I have an 85 Z31 N/A that has a difficult time starting when cold. If I let the fuel pump prime a few times before starting or use starting fluid she will fire right up. She will also stay running and restart without any issue for the rest of the day. I have installed a new fuel pump, and FPR, checked the fuel pressure, spark, vacuum, and the ECU is clear. Everything seems to check out as per the FSM. The only strange thing I see is the FSM has 2 different configurations for the FPR fuel hose routing, one for turbo and the other for N/A. I have an N/A that appears to be routed like a turbo. Any input would be greatly appreciated. Thanks

mac , has filter been changed yet , because it's POSSIBLE that "cloggage" that settles and thickens due to overnight "Cold" , and "downtime" - juuuust opens up enough under a long protracted crank - whearas the "PULSES" of fuel (yes all the way from pump in tank through hose - squeeze hose @ idle you can feel this) churn they're way through = finally starts / runs and then warmed-up motor , coupled with jouncing around on road will keep this "OPENED UP PASSAGE" until next morning cloggage again . This sh#@t really happens Now it IS winter and assuming a very cold start another possibility is plug (s) have fouling (oil , carbon,coolant?) coupled with dew/condensation it can be an "extended crank" needed to get that situation going too Just possibilities G T 2/22/2018

macgiver wrote: ↑

Thu Feb 22, 2018 6:14 pm

mac , has filter been changed yet , because it's POSSIBLE that "cloggage" that settles and thickens due to overnight "Cold" , and "downtime" - juuuust opens up enough under a long protracted crank - whearas the "PULSES" of fuel (yes all the way from pump in tank through hose - squeeze hose @ idle you can feel this) churn they're way through = finally starts / runs and then warmed-up motor , coupled with jouncing around on road will keep this "OPENED UP PASSAGE" until next morning cloggage again . This sh#@t really happens Now it IS winter and assuming a very cold start another possibility is plug (s) have fouling (oil , carbon,coolant?) coupled with dew/condensation it can be an "extended crank" needed to get that situation going too Just possibilities G T 2/22/2018

Thanks for the reply macgiver. Yes, I have a new fuel filter, plugs, and wires. But I may just have to run new fuel hoses from the tank to eliminate the possibility of a blockage in the line. And as far as it being winter.. I'm in Miami, so a "cold" start is totally relative to your geographic location!

mac , quick response ! Yeah , gotcha , I was thinking about that "routing difference" , was going to ask if it still connects from "A" to "B" , that could have been a problem - that would complicate my reply .
I see that your saying 'Hoses were messed with" by a "Genius mechanic" in the past Good luck ,Glen 2/22/2018

Unless you can find some physical reason why the line routing changed something then very likely the ways the lines run have nothing to do with the problem. Lines can be run 500 different ways and if thought out still work fine.

Second sentence................

'If I let the fuel pump prime a few times before starting...'

There are commonly check valves in EFI fuel lines to prevent fuel running backwards at long shutoffs, a check valve not working to allow backflow might do that..........the pump having to repurge the entire line again at cold start.

I don't buy the filter clogged while cold bit at all. Why? Because the filter would have to be so close to being 100% clogged to allow that that it already needed changing, it just being that the typical owner did not do it.

New hoses from tank? Ridiculous, get an airblower and blow through them, if you have flow there is no blockage there. Not one anyway, the car runs fine otherwise..........THINK guys.

mac here ,amc49 got some good questions here , I think using some formidable knowledge & logic on the "way out " theories bumping around the post. Now I'm thinking - what's the car 1985 ? and what's the miles on this 32+ year old vehicle , you know. Of course we're hearing a "REAL" problem - then again has'nt everyone had an extremely tired old car chugs along you know , quirks that you never figure out . I do hope a solution is found ,"in a Perfect world" . G 2/23/18

mac, amc49, Thanks for all the input. I really appreciate it. To answer a mac's questions... the car only has 79k on it. Now in regards to the check valve on the fuel line, I had read about that before, and I would gladly investigate that... I don't recall seeing anything like that when I replaced the fuel pump... so where along the line should it be? Thanks

mac , I've see most chk valves keeping the prime to the motor all the way back near the tank , and what amc refers to is the more likely thing to lose "standing pressure" is - the pressure rgulator @ usually end of fuel rail that leaks back to tank will lose your prime . Now as amc mentioned ,getting into fuel lines etc. - be best to "blow through" , as a test & a "clear" . GT 2/23/2018

macgiver wrote: ↑

Fri Feb 23, 2018 9:10 am

mac , I've see most chk valves keeping the prime to the motor all the way back near the tank , and what amc refers to is the more likely thing to lose "standing pressure" is - the pressure rgulator @ usually end of fuel rail that leaks back to tank will lose your prime . Now as amc mentioned ,getting into fuel lines etc. - be best to "blow through" , as a test & a "clear" . GT 2/23/2018

Well I know the FPR is good. I will try blowing air thru the line to clear any blockage. By chance do one of you fine gentlemen have part number for that check valve? I'd hate to drop that tank again, but I guess you could put a check valve anywhere in the li e before it gets to the engine. Thoughts

Blow forward to not damage any checking in there. You'll think you have a blockage if you blow backwards, the check(s) will seat and no flow. Dunno about Nissan but many domestic pumps have the checks right in pump outlet nozzle or in pump module lines. The FPR is the check up front.

Quick way to check if checks are leaking; a simple fuel pressure check, shut down motor and the pressure should not drop completely for say an hour, certainly not immediately.

amc49 wrote: ↑

Fri Feb 23, 2018 10:05 pm

Blow forward to not damage any checking in there. You'll think you have a blockage if you blow backwards, the check(s) will seat and no flow. Dunno about Nissan but many domestic pumps have the checks right in pump outlet nozzle or in pump module lines. The FPR is the check up front.

Quick way to check if checks are leaking; a simple fuel pressure check, shut down motor and the pressure should not drop completely for say an hour, certainly not immediately.

Already did the bleed test... and pressure stays good for more than an hour. But as said before if I prime a few times before I crank it she will start. Sometimes if there is too much fuel in there she revs up high and then shuts down. And you can smell the exhaust gas venting out of the air intake (got it open at the moment) After that she will start right up. Or if I spray a little starting fluid, she will start right up and run normally. Banging head on wall at this point.

Check the ECU for coeds, check the cam and ignition timing, if that all checks outstart testing the sensors one at a time.