparent at first as I didnt notice the burn masks untill the car didnt start anymore.
Got it replaced, it is running like new.
Thanks again everyone for suggestions!

03-13-2012, 06:57 AM
Thanks for the followup and letting us know what the resolution was. Glad we got it figured out.