Tried everything and the more I fix the worse it gets HELP!!

[newboyspo]

Hi,I have read every post I can get my hands on from this sight You guys rock!... anyway here goes

I have a 90 ka24e with 179000mi (not Calif.) that had a rough idle and lost some of it’s get up and go and would not idle high on cold startup. (ECU reads 55) Changed plugs, changed c &r, changed oxygen sensor, ran some seafoam through it, checked the timing,I checked all the connections from the harness (temp sensor included)and the vacuum lines and found a crack in the large line going to the IACV and replaced it (no small task that) and while I had it out I shimmed the spring on in the IAA unit as per an article I read on here a couple of days ago. Put it all back together and the car started fine and idled high (it was cold) then idle went down and it died, so I unplugged the TPS and set the idle to 650rpm, plugged it back in and it idles solid at 750rpm. But now it is poppity popping (running rich I think?) when I let off of the gas peddle and anything above 2500rpm it stumbles and shakes like crazy. I read today about someone with the same symptoms that unplugged the vacuum line to the EGR valve and it cleared up. Sure enough I unplugged the vacuum line to the top of the EGR and stopped it up with a bolt and all the poppity popping and stumbling quit. BUT! It smells like a gas pump from behind, and the power is still lagging?? Btw ECU still gives a 55 I did press in on the EGR diaphragm and it did kill the engine. Can you please help me choose which part to change out? BPT, EGR, ??????

Thanks,newboyspo

[newboyspo]

P. S.

I replaced the fuel filter with a new one from a 300zx also

[NISTECH]

You may have a restricted exhaust. This would create enough back pressure to close the bpt. Best way to determie if this is the case, Disconnect the hose under the BPT and have all other hoses connected then drive it again and see if it dies out still. If it doesnt then plugged exhuast is tyour likely cause, cat came apart or something like that.

[newboyspo]

Thanks for the help,

I just put a new cat and 2.5" pipe all the way back so I hope it's not restricted....

I took the fuel rail off and pulled the egr out (p in the b) and found that only one of the two bolts were in it, also one of the three bolts from the mount between it and the intake were missing also, so I bought a new egr valve (it needed it!) but before I re-install it, I found a vacuum pot thingy behind it (see picture) that seems to run some kind of rod attached to the intake. when I apply blow or suck to the vacuum end of this pot it just make a hiss (leaks)

question #1 what the H*** is it? can I just plug off the vacuum leading to it (looks like a real cow to get out of there) and, if I have to replace it how does it come out??

thanks for all your help

[Touchdown038]

That's your swirl control valve, it controls the butterflies in your intake manifold. Leave the vacuum hose connected on that.

[newboyspo]

Ok I understand that I need it hooked up,

but if it is vaccum controlled and when I suck or blow on the tube connected to it and it makes a hiss sound (leaking vacuum) it needs replaced?

also I can't remember if the fuel filter goes on the back or the front of the feul rail (back being the fire wall side)??

Thanks for all the help

[Touchdown038]

Possibly. Check the hose connected to it for cracks, and if the hose is fine, it probably does need replacement.

[InsanityInc]

Don't the secondary butterflies default to open if no vacuum is applied?

[newboyspo]

If it does defualt to an open posion I will leave it for now.. the Hose I used on the valve was a new line that I use for testing.. it is the pot that is leaking...

I tried to remove the two screws from it to change it out or to take a look at it but I cannot get them loose (the fool that put screws in there instead of bolts should be drawn and quatered!!) anyway, the only way I am going to get it outa there is to pull the transmission and engine mounts an try to move the block foward... might as well rebuild the head and plug the suckers off...

Thanks for all the help!!

I think I'll just get a de' rebuild it and drop it and the ecu in there.. I love the car but this rough idle and guttless pickup is for the birds... my son has a 91 with air and it smokes mine....

Sorry about the blowoff there.. I'm just a little frustrated...

[InsanityInc]

You can buy something called an offset screwdriver that can help you get it off. It's basically a screwdriver that works like a socket wrench, or just an attachment for an actual socket wrench. And if you need a new one, I'll see if either of the ones I have works right.