Piston Slap VS Not starting - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

undercoverdjay · 02-28-2005, 08:46 AM

So my new 92 hatch wouldnt start this morning. Unfortunatley I have to drive this car in the winter. It got pretty cold last night so Im supecting the lines to be frozen or possibly the fuel pump. However, my car has a rebuilt engine as of 7,000 miles ago. According to the guy I bought the car off of, who also did the rebuild, he said that when he used forged pistons he got piston slap when the motor was cold until it warmed up. I dont recall what brand he used but when he rebuilt his other KA-T setup, he had quite a lot of piston slap so he decided not to go with the same pistons with this setup. My question is, can piston slap induce not starting? The car seemed to have great compression on the trip home before I parked it for the night. No over heating, not surging, nothing from the norm. The car was left with around a 1/4 of a tank of gas and I let it run for about 30mins before shutting it off since it was so cold. The only other thing I can think of was when I primed the fuel pump before starting, I heard it gurgling like the fuel delivery was uneven. That and the cold weather are leading me to believe its frozen lines. the kicker.....you can smell unburnt raw fuel from the exhaust. HELP please

update.

if i unclip the injectors and crank it over, it seems to want to start but dies soon. Leading me to believe its a weak spark perhaps. I grounded the plugs and they appear to spark fine. I replaced the coil wire, nothing. The only indication it could possibly be my rotor because one of the screws that held the cap on was backed out a ways and pretty loose. I pulled the cap off and checked the rotor and the contacts, they all seemed good. What else? I ran an ECU diagnostic and got the happy code 55, everything is kosher. Now where do I go from here?? Any and all help is greatly appreciated.

shinrekka · 02-28-2005, 02:17 PM

starter maybe, everyonce in a while i couldnt start my car, completly random. Maybe a starter, stickey relay for the feul pump maybe.

undercoverdjay · 02-28-2005, 03:30 PM

well i pulled the plugs and changed them, they had raw gas on them, checked for spark, all is well in the spark department. As far as i know it's gotta be air related. I just dont understand what can happen over night when the car was running when i parked it. please help! I need this car asap

ledzeppelin240 · 03-01-2005, 12:23 AM

Well you have found out you are getting fuel, and spark. How about compression?

undercoverdjay · 03-01-2005, 09:27 AM

Yeah I'll need to test for compression, I suppose thats my last resort. The distributor cap was a little bit loose, one of the screws was turned all the way out, I pulled the cap off and checked the contacts and everything seemed fine. There was no moisture in the cap at all. Im at a loss here. I suppose the only thing to check would be compression, but if there wasent enough compression to start it, why would it run to my desintation where I parked it? Also how could it change over night not running?

Muzzy · 03-01-2005, 08:27 PM

wth is piston slap?!?!?

undercoverdjay · 03-01-2005, 09:07 PM

when the pistons are cold before they warm up the piston is actually smaller than normal and therefore will slap against the cylinder walls while running making a clanking noise until they warm up. Generall common with forged pistons. Some are worse than others.

02-28-2005, 08:46 AM	#1
undercoverdjay Zilvia Junkie Join Date: Apr 2004 Location: Potsdam New York Age: 41 Posts: 594 Trader Rating: (2) Feedback Score: 2 reviews	Definitely an electrical problem now So my new 92 hatch wouldnt start this morning. Unfortunatley I have to drive this car in the winter. It got pretty cold last night so Im supecting the lines to be frozen or possibly the fuel pump. However, my car has a rebuilt engine as of 7,000 miles ago. According to the guy I bought the car off of, who also did the rebuild, he said that when he used forged pistons he got piston slap when the motor was cold until it warmed up. I dont recall what brand he used but when he rebuilt his other KA-T setup, he had quite a lot of piston slap so he decided not to go with the same pistons with this setup. My question is, can piston slap induce not starting? The car seemed to have great compression on the trip home before I parked it for the night. No over heating, not surging, nothing from the norm. The car was left with around a 1/4 of a tank of gas and I let it run for about 30mins before shutting it off since it was so cold. The only other thing I can think of was when I primed the fuel pump before starting, I heard it gurgling like the fuel delivery was uneven. That and the cold weather are leading me to believe its frozen lines. the kicker.....you can smell unburnt raw fuel from the exhaust. HELP please update. if i unclip the injectors and crank it over, it seems to want to start but dies soon. Leading me to believe its a weak spark perhaps. I grounded the plugs and they appear to spark fine. I replaced the coil wire, nothing. The only indication it could possibly be my rotor because one of the screws that held the cap on was backed out a ways and pretty loose. I pulled the cap off and checked the rotor and the contacts, they all seemed good. What else? I ran an ECU diagnostic and got the happy code 55, everything is kosher. Now where do I go from here?? Any and all help is greatly appreciated. Last edited by undercoverdjay; 02-28-2005 at 07:44 PM..

03-01-2005, 12:23 AM	#4
ledzeppelin240 Zilvia Addict Join Date: Sep 2003 Location: Sinse Posts: 688 Trader Rating: (0) Feedback Score: 0 reviews	Well you have found out you are getting fuel, and spark. How about compression? __________________ Anyway, no drug, not even alcohol, causes the fundamental ills of society. If we're looking for the source of our troubles, we shouldn't test people for drugs, we should test them for stupidity, ignorance, greed and love of power. Looking for: JDM S13 OEM Sideskirts

03-01-2005, 08:27 PM	#6
Muzzy Zilvia FREAK! Join Date: Jan 2003 Location: TX Posts: 1,555 Trader Rating: (0) Feedback Score: 0 reviews	wth is piston slap?!?!? __________________ lemme have a dollar

02-28-2005, 02:17 PM	#2
shinrekka Zilvia Member Join Date: Oct 2004 Location: Long Island Posts: 251 Trader Rating: (0) Feedback Score: 0 reviews	starter maybe, everyonce in a while i couldnt start my car, completly random. Maybe a starter, stickey relay for the feul pump maybe.

02-28-2005, 03:30 PM	#3
undercoverdjay Zilvia Junkie Join Date: Apr 2004 Location: Potsdam New York Age: 41 Posts: 594 Trader Rating: (2) Feedback Score: 2 reviews	well i pulled the plugs and changed them, they had raw gas on them, checked for spark, all is well in the spark department. As far as i know it's gotta be air related. I just dont understand what can happen over night when the car was running when i parked it. please help! I need this car asap

03-01-2005, 09:27 AM	#5
undercoverdjay Zilvia Junkie Join Date: Apr 2004 Location: Potsdam New York Age: 41 Posts: 594 Trader Rating: (2) Feedback Score: 2 reviews	Yeah I'll need to test for compression, I suppose thats my last resort. The distributor cap was a little bit loose, one of the screws was turned all the way out, I pulled the cap off and checked the contacts and everything seemed fine. There was no moisture in the cap at all. Im at a loss here. I suppose the only thing to check would be compression, but if there wasent enough compression to start it, why would it run to my desintation where I parked it? Also how could it change over night not running?

03-01-2005, 09:07 PM	#7
undercoverdjay Zilvia Junkie Join Date: Apr 2004 Location: Potsdam New York Age: 41 Posts: 594 Trader Rating: (2) Feedback Score: 2 reviews	when the pistons are cold before they warm up the piston is actually smaller than normal and therefore will slap against the cylinder walls while running making a clanking noise until they warm up. Generall common with forged pistons. Some are worse than others.