electrickhillbilly Posted January 22, 2014 Share Posted January 22, 2014 I have a 1992 pathy and it will not start when the engine is warm or any time after it has run for a few minutes. I am getting spark and have replaced plugs, distributor cap, and rotor. I have a pressure gauge t'ed into the fuel supply line and am getting 40 psi with key on engine off and 33 psi with the engine idling I have put ecm in mode 3 and am getting code 55. first thing in the morning it starts just fine probably turns 1 or 2 revolutions and its running and idling smooth if you turn the engine off it will not start unless it sits for a couple of hours. I am an experienced mechanic but this thing has me stumped for now, any help would be appreciated. I have a 1995 parts car parked next to it so swapping parts is easy I also have the 1995 fsm and have been following troubleshooting procedures but cannot find anything wrong Link to comment Share on other sites More sharing options...
5523Pathfinder Posted January 22, 2014 Share Posted January 22, 2014 Something similar happened to mine a few years ago. Ended up being the ECCS relay(damage that I didn't know about+moisture=failed relay. It's in the right fender relay bank. Oh, when it doesn't start, does it crank over or just click? Manual or auto trans? Link to comment Share on other sites More sharing options...
peejay Posted January 22, 2014 Share Posted January 22, 2014 Hmmm...have you tested the injectors for leakage? Will it start when warm/hot if you give it some accelerator pedal? Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 22, 2014 Author Share Posted January 22, 2014 (edited) Thanks for the replies It's an auto trans and the starter always cranks. I will try and swap those driver side relays around see if that doesn't help, it doesn't seem to matter what position the throttle is in when it doesn't start. When it is in "no start mode" it will fire on starting fluid but dies as soon as it burns up the starting fluid. Next morning it will start right up and run good until it's shut off again. I have a spare injector rail with a fuel pressure regulator on it if nothing else works I am going to run fuel to it and plug it into the passenger side injector harness and see if the injectors are working. Going to have to warm up a little for that it's supposed to be 5 degrees tonight here my 22 year old wiring harness will be less brittle when it's warmer. Edited January 22, 2014 by electrickhillbilly Link to comment Share on other sites More sharing options...
Alkorahil Posted January 23, 2014 Share Posted January 23, 2014 I have a 1992 pathy and it will not start when the engine is warm or any time after it has run for a few minutes. I am getting spark and have replaced plugs, distributor cap, and rotor. I have a pressure gauge t'ed into the fuel supply line and am getting 40 psi with key on engine off and 33 psi with the engine idling I have put ecm in mode 3 and am getting code 55. first thing in the morning it starts just fine probably turns 1 or 2 revolutions and its running and idling smooth if you turn the engine off it will not start unless it sits for a couple of hours. I am an experienced mechanic but this thing has me stumped for now, any help would be appreciated. I have a 1995 parts car parked next to it so swapping parts is easy I also have the 1995 fsm and have been following troubleshooting procedures but cannot find anything wrong So it is temperature/time related. Starts fine when cold, will not restart after it is warmed up. First, try unplugging the IACV regulator when it will not start and see what happens, with it cold outside the IACV may be stuck/getting stuck. The IACV is essentially an electronic choke for your vehicle. If it is stuck that is why you can get it to fire up with starter fluid. If it still will not start you can probably rule that out as an issue. Next, do the same test with the throttle position switch. However, I am thinking this is an Engine Temperature Sensor and/or O2 Sensor issue. The ECU goes into closed loop and starts monitoring signals from these sensors after running for 6 mins or the vehicle engine temp is over 68F both of which fit your symptom description. After the vehicle cools down below 68F it will start for you because it is not monitoring the signals yet till it gets warmed again. Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 23, 2014 Author Share Posted January 23, 2014 (edited) So it is temperature/time related. Starts fine when cold, will not restart after it is warmed up. First, try unplugging the IACV regulator when it will not start and see what happens, with it cold outside the IACV may be stuck/getting stuck. The IACV is essentially an electronic choke for your vehicle. If it is stuck that is why you can get it to fire up with starter fluid. If it still will not start you can probably rule that out as an issue. Next, do the same test with the throttle position switch. However, I am thinking this is an Engine Temperature Sensor and/or O2 Sensor issue. The ECU goes into closed loop and starts monitoring signals from these sensors after running for 6 mins or the vehicle engine temp is over 68F both of which fit your symptom description. After the vehicle cools down below 68F it will start for you because it is not monitoring the signals yet till it gets warmed again. Thank you Rob for the good troubleshooting info. I tried unplugging the IACV and then the throttle position switch, I also switched MAF and Coil out still no start. I am with you on thinking it may be temperature sensor. Tomorrow it is supposed to get above freezing and I will change the temp sensor in the thermostat housing with one from my parts car but I am totally willing to try anything that will get my pathy running. Edited January 23, 2014 by electrickhillbilly Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 27, 2014 Author Share Posted January 27, 2014 92 Pathfinder still wont start I am starting to feel like this issue is definitely temperature related, engine will only start when outside temperature is low. I have changed temp sensor with a used but functioning one and cleaned all under hood harness connections with contact cleaner and coated connections with dielectric grease still hoping for o2 sensor problem won't be able to get new one until later this week I think that cold air being richer in oxygen is allowing it to start somehow Link to comment Share on other sites More sharing options...
adamzan Posted January 27, 2014 Share Posted January 27, 2014 Which coolant sensor did you change? There are 2. One is for the gauge (1 prong with a spade connector) and the other is the one that affects how it runs, which is a 2 prong one with a yellow connector. They are right beside each other to the left of the distributor. Just a thought. Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 27, 2014 Author Share Posted January 27, 2014 Thanks for the info, I did change the yellow 2 prong no help. The frustrating part about this issue is there have been no symptoms it was running great. When I can get it to start still runs good until it gets shut down. Link to comment Share on other sites More sharing options...
adamzan Posted January 27, 2014 Share Posted January 27, 2014 (edited) Since you say it will fire on starting fluid could it be maybe the fuel pump is weak when it is hot. I know you said the pressure is good. But since you have a parts car swapping the pumps couldn't hurt. Here are the specs for the fuel pressure and other things you might want to check. Sorry for the small font but I wanted to fit it in on one page. These are taken from the service manual EC section. Edited January 27, 2014 by adamzan Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 27, 2014 Author Share Posted January 27, 2014 Adamzan, thanks, maybe both pumps are bad? I have all ready changed it with my parts car pump, reads 43 psi til the relay kicks out, when it starts it will idle at 32psi these numbers are gotten with vacuum unhooked from FPR because that's how it was when I got it and intake will have to be split to put vacuum hose back on, when I do that I will replace FPR. I live in extreme North Arkansas it's 18 degrees right now headed towards a low of 2 tonight so intake splitting will have to wait a few days. My garage is full of my other D21/wd21 parts so I have to do it all in the driveway. Link to comment Share on other sites More sharing options...
adamzan Posted January 27, 2014 Share Posted January 27, 2014 You shouldn't have to split the intake to put the hose back on, I changed my vacuum hoses recently and was able to just swap the new one on. if you get a small mirror you should be able to see the nipple it goes on. Also the FSM says it should have 43psi with the vacuum unplugged. Have you changed the fuel filter? Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 27, 2014 Author Share Posted January 27, 2014 Filters good I was going to change the FPR, in fact the whole injector rail, with a known good spare that I have and maybe the whole air collector assembly if needed Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 30, 2014 Author Share Posted January 30, 2014 I plugged an injector test light into the number 1 injector and caught a time when it went from no start condition to start and have determined when it won't start it is because it is not getting an injector pulse. It still reads 55 in mode 3 when it does start Link to comment Share on other sites More sharing options...
Alkorahil Posted January 30, 2014 Share Posted January 30, 2014 No injector pulse...hmmmm. ECU, Distributor or O2 Sensor sine we have ruled out coolant temp and throttle position switch already. Dont think it is a distributor issue - it would kick and buck and die on deceleration all randomly and would not start when it is cold. You are not getting any of that. Though your timing could be way--off have you check that as well? This leaves me thinking O2 sensor still. ECU would be the last thing I look at. All of these sensors feed information to the the ECU, if the ECU has all the inputs it sends a signal to the injectors to fire: Camshaft Position Sensor - engine speed and pistion position Mass Air Flow Sensor - Amount of intake air Engine Coolant Sensor - temp of coolant Heated Oxygen Sensor - density of oxygen in exhaust Throttle Position Sensor -throttle position Throttle Position Switch - throttle idle position Neutral Position Switch - neutral position Vehicle Speed Sensor - vehicle speed Ignition Switch - start signal Battery - batt voltage The amount of fuel injected from the fuel injector or the length of time the valve remains open is deterined by the ECM. the value is preset by engine operating conditions determined by input signals from both the camshaft position sensor and the mass air flow. The amount of fuel injection is compensated for to imporive engine performane under various operating condition as listed below: Fuel Increase During warm up When starting engine During acceleration Hot engine operation Fuel Decrease During deceleration Mixture feed back goes: ECM sends injection signal pulse to injector Injector releases fuel into combustion chamber. Engine combustion. O2 Sensor sends feedback to ECU. Repeat step 1 Link to comment Share on other sites More sharing options...
electrickhillbilly Posted January 31, 2014 Author Share Posted January 31, 2014 I am starting to agree that it is either the ecm itself or the 02 sensor, right before it started doing this it snowed about a foot and I had the pathy filled with people and dogs driving around in deep snow every day for a week. Timing was spot on when I did a tune-up right before all this started thank you Alkorahil for your continued help. Link to comment Share on other sites More sharing options...
Alkorahil Posted February 1, 2014 Share Posted February 1, 2014 Let us know what the fix ends up being! Link to comment Share on other sites More sharing options...
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