swap problem, searched for hours.

[whoareu]

okay. me and a couple of friends are swaping an s2 rb25 out of an s13 coupe into my s13 convertable. we are just about complete. we started it up and it just isnt running like it should. well it doesnt want to run at all. i have to give it gas to get it to start and then it runs as though it has a vacuum leak. so i suspect a (you guessed it) a vacuum leak. any tips or suggestions. the engine ran fine before the swap. and it is stock except for the greddy IM and safc. any help would be appreciated. and like i said i have searched for like 5 hours on this and nothing really popped out at me that said "hey check me".

p.s. if your nice i'll post pics. and it will make most of you feel very good because my engine bay is filthy.

[Vkoslak]

intercooler piping? MAF? What's with the safc?

[GTS-T 240]

what is your fuel pressure? and did the vert have a running motor before you put the rb in it? there might be a problem in your fuel system if it had been sitting w/o a motor.

[whoareu]

intercooler piping? MAF? What's with the safc?

i dont think its the piping, and the maf is the same one that was on my friends car, its a z32 maf. and no the s13 had a running ka when i pulled it. it did have a a vacuum problem when i pulled it though.

[mott6904]

No one can tell you where your vacuum leak is. Search for "how to make a vacuun leak tester" and you find what you need to make a leak tester. post up after you have rulled out or fixed the vacuum leak

[apex_7]

Its pretty weird... the car has trouble starting up so you have to give it a little gas. We replaced the plugs and it is getting proper fuel pressure. It has a Q45 throttlebody which wasn't on the other guys car that the engine came out of, I think this is the only thing that was changed.

Whenever you think the idle would smooth out after giving it a little gas for 30 seconds, it goes to like 600rpm and stumbles a bit and then revs up to 2000 or so by itself. It seems like a vacuum leak, but all the nipples on the GReddy manifold are either plugged or going to something (BOV, Wastegate, Intake pipe, brake-booster).

Any suggestions? Injectors maybe? I'm all out of ideas here so any suggestions would be much appreciated!!!

[mott6904]

I gave a suggestion make a leak tester make sure you dont have a leak. What is your tps set at? If you changed the throttle body then i would say that you didnt set your tps right.

[whoareu]

Apex- thanks for chiming in, i knew you could describe it better than me.lol. and the tps voltage will be the next thing i check when the garage opens tomorrow. where do you measure this at? i searched and found 2 threads but neither were helpful.

[mott6904]

Oh man off the top of my head, There is two connectors coming out of the tps. one is on the body and the other is a loose connector. Backprobe the middle wire in the loose connector. it should be set between .4-.5 volts when the throttle is closed. When the throttle is opened all the way it should read 4.5 volts. Then you need to check continuity on the other connector, that sets your idle switch. It is the middle wire and i cant remember what the other wire is. I searched and found 59 results if you want a more solid answer search threw here Type in tps and then use the scroll down menu and click on rb20/25/26 engine section. This has been covered tons of times this is all the info im going to look up on this. zerosearch

Fix your tps and then get back with us with the results. Before you set the tps make sure you pulled out the cold idle plunger on the q45 throttle body or you will have to reset the tps sensor when you do that.

[whoareu]

Mott thanks for the reply, wtf is the cold idle plunger? damn, just when i find one thing out i have to do something else before i can do the one thing i was trying to do. lol, are you f***ing with me i just searched and came up empty???

[whoareu]

ok still nothing on the cold idle plunger. lol but i did chang the voltage. it was at like 1.38v so i knocked it down to .45v and she started right up, however she idle's weird. she will idle at around 6-700 then bounce to about 2900 and then down to about 500 and just keep doing it. any idea's? my thoughts are something is wrong with the tps/tb.

[mott6904]

For the cold idle thing on the throttle body i tried finding a picture of it but no luck. ON the front of the throttle body there is a little plunger that pushes up against a spring or a bar i cant remember but you take off the little spring. it is on the same side where you hook the throttle cable up at.

On the setting the tps correctly you need to make sure the idle switch is engaged if not then your s*** will bounce all around like that. Do it by checking continuity between the middle and one of the outside wires that are built into the housing of the tps. Im not sure which wire it is but i know you use the middle. You will have to look up a wiring diagram to by sure.

After rereading your thread are you sure the car was tuned for the z32 maf if not then it will probably run really weird.

[whoareu]

UPDATE>>>

Alright so here is where i am now. i think i am having a maf issue. the tps is good i beleive i have it set at .45v the problem lies with starting the car. when i try to start the car with the maf connected it will start then imediatly die. if i unplug the maf it will start and run. it will idle around 1300-1500rpm's but it sounds great. i dont think there are any vac leaks. any thoughts. oh and the safc does read A/F when you hook the maf back up but only shortly unless you give it gas because it will die. of course.

[xiaphin]

Reminds me of this video when searching for SR20 gt2871r vids

http://www.youtube.com/watch?v=MLsZmniSWYs

comments say MAF was too close to the turbo, wouldn't think that would be the problem since engine ran in friends car. Worth looking at nonetheless.

[whoareu]

actually heres a video of mine just made it today. never mind my kentucky accent. lol

http://www.youtube.com/watch?v=8afJ6DT9yCU

oh and i was wrong about the maf. it is not a z32 maf. it is a pink label, which i guess is the stock rb25.
Modified by whoareu at 8:55 AM 4/18/2009

[whoareu]

so no one on here has any thoughts. heres another video.

http://www.youtube.com/watch?v=0yeqG_UoH68

[GTRs13]

Alright here's my thought:

-Dude, there are a ton of butt-connectors in there, you should really be solder and heat-shrinking all of your electrical connections.

With that said, you really need to start at square one.

The car will run without a SAFC obviously, so I think you need to go back to your stock wiring and clean it up.

This will be the best way to determine your problem. When you elminate as many variables as you can.

[whoareu]

Alright here's my thought:

-Dude, there are a ton of butt-connectors in there, you should really be solder and heat-shrinking all of your electrical connections.

With that said, you really need to start at square one.

The car will run without a SAFC obviously, so I think you need to go back to your stock wiring and clean it up.

This will be the best way to determine your problem. When you elminate as many variables as you can.

all those butt connectors are just radio. i dont use butt conectors on anything else. not even sure why i used them there. i think i was just rushed. every thing else is soldered.

[USMCgetsome]

GET OFF YOUR ARSE AND TRACE THEM WIRES TO THE MAF AND TPS! STAT! tell us the color of wires at the connector. Also get some voltage readings from both sensors.

[whoareu]

i have traced the wires and am 95 percent certain they are not crossed, only reason i say 95 is because there are areas with the factory wire covering still on them so unless the factory focked it up the wires should be correct. the tps should be accurate, i am measuring .46v closed is there something else with the q45 i should be checking. i cleaned the throttlebody really well before i installed it also just fyi. i also tried etxra grounds on the maf ground to no avail. tried swapping the signal wires just in case also did not work.

does this help with your diagnosis?

[whoareu]

GET OFF YOUR ARSE AND TRACE THEM WIRES TO THE MAF AND TPS! STAT! tell us the color of wires at the connector. Also get some voltage readings from both sensors.

wont be able to get voltage readings untill tuesday.

[s13_240_rb20]

Silly questions here, but: Have you been driving the car so that the ECU can monitor the engine performance and adjust itself accordingly?

If you barely hold the gas pedal, is there a miss as you are crossing 2000 rpm??

Now this is probably a reeeaaaallly stupid question...probably so stupid that you will doubt my first 2 questions, but here it is:

Are you using the stock TPS on that throttlebody? Are there any problems with matching up that throttlebody/TPS/MAFS combination? (such as TPS expecting different voltage levels from MAFS?)

--TJ

[GTRs13]

Whats the AFC Reading for airflow at idle.

And

Are you *positive* the AFC airflow wires are correct?

What happens if you bypass the AFC, and hook the MAF wires up stock, with the MAF plugged it?

[whoareu]

Silly questions here, but: Have you been driving the car so that the ECU can monitor the engine performance and adjust itself accordingly?

If you barely hold the gas pedal, is there a miss as you are crossing 2000 rpm??

Now this is probably a reeeaaaallly stupid question...probably so stupid that you will doubt my first 2 questions, but here it is:

Are you using the stock TPS on that throttlebody? Are there any problems with matching up that throttlebody/TPS/MAFS combination? (such as TPS expecting different voltage levels from MAFS?)

--TJ

1. havent driven the car at all yet.2. with the maf pluged in and the throttle pressed the car will stay on but runs rich, and as soon as you let off the throttle it dies.3.i am using the stock tps on the q45 maf and it is reading .45v closed. which from all my searching has told me is correct.

[whoareu]

Whats the AFC Reading for airflow at idle.

And

Are you *positive* the AFC airflow wires are correct?

What happens if you bypass the AFC, and hook the MAF wires up stock, with the MAF plugged it?

one of the things that gets me is that this setup was installed on my friends car and then swapped over to mine and it was running perfectly on his, none of the wires were unhooked such as the maf or afc or ecu, it was all just harness stuff so it was plug and play. (supposedly right) as far as i can tell all the wires are correct i have gone over the wires but have not tried bypassing the safc yet. just figured it made more sense to check the maf first.

[truckskinjoe]

just a few thoughts,is the maf installed in the right direction? a very easy vacuum leak detector is a simple piece of hose, say 1/4" id x 2' long. hold one end to your ear and the other around your engine bay, you will hear the whoosh of a vacuum leak as you move it around and be able to home in on it precisely by the sound.

have you verified all your wiring connections? simply pull the plugs apart and reinsert them until you feel them hit home.

have you printed a vacuum hose diagram and followed each of them? not more than 10 minutes to do that.

Good luck

[tight240]

All your voltage readings you should be able to use the SAFC for that, plus do you have the settings for the HW right in the SAFC? Maybe with the SAFC being disconnected from battery power it whiped out the settings. If your not going to disconnected the SAFC then make sure all your settings are right, i had this problem with my S2 and come to find out, i was not getting a MAF voltage reading to the ECU, so i installed the SAFC to find that much out. SAFC is not just for tunning it can be a good diag tool as well, you need to google the SAFC manual, because you should be able to check voltage to the TPS and MAF using the SAFC.

[whoareu]

as far as i know all the settingds sre still in there. i checked asnd the in is 4 and the out is 4 and this is for the stock maf. by the way i ordered another e60 maf today for 40 bucks. i will try cleaning the old one and checking a few other things tommorrow. also will use my datascan tommorrow to help diagnos so hopefully that will help.