Apex Posted January 15, 2008 Report Share Posted January 15, 2008 My girlfriend and I just bought a '91 Grand Prix DOHC 5 speed for her to drive for a while. Went outside this morning to start it and it fired right up but died 5 seconds later. Now I can't get it to start again. It cranks over just fine but just never fires. The car has 170,000 but it had a newer motor (with about 100,000), along with new timing belt, water pump, alternator, and clutch all put in 5k ago, also had the injectors removed, cleaned, and checked. Any ideas? It's has had a slight misfire at idle since we bought it but it's hardly even noticeable, and the fuel pump sounds great when you turn on the ignition. I live in MN and according to weather.com it was about -3° right now and it says it "feels like" -20°. But like I said it cranks over just fine it just doesn't fire up. So I checked the ECM codes and came up with quite a few. Not really sure where to begin on all this.... Code 23 MANIFOLD AIR TEMP (MAT) or INTAKE AIR TEMP (IAT) CIRCUIT (LOW TEMP) Code 34 MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR (VOLTAGE LOW-HIGH VACUUM) Code 35 IDLE SPEED CONTROL (ISC) CIRCUIT Code 42 ELECTRONIC SPARK TIMING (EST) CIRCUIT Code 39?? Any one know what this one is? Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted January 15, 2008 Report Share Posted January 15, 2008 Does the tach move when you crank it? Quote Link to comment Share on other sites More sharing options...
Apex Posted January 15, 2008 Author Report Share Posted January 15, 2008 It moves slightly downward in sync with the rest of the gauges as it should. It doesn't even try to fire at all just cranks away. Just checked one of the plugs and it is getting spark.... I tried to rent a fuel pressure gauge to see if its getting pressure but no one rents them and it costs $55 to buy one, that seems pretty high to me for a tool I'd use maybe a couple times... Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted January 15, 2008 Report Share Posted January 15, 2008 It moves slightly downward in sync with the rest of the gauges as it should. It doesn't even try to fire at all just cranks away. Just checked one of the plugs and it is getting spark.... I tried to rent a fuel pressure gauge to see if its getting pressure but no one rents them and it costs $55 to buy one, that seems pretty high to me for a tool I'd use maybe a couple times... Is the fuel rail schrader valve accessible easily on the DOHC? If so, take the cap off, and press center and see if fuel squirts out. Thats an easy "go, no-go" test. Quote Link to comment Share on other sites More sharing options...
toms92gpse Posted January 20, 2008 Report Share Posted January 20, 2008 So I checked the ECM codes and came up with quite a few. Not really sure where to begin on all this.... Code 23 MANIFOLD AIR TEMP (MAT) or INTAKE AIR TEMP (IAT) CIRCUIT (LOW TEMP) Code 34 MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR (VOLTAGE LOW-HIGH VACUUM) Code 35 IDLE SPEED CONTROL (ISC) CIRCUIT Code 42 ELECTRONIC SPARK TIMING (EST) CIRCUIT Code 39?? Any one know what this one is? That many codes at once time would lead me to believe either a bad/broke engine ground/connectioin, or a bad PCM. Quote Link to comment Share on other sites More sharing options...
White93z34 Posted January 20, 2008 Report Share Posted January 20, 2008 Code 39 is clutch circuit switch error, I believe it is triggered by 3 or so 40mph-0 stops with the fault present. I get this code all the time, but my car is also not originally a MT car, and I have yet to hook up the clutch switch, so with that said look under the dash and investigate the clutch pedal switch. Quote Link to comment Share on other sites More sharing options...
Mr_Efficiency Posted January 20, 2008 Report Share Posted January 20, 2008 Without the clutch pedal switch engaged the car wont even crank over tho, so if that was faulty you would get nothing at the key when you tryed to start it. That many codes would lead me to think they may have been stored up from the past motor that went bad and various other things, clear the codes and try to start it a few times and see what comes up. Quote Link to comment Share on other sites More sharing options...
Turbo231 Posted January 20, 2008 Report Share Posted January 20, 2008 Keep looking for a FP gauge...I purchased mine for $20, and to be honest, is one of those tools no fuel injection mechanic should be without as it works on all cars. I agree that the "cascade" of error codes may have been caused over time or as one thing fails, it tends to trip a whole bunch of things. You've checked for spark...good. That takes out a lot of ignition things, such as crank sensor and ICM...next is fuel. The pump may run, but putting out crap for pressure which would yield a no start. One thing would to try (I can't believe I'm saying this) is try some starting fluid...if you get a sputter, then you're dealing with a fuel deliver issue. You can also pull a plug and see if it is wet after a long period of trying to start. You're battery is going to love you in this cold...that's for sure. Quote Link to comment Share on other sites More sharing options...
White93z34 Posted January 20, 2008 Report Share Posted January 20, 2008 Without the clutch pedal switch engaged the car wont even crank over tho, so if that was faulty you would get nothing at the key when you tryed to start it. there are 2 clutch pedal switches, I should have been more clear. there is a switch at the top of the pedals travel near the brake light switch that tells the PCM where the clutch pedal is, that is what causes the code 39. the other one has no bearing on the pcm, but is just a safety switch, Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.