1997 Protoge Driveability Issues

Hey everyone, just wanted to relay an issue I recently had with my 1997 Protoge. The vehicle started showing signs of a rich fuel mixture. In cold weather especialy, or anytime the engine was cold, engine would buck and sputter until higher RPM was reached. When warm, the vehicle would start to die out at idle <IE approaching a light> Rpm would drop to under 500 RPM but usually would not stall. Normal driving, power loss could be noticed but actual driveability was not impaired. 1.5 L DOHV motor with 5 speed manual trans, no AC. On the analyzer, HC PPM was upwards of 1100 after the cat, CO2 was down to 6 %, and CO was high while O2 was slightly high. Scan data showed a code P1170 - O2 sensor reads voltage over .9 V for more than 25 secs - <Low O2 levels - Rich> O2 reading was staying at .95 V and Fuel trim was -87% long term and -128% short term. Long story short, she was running rich as can be. All sensors were in operating range. Fuel pressure gauge was inserted and fuel pressure was at 89 PSI constant all times. Recent new filter installed so no restriction there, return lines were inspected and no damage was found. Regulator was checked and found to be seized completely on - could not be moved with cmpressed air even. Never seen one fail so bad but 220 000 km on car so nto bad. Got new regualtor, did a presure check and all is back to operating range. Cleaned injectors, changed oil due to cylinder wash, and cleaned and regaped plugs. Boom all emissions are perfect, and fuel economy has more than doubled.

If anyone has run into a similar driveability issue, check your fuel pressure. These cars have an amazing adaptive fuel management system and will adapt to almost any issue in the fuel system. Remember all this running issue and pressure issue, and only gave an intermittnet O2 code.

Hope this helps some guys out there. THese cars are great, Since the repair the car has gone from doing 100 km/h in 5th gear at 3500 rpm to 110 in 3rd at 3500 rpm.

Thanks for posting that information.

Clifton

I have 240K on my protege and have been getting a 1170 code for awhile. It would only show up when I was driving on the interstate with my cruise control on. The car ran fine though. I was looking for a new front O2 sensor when I read your post. I had replaced my old one and started getting the 1170 a couple months later, so I had assumed that the one I bought was defective. This weekend I pulled the purge control and it seemed to be stuck. I used my air compressor to blow air through backwards and it seems to have freed it up. I did a 20 mile stretch on I75 and I haven't had an error yet. You may have saved me a few bucks.

Glad to have helped

It turns out that the P1170 error was due to the front O2 sensor. I got an off brand on ebay and it turned out to be bad. Of 4 that I've bought from ebay this has been the only one that was bad.