89' 240sx Coupe SR20DET Idle Hiccuping

[g2blkemike]

Hey guys,

I recently bought this car. It had no exhuast past the downpipe, i installed a generic free flow cat and 3" catback.

I have been driving it around for about 2 days now and i'm noticing a hiccuping at idle.

A few times it has bogged down for a few seconds as though it was starving for fuel when taking off. I replaced the filter and pulled and checked the fuel pump, ( the pump is not a walbro , its a denso 1020 supra tt pump) the pump looked okay.

I posted this little video for you guys to see whats happening, i really need an answer fast, it is making me uneasy not knowing what i have going on.

you may hear a metallic vibration in the video, ignore it please, i just removed one hanger and i have to replace it.

You'll notice the first hiccup after i rev the car a second time to about 4K rpm and after the tach stablizes.

Note: the car will run and drive fine, boosts good and strong. no jump idle either.

Modified by g2blkemike at 11:18 AM 12/15/2006

Modified by g2blkemike at 11:21 AM 12/15/2006
Modified by g2blkemike at 7:00 PM 12/15/2006

[kris nissan for life]

hey there mit be some **** in your fuel filter or cables are old

thats all i can think of lol

[g2blkemike]

Hey i put on a new fuel fiter today , the old one emptied okay no gunk.

The fuel pump did not have much gunk either...

[g2blkemike]

Hey if you cant hear it in the video.. it runs smooth, then does a "putt" sound then smooth again then maybe some more " putts" randomly

thanks

Mike

coil pack issue???

[sean58888]

is it burning rich at idle blowing black smoke?do you have a adjustable fuel pressure regulator?

[g2blkemike]

Hey it only puffs black when i rev it up, its clear at idle.

I dont know if i have an adjustable fuel pressure thing

also i noticed a coolant leak on the hose that goes behind the engine to around by the intake manifold... does that have anything to do with it?? if anyone knows what that hose is called, let me know so i can get a new one:)

I was thinking of cleaning the MAF tonight and switching the coil packs one at a time from my buddy's sr20det.

what do you think of that??

Mike

[180fan]

check over your fuel and ignition. how's the timing and do you have leaking injectors. The need to check over the grounding circuit for the mafs is always a good idea.

[g2blkemike]

No leaking injectors,

i tested unplugging the injectors one at a time, and it made a difference as i unplugged them.

i did replace a fuel line from the filter, someone used a vacuum line not fuel line!!

it fixed the fuel smell under the hood.

i'm noticing weak starts now, it cranks fine, and then stutters and stutters , i press teh gas a little and it starts to catch and run smooth, once it does fire up, its strong as hell and smooth, still hiccups at idle though

i'll try to check the timing .

Mike

[g2blkemike]

So i go to switch coil packs from my buddy's sr, and after i open the cover, i notice that there is no bolt on the first coil pack, i touch it and it moves off easily!!!

i pull it out and it was barely on the damn plug!!!

i say those idiots did not bolt it back in., and the bolt was mssing.when i look down to see the spark plug i see the bolt sitting at the base of the valley!!!!

i put it back in and bolted it down and the stutter is gone!!!!!! i'll veryify this for sure tonight, but it idled for 3 mins without a stutter, and i may mention that it fired up faster and smoother!!

i think i got it!!!!!!

[g2blkemike]

Well come to notice , its not fixed.

i switched all the coil packs from my buddy's into mine, and same damn thing

i'm thinking plugs, i switched them out today , they look good, but a few were bent a little off than the other ones.

i then noticed that the last duuf broke off the bolt in the valve cover!!! so i had to drill it out. i gotta go get a tapping set tomorrow and find out where i'm gonna get another freaking bolt from.

i did mess with the MAF and i noticed when i unplugged it and pluged it back in, it was idling at 2k! i unplugged it while it was on again and it kinda almost died and i heard a lot of putting putting... maybe its a dirty MAF, the filaments look clean, after i re assemble it i'm gonna check the timing.

Mike

[redtop91]

Hmm I can tell you right now that no one will be able to tell you what it is. I did my swap myself and I have the same problem to this day.

[g2blkemike]

wow, are you serious??

does this affect the driveablity of the car at all??? is it still reliable??

I put in new ngks ix and i reassembled everything, and its idling high now at 2k but drives great, still hiccuping a bit though

let me know man

[email protected]

[redtop91]

The only things I havent done to solve the problem (short of major engine break down) is change the injectors, oil, and spark plugs.

[180fan]

Well with the mafs unplugged, it will go into "safe mode" with a rev limit and such. Pull the plugs and tell me the color of the tips. It'll shed much more light on what's going on. Personally I think you've got grounding issues. That always seems to be the case and one of the first things I always check for especially on engines pulled from a junk yard aka your SR. Did you also check for vac leaks and fuel pressure?

[g2blkemike]

hey

plug 1 was tan center and black tip but the little arc piece was a little off to the side

plug 2 was black and tip was fine

plug 3 was tan

plug 4 was tan

they were ngk r's or something.

grounding issue, if i was to put a heavy ground strap from the engine block to the body , would this appease the ground issue?

no i havent checked my fuel pressure yet, i'm having difficulty finding a gauge

mike

[g2blkemike]

also, for the life of me i cannot find the damn idle screw!! i feel like a moron!

[g2blkemike]

Nevermind i found it!!!

[g2blkemike]

OK i found the idle adjust screw and adjusted it as much as i could for making the idle lower, it wouldnt go below 1400rpm

i then twisted the the accelerator linkage to the resting/closed position and the idle when down a bunch.

i shut the car off to adjust it if i could, and i noticed a screw at the bottom of loopy linkage to stop the throttle, when i pulled the linkage upwards to gain acces to the screw i noticed that the linkage was bent out of shape,

i simply took my small cresent wrenche and bent it back into shape and i started the car up and whala! 500rpm idle

i then used the screw and upted it to about 700/750ish

i drove the car and found out that when i clutched it went down pretty low to about 300 200rpm, and it backfired a few times.

so i'm sure its a timing issue now, i just got back from the parts store to pick one up.

wish me luck!

Mike

[180fan]

grounding with just one strap usually isn't enough. the mafs usually has a separate ground just for itself. Usually the one that I see make a world of difference for the sr's is the ground at the head and also at the intake manifold. It tends to smooth things out a bit more.

[g2blkemike]

any ideas on getting the timing light to work??

i just put it to power and put the sensor thing around the first coilpack wire right??

i get the lights but the marks on the pulley are not steady enough to read.

do i have to put the sensor somewhere else??

thanks

MIke

[g2blkemike]

ok i got the light to work, but the markings are at least 3 inches left of where the peg is,

do i just move the distributor until they get closer??? its a ways to go..

Mike

[180fan]

bingo.

[180fan]

remember to pull the plug on the tps and to have the idle set to 800 ala the iacv first with the engine warm before checking timing.