Ok my car is still running lean and making a popping noise. The following have been replaced to see if it could fix it but obviously nothing has;

Bosch o2 Sensor
New Puel Pump Sending Unit
New Walbro 255lph Fuel Pump with new filter (my old filter was black)
New Spark Plugs
300zx Fuel Filter
Swapped ECU's with Mr.Gone's spare ECU (will send it back Monday) Thanks!


Eric93se suggested that it might be the o-rings on the fuel injectors or possibly the fuel injectors themselves in my last thread. I have no time to be working on my car so I have my close friend (mechanic) working on my car while I am at work and dealing with school. Eric if possible refresh me on exactly what I should tell my mechanic. Everyone else if you have any suggestion as to what I should have inspected to possibly cure my problem please feel free to suggest guys. I hate not having my car and driving the family 1992 Honda Accord beater sucks the fat one! All suggestions are welcomed and appreciated.

Thanks,
Diego

 

what happens when you hook up a scaner for codes any thing also did you try the konck sensor e.x. detantion seneor or maf

 

have you checked any other sensors yet?

under what conditions does this happen? Idle, or while driving?

could be a failed injector, could be clogged, could be your TPS going bad, could be a dirty MAF...

 

Well the scanner doesn't pick up any codes because I believe there has to be a check engine light for it to come on but it hasn't thrown any codes.

Matt can you suggest what sensors should be checked? I know you're a busy guy but I would appreciate it greatly. Well at idle its popping and when you throw propane through the intake the popping goes away because the mixtures becomes rich. It also happens sometimes when I am dirving like I could be flooring it in 3rd gear and all of sudden my response for gas goes away and I have to let off but once I let off and go back on to the gas its like nothing ever happened. Also sometimes just driving in 5th gear on the highway the car just turns off, not hesitation or anything it just turns off but when you start it up the car runs like nothing ever happened. Its a hard problem to diagnose and appreciate the suggestions and I am getting on the phone now to tell them to my mechanic.

Thanks,
Diego

 

just curious, the propane thing, does the propane go threw the maf?

I guess that wouldnt really make too much of a difference. hmmm, One guy just cleaned his injectors and his problems went away, you could aways just replace the O-rings and ohm them. Just make sure they are all working, then everything fuel wise will be checked. hmmm

 

Have you checked the fuel pressure regulator?

 

I'd check the MAF and TPS first...
sounds like you've got two different problems here though.. the idle is one thing, the running part is another.

 

no more factory freak huh? If your not to keen on spending the money on new injectors I know the ones in my old engine were in good condition (if andy still has it) if you need anything off that engine go ahead and use whatever you need.

 

How do you go about checking the fuel pressure regualtor. Actually before changing the fuel pump the PSI at idle was 40psi which i think is fine so I think the regulator is working fine. Looks like he's going to clean the EGR valve, IACV and take out all the injectors and have them serviced.

The propane does go through the MAF so if the readnigs are changing then I guess it is working. Mr.Gone your ECU will be shipped back to you on Monday using Airborne Express next day service. Thanks for letting me borrow it, I appreciate it greatly. Also what were the prior problems before your friend changed his injectors.

 

Jason thanks a lot for the offer in parts but I think if I need injectors I will get new ones. Ha ha factory freak I know but this is just a bump in the road in time and replacing parts I will be back to kicking your *** . You better hope you get that turbo soon lol. Seriously I appreciate your offer.

 

if a sensor is messing up the real time diagnostics should be able to pick it up. only thing is you need someone else in the car to help you do that. need to turn the ecu to mode 5 and have a friend watch the blinking and be sure to have him write down what it is doing at the same time.

that should work for you if any sensors are acting up. good luck!

 

Juan knows about a guy that will fix the injectors, his freind had the guy do his and he was happy.

 

Thanks guys I appreciate it a lot.

 

40psi fuel pressure is to high at idle it should be 34 psi was the pressure test taken with the old pump or the new walbro one

if the pressure is that high you should not be running lean you should be running rich

what was your FP at WOT it should be 43

 

He did the mode 5 check and there were no blinks according to what he told me over the phone. This is frustrating where nothing breaks but there is a problem. The car runs fine it just acts up at times when driving and it has that popping noise at idle. Well i'm going to order more parts and he's going to do some more testing to see if he can determine the problem. I'm sticking with what Eric93se said and I think it might be injectors. Well gotta obtain a new intake manifold gasket before my mechanic will take apart the intake manifold to get to the rear injectors but he told me he doesn't want to do it until I get the gaskets. Thanks once again guys.

 

Actually, just reading that i think that you have a problem with the injectors or the harness (loose plugs). Mine did that and all it was that the connectors on the plugs had gotten corroded.

 

Beck/arnley makes a kit that comes with ALL gaskets and o-rings needed to do the job right. I dont remember the cost but I think its around $80 (comes with everything needed). I cleaned out the filter screens on the injectors without sending them out, I just inverted them in a bath of alcohol and a paint brush (could use gasoline, but thats a bit more dangerous) plus using the alcohol you get to see all the debree floating. Also the fuel rail seats need to be cleaned of any old o-ring residue (I used acetone and a q-tip).

If your fuel press reg. is not working properly, then that too can cause some problems. I don't know the specs right now for idle and wot pressure, but I'll check the fsm later.

 

I believe Matt said in my last thread that stock at idle should be 39psi, my car was at 40psi. If someone could double check that for me I would appreciate it greatly.

 

just pulled out the FSM...
it's 36psi at idle, 43 at WOT.

If you've got anything over about 35psi, at idle and 41 at WOT then it's not your problem.. running a little lean won't cause those kinds of problems, but a bad injector or connector will.

 

Nissans with bad injectors?
Never heard of such a thing.

 

d*mn i need to stop thinking that all of the specs for the 4th gen are the same as 3rd your right i just found 36psi at idle in the fsm but at least i was close sorry for the misinformation i need to start doble checking facts before i post

carry on

 

In your previous thread you mentioned that you use some MODIS tool to read computer data. Why are you so sure that this thing gives you correct info? May be it's just broken... Try to get real OBD-I scanner. Just a thought...

 

thanks guys.

 

oh yeah I forgot, if you want new injectors speak to Hogan he said he would take of anyone who needed oem stuff.

 

1) Take out all your plugs. See if 1 or 2 look diff than the others. If not, the injectors are "probably" ok.
2) If one or more of the injector o-rings were bad and leaking, it would make the car run too rich, not too lean.

I would borrow someone's maf and see how it runs

 

run rich or worse...

 

no rush doesnt have to be next day lol.

 

Yeah Jason I have seen Hogan to often this week lol. But he does take care of me.

Will do that Jeff, thanks for the suggestions guys.

 

Jeff, If one cylinder is running rich, then the ecu will see the extra gas reported by the 02 sensor, then the ecu will make the injectors shorten their pulse width making the mixture lean. So the mix will be good for the bad injector(s), but lean for all the good injectors, understand?

 

Have you seen that happen before? That's an interesting theory. I still think he should remove the plugs and see if one looks different. If that one cylinder is seeing THAT much gas to have the ecu shut down the other injectors that much, it SHOULD look different.

 

Thanks guys. My mechanic is taking apart the intake manifold to inspect the rear fuel injectors. We'll see how things go and I will keep you guys updated. Eric your theory makes sense, I just hope something like that is my problem.

 

He already checked his plugs in the previous thread, I believe he said they were white, for the most part. I dont think that going to tell the full story. If just one cylinder is running rich, and unburned gas gets expelled, the 02 sensor is going to tell the ecu that he's running rich, then its going to lean out ALL the injectors to compensate. It's very crude dude, an ideal car would have individual 02 sensors for each cylinder and its own knock sensor as well.

 

Yes its very crude Eric I agree. Well tomorrow morning I will be spending the whole day at the shop taking stuff apart and trying to figure out whats wrong. Hopefully tomorrow we find the culprit and I will update everyone. Thanks once again guys.

 

my offer still stands ill give you 100 bucks for that hunk of junk

 

In your dreams buddy. Bump in the road it will be fixed in time.

 

Im gonna go tommorow to fix my belts.

 

I already dibbed the twin car.

 

actually while your down there under the manifold, its a good idea to check out the knock sensor since your near 100k anyway

i still want to put a little money on that maf though.. o well lets see what happens tomorrow

good luck

 

I might swap MAF's with Jason while he is there.

 

i wanna say its the injectors. my friends 240 was running like a tractor and we figured it was a backed cat. changed the cat still no change. one of the injectors was clogged, replaced it with a (dare i say) used one and he was on his way. he sent the rest that he bought on ebay to some place in fla to get rebuilt and recalibrated