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Code 45 Leaking Injector And Smog Again!


msavides
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So I have been battling this leaking injector (CODE 45) For about 3 years now. Coincidentally right after i install my thorley Headers (Probably not related)

 

2 years ago I when smog time rolled around I took the chance and cleared the code and took it in to be smogged. I sat there nervously watching as the smog tech guy run the truck through its paces and my heart sank when at the end of the 25mph test the little yellow light popped on. The smog guy immediately let off the gas and got out of the vehicle. He then disconnected all the equipment and proceeded to put the stuff away. He then got in the truck to back it out and i noticed he took a double take at the yellow light. He then proceeded to back out the truck. He then called me over to the truck and told me that there is a problem with my truck but I was lucky since the data was already sent to dmv. But for me to get it fixed.

 

Some of you guys may have seen my list(in a few posts) to things i have replaced trying to remedy the problem. A few people have offered advice and I have tried pretty much everything.

 

Well guess what that was 2 years ago and guess what I get to do every 2 years. Time for smog again. I went through my truck again trying to double check everything. I found a small exhaust leak at the collector pipe on the drivers side. I fixed the leak and began to think could there have been a leak there the whole time that just got progressively worse to the point it was audible. I drove the truck to work and back today to test to see if i could get the CEL to come on before i tried to take it in to be smogged again. I followed the procedure in the Nissan manual that is suppose to get the light to come on. warm engine, drive truck to get the rpm over 2600 rpm for 5 secs, then let idle for 10 secs, repeat 10 plus times.

 

I did this about 50 times no light. so driving to work and back is 150 miles round trip in the bay area. In the morning it is light traffic so i pretty much drive 70mph the whole way there. On the way back in the afternoon it is stop and go reaching 70 mph and the abrupt stop 20 to 30 times on the way home. Still no CEL. So I decide to go for it and take it directly to the smog shop right from work.

 

well there was a 30 min wait at the smog shop. so i let the truck idle until they could get to it. Then they drive it on to the dyno, and I looked through the window in the waiting room and see that my light is still off. I am thinking everything is good, I finally got this thing licked. then the 25 mph test and the FRIGGIN light pops back on again! ARGGGGGGH. SO I am waiting for the guy to come in and tell me I failed. The guy comes in and said I am good to go. Never said a word. I paid the man and got into the truck to go home. Sure thing CEL light burning bright.

 

So Good news, I passed and I have 2 more years to find the problem. Bad I Still have the problem.

 

Off the top of my head here is what i have done.

 

Replaced and tested all 6 injectors, Replaced o2 sensor, Cleaned and even tried a replacement MAF, Checked for vacuum leaks, Replaced fuel filter. More things that i can't remember off the top of my head.

 

Any insight would be appreciated.

 

Mark

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Did you check for proper fuel pressure?

 

B

 

 

That is one thing I have Not done Yet. I loaned out my Fuel pressure tester, I will have to test that, when I get it back. Hopefully this weekend.

 

Going wheeling with some ford guys sunday. Hopefully the guy that I loaned it to is done with it and i can get it back from him then.

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Ok

 

check fuel pressure today and it is right on the money. Exactly as the Nissan manual states. 34 psi at idle with vacuum on the regulator and 44 psi without vacuum on the regulator.

 

Fuel pressure drops gradually as I add vacuum to the regulator.

 

 

I also replaced the throttle position switch/throttle position sensor. This is the biggest pain in the Butt I have ever had. Adjusting this thing is a royal pain. This thing is touchy and you have to have patience and adjustment skill that would make NASA Proud. I spent over an hour trying to get this thing adjusted per the nissan manual. finally the best I could do was at base idle(without aac connected) 740rpm. got continuity to disconnect at 1190. I am 50 rpm out of spec. but I could not get any better without spending another 2 hours working on it. The main problem is when you tighten the screws it changes sometimes bu a whopping 200 rpm. This was very frustrating.

 

I really hope this fixes the problem, But I am not optimistic, cause I don't see how the TPS can have anything to do with a leaking injector code.

 

UPDATE! this is not fixed. Still have code 45. came on 2 times on me tonight just driving around town. Any other ideas I should try?

Edited by msavides
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This would be tough, but see if maybe it's your ECU? Don't know if that would be possible unless you have a parts truck, or know somebody who would be willing to loan you their ECU for a while. Maybe B's parts truck? I'd let you use mine but well you know TBI vs MPFI

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I may need to mess with the TPS but had heard that is was a major pita, thanks for the confirmation... :blink:

 

I really don't have any good ideas for you. Have you checked a FSM to see if they recommend any test procedures??

 

As for cross testing the ECU, yeah, you can borrow mine. It is off of a 95 from New York though. I don't how much of a difference that would make. :shrug:

 

B

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I wonder what defines the "leaking injector" part. Does the ECU measure signal strength to the injector or fuel pressure or what? Far stretch, but if the ECU expects a certain return signal from an injector and doesn't get it, say from a teeny tiny bad connection, then maybe that's what's throwing the code?

 

It's late and it sounds good at the moment, so there. :lol:

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I wonder what defines the "leaking injector" part. Does the ECU measure signal strength to the injector or fuel pressure or what? Far stretch, but if the ECU expects a certain return signal from an injector and doesn't get it, say from a teeny tiny bad connection, then maybe that's what's throwing the code?

 

It's late and it sounds good at the moment, so there. :lol:

 

 

Basically running rich or the o2 sensor sensing your running rich. if the computer and all sensors are working properly the ecu will close down the injectors to get it to lean out. if the o2 sensor still sees a rich condition it assumes that an injector is leaking and that is why it is still at a rich condition. then it trips the code.

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Check your grounds on your intake. It's possible one of them is loose/corroded and may be related. Other than that, I have no idea. I only say that, as you said it happened when you did your headers, and I assume you didn't hook up the ground strap to the headers that used to be connected to the manifold heat shields.

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Check your grounds on your intake. It's possible one of them is loose/corroded and may be related. Other than that, I have no idea. I only say that, as you said it happened when you did your headers, and I assume you didn't hook up the ground strap to the headers that used to be connected to the manifold heat shields.

 

I rerouted the ground straps to adjacent bolts in the vicinity. I also checked the engine ground with a volt meter. it was 00.000. Quite impressive to have no resistance. I noticed when i replaced the tps sensor that the distributor ground wire had broke off the connector and I replaced that. The only thing that has changed not is the CEL comes one reliably now instead of intermittent. I obviously fixed something to make the light come on every time all the time. Just another bit of info that could be something or could mean nothing.

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I rerouted the ground straps to adjacent bolts in the vicinity. I also checked the engine ground with a volt meter. it was 00.000. Quite impressive to have no resistance. I noticed when i replaced the tps sensor that the distributor ground wire had broke off the connector and I replaced that. The only thing that has changed not is the CEL comes one reliably now instead of intermittent. I obviously fixed something to make the light come on every time all the time. Just another bit of info that could be something or could mean nothing.

 

 

I found another TSB on the code 45 CEL. It involves checking the ecu ground. It comes from pin 115 to the body under the passenger seat. I check my ohm reading there and at pin 115 they were both at 0.00.

 

so still looking for the problem.

 

I got to thinking, if i can't find the problem. what would be the possibility of a non-California ECU working in a California truck. I have read that some people have installed a California ecu in a federal truck and everything worked great except they kept getting an egr temp sensor CEL. Since there in not one on the federal truck. My thought is that the federal computer will ignore the egr temps sensor that a California truck has and will work perfectly. and since the federal ecu does not have the injector and egr codes I should not have the CEL come on and should not have a problem passing the visual inspection at the smog shop.

 

Does anyone know someone who installed a federal ecu into a California truck?

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