Troubleshooting ECU code 45 from 93 Nissan Altima

willydog,

I looked in my 1992 Pathy manual for EC 45. I am assuming it has very similar ECU firmware as your Altima. It seems to be leaky fuel injector/s.Your symptoms are indicative of fuel injector problem. Do you have access to a fuel pressure gage? You could put on the fuel rail and see if the system holds pressure after cycling power to the fuel pump. I think it should hold within about 5 psi for 2 minutes. As far as tracking down the offending injector if the fuel pressure test fails you could let the engine cool after a warm up then turn on the ignition to get the fuel pump to cycle and crank the engine with the coil wire disconnected and grounded to the engine. Also you need to disable the fuel pump during cranking. The idea is to get the leaky injector/s to release gas into the cylinder and then see the gas on the spark plug. This sounds complicated and I would invite someone else to pitch in on a better way finding the leaker.

Good Luck Sparky

I don't know about the code, but seen something very similar happen with a Mass Air Flow (MAF) sensor on a friend's car.

Remco

Thanks guys - from what I've read, you can use a listening device to listen for a bad injector - if that happens, then the problem is (at least partially) identified.

The car is running rich - but I should correct that it's not a strong smell from the engine compartment - the exhaust definitely smells rich though. It looks like my gas mileage is somewhere around 10% off too. Some other symptoms:

• If I cluch in at very low RPM's, the idle remains fairly strong.

• The idle has hunted in th past all the way from close to 0 to 900 RPM. After using 5 gas cleaners over the last 6 weeks, it seems pretty solid at around 600-900 RPM.

Does anyone know if things like the IACV/AAC and the EGR can be component tested thorugh software? I'm using the freeware version of conzult, with a board I bought off ebay. If there is anyway I can do some tests with software, that would be ideal. It's getting cold up here, and I don't have access to a warm garage to do some component testing with the volt meter. I checked the EGR, but I believe it all needs to be taken apart and cleaned, and I would prefer to isolate the failing component first.

Thanks in advance for your courteous replies. Bill

check for an excessive voltage drop on the ground wire at the air flow meter.

The above described condition can cause the injector leak code to be stored

if the drop is in excess of .020 volts or more you have a problem

Gentlemen - all good things. I know, I know. This is so old school, I really need an ODBII vehicle, but they aren't "all that" either probably.

I think the IACV is definitely sticking though too.. As a test - when I turn the AC on, the idle goes up slightly - as expected. However, when the compressor shuts off and the idle drops - it drops all the way to zero and stalls. Am I smoking crack, or is this classic symptoms of sticky valve? Based on experience - does anyone know what code ECU throw with the classic "sticky valve" problem ?

Interestingly, I took the car out on a good 200 mile ride at between

80-85 MPH solid the whole way, so those injectors got a good nice scrubbing. Now the car seems to be running *very well*, which is interesting. I weened it off the cheapola gas treatements I bought in bulk from SamsClub for $.75/ea. running 5 back to back before I noticed a changable difference. It still idles high - like at 880 RPM, but it does hold a good steady idle without hunting too badly. I can even shift again into neutral without having it stall out. If I goose the throttle, I hear what sounds almost like a sputter/backfire coming from the engine area. (fuel injector?). I don't smell gas... so anyway I don't goose the throttle anymore and am just hoping it's something else.

I just want this car to get me another couple years. I've changed the O2, distributor (twice - once including the aftermarket fiasco), plugs, wires, cap, distributor, fuel filter, air filter. The only things that I know of that need to be cleaned are:

• EGR (cleaned and replaced?)

• IACV - cleaned up and verified functional

• PCV valve (?)

Does the ground to the MAF problem just all the sudden start happening like that? I've been reading other's symptoms and they don't sound like mine.

Add cleaning the throttle body to your list.

Thanks. The throttle body was cleaned last year, but I'll have it done again. I've got enough money sunk into this car that if I can drop another $200 for another two years, that would be awesome. I mean I baby this car. It still has the original rear drums, and the engine is in mint condition from the engine degreasings I used to do in "the day" with this vehicle.

If I bring it to my mechanic, what do you think is a reasonable quote for the following work:

• dismantle and clean IACV, veryify correct behavior via component test

• check EGR valve - component test and clean/replace

• clean throttle body

• diagnose wet spark plugs and noisy injector.

I'll even let him use my consult card to pull codes. Most mechanics are capable of using it, and the freeware software is very nice. I just ordered a 10" cable for the laptop. If he would be receptive. I'm thinking about 2 to 2.5 hours labor for the above work? (around $150-$200 here). Am I going down the wrong path with this? Thanks.