Ca running lean with sudden throttle change

Post by **bias** » Tue Jun 17, 2008 3:19 pm

I have been fighting this issue for a while. I just can't figure it out. When I'm cruising at 40mph or more and I get off the gas and then back on at all, my engine hesitates from a lean out and then richens back up. My bov is venting to the atmosphere but at a 40 mph cruise it's not even open? Could it be my maf? I had issues with it before but I cleaned it an no more codes. This is this is the only issue stopping me from finishing up on my car. Please help..

Post by **r34 gtr** » Tue Jun 17, 2008 4:38 pm

You could just be a victim if crappy 80s EFI technology.

Post by **bias** » Tue Jun 17, 2008 4:52 pm

That would really suck! It may be time for stand alone?

Post by **r34 gtr** » Tue Jun 17, 2008 4:57 pm

Or a better tune?

I'm not saying you are a victim, I'm just saying its possible.

Post by **ca18detgabby** » Tue Jun 17, 2008 5:51 pm

how did you know that you were leaning out? I would consider dirty injectors and maybe changing the fuel filters.

how is the fuel pressure treating you?

Post by **bias** » Tue Jun 17, 2008 6:14 pm

I'm using aem wideband. It leans out to flatline for a second then comes back. I have a eprom for 460cc injectors but I have 450cc because they were a drop in uprade. Could that -10cc across the rail cause this problem? I have yet to replace my fpr but my pressure reads about 32psi at idle.

Post by **ca18detgabby** » Wed Jun 18, 2008 2:46 am

bias wrote:I'm using aem wideband. It leans out to flatline for a second then comes back. I have a eprom for 460cc injectors but I have 450cc because they were a drop in uprade. Could that -10cc across the rail cause this problem? I have yet to replace my fpr but my pressure reads about 32psi at idle.

Im not 100%, but I would guess your issue is the 32PSI.... no way 10CCs would kill like that.(or you would experience even a worse lean condition at WOT). seems to be the only issue that would change at WOT and not cause a serious condition at WOT........

like I said Im not 100%, but 32psi is low compared to the 36PSI per the FSM

Post by **r34 gtr** » Wed Jun 18, 2008 4:24 am

Thats 36psi STATIC pressure. Its right where it needs to be. I see lots of cars that do this, so don't feel like you are alone. It takes a second for the ECU to start adjusting things when you move your foot. You want annoying? my car goes full lean for a second when I let out the clutch without first revving it up a few thousand rpm. I mean you can hear the thing detonating, but at 850rpm, whats it gonna do? Throw a rod? I think not.

You can try cleaning everything really well, and replacing your fuel filter. It may help. it may not. It going lean like that isn't hurting drivability is it?

Post by **The_Chosen_One** » Wed Jun 18, 2008 7:12 am

Wait soo let me get this straight? You'll be crusing and when you get off the throttle like it goes to 0% throttle your car leans out to max?

So than when you get back on the gas you have a richness problem?

Well for one thing the lean isnt a problem its actually your ecu cutting power to the injectors to save fuel. This is done on practically every fuel injected vehicle and its activated when the motor is above a certain rpm which I believe on Nissans is 1500 rpms.

The richness issue I would not be surprised if it was from the BOV. What kind of BOV do you have? Just because you dont hear you BOV opening doesnt mean its not opening. Why dont you try recirculating your BOV and see if continues. Also you dont have to be boosting for the BOV to open.

Post by **bias** » Wed Jun 18, 2008 9:33 am

It runs fine until I try and give it throttle. I can be at rolling at 40mph with 0% throttle and no issues but soon as I give it any gas it leans out to flatline then it starts to richen up. I tried cleaning everything and checked for vac leaks and fixed anything I saw out of wack. It runs better now but that hesitation seems like it could be causing problems. Yesterday I pulled out in front of a Audi TT and hit a little to keep my distance. This dude just went around me? I gave it more gas but my car just didn't move like it has before. That really pissed me off. The only issue is the lean to rich thing it's doing. I also have been having problems with my fast idle. I don't have any smoke issues at all. Is the stock ECU that slow to respond when you change throttle position? Could I get emanage or Safc (neo) and tune these gremlins out?

Post by **r34 gtr** » Wed Jun 18, 2008 4:39 pm

Put a Motec M4 pro and a GT3096R on there and never have that problem again.

Post by **bias** » Mon Jun 23, 2008 8:37 am

Ok I have all the lean out issues fixed. I had a leak in the fpr line. I didn't notice it before? Now when I get to about 5500 rpm the car breaks up to about 6k then pulls hard to 7500rpm? tried changing coilpacks and ignitor but it jut got worse.

Post by **r34 gtr** » Mon Jun 23, 2008 12:08 pm

Hmm. Whats your fuel pressure like?

Post by **bentvalves** » Mon Jun 23, 2008 7:12 pm

Tim you do not hear your car detonating at 850 rpms with a iddy biddy bit of load on it you hear it lean misfiring sir.

I should make you smoke science weed when you get to NH for being so silly.

Post by **Liquid_Neon** » Mon Jun 23, 2008 8:49 pm

bias wrote:It runs fine until I try and give it throttle. I can be at rolling at 40mph with 0% throttle and no issues but soon as I give it any gas it leans out to flatline then it starts to richen up. I tried cleaning everything and checked for vac leaks and fixed anything I saw out of wack. It runs better now but that hesitation seems like it could be causing problems. Yesterday I pulled out in front of a Audi TT and hit a little to keep my distance. This dude just went around me? I gave it more gas but my car just didn't move like it has before. That really pissed me off. The only issue is the lean to rich thing it's doing. I also have been having problems with my fast idle. I don't have any smoke issues at all. Is the stock ECU that slow to respond when you change throttle position? Could I get emanage or Safc (neo) and tune these gremlins out?

Eww a TT? dam... those fat pigs shouldnt be driving past any of us... even the broken(like mine!) CA's are faster

Post by **r34 gtr** » Tue Jun 24, 2008 5:24 am

Ks13, yes, yes you should do that. By the way, I'll be up there in a few weeks. Maybe two? I am going to be up there for a two week minimum. We are going to kick it. Look for a blue and gold subaru and a black s13. We will be easy to spot because we will be flying large confederate flags behind the cars.

Post by **roplusbee** » Tue Jun 24, 2008 5:29 am

Liquid_Neon wrote:
Eww a TT? dam... those fat pigs shouldnt be driving past any of us... even the broken(like mine!) CA's are faster

Lol at that

You say that you have an EEPROM tune right? Are you doing the tuning yourself or did you have someone tune it for you? Also, my car did the hesitation/stumble thing at around 5500 RPM before, but I have a rich condition, vacuum leaks, etc, but it only happens every once in a while. If you are sure that you have eliminated all physical issues, I would take a good look at the tune if you have the means. Double and triple check for leaks and faulty components and such. Then check the tune.

Post by **bias** » Tue Jun 24, 2008 10:16 am

Yah it sucked! I was pissed! I managed to get most of the bugs worked out. When I crank it it idles low for a few seconds then goes up to fast idle? The only thing now is that when I get on it, it pops like hell from 5500rpm to 6K then rockets to redline. I haven't had it tuned yet. I was trying to get it running as good as I could before I got a piggyback to dyno and tune it. It's one thing after another. Whenever I get one thing fixed something else wants to screw up. Gotta Love the CA one day it makes you happy the next day it makes you sad. The perfect "Love Hate Relationship".

Post by **roplusbee** » Thu Jun 26, 2008 1:36 am

I love my CA even if it does give me issues from time to time. Hopefully you get all of the bugs worked out once and for all. Then you can really have some fun.

Ca running lean with sudden throttle change

Ca running lean with sudden throttle change

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