Fault code 45, poor idle, hesitation when cold

[crackler]

This is for a 92 240sx SE w a 5spd KA.My ECU is throwing fault code 45, leaky injector, and when the motor is cold (once it gets past the initial "warm up" high idle), the idle some times oscolates between 500 and 1000 RPM's (sounds like it has huge cams), it doesn't always idle like this but it is frequinent. the idle also drops low when I enage the clutch when I go to stop.

The most noticeble problem, and the one I am most conserned with is the hesitation. Once the Motor is "warmed up"(not idleing high) but still cold, when I go to feed fuel back in while shifting or feeding in fuel to take off from a stop, the motor will bog down, instead of accelerating. then after a few seconds it will pick back up and go like normal. It only does this when it is cold, and sometimes it is worse than others.

My friend who is a dealer tech checked AllData and gave me the print out, it said for the leaky injector code, could be any sensor input that can cause a "rich" fuel signal can cause an injector leak code. And, Any cause for excessive fuel pressor can cause an injector leak code. Then it said to check:

1. Consult Alpha Test (WTF???)

2. Mas Airflow sensor test. (I cleaned the MAF, and check the ground (center pin on harness) and it was less than 1 ohm.

3. FPR test. Checked Fuel pressor, idles at about 43 psi, and w a vac pump hooked up, the pressor will drop when vac is applied.

4. Injector leak down test. All new o-rings installed when code was first thrown.

5. Engine coolent temp sensor test. ECU sensor all ready replaced due to throwing code previously, Borg Warner unit

6. o2 sensor test. Replaced when I got the car about 1.5 years ago

7. Quality control check. (WTF???)

I have irridum NGK plugs (they are white in color), new cap, rotor, wires, fuel filter o2 sensor, ECU temp Sensor 1.5 years old. And I also have a K&N drop in filter.

Also this problem started all at once, it didn't develop slowly, and I have also cleaned out the IACV same time frame as above. I think that is everything. And my fuel mileage has gone to poo. I think my exhaust is also smelling of gas, but has always smelt rich, I'm not sure if it worse than before or not.

Sorry for the long post, and Thanks for any help you can give me.

[180fan]

1. Your injector(s) could have some crap in it that's keeping it stuck open.

2. Give your CTS a wiggle. I've seen a few loose connections on that whore before. Otherwise you might want to yank the cts out and see if you've got buildup on the tip. Ha ha ha head cheese.

3. you check your timing yet?

4. did you check the inside the intake manifold just behind the throttle body for crap clogging the vac ports?

[crackler]

When I changed the o-rings on the injectors I soaked them in carb cleaner for along time, from the way my spar plugs look, I think my injectors are ok.

My timing is good.

CTS???

I cleaned the throttle body a while back, I will check again, and see what it looks like.

Whats weird is it is fine once it is warm, I would think most of these things would cause a problem all the time if they were having an issue?

Thanks for the suggestions. I will check tomorrow if I get time, if not I will on saturday.

Any more ideas from any one else?

[180fan]

just cuz they're not leaking past the o-rings don't mean they're not sticking open. Then again, your plugs wouldn't be tipped white then.

CTS = coolant temp sensor.

If it's fine when it's warm, it'll be your CTS.

[crackler]

I replaced the ECU CTS about a year ago w a new borge warner unit.

[crackler]

I got caught off gaurd with some stuff this weekend, and I had to help a freind replace his CTS on his VW, so I haven't had time to do anything yet.

I had to drive down to Oklahoma city friday night and came back saturdaynight, I avaeraged about 17 MPG. That seems a little low. i think it is still runing rich all the time, but the hesitation goes away once its warm, it still idles poorly most the time. I am going to go through the TB and seafoam the intake as soon as I get time.

BUMP for some more help.

[OO_OOPS]

Hi!

I'm having the exactly same idle problem. Poor Gas mileage, Code 45 and idle irregularly. I've got new fuel injectors with new o-rings, new O2 sensor and still the same. Did you sovle you problem? If so how did you do it?

[rogoman]

Remove the spark plugs one at a time to see which ones are wet with fuel.

Another thing you can do to check possible injector leakage is to unbolt the fuel rail from the intake manifold and pull off the entire assembly. Keep the fuel hoses still connected and don't remove any individual injectors. Also keep the electrical connectors on the injectors. With the assembly now away from the intake, turn the ignition key to the run position WITHOUT STARTING THE ENGINE. Now observe each injector to look for leaks. There should be no drips.

Make sure you have at least 4 spare insulator rings for the injectors in case some are damaged during rail removal.

[crackler]

OO_OOPSI still have it. I replaced the MAF and cleaned the O2 sensor. The MAF did nothing to help, the O2 sensor seemed to help some, but it might be bad alltogether.

Rogoman,All my plugs look good.

I found a vacume line that was off, and cleaned out the IAA, but neither did much good. I am wondering if it is the sensor that sits down inside the intake, it is an idle control valve or something, big square deal that sticks out twoards the firewall, with a plug on one end and a vacume line on the other. I am basically grasping at straws now.

And sorry for the slow response I had given up getting any hwelp on this, and I figured it was 10 pages backm by now.

[crackler]

I also replaced my plug wires again, Lifetime Warrenty FTW, due to one having a torn outersheilding. And I replaced the CTS with a new unit as well, still the same thing.

[crackler]

After driving it for a few days, cleaning the o2 sensor off seamed to help alot, Istill need to check for codes but it is much more drivable when cold, almost no hsitation now.

[vvaffle]

Any updates on this? I am getting almost the same issues. I thought that code 45 was a California only code and that it would make the check engine light turn on. I didn't think my car was a california car and the check engine light wasn't on while driving.

[crackler]

It seams that cleaning the o2 sensor cleared everyting up, I still haven't checked my codes though. Mine didn't throw the light either.

Replaced O-rings and cleaned injectorsFixed Vac leaksCTSPlugs, WiresTimingClean Trottle bodyCheck EGRCheck/ Clean MAFCheck / Clean o2 sensorCheck FPR

My friend who is a dealer tech checked AllData and gave me the print out, it said for the leaky injector code, could be any sensor input that can cause a "rich" fuel signal can cause an injector leak code. And, Any cause for excessive fuel pressor can cause an injector leak code.

If you check the FSM there is a section for trouble shooting cold hesitation, I think it is in the EM section, I think.

This is what alldata said to do:

1. Consult Alpha Test (WTF???)

2. Mas Airflow sensor test.

3. FPR test.

4. Injector leak down test.

5. Engine coolent temp sensor test.

6. o2 sensor test.

7. Quality control check

I also saw another post some where, it said to pull the fuel rail, with the harness and injectors all hooked up, juast unbolt the rail whole from the manifold, then turn the car on, but dont start it. with the ignition turn "on", but the car off, check the rail for leaks. Doing this will prime the pump w/o firing the injectors, that way you can look for leaks around the rail. That is what I read anyway, so take it for what it is worth.

Hope that helps.

[crackler]

If you check the FSM there is a section for trouble shooting cold hesitation, I think it is in the EM section, I think.

Correction:

It is in EF & EC page 69.