vito324

Alright, so I left my SC400 sitting in my driveway for about a week without moving it and now when I crank it it just runs really rough and only stays alive if I keep the gas pedal going and while this is happening I get a rich exhaust. I've already tried changing the spark plugs and coils with no luck. I've searched a lot on here and it looks like it may be the throttle position sensor? I'm not getting a CEL and so I'm pretty stumped.

Any help will be appreciated, I need to get this running asap. Thanks,

-Steven

vito324

anything anyone?

Kira X

iTrader: (24)

It's most likely the fuel pump ECU going out. Search for "12v fuel mod" here on the forums and that should fix it. If you can't find it, I'll send you a link.

Since I'm on an iPhone, it's hard for me to post it now.

willhickey

iTrader: (1)

not if it smells rich right? vacuum leak? try disconnecting the maf sensor and see what happens.. pm me if that doesnt work take a look at the cap and roters also please

vito324

I don't see any vacuum leaks. But unplugging the MAF just makes the problem worse. I can't even keep it alive by giving it gas then. I suppose I could change the caps and rotors tomorrow and see if that does it.

el400

i had the same issue when i got my sc400 2 weeks ago.I change the plugs and wires and it runs alot better.How old are the wires on the car?

vito324

Well, I ended up replacing the caps, rotors, and wires. No effect. I'm still having the same problem. Should I try the fuel pump mod now? Or is there something else that could be wrong?

FatBrian81

iTrader: (2)

Check this thread out, theres a ton of good info in here
https://www.clublexus.com/forums/sc-...on-issues.html

brad11140

iTrader: (3)

Before yo jump in and try the mod on the fuel pump ECU, jumper your fuel pump in the diagnostic connector. Fp and +b. If that fixes the problem than you know you need the mod or a new ECU. Rough idle sounds like vacuum leak, EGR valve stuck open or your iac valve stuck. Check the obvious lines than check your iac next. After sitting awhile it's possible that valve is stuck. Good luck.

vito324

Okay so I jumped the fuel pump and now it doesn't run unless it is jumped. But the problem seems to have gotten worse. When I turn the ignition to the "on" position, I hear a loud click for a few seconds. What is this click? And now when I try to start it, it rolls over for a second and then all I hear is a loud squeal until I turn the key off. What could this be?
Sorry I'm lost with this thing and have no idea what to do next but I'm hoping to get this thing running this weekend.

brad11140

iTrader: (3)

Ok so when you jump do you mean the engine will only run with it jjmpered or the fuel pump? When you say loud squeal are we talking about an electronic squeal or like a belt slipping squeal. Where does it sound like this click noise is originating. Engine bay. Dash. Fuel pump area??

vito324

The clicking and squeal are both definitely coming from the engine bay. As far as the squeal goes, I'm not entirely sure. I'm working on this alone right now so I can't pinpoint exactly where. But the car won't stay running at all at the moment. And I don't hear the fuel pump running unless it is jumped. I'm pretty sure I need the 12v mod.

brad11140

iTrader: (3)

Yeah you may need the mod. But it would appear there are bigger fish to fry. You can hear the fuel pump running and you can hear fuel circulating at the intake manifold I assume. So you have fuel. You know you have air. Spark is the last thing to check. And if it was idling rough and has hit or miss starts maybe one of your coil packs is bad. I would inspect those and make sure the clicking and squealing is not coming from a blown up coil pack

brad11140

iTrader: (3)

I just re-read through your postings and saw that you changed coils. Make sure they are connected properly. Have you did the voltage checks on the MAF. Checked calibration of the TPS. I realize these things are probably not clicking or squealing. You need to get a buddy to help you figure out where these noises are coming from.

brad11140

iTrader: (3)

Also, check for stored codes, even if you don't have a CEL