SOHC bogging

[LOUD240]

need some ideas here
1990 240 sohc hatch stock all emissions intact
I accelerate from a stop it bogs I give it more throttle then it picks up seems to only bog under load , its real bad with the A/C on does this in any gear, and pulling up hills bogs down

Pulled and cleaned EGR valve , new cap rotor plugs an wires all new vacumm lines and I do mean all!! Replaced coolant temp sensor (ecu one 2 wire) flushed radiator clean oil
I swapped in a 5 spd 3 years ago car has always had this bog but sometimes its better than others
any ideas ? Help !!

[RedSiBaron]

My 90 singlecam used to bog real bad as well, only thing I've done that you havnt is replace the fuel filter, clean maf when adding a NON oiled filter, and I've fixed some wiring on the secondary engine/trans harness. Maybe try checking injector connections. I had a couple missing the retainer clips when i bought it, and the connection was finicky and the car would bog sometimes and run rough and the bad motor mounts seemed to amplify it. Take a small file, and clean the connectors on the injectors and clips,(mine had green oxidation on them) and also put some di-electric grease in there. I know that did help with my hesitation.

I've also done motor mounts which may have been a contributing ffactor since one was in two pieces.

Previous few owners of my car beat it to hell...check out your tps too.

I've had tons of problems on the car and just been fixing things, so im probably not much help because things have just been improving on it as i cleaned/adjusted/fixed everything haha.

[Redred]

I want to bring this up because my single slammer is having serious hesitation in every gear and some times no but most times yes I just put a semi new injector wire harness on some of my clips are green so I will clean those I still have the old 1 so I'll keep all the extra clips

[LOUD240]

I went over to nissan tonght and Im taking to service in the morning and they are going to pull my CEL codes they seem to think it might be my B.P.T. valve that controls the EGR valve opening and closing
so we'll see what happens
I have cleaned all the injector pins in the past so they are good, I have replaced every single vac line in the car cleaned out every thing I could unbolt I even locked the swirl control valve open to no avail
I'll post tommorow night what I hear from Nissan, cant beat a free car exam ( work for a company that owns a nissan dealership!! WWHHooo hooo

[Redred]

Please get details for me I'll be your best friend this is killing me

[240sohc]

i have a feeling my bpt valve is malfunctioning too. awating your results, dino.

[RedSiBaron]

Ok, so im new to KAs, only had my first s13 since like december (oh shit, I said first :facepalm:) and most of my old japanese engine knowledge comes from my old as hell pre obd0 honda motors (honda guys don't even know these things) and they are very different from the KAs.

So that said, is there a thread somewhere that breaks down the ins and outs of the KA (especially single cam)? it seems every time I read a new thread I find some new thing nissan added to control something (and most of the time its emissions related and someones talking about blocking it or dissconnecting it, etc).

What's the purpose of the bpt valve? And can't you just dissconnect the egr system if you don't care about smog? And whats this swirl valve you mentioned locking?

For such a simple motor, it sure seems like nissan complicated the hell out of it.

[tommytwo40hands]

Ok, so im new to KAs, only had my first s13 since like december (oh shit, I said first :facepalm:) and most of my old japanese engine knowledge comes from my old as hell pre obd0 honda motors (honda guys don't even know these things) and they are very different from the KAs.

So that said, is there a thread somewhere that breaks down the ins and outs of the KA (especially single cam)? it seems every time I read a new thread I find some new thing nissan added to control something (and most of the time its emissions related and someones talking about blocking it or dissconnecting it, etc).

What's the purpose of the bpt valve? And can't you just dissconnect the egr system if you don't care about smog? And whats this swirl valve you mentioned locking?

For such a simple motor, it sure seems like nissan complicated the hell out of it.


You can search and find all that info on here or google..i deleted my emissions a few months ago, it's not very difficult, you just have to figure what needs to be taken off..you'll need to get an egr block off plate (ebay) and make sure you know someone that can weld the hole in your header after you take off the egr pipe..i believe you only keep 2, maybe 3, vacuum lines (brake booster&fpr)


Also you wil need vacuum caps, the thick rubber ones and the cheap silicone caps..and new gaskets for you intake manifold, gotta take that off to get to the butterflies

[LOUD240]

the bpt valve is what tells the EGR to open and close , i picked up 2 at the junk yard today
Deleting the emissions system is not an option for most of us , and most of these parts actually make the motor run correctly , like the swirl controll valve actually makes the engine run better by limiting the amount of air entering the motor during idle and entering in to acceleration
So telling people to just delete the emisions is just not a good practice
deleting parts from the emisions system does not gain power in most situation

[tommytwo40hands]

yea i hear ya..im lucky that i have no smog checks...but i only did it because i had alot of vaccum leaks and the previous owner of my car used vice grips to hold the egr pipe and crushed/cracked it while trying to loosen it..so i said eff it and yanked it all out

[LOUD240]

well here in Cali we have a pretty strict smog law to deal with, a ref ticket for smog delete will cost ya $500.00 plus parts and labor to fix it , your lucky there in Homer Simpson land

[LOUD240]

well I put in all new injector plugs and replaced the fuel pump sock filter and a junkyard BPT valve and it is running way better , still has a really small hesitation but I think it may be due to a small exhaust leak at the exhaust manifold that I am going to fix tommorow .Also going to put the 2 new injectors in an see if that deliversany improvment.
Lastly next week I'll replace the fuel pump thanks to Rich (240SOHC). after i get the exhaust leak fixed I will probably just pull and clean all the electrical connectors on the air valve relays
So I'll keep throwing up whats happening on this thread till Ipin it down!!!!!!

[LOUD240]

ok so i changed all the injectors the BPT the injector plugs and seal kit, cleaned the egr car still hesitates pretty bad ECU code is reading "32" egr function but it is a pretty exspensive maybe to spend $90 on an egr and have it be the control valve under the throttle body
maybe the egr temp sensor but thats $150.00
any help ya all might have chime in

[Redred]

Check your fuel pump and see if u have rust I'n your fuel tank if the car sat for a long time without being driven that's probably your problem

[Redred]

Loud check that before buying anything else I'm sure that's the case

[LOUD240]

got a fuel pump today , i had the sender out replacing the sock filter last week and the tank looks good inside , going to put the new pump in in an hour or so we'll see

[LOUD240]

Update---- put in a new fuel pump , CEL light is off and the car is running perfect , no bogging no hesitation -=-perfect!!!!!!

[240sohc]

glad to hear that your issue is resolved.

[LOUD240]

and a big thanks to Rich (240sohc)