sr20det Bogging/Hesitation in boost

[ford_o]

hello i drive a 89 240sx with a red top swap.. the car is basically stock but with a fmic, intake, 3 inch downpipe and exhaust.. the car drives fine outta boost and even drives good in boost around 4 psi, but anymore after that it starts bogging down on me like it not getting enough fuel or something, i,ve had a problem like this before but people said it was the plugs, ive got new plugs in there now and same problem any help would be thankful if you need anymore info i'll be glad to try to help!!!!

[VNG704]

do you get smoke out the exhaust? Check the IC pipes/couplings if they are loose which causes leaks.

[ford_o]

i looked at the pipes didnt notice anything loose the vac sits fine on 20 at idle so i dont think that could a problem but possible, and no smoke comes out but when i sit at idle i do smell fuel ..?!?!?

[kernel]

Change your coilpack, if you have spare set.

Or if you have a friend nearby with a SR20DET, try his coilpack.

I'm sure you have a problem with them.

[ford_o]

ok i'll check those but if it would be one of the coilpacks wouldn't the car have bogging problem outta boost also?

[lightsource]

ok i'll check those but if it would be one of the coilpacks wouldn't the car have bogging problem outta boost also?

Not necessarily. I had water in 2 of 4 of my coilpacks when I first got my redtop, the car would show problems at around 5k RPM+.

Do you have a side mount or a front mount?

Also check the wiring for your mass airflow sensor.

[ford_o]

cx racing fmic setup!

[kernel]

No, when I got that problem. I had no issue at all when out of boost, right when it came into boost, I was bogging like you say.

It could be a fuel pressure issue as well. Clugged(?) fuel filter or fuel pump running out..but I'm sure it's your coilpack.

[ford_o]

ok i'll check them!! yeah i was thinking maybe my fuel pump isn't doing the job its a new a fuel pump but not 255lph would that make a diff?!?!

[lightsource]

Clugged(?)
Clogged

Do what VNG said, depending on how old the kit is... You might want to change the couplings... Just to be safe, if I was having a problem like this I'd double check that stuff.

But like munkfu said it's probably your coilpack(s).

ok i'll check them!! yeah i was thinking maybe my fuel pump isn't doing the job its a new a fuel pump but not 255lph would that make a diff?!?!

i'd check your fuel FILTER before I checked the pump, you could have a brand new pump and have a shitty filter and get problems from that... How old is your filter? and do you have the Z32 or the stock one.

[ford_o]

z32 filter i swap it when i got the swap done bout 4 months ago

[ford_o]

just checked coils there getting spark... maybe its a fuel issue :ghey:

[kernel]

Coilpack can spark very well and still be defect under boost.

Like we said, you could have a defect coilpack and still run very well under vacuum and above a certain PSI.

I tell you, change all your coilpack with another set and see if it still do it.

It took me a while before I notice it were the coilpack..I took the set from my friend SR20 and installed it on my engine, then bang. No more hesistate under boost.

If after trying another set of coilpack it still doing the problem, then it could be a fuel issue !

[fliprayzin240sx]

Double check for boost leak and what spark plug are you using/gap?

[ford_o]

Well actually i'm running NGk heat range 5 but tommorow I'm gonna buy ngk heat range 7 to see if there is a diff or not. The 5s seem to be hot. Maybe that's the problem!!!!

[luckky]

try your plug gap first then look into the packs. (how much does a set of packs go for anyways?)

on a side note. How did this guy not get flammed? There is a millllion posts on this lol all with the same answers. But good luck man! let us know how your diagnosis goes!

[ford_o]

tried the sparkplugs bkr7e ngk and no luck

[s14_mike]

try to see if you have the vacuum line plugged into the wastegate, if unplugged it could be causing the car to have that bog type of feeling that you are experiencing.

[ford_o]

just got a set of good working coilpacks same problem :bash: ....i've noticed tho that i can hit full boost but around 4k-up my car still starts to shut down! maybe its a fuel problem.. any more ideas for me thanks?!?!

[Blues13]

Did any of the ignition changes seem to help it at all? Did it make any difference? Did you try swapping the ignitor?

I'd double check again for any boost leaks, re-tighten all the couplers, check loose vacuum hoses, and gap down the plugs down.

If the plugs show any signs of abnormal wear, like sooty (rich) or white (lean) then I'd send out your injectors to get check/cleaned/balanced.

[ford_o]

no i didnt really notice any difference, i swapped the ignitor when i did the swap bout 3 months ago. im gonna double check everything today. does anybody think it could be something else beside a spark issues?!?!?!

[godsmack]

Take all couplings off and check for cracks. If a coupling is cracked it will have same effect. Especially the one off the turbo to hot pipe if you have an aftermarket header the header will melt the coupler and cause it to open under boost.

[ford_o]

ok i'll check thanks

[cotbu]

I think OP is feeling Break up and not Bogging, hence the / hesitation. I think it's either timing, fuel/injectors, TPS or mafs.

Does the car, when switched to a higher gear allow you to boost smoothly past 4-4,5Krpm?
Check fuel pressure, Tps voltage closed and open. check ecu for mafs code, CPS code(cas) and or knock<----not likely!

[ford_o]

maybe it could be more of a break up but it feels like my car is shutting down, it drives fine outta boost with no problems what so ever, even in full boost (7psi) the car drives strong until i hit 4500-up rpms then it starts to have this break up/hesitation problem then i just let off the gas. every gear does it!!! the car is very close to running perfect beside this. when i had first had this problem people said to change my spark plugs and it would fix it for a day or two then i changed my coilpacks and with new plugs and still same problem!!!!!

[lightsource]

looks like someone may need to go to an SR shop.

[KiLLeR2001]

Fuel problem? Check the ohms on each injector with a multimeter, they should be ~11.5. Also, what FPR are you using? 43psi w/ vacuum disconnected?

[ford_o]

im using stock sr fpr! i'll check the injecters when i get a chance.. can i get a meter at autozone?!? how do i check fuel pressure also?

[whereda40at]

check for an exhaust leak from the head to the exhaust manifold. i had the same problem and saw that my block was black. used to be fresh. not so fresh looking now. but my gasket what fucked up. if the exhaust is not making it to the turbo to spin it then you are having less power and too much fuel causeing a bogg.

[ford_o]

i'll check but my turbo seems to spool up fine and hits full boost(7psi) until i reach around 4500 rpms. thanks

[ford_o]

i checked all the injectors and the first 3 avg. around 12's and the last one hit 13's is this good?

[ford_o]

i checked my tps just in case but i wasnt for sure how to get a good reading but i tried just how people said too and with connector unplug i got 1.39ohms that dosent seem to be right but i might need a little help on how to test this part!!!

[sridings13]

get volt guage and see what voltage you are getting while the car is running. my friends SR had a weak altenator and would just die in power under boost

[ford_o]

i have a clutch fan and i dont see how i could check it with the car on!!

[johngriff]

To check the coilpacks, take a infrared temp reading off the top of the coilpacks.

Sounds like ignition / ignition timing to me.

[ford_o]

also i just checked my alt. with my car on i was getting a signal at 14.4 so im pretty sure thats cool! could my tps just be outta wack? i,ve searched but i still dont think im reading it right!! any help would awesome thanks

[ford_o]

any one???

[jedi03]

i have similar issue, sometiems bogs...my fuel lines to fuel rail are currently leaking...prob gotta replace the soft lines outta my pump as well...

[Rapier46]

coil packs or fuel problems. Mine did similar, turns out a it had a rusty tank. check the fuel filter in engine bay. if its disgusting, the tnak should be checked.

[ford_o]

i think im gonna buy a 255 lph fuel pump and see if anything changes mayb a fpr too idk tho!!!

[ford_o]

i just checked my ecu it was code 55 which says no malfunction, so mayb i just need a bigger fuel pump cuz i dont think a fuel pump throws a code!