OBD1 KA and code 45!?!

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niceguy
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OBD1 KA and code 45!?!

Post by niceguy »

Hey guys, I've had an intermittent battle with this code for some time now and it's driving me nuts. It's a '93 Altima that's back to NA for now and has been giving me a code 45 (leaky injector or overall very rich condition) off and on for some months.

Due to the original parts being nearly 20 years old, I replaced over time the FPR, all 4 injectors (2 measured 30ohms vs the factory 11ohms), the coolant temp sensor, O2 (from being contaminated from the rich condition), plugs/wires and MAF (junk reman).

Typically a code 45 on fed spec engines is when the engine is beyond the ability of the ECU to compensate (>10 or 20%, can't remember which). Most of the major components I replaced could cause a 45 but aside from another bad MAF, I'm at a loss.

Just wondering if anyone here has had this issue or suggestions on testing/troubleshooting.

Thanks guys
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supakat
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Post by supakat »

Check fuel rail for leaky o-rings.
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niceguy
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Post by niceguy »

Thanks supa, even though the new injectors came with new o-rings, there's always the possibility of one getting a slit or torn when reinstalling the injectors.

However, if there is a torn o-ring(s) , shouldn't the corresponding plug be covered in raw fuel? I just found the code and am going to check the plugs this evening when I get home...

The car's an auto and I just threw a 2000 model auto that has the 4.08 vs the old 3.61 so it should rip pretty good when I get the turbo back on next year!

Thanks again buddy
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Post by supakat »

Depends on how bad it is torn. It seems that it is something mechanical/physical that does not involve a sensor. A low output coil could do this as well. Not enough juice to plugs.
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Post by niceguy »

Yeah, coil is original so nearly 20years old lol....It seems like reman MAFs even from O'Reillys are a crap shoot like distributors so after checking plugs for fuel I'm going to plug in Datascan and take a few datalog drives to see what's going on again....

No black soot from the exhaust but gas mileage is getting hammered!
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Post by niceguy »

Checked the plugs while I had just a few minutes and all 4 have the same look. Ground electrode is tan/grey, center electrode about the same, electrode porcelain is white and on all four plugs, the bottom few threads are carbon black (near the electrode/bottom of the plug).

The plugs themselves have no wetness or smell of fuel either. Just the very bottom threads have black carbon/soot traces but the electrodes and porcelain have no signs of it...

Can't find my consult cable so that will have to wait. I decided to plug my EGR as a test though I doubt that will help since I have no drivability issues as it is. If it weren't for the poor fuel economy, I wouldn't even know I had a rich code.

I've also checked the injector and engine grounds and they seem to be fine. Sometimes I hate older Nissans lol....
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Post by 702S13 »

What's your fuel pressure like?
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Post by niceguy »

Not sure offhand, I'm going to get with a friend this weekend that has a fuel pressure gauge. I'd really like to just install one inline so I don't have to fool with depressurizing the fuel system and wasting gas,etc....

I installed a Walbro 190 pump about 3 years ago.

What's crazy is that as soon as I installed the new injectors, the car would fire up within a split second of turning the key and I'm not exaggerating! Now the car has to turn over a few times to fire so I can see where it could be a fueling issue possibly.

I hope to get the pressure at least checked today if at all possible. I really appreciate the help guys. I actually like troubleshooting things but when you don't have all of the tools or proper time (working 10-12 hours shifts every week), it's gets a little annoying lol...

EDIT: I may be missing something but so I'm clear, could low fuel pressure even affect gas mileage? I'm getting about 20mpg in the city....
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Post by niceguy »

Update: A local race shop, BB&T racing had an Aeromotive fuel pressure gauge. Hopefully it's accurate!

Anyway, just installed the gauge/t fitting and at idle the car is showing about 37lbs of pressure with the FPR vaccum line hooked up and about 48lbs or so with it disconnected.
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Post by niceguy »

Ok I haven't had time to change the FPR (will do this week) but did notice some more odd fuel pressure readings.

Usually as soon as I shut the car off after it's run for a few minutes, the Aeromotive fuel pressure gauge shows about 40lbs or so and it takes probably 15-20minutes for it to drop below 30lbs which is about spec according to the manual.

However, I noticed last week the gauge showed about 35lbs of pressure as soon as I turned the car off and then tonight, I happened to pop the hood to check the oil and the gauge read 30lbs-as soon as the car was shut off.

Something's obviously not right but I'm wondering if there's any way to pinpoint if it's the pump or the FPR? The car is actually running stronger than usual for some reason but just thought I'd get your thoughts on this.

So far what I know: At idle, fuel pressure is around 36-37lbs with vacuum and 46lbs without vacuum but rock steady. (Haynes says 32-38lbs vac/38-46lbs no vac is ok)
Injectors/o-rings do not appear to be leaking, all fire the same amount of fuel and plugs look good.

Thanks!

Jeremy
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Post by niceguy »

Ok just an update for any who care lol: I replaced the fuel filter and FPR with another O'Reilly Borg Warner (BWD) brand unit. install everything, prime the pump and fuel pressure hits 36lbs and then starts dropping immediately down to about 10lbs!

It takes all of 1 minute to drop down to 10lbs of pressure, so I reprime the pump, take some taped up pliers and clamp down as best I could on the return line just after the FPR, and pressure seemed to stabilize.

I also retested, priming the pump and clamping the inlet line between the filter and Aeromotive fuel pressure gauge and it didn't stop the pressure drop so it definitely seems to be another freaking defective FPR from O'Reilly.

In case you're wondering all lines are tight and I left the rail unbolted and propped up and no gas leaked from the injectors.

I'm ordering a new FPR from Nissan for $86 and hope this fixes the problem once and for all!!
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Post by biggie »

Got that much money could have just went with the Nismo Adj FPR. But hopefully that fixes it.
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Post by niceguy »

Well the O'Reilly FPR was $77 itself, so the Nissan unit was only $9 more. Actually Nissan list price was $115 but I've known the parts manager for some time so he knocked it down to 'wholesale', according to him. Credit card makes things easier lol.

I actually checked around for the Nismo unit but couldn't find one under $120 last week when I looked so I just gave up on that...I just want it fixed for now.

Even though I've been running a Walbro 190 (cheaper than the OEM pump was at O'Reilly) for a few years, another fellow I know is running the 255 model with the stock FPR and he's rock steady at 34/43. I don't want to band aid the problem, just figure it out as I'm tired of messing w/the fuel system haha...
niceguy
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Post by niceguy »

Well, I'm bumping this 7month old thread for anyone that like me, sometimes find a thread with the exact issue they have only to find that no one ever found a solution or reported back...

I actually fixed the code 45 (generic injector leak code) on my '93 Altima a few months back but never got around to posting the answer.

Anyway, it was my fault. I had been dealing with this code for a couple of YEARS, yeah I'm busy and lazy lol but eventually found the MAF harness connector was shot, and after having the connector ziptied for a year, the signal lead wire broke inside the connector.
Being always in a hurry (and a little lazy), I cut a 6" length of a junkyard Altima MAF harness/connector and as a test, used crimp connectors and electrical tape. Well, the test initially worked and the code went away but I forgot about the ghetto wiring and code came back and drove me nuts until I remembered the crimp connectors.

I honestly didn't think it was the issue but figured what the heck, so I removed the MAF harness, cleaned it, soldered it, shrink wrap, tape, loom,etc and no code in the last 6 months.

You full time gearheads probably already knew this but maybe this will help someone down the road...So to make a short story long lol....

Jeremy
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Post by Walperstyle »

major thanks to the followup. This site depends on people posting answers to issues they have.
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Post by sdaigle240 »

good work on the fix and reporting back!
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