so im getting no ECU trouble codes now but my car still wont rev over 2k...we verified that the ECU is retarding the timing tats why it wont rev higher. but waht could be causing this. Weve checked both crank sensors and cam sensor and the sensor and circuit is good. Anyone have tips clues or suggestions? im stuck now....sick of this crap...thaniks

 

do u still have the turbo on? If so it seems like its not max freindly

 

Don't you think this problem has to be along the lines of the MAF???

 

I'm going with the MAF as well.

 

could be, i checked the MAF sensor circuit but not the MAF itself, i dont see why the ECU would retard timing from a faulty MAF sensor tho. right now its a new MAF but before when i had a bad MAF my rpms would fluctuate alot...and poor gas mileage.

it shouldnt be the turbo, cause its not a mechanical prob.

 

I still think its the MAF. Reason being that the MAF sends a signal to the ECU telling it how much air is going through the intake system. The ECU then calculates how much fuel is needed to compensate. Since you checked the MAF circuit and you said it was okay, and the MAF runs off of a hotwire system, could it be that the wire in the MAF is malfunctioning? Your ECU probably isn't going to throw any more codes right now, but it will come up soon. I had the same thing happen when I had my S-AFC and the wire to the MAF came loose. I couldn't rev above 2000 rpm. Reason being is that when the ECU is getting a really low voltage from the MAF it will accidently compensate with more fuel because your TPS is telling it to do so. It gets the low voltage, realizes its mistake, and tries to correct it by retarding the timing to even things out. If you can, try swaping the MAF one more time. That may just be the problem.

 

Hmmmm... massive retardation huh.....

I would think the det sensor is going mad crazy but you get no error codes. Very odd. Faulty maf would through ecu codes also.

I wonder if you disconnect the det sensor and see what happens. I'm sure the ecu will throw a code but you should be able to see if it revs past 2k.

 

What's up, how's the Bay area. I'm still getting use to the Fla way of living. I was going the say the same thing about the knock sensor if the VQ has one like the VE. This pass week-end I was playing around with mine knock sensor and when it's unplug it does set a code 34 but doesn't turn on the MIL. Cheers

 

Hi. I have no idea how the bay area is. I live in Seattle. hehe

 

hummm ill check out the MAF again i guess....i might try swapping out the JWT ECU for my spare one and see what happens.

 

Well, I swapped out the ECU and it's not that...swapped out the MAF and it 's not that. Any other suggestions?

 

Would resetting the ECU help at all? I know you put in another one, but maybe they "learned" to stay in the mode it's currently in. That's about the only thing I can think of. It wouldn't be an O2 sensor somewhere would it? Good luck.

 

All vaccuum lines connected? I'm running out of checks here...

 

I think something must have disconnected somewhere. Have you checked all sensor conections across the engine??????

 

yes i have....many times

an O2 sensor was bad before but we took care of that already. Cam and crank sensors are good. TPS is good....no check engine light....what da hell is wrong with the car? this is really driving me nuts. i hate this stupid car. i should sell it but its totally not worth it.

 

Okay, so we know its not your O2 sensor, Cam sensor, Crank sensor, ECU, or MAF. Does the engine rev to 2000 and cut off as it would if you hit the rev limiter? If so, it may be an ignition problem. Check your plugs, and coils. You may have to upgrade your ignition to put up with the extra boost and fuel. Also check all fuel lines just to rule out that there is no fuel cut-off at certain rpms. Your fuel management unit may be limiting your output. This seems like a really hard problem to diagnose!! Maybe you might have to get it scanned. The ECU may have a log of data that may be the problem, but it doesn't catagorize into a code.

 

thanks i appreciate your help, the ECU is retarding the timing at 2krpm thats why it wont go over 2k. im getting normal fuel pressure. I have a Snap On scanner that ive been using. I HIGHLY doubt the ignition needs to be upgraded. a coil over plug system is a very strong ignition system that i dont belive needs to be upgraded on boost. We've tested the coils and they still fire effectively at 70kv. ughhh

 

You hate it now but the work will pay off. I'm still researching.

 

well...yes and no, if you been following the issues with the car you know its not a short list, every time a prob arrises, then we go "oh itll be good in the end, itll be worth it" but when is it worth it? it NEVER RUNS RIGHT, i cant even have te car running long enough to enjoy it.

 

Try disconnecting the knocker(!) sensor and running the engine?

 

what does that do?

 

I've followed but I bet anything this problem is a simple issue. Definitely hard to find though. What about running a diagnostic on it?

 

what excatly is running a "diagnostic" on it tho? i have a scan tool that ive been using, and ive been going through the possible circuits at fault going step by step.

i have 1 thing left to try that might be AFC related, somehow on my friend Prelude his V-AFC went nuts and his car wouldnt go over 2k either.

 

Well it should at least make the car behave differently. If so it might be a faulty unit. Bascily you just want to see if disconnecting it will allow the car to rev over 2k.

Hmm AFC huh? Try calling Apexi tech support?? Maybe there is some odd default value. Anyway of disconnecting the AFC functions easy to confirm?

Good luck, this shat must be frustrating as hell. Deezo. Turbo has been running "diagnostics" the whole time! lol

 

ok i disconnected it and started up the Max and it didnt do anything. i accidently unplugged the MAF and it wouldnt start, so then i checked to see if the ECU would throw a code and what do you know...my ECU doesnt throw a MAF code if my MAF is disconnected....odd, but i havent figured out my prob yet.

 

True!!! I was thinking more along the lines of a race shop with a good diagnostic machine for modded engines of this sort. In the PC world, I get issues that run me into the ground when I get to the point when I ask another tech to look at the issue and they will do something I didn't think to do. Then, I'll figure out the problem and know what I'll need to do to fix it.

 

ok, we checked out the MAF circuit and went step by step according to the facotry service manual. it cehcks out fine so ill eliminate tat from the list of probs. next we'llk check out maybe knock sensor and TPS, doubt its those but im all out of ideas...anyone else can offer an educated guess?? man i wanna get rid of this car but i cant sell it in the condition its in rite now.

 

Why dont you bring it to a shop just like someone said earlier. I can think of may be 2 shops that might be of some help. Thats only if you want to know. But hay they said if you have the money they can do it. Thats what they told me. Anyways Good luck hope the car runs soon I would love to see and record this on tape at least once. Good luck

 

well my friend owns a Nissan specialist shop in San Mateo and 2 of my friends work there, so i dont want to pay them when my friends could juss come over to my house and help me out. ive asked them before and they told me to check out the things i been looking into.

 

Thats coo I was just saying because at tech 3 they offered alot of
weird things to me i was considering however if possible the 2jz twin turbo engine swap into my 85 corolla (sounds good but is it possible)
i asked if they could really do it they said if you have the money we can do anything. Heh dun know bout that wun. Oh well good luck wit the car.

 

yea thats true, anything is possible with money. Tech3 isnt bad, they been around for awhile.

 

bump

 

how nice of you....heeh

im not offer $100 in cash or mods plus room/board and food for whoever can figure out my prob...

 

Yo njmax - those are some sweet azz rims on that SE-L...just had to respond

 

matthel, dunno if this is of any help, probably quite stupid, but Wayne's (nizmolee) max was doing the same thing.. it was a vaccuum on his intake.. we tried the TPS and i forgot what else, but in the end it was a vaccuum ..

good luck man

 

ill check it out...but what do you mean by vaccum?? like a line that was unplugged? its weird that that would cause this prob but we'll see. If you suddenly see $100 in your paypal account that means you were right and your my hero!

 

Actually he may be right!! On your stock intake system, there are three hoses. There is on that goes to your Crankcase Vent System, and one that goes to the Idle Control Valve, then there is another small hose, that I don't know what its used for, but its on there. That hose may very well be a vaccuum hose of some sort that it needs!! Does your intake piping from your intercooler have provisions for two hoses to be connected? The Crankcase Vent can have just a breather on it to be fine.

 

Matthel, yes i meant intake system. The people who installed wayne's PR CAI forgot one of the vaccuum lines and sent the car into POS mode. I didnt believe him at first till i drove it.

No matter how hard you floor it, you only get like 2k rpm. SUCKS.

If I'm right, sweet, just lemme know if it works out.

Figure since i havent heard by now im wrong.

 

Either that or you were right and he's out having fun boosting!!