SR startup problem and tach problem
SR startup problem and tach problem
Well, thanks to many on this board, I did my blacktop S13 swap into my 91 240sx myself and my engine even cranked on the first try! I primed the motor with the CAS pulled till the oil light wen out and to my amazement the engine even started on the first try!!! Now since Im shared my good news, now for the bad news. First off, the tach doesnt work. Im pretty sure I have the connector to the dash wired properly, (yellow wire with red stripe) but I have no tach. Another very strange thing is that the engine wont idle. As soon as I start it, the engine revs rather high, I dont know exactly how high since I dont have a tach, but the engine does build boost, and wont have vacuum at idle. Ive checked to see that all the vacuum lines were connected, and everything seems in place. Could this be do to a bad MAF? or is it something else. Someone please help me.....I feel like Im so close to finishing this but I havent been able to even drive it yet!
bad mafs = try unplugging the mafs and revving it....wont go past 2.5K but does it run/idle better? if so prolly a bad mafs
is ur car a 89-90?if so ull need the cluster from a 91-93 or JDM cluster the sohc tach wont get driven right from the DOHC.....hook up a wideband and see what its doin when the idle goes screwy....try checking timing as well (ignition and cam timing)......alsotry adjusting ur idle
is ur car a 89-90?if so ull need the cluster from a 91-93 or JDM cluster the sohc tach wont get driven right from the DOHC.....hook up a wideband and see what its doin when the idle goes screwy....try checking timing as well (ignition and cam timing)......alsotry adjusting ur idle
I do have a 91 240 which is a DOHC, so I dont think that I need to switch out the tach. As for the MAF, I tried unplugging it, and the car wouldnt start, so then I started the car and then unplugged the maf while the car was running. The revs did drop, but the motor was reving up and down very quickly. THe only way I can explain it is that its like bliping the throttle over and over very quickly.
you don't have vacuum? uh yeah, that right there sends red flags galore on your idle issue. so how's your vacuum setup? do you have caps on all vac lines that aren't being used? replace your vac lines with new hoses. the vac setup i've got is this. there are 3 vac ports on the throttle, two on top one at the bottom. the top, i've got one going to the bov, and the other (farthest away from the driver) going to the fuel pressure regulator. the bottom one is for the carbon canister, and i've got that capped. at the back of the intake manifold, there's the vac port for the brake booster. Do you have that hooked up? On the cold pipe, there's another vac line for the wastegate actuator. That should be it, all other vac lines are unnecessary. If you want to take it a step further, if you look at the top of your intake manifold, you'll see a pipe that runs to the pcv in the valve cover. I made that pipe disappear and ran a hose from runner 1 to 4 and put a breather on the pcv instead.
I have all the extra vaccum lines capped and brand new lines running from the vaccum ports on the throttle body running to the BOV and the FPR. I also have a brand new line running from the back of the intake manifold to the brake booster. I cant see any other ports that need to be plugged. Considering that the engine keeps surging, Im assuming that it has to be a very bad vaccum leak but I dont know where else there are vaccum ports.
Check to make sure your BOV recirculation hose is connected, and the intake tube to the turbo is tight. That could cause the MAF to read wrong. After that, check all of your connections on the intercooler piping.
I'd also pressure test the intercooler. The rubber seals were hardened in mine, so they weren't sealing on the corners. Went back and took it apart and RTV'd that sucker and she holds boost great now.
I'd also pressure test the intercooler. The rubber seals were hardened in mine, so they weren't sealing on the corners. Went back and took it apart and RTV'd that sucker and she holds boost great now.
if you've got a suspected leak at the ic, pressure test it. I filled it with water, capped one end of the ic and put a long silicone hose on the other end and turned it into a large bong like thing and blew into it.
intake manifold spray one area at a time with carb cleaner. it'll seal up the suspected leak for a second before drying out but when you see the bump up in idle that'll tell you where your leak is.
I did the water test on the rest of the piping for my ic system.
more carb cleaner for the throttle.
intake manifold spray one area at a time with carb cleaner. it'll seal up the suspected leak for a second before drying out but when you see the bump up in idle that'll tell you where your leak is.
I did the water test on the rest of the piping for my ic system.
more carb cleaner for the throttle.