97 Pathy SE wont start when warm?

[fixinto]

Oh ya i have been meaning to ask you because i dont know myself. The FSM says shorted for the TPS closed position, Well when i set mine, the lowest ohm reading i got was 19 to 20 ohms in the closed position. My question to you is, when you set yours did you use the continuity check or ohms? IF you used ohms did your TPS read 0 at the wide open throttle pins when it was in the closed position? It has been driving me crazy and want to know mainly for my own knowledge. My OBDII reads 94 percent at 100 percent wide open throttle but that is the only strange thing i have going on that im aware of, and i was wondering if the ohms were really supposed to be 0, when it calibrated, did the 20 ohms make 6 percent difference on the backside.

 

 

thanks for any feedback

 

Pat

 

 

[JeffsR50]

I didnt really mess with my tps,

unfortunately my reader is el-cheapo, it does provide some freeze frame info but thats it over the actual codes.

 

First thing in the morning? she starts first crank.

drive to work, turn it off. ... try to start right away? cranks and cranks but wont turn over. Ran great getting me there.

 

let it sit for a few hours.. will usually start on the second try -several cranks.

 

a little squirt of starting fluid into the intake - (been using the iac port before the throttle plate) starts every time.

 

still leaning toward the fuel injectors leaking, BUT the hard start is immediate after shutting her off.

 

I did notice that on one of nissans service reports they suggested disconnecting the evap pressure sensor prior to blowing out the charcoal. (didnt do that)

I wonder if Im not getting some kind of vapor lock as a result of the pressure sensor taking a dump? I know that many of us dont believe the evap can mess up the whole show, but when I look up "hard starting when warm" in the service manual, faulty evap system is one of the possible causes. not sure exactly how to test that sucker.

[Rebelord]

Good theory and direction to go.

 

Sent from my Moto X

[JeffsR50]

ok, now i may be getting warmer. Open the gas cap? pretty sure its sucking air in, not blowing air out. hmmm. this is not normal, is it? perhaps a bad pressure sensor is not opening the evap valve and venting properly?

wow pressure sensor $362.99 autozone.

yikes!

 

 

Edited September 17, 2014 by JeffsR50

[fixinto]

I will have to take a look at the FSM to see whats what with that feature. But im thinking that it may not cause your problem. But it never hurts to check it out. Let me see if i have it straight so far, Fuel pump / Filter, / cleaned maf, / cleaned throttle body / new evap canister / new dizzy / cap / rotor/ thought i may have seen plugs / wires in there too somewhere....

So if we look at this objectively, i guess a good question to ask would be, What causes fuel cut off, but not spark cut off while reading from the sensors? Temp Sensor, MAF i believe, Malfunctioning TPS possibly, Crank Sensor, Cam sensor, ....O.K. i think thats about it. There are probably a ton more things but thats all i have right now, as i look behind me and see my butt dragging the ground about 4 foot back. Now another good question to ask would be, What causes "said" issue without throwing a Fault code and tripping the CEL. hmmmm... Considering that your truck starts cold and runs "normally" I'm assuming until you cut power. then upon restart it says F.U. basically. well you can unplug the M.A.F. and see if she fires next time you turn it off hot. Just dont rev it overly much. let it idle. U can do the same with the TPS. As far as bleeding fuel pressure it would have to be bleeding super fast for it not to start when u turn it over right when u turn it off. so in my opinion thats out "for now"

so just for now i would say, try the sensor trick, if it dont work, DOH, but its an easy and free test. Also when you turn your key off be sure its off for at least 5 to 7 seconds and then when you turn it forward again, listen for your fuel pump to hum the happy song. That will let u know if it is even acting like its going to comply when you turn the key.

So if you have a hum, and the sensor trick dont do it for you. We need to ask, what cuts the actual injector pulse needed to fire the injectors on startup. But after its started runs fine. Still having me leaning toward MAF / Crank / Temp sensor. the temp sensor is the one under the intake not the one on top of the intake. I hear that thing causes all kinds of flakey stuff to go on.

I am hitting the sack. Thats all i have for now. But if you cant nail it down and do decide to go after something where you remove your intake, i highly recommend replacing the Valve cover gaskets while your in there. But hopefully one of these works.

I am not sure that you can unplug the temp sensor and fire it up i have never tried. Anyways, let me know how it goes. I am rootin for ya. Oh and before i forget, your speedo / tach is working fine right?

 

Anyhow, Have a good one. hope i didnt on and on too much, i do that a bit when im tired

 

Pat

 

P.S. i would say the cam sensor is out because you replaced the dizzy.

 

 

 

 

 

 

Edited September 18, 2014 by fixinto

[fixinto]

Late edit to my post, it would appear that the Crank position Sensor doesn't control the engine function, it is there to monitor for misfires, "according to the service manual" So maybe scratch that one too. so now we r down to TPS / MAF / Temp Sensor.

Also i would ohm out the resistor for the ignition system. "dizzy" you can find the Pin outs and the plug location in the EC section of the manual. it is supposed to read 2k ohms i think it said. So if you are heat soaked, and it wont start and u have a meter handy, there you go. I am hoping that the sensor disconnect tells you something though.

 

 

bed tired

 

Pat

[JeffsR50]

sure appreciate your help, ..

 

ok again she started right up this am, get to work today, crank and crank no start.

I unplugged the MAF, tried to start - no luck.

unplugged the TPS (both clips?) - again, no love.

 

seems more and more like some kind of fuel pressure/ vapor lock thing.

 

When I seafomed the intake, it had some time where it started on each try...I figure the seafoam itself was acting as starting fluid while there was still some in the intake.

 

EVAP vapor pressure sensor or still maybe injectors? ...dunno. I will remove the pressure sensor when I can (have to pull the canister again to get to it) and try to test it with the ohmeter and some sucking and blowing. ptooey

I did find a used one for 25$ online

[JeffsR50]

ok, on break today i went and was pinching vacuum hoses, looking at the intake- and doh! found that the left side tiny vacuum hose at the back of the manifold was off! holy moly..Im fairly sure I connected that before ...but now that its back on she seems to want to start easier. duh. I sure hope that thing has been off this whole time and causing this demon. ...Ill report back after errands tonight. (crossing fingers)

[Rebelord]

oh wow. Ya, hopefully it gets you going.

[fixinto]

passenger side behind intake? fuel regulator for the lose. =) should drive a lot better. Mine didnt hard start when it was unplugged but it sure did hate when u put a load on it on the interstate. hope that fixes you up. Keep us upto date. in the mean time i am looking for a place but anything i can throw at you on the quick and dirty i will keep firing until i run out of ammo. After i get settled somewhere i will do some deeper digging if required.

 

best of luck

 

Pat

 

[JeffsR50]

thanks again guys!

 

pleased to report that she started every time I turned the key this afternoon. (no popping the hood required). I must admit that I don't think I would have found this without actually sticking my hand back there to feel the hoses. ..couldn't believe it when I realized.. pushed it on...started on like the 4th crank.

then she was good 4 times off and on for errands... definitely hot soaked...and in a much better mood. Ill be putting some miles on tomorrow.

sure hope this does it... I think were good to go.

[Kingman]

Makes sense in a weird sort of way. Ether burns much faster and hotter than gas, so the heat from spraying that in the intake allowed the flooding engine to fire up in addition to the vacuum leak. Vacuum is drawn on the FPR at idle/cranking with the throttle plate closed, when an engine revs it loses vacuum. No vacuum on the FPR at all would cause it to open fully causing a rich condition. If Nissan kept to their old ways, there's a valve in line somewhere in the engine bay for the FPR. For hot starts it holds vacuum fully on the diaphragm so the engine is as lean as possible when starting. Although I've personally never noticed a difference with this valve bypassed.

 

Hope that's the end of it!

[JeffsR50]

yep I think the combination of the FPR hose being off the intake, along with the open throttle plate due to the fast idle cam was just enough extra air to keep her from firing. (and apparently the extra fuel given for cold start was enough to make up the difference) explaining the cold/ warm start difference.

 

sooo stoked to have this figured out finally- finally feel like I can do some primping -carpet shampoo, etc.

[JeffsR50]

[JeffsR50]

Happy you got the fast idle cam sorted, mine took a dump "well the thermal element" and i priced one at 150 and special order, so instead i backed the screw off, and flipped that rascal over backward." ECU still idles it up to 1200 on cold start so that little bastage is a .....piece of $H*& anyways. as far as i can tell you dont even need it. "maybe it makes a difference in sub 0 or something" /shrug, coldest ive cranked it with it unhooked is 4 and wind chill -7 F worked fine for me.

About your fuel delivery. 1. make sure you put the filter on in the proper flow direction. 2. make sure the purge for the vapor in the gas tank isnt stuck open 3. make sure your regulator is ..well um regulating hehe. .....wish i had some more free suggestions but i think that will probably do for now. However, if you take care of those 3 things that eliminates everything from the rails backward for fuel delivery.

I am not sure if you had the intake off. But make sure the vacuum line behind the intake "closer to the passenger side" is hooked up to the regulator, and be sure the rubber vacuum line connecting one part of the metal piping to the other isnt boogered.

Personally i think that if it were a vacuum leak it would make a rough stumbling idle at best and a choked out kindof trying to die thing going on if it were worse. So i dont really expect it to be that, but i just thought i would throw it out there. Also give your steering wheel a bump left and right, and make sure it bumps it up 50 to 100 rpm, that is a quick and dirty way to see if your IACV is functioning.

 

P.S. if the vacuum line is off of the regulator, it will cause, poor fuel eco, slight valve chatter under load, "like uphill on the interstate and such" not telling you how i know that either "cough cough"

 

Making progress, keep up the good work.

 

Pat

 

 

 

Yep you called it.

Edited September 19, 2014 by JeffsR50

[fixinto]

Congratz bud, happy it gotcha lined out.!!!! Cant believe some of my advice or endless ramblings actually helped somebody for a change, LOL....

 

Congratz again man.

 

Pat

 

 

[JeffsR50]

Ok, been so busy I havent had a chance to post for a few weeks, but....

Hard warm starts are baaaaack. yep... lame. this issue is becoming a bit like herpes.

 

cold start in am - fires right up. drive for a few, turn it off, wont start without starting fluid. -

 

BUT! - I did find out some good info last night - I had prev thought that the crankshaft position sensor was related to spark when it came to the pcm -.and had eliminated that as the problem since she has spark.. turns out? If the crankshaft sensor isnt sending a signal to the pcm while cranking? - it shuts down the fuel pump. ding! now this sounds just like whats happening to me.

 

..now just a matter of getting my orangatan forearm up into that mini-squeezy gap to get that damn thing out. may just have to hire a skinny armed mechanic to do this one.

[fixinto]

support the rear of your trans with a jack remove the cross member, then lower the jack a little bit to give you room to work bud =) long as the bolts in the cross member arnt froze up you should be good.

 

Pat

[fixinto]

Also double check the fuel regulator hose to make sure it didn't ninja off again ;P

 

 

ahah

 

pat

[JeffsR50]

Damn...ok its been cold here and as a result I have had very few starting issues -shes run well, but ...this am was very cold, she started right up (groaned a bit) ...warmed up , drove her a few miles, realized I had no heat from the heater although I had temp in the eng...no sooner than that my temp skyrocketed, pulled her over just in time for the top of the radiator to explode right off. DOH. (Ill post pics when I can)

Ill be towing her today and looking at installing a new cooling system. *&^%$

[JeffsR50]

so, Im assuming that becuase my first symptom was no heat at the vents, that my thermostat went south. ...But! can a stuck closed thermostat cause a radiator to explode?

Ill plan on a new water pump and thermostat with the new radiator install, ...I sure hope this isnt a head gasket.

[JeffsR50]

 

Not good man. I figure the cap was faulty - (It should have blown?)

 

Edited November 13, 2014 by JeffsR50

[fixinto]

clogged heater core line will cause no heat at the vents too. The bypass valve on the cap should open when the engine cools off allowing your overflow tank to fill any void in the cooling system. "like if it were low" Don't really know where i got the info so take it with a grain of salt. i will browse the manual when i get a chance. havent had chance in a bit do to long hours and arse draggage.

 

i would hit a yard for a new rad, while i had it apart i would take a look at the heater core lines just as a double check.

when i say take a look i really mean " unhook the input line and output line, put in some cleaning solution thats friendly to soft metal, stuff the output line in an empty milk jug and hose clamp an air hose on the input line" Don't recommend going over 20 to 25 psi at the most. make sure that it flows the cleaner and left over anti freeze into the jug if it doesnt....that will be a fun job getting that dood out of there. If you are going to replace the thermostat, do the water pump too, u may as well. and if you are that far down, ya you guessed it, timing belt time. Just be crazy careful. double / tripple / check everything, because hell of a long way to go if something is wrong. Hate that happend to her. I am still trying to put together the heat soak / no start issue. everything I am coming up with is still in the fuel regulation area. either your regulator is defective, you have a vacuum issue involving the regulator circuit, "rubber and metal piping" or hmm im not really sure at this point. Sensors are pretty much out because you can start it with starting fluid........wait....something just hit me. Do you have a manual or auto trans? If its auto, maybe your neutral safety switch is going bad. cheap ohm meter would tell you, just measure it cold, and get your reading then when she wont crank measure it again. wont be the first electronics device that flaked out after heating up. hmm worth a look. and if its a manual trans, have a similar switch mounted where it will be pushed by your clutch. heat soak theory dont really apply to that being that it is located inside the cab.

 

Good luck getting her back on the road. but im sure you can find plenty of good radiators at a salvage yard fraction of the $ as a new one.

 

hmm now that i think about it, the neutral safety switch may not even let it crank over at all if it were bad, dangit, now i have to go read

pat

Edited November 14, 2014 by fixinto

[adamzan]

Sounds like a head gasket blew to be honest. I'd be pressure testing that after you get a new radiator.

[JeffsR50]

yep either way it sucks balls.

 

fix- yeah its a manual trans. I figured on doing the water pump, once the rad was out. ..then I read about the timing belt removal requirement to get to the thing- the sticker on the hood says the timing belt was replaced 30k miles ago.

hoping think they did the water pump too,....do I risk doing just the thermostat and radiator?: - then a power flush at the local lube joint. ?

 

- the only reason I might even consider this is the fact that the thing runs very well once we're on the road. Idle is a purr. throttle response is good, and she has never had her heat go beyond the halfway point (ever) before yesterdays fiasco.

...also? there is really no sign of any oil leakage from either of the heads - I climbed underneath before I bought her and was stunned at how dry her belly was.

 

nevertheless, a compression test may be in order, and I will check those heater lines.

Edited November 14, 2014 by JeffsR50