RB25 Starts but wont run

[Harley80]

So i got a 97 stagea with rb25 and it’s having issues running it starts runs for a good 10 or so seconds than shuts down used to run horrible for a few seconds till i cleaned what i believe is the IACV now it runs healthier but still shuts down previous owner ran the fuel filter backwards before realizing than putting it the right way. Cam angle sensor was replaced aswell some things are unplugged under the dash and i have no clue where they go cause previous owner did some uhhh funny wiring theres also a random plug in the engine bay where i have no clue where it’s home is lol. Vacuum is good and spark is good even when running so i’m at a loss previous owner also ran regular and i was told it needs at least premium. I guess i’m kinda lookin for some tips on other things to check i probably left out a few things i checked. Thank you all

[PranK]

Hi and welcome to  !

I'd be taking some pics of the plugs and wiring you've found and posting them up. The guru's on here will be able to get more from those than your descriptions of them.

 

[Harley80]

On 22/10/2024 at 9:52 PM, PranK said:

Hi and welcome to  !

I'd be taking some pics of the plugs and wiring you've found and posting them up. The guru's on here will be able to get more from those than your descriptions of them.

 

I will try to get some pics today if i remember haha how would i go about putting them on here is there a way to do it from a phone it says i need a link? Thank you!

[PranK]

Just click/tap the link at the bottom of the editor that says 'choose files'.

[MBS206]

With the idle, have you reset the base idle screw with the IACV unplugged?

Very likely the base idle is set far too low. 10 seconds sounds about right for the ECU keeping the IACV open at about 1000rpm, then it should settle for about 650-750rpm (I can't remember the exact rpm point). If the base idle is too low, it can cause the car to stall.

[Harley80]

42 minutes ago, MBS206 said:

With the idle, have you reset the base idle screw with the IACV unplugged?

Very likely the base idle is set far too low. 10 seconds sounds about right for the ECU keeping the IACV open at about 1000rpm, then it should settle for about 650-750rpm (I can't remember the exact rpm point). If the base idle is too low, it can cause the car to stall.

I believe so haha don’t quote me on it my old shop foreman is helping me out. I also totally forgot to mention cause i’m a dumb dumb when you even try to give any throttle it chokes it out quicker if that’s any help. I gave the MAF a clean really wasn’t that dirty. He recommended i check the o2 sensor one day idk if that will have any effect?  

[Harley80]

56 minutes ago, PranK said:

Just click/tap the link at the bottom of the editor that says 'choose files'.

Here's some photos of wiring i cannot find the homes for the first one i didn't realize till after has a few more hidden behind them so there's a couple more but that's what i could find. Thank you!

 

[Harley80]

59 minutes ago, MBS206 said:

With the idle, have you reset the base idle screw with the IACV unplugged?

Very likely the base idle is set far too low. 10 seconds sounds about right for the ECU keeping the IACV open at about 1000rpm, then it should settle for about 650-750rpm (I can't remember the exact rpm point). If the base idle is too low, it can cause the car to stall.

I'd try to send the video of it running but idk if that's possible? Sorry I'm very new to this i usually work on old american cars so this is all very new to me lol

[Harley80]

12 minutes ago, Harley80 said:

Here's some photos of wiring i cannot find the homes for the first one i didn't realize till after has a few more hidden behind them so there's a couple more but that's what i could find. Thank you!

 

I don't even know is those worked i can no longer see them

[MBS206]

Those didn't work. Depending on if you're on a phone or PC, you can click the add files button, select each photo one at a time (pick one photo, tell it to upload, click 'add files' again.)

 

It sounds like a few things are unplugged, one is possibly the AFM (or wrong AFM) or the TPS.

 

I've had the same issue before too leaving the temp coolant sensor unplugged, but that only became an issue once the car got hot.

To know what the base idle is doing, unplug the IACV (electric plug to it), and see if it'll start up, and what the idle tries to sit at. It will be interesting if it can even start with the IACV unplug, and that would be a big clue too if the idle screw is set too low.

 

Will wait for the pictures to load again so we can check plugs.

[Harley80]

43 minutes ago, MBS206 said:

Those didn't work. Depending on if you're on a phone or PC, you can click the add files button, select each photo one at a time (pick one photo, tell it to upload, click 'add files' again.)

 

It sounds like a few things are unplugged, one is possibly the AFM (or wrong AFM) or the TPS.

 

I've had the same issue before too leaving the temp coolant sensor unplugged, but that only became an issue once the car got hot.

To know what the base idle is doing, unplug the IACV (electric plug to it), and see if it'll start up, and what the idle tries to sit at. It will be interesting if it can even start with the IACV unplug, and that would be a big clue too if the idle screw is set too low.

 

Will wait for the pictures to load again so we can check plugs.

It does start with it unplugged it ran a lot healthier after i cleaned it out a bit it still kinda idles rough sometimes and shuts down quicker but when it sounds healthier it runs longer but even when you attempt any throttle it like instantly chokes it out and the car is like NOPE no throttle for you lol. also only options i have to put photos are to only use links or URL and that is what i did and i could see the photos till it refreshed and now i can't see them lol

[GTSBoy]

You can't post images until you have like 10 posts or something.

[PranK]

1 hour ago, GTSBoy said:

You can't post images until you have like 10 posts or something.

My apologies @Harley80 I forgot about what @GTSBoysaid. I have fixed this for your account now so you can upload images. 

[Harley80]

5 hours ago, PranK said:

My apologies @Harley80 I forgot about what @GTSBoysaid. I have fixed this for your account now so you can upload images. 

Oh hahaha i thought i was missin something lol

[Harley80]

Here’s a video of what it’s doing excuse my finger we lost that plug when i took the video but found it yesterday. That’s when it sounds a lot healthier sometimes is really struggles to idle and chugs still it shuts down

Edited October 25, 2024 by Harley80