Strange Idle And Boosting

[carl h]

ok so my engine likes to give me all sorts of trouble, guess she doesnt like being in a s14 chassis.......

anyways im currently trying to rid the car of the current grimlin, crappy idle and transitional boosting problems.

at idle the car seems to have a light miss, but not like an outright dead coil pack

occasionaly the car will not idle worth a damn and others like a champ, it seems that weather has no effect on this and it will do it at any time.

also something that has developed is when im at cruise and i suddenly go wot where boost comes in hard (4kish) the car will 'buck' and stutter for a moment then go on its way and haul ass like normal.

im not sure what it could be and i dont want to spend 400$ on splitfire coils if i dont have to.

[Redback]

try these ive had this trouble...

try resetting the ecu's.....

check and make sure of a good earth connection to the block....

if this doesnt work get a spanner or something and give each coil a little tap on idle and listen for missfire..... if you find one then replace it....

id recomend doing it in that order aswell..... could save you money if it is only something small.

[Links]

Stuttering could sound like it is going into rich&retard mode, this can usually be if you are running too much boost and it'll hold or hesitate for a second before picking back up..

- are you running stock boost..

- what other mods have you got..

- which engine exactly is it?

have you had a chance to plug in a consult cable and check that all your sensors are doing ok + maybe raise the idle RPM to see if it makes a difference, don't believe this is permanent - however it would give you an idea..

also try using calumsult which lets you record the data, go for a spin than check back through the ignition timing so on and so forth, it might help isolate the issue at 4,000 rpm..

[race_snooze]

hope its not the same problem as Abo bob who had rough idle found to be ring land. Check your compression. after you have tryed all else.

[carl h]

engine is out of a r32 and its a rb20det

currently the car has the following:

garrett true gt30r with .63ar turbine

720cc injectors

z32 maf in blow thru

tomei 260/8.8mm cams on intake and exhaust

remapped ecu to suit injectors and maf

the car JUST started to do this as before it would hold a rock steady 600rpm idle any given time of the day, so im not sure whats going on.

[caz]

Hey Carl h,

Im not sure where you are, but if you were wanting to record some engine data and graph it , to see whats happenning ,I have the cables, DataScan 1-4 and the Datalog graphing software on my laptop if you want to borrow it. Can also reset ECU and do power balance(drop each cylinder)Im Wollongong way, NSW.

Cheers, Caz..

have you had a chance to plug in a consult cable and check that all your sensors are doing ok + maybe raise the idle RPM to see if it makes a difference, don't believe this is permanent - however it would give you an idea..

also try using calumsult which lets you record the data, go for a spin than check back through the ignition timing so on and so forth, it might help isolate the issue at 4,000 rpm..

<{POST_SNAPBACK}>

Edited November 7, 2005 by caz

[T04GTR]

the afm is the problem here.

its not like a bosch afm[vl commo etc] it boesnt have a burn off function like the vl one.

its a thick film type. [bosch LH type]

once any crap gets on them it stays there and buggers up the signal causing your exact problem.

to be sure remove it and clean it gently with brake clean or contact cleaner. but not carby cleaner[leaves a oily residue]

hope that helps.

[gawdzilla]

ok so my engine likes to give me all sorts of trouble, guess she doesnt like being in a s14 chassis.......

anyways im currently trying to rid the car of the current grimlin, crappy idle and transitional boosting problems.

at idle the car seems to have a light miss, but not like an outright dead coil pack

occasionaly the car will not idle worth a damn and others like a champ, it seems that weather has no effect on this and it will do it at any time.

also something that has developed is when im at cruise and i suddenly go wot where boost comes in hard (4kish) the car will 'buck' and stutter for a moment then go on its way and haul ass like normal.

im not sure what it could be and i dont want to spend 400$ on splitfire coils if i dont have to.

<{POST_SNAPBACK}>

do yo uhave a WB02 with the car? My guess is an initial over richness when you first romp on the pedal. Fuel is getting dumped while there isnt much load yet, or you may just have a flat spot in your map. Try looking at it with a WB02.

My motor has the same miss you're talking about at idle occassionaly. Typically its when the motor is wawrmed up. It's like a stutter/miss, and sometimes it even chokes the motor out. I also think this may be do to fuel building up over time in the cylinders at idle, and being too rich. Its either that, or the coil packs on their way out. My MAFs seem to be reading fine via pfc. I'll update on it once my WB comes in and i check that out.

[carl h]

do yo uhave a WB02 with the car?  My guess is an initial over richness when you first romp on the pedal.  Fuel is getting dumped while there isnt much load yet, or you may just have a flat spot in your map.  Try looking at it with a WB02.

My motor has the same miss you're talking about at idle occassionaly.  Typically its when the motor is wawrmed up.  It's like a stutter/miss, and sometimes it even chokes the motor out.  I also think this may be do to fuel building up over time in the cylinders at idle, and being too rich.  Its either that, or the coil packs on their way out.  My MAFs seem to be reading fine via pfc.  I'll update on it once my WB comes in and i check that out.

<{POST_SNAPBACK}>

i do have a wideband o2 in the car, at idle it reads 12.5-12.8:1 when its a nice smooth idle but when it gets erratic it usaly reads bout 13.5-14:1.

while i do occasionaly get some oil on the maf (blowthru) i cleaned it a week ago or so with no change in idle characteristics.

im starting to think its my dodgy chip tuning skills combined with 13 year coils that are on their way out..........

what im guessing is happining is that when i go from cruise to wot afr's hit 10's or so and the car cant fire on 10:1, however when i roll onto boost afrs are usualy in the 11.5:1 range so its ok and not terrible.

gonna try something with the chip tune and see what happens, cut might just be due to obcene fuel, however ive got enough money now to buy a pfc and some splitfires so we will see what happens.