94 Q running rich

[cmccort]

I dropped my car off at Euro Imports this week due to acceleration problems and the car cutting out when you give it gas. These guy's spent three full days pulling the car apart trying to find the problem, plugs, fuel pump, maf, fuel filter, checked the fuel presssure and voltage on regulaters they simply could not find the problem. I got a call this morning telling me that they re-positioned the fuel pump and put a full tank of gas in it and the problem has been solved but the car is running very rich. They are unable to get any readings from the ecu that anything else is wrong and I'm bieng told that it could be running rich due to the ecu bieng flashed for the nitrous set-up and that their is nothing that can be done becuase it is controlled by the ecu????? This is costing me a lot of money and I am concerned that the problem still will not be fixed.

Does this sound right? I asked about the FPCU and he told me that they usually either work or don't work and he seems to think mine is working. Any feedback would be very much appreciated.

Thanks

[cmccort]

If anyone has any experience with this I can call you if it would be easier my # is 6023157340.

Thanks

[96Qowner]

I wonder if it would be kosher to have your guys call Byron at T3 Smyrna ...

http://www.t3auto.com/

After reading through your old posts, I see that you've been chasing this problem for a month. Someone on the forum should have solved this for you by now. In the absence of more expert opinion, I'll just ask if you've cleaned the intake path and are sure of your injectors. Your FPCU could still be intermittent, but that seems less of a problem after all the work Euro did.

First, it bogs on full throttle, and now it just runs rich ...

"repositioned the fuel pump"?
Modified by 96Qowner at 9:30 AM 7/13/2007

[maxnix]

Wel, did they check the FP pressure at all 3 settings? If it is running, it is probably working. How do they know fuel pump is good?

You might need to get to someone (like a dealer) who can run a power balance test witha consult and isolate a problem cylinder, if there is one.

Immediate suspicion would be a bad lower O-ring on an injector.

Any known good MAF to switch out, or other early good ECU?

[96Qowner]

Immediate suspicion would be a bad lower O-ring on an injector.

Any known good MAF to switch out, or other early good ECU?

Yeah, stuff like that. But, sheesh, he has too much time and money into this problem already - still has to deal with the active system. The more I think about it, the more I'd have 'em call Byron. What's to lose? He can always say no. Byron is probably the most experienced G50 tech in the country. He'd know if anyone would.

[cmccort]

Yeah, I am really dissapointed that I am having all these difficulties, I have wanted a Q for a long time. I really want to get the problem solved how can I reach Bryon?? Thanks for your help.

The shop tells me that all of the injectors check out both the MAF and fuel pump have been replaced. The shop feels confident that it is fuel delivery problem?? I wonder if I should replce the FPCU next it is the original with 138,000.

[96Qowner]

The T3 phone number is in the link. 404-794-7700

But I think it'd be more proper to have your guys call him, not you - professional courtesy 'n all.

[Q45tech]

Unfortunately INET DIAGNOSIS is difficult and time consuming because of all the data [voltages] required to be transfered back and forth.

With Nitrous JWT just slams the injector open time from a NA Normal WOT of 10-11 millisecs to ~~13-14 millisecs when the Nitrous program engages.

And lets the Nitrous/oxygen flow fill in the blanks.

Without Nitrous flow = pig rich.

Present Consult data in a WOT run: injector time, MAF, coolant temp, advance. etc etc.

After working on my C43, I am positive that European experts cannot think in Japanese ways.........you chose the company to do diagnosis, why not dealership?

[96Qowner]

Without Nitrous flow = pig rich.

Hm, he blew a fuse when he grounded the wrong terminal on the FPCU. Might have affected the ECU?

[cmccort]

I chose this shop based on a recommendation from AZhitman here on the forum. This shop works on BMW and Inffiniti only and I they seem to know what they are doing. I believe the problem is the Nitrous, I contacted T3 and they even told me that you have all kinds of possibilities when introducing nitrous. I did contact JWT who informed me that if the nitrous switch is on it engages the system whether or not you are using nitrous and this will cause the car to run rich. I called the shop and they are going to check and see if the switch is on. If I continue to have problems I will simply remove the NOS system and replace the ecu with a NICO upgrade. Thanks for your help, if you can think of any other feedback please don't hesitate to share.

Regards

[sdkhalsa]

Here is a simple question. Is the rich mixture system wide or can it be narrowed down to certain cylinders? Did you run a cylinder isolation test with a Consult? Does the car run with a miss? Does the car start in the morning with a big white cloud? When they worked on your car did they note a carbon build-up on all of the spark plugs or just some. It is very common for the Q's to have injector problems, and I just tracked down a big leakage problem (running very rich on my 94' Q) with the injector o-rings. In connection with this idea, how old are your injectors? How much mileage do you have on the vehicle? I think that if you put out a few more pieces of info., this group can figure out the problem. If you are mechanical, I would definitely recommend getting a laptop consult (Nissan Datascan) set-up. For about $100, it will save you thousands.

[maxnix]

Yeah, the switch is the best place to start.

Buying a modified a model just means you need a deeper piggy bank. But it will be unique when it gets going.

[cmccort]

The rich mixture is system wide, the shop said they pulled all if the plugs and they are black. The old plugs were horrible. The car runs now and does not bog down but something still does not feel right. It is very sluggish off the line and when you accelerate hard you can hear a tremendous amout of what sounds like spark knock. The shop says that all of the injectors are good, the car has 138,000 miles on it. Another concern I have is after driving the car around town today I noticed that when I am accelerating hard the temp gauge gets up around the top slash mark, it does not go above it but get's right there at it. Is this normal? I will invest in the laptop consult you reccomended where is the best place to get one? I think I am just going to pull the NOS system out and put in a new ECU and go from there.

Thanks

[96Qowner]

The dash thermometer is barely accurate. By the time it starts moving off center, the motor is already too hot. You have a problem with operating temperature, now - swell. The thermostat tends to fail slowly, and if it hasn't been replaced, by all means do so, and only with OEM. It is NOT normal for the temp gauge to move above halfway.

Has anyone determined if your knock sensors and their harness are ok?

What was up with the JWT nitrous switch? Was it on or off?

[cmccort]

The nitrous switch was on, I sat there with the Service Manager and when you switch it on the car would stumble, turn it off it seemed fine. I mentioned the KS to him when I dropped it off but did not get any feedback from him after that. I think I will replace the thermostat this weekend. I'm wondering if the KS arre bad and that is why sluggish and creates so much noise. Is ther a way to tast the KS?

Thanks

[qsiguy]

cmccort,

I have a couple things I can do for you. I have my old stock '94 ECU w/TCS I can loan you for testing. I also have a consult cable with my laptop w/software that we can use to check a few things out like trouble codes that the shop may not be able to see if they don't have a consult.

I don't see how the fuel pump or FPCU would cause a rich condition, rather a lean condition if they weren't working properly. ECU seem more likely. Do you still have NOS on it?

Let me know if you want to get together.

[maxnix]

cmccort,

I have a couple things I can do for you. I have my old stock '94 ECU w/TCS I can loan you for testing. I also have a consult cable with my laptop w/software that we can use to check a few things out like trouble codes that the shop may not be able to see if they don't have a consult.

I don't see how the fuel pump or FPCU would cause a rich condition, rather a lean condition if they weren't working properly. ECU seem more likely. Do you still have NOS on it?

Let me know if you want to get together.

This is a great and generous offer. Pursue it!

[cmccort]

That is an awesome offer, I would gladly take you up on it. With the money I plan to sink (Need to sink ) in this car every little thing will help. I will gladly compensate you for your time and effort. Please let me know when and where you would like to get together my cell phone 602 315 7340 call anytime. FYI I live in Verrado what part of Phoenix do you live in? Let me know, and again thank you.

[cmccort]

I forgot to answer your question regarding the NOS, I went to fill it up yesterday and found out that the bottle was over 5 yrs old so nobody will fill it. I dropped it off at Phoenix welding supplies to have it hydo-tested and re-certified. I pick the bottle up next week with a refill so I can finnally try the nos and determine what direction I want to go. I have to tell you that even with the suspention riding like crap and the sluggish start the car is very fun to drive. I loved getting on the freeway and going from 70 mph to 100+ with little effort. I look forward to getting it fully restored and using it as a daily driver.

[sdkhalsa]

Your mention of the KS earlier was interesting. With the consult you can track the timing under load which will normally retard with a bad knock sensor at the point which it stumbles on acceleration. As to the current best source for consult equipment, there was a recent article on q45 forum about the current status. Nissan Datascan can be had for about $25 through PLMS the Australian group(http://www.plmsdevelopments.com/consult_if.shtml). The connector for your laptop I think is advertised on ebay(http://cgi.ebay.com/ebaymotors/NISSAN-E ... enameZWDVW), although I think that there are better souces.

[sdkhalsa]

If you order this interface which appears to be the same one that I have, you will probably want to order a better connector to the data port. Let me know and I can locate the source, it is about $30

[qsiguy]

I have everything we will need already. My consult cable setup works great on both my '93 ECU and my '94 ECU. I have Nissan Data Scan as well as ECU Talk. Both have nice features we can check out. If you have a knock sensor issue it will show up in the consult. I know this because I have a bad knock sensor Unless your car has a problematic diagnostic port we shouldn't have any trouble checking things out.

I actually live out in Queen Creek but I work close to Sky Harbor. Broadway/40th Street area. My cell is 602-570-1307. I work M-F about 8-5 and am pretty flexible. If you want to stop by we can plug in the consult and check it out then swap the ECU if you want to.

I just noticed your stats on the left..Is this a '96 model? If so, I don't know if we can swap out for a '94 ECU. Also, I dont' know if the Consult is compatible. IIRC, the '96 models have two plugs, OBDII and the Consult plug. Can anyone confirm the compatibility of the '94 ECU and the Consult operation?

[cmccort]

No it's a 94, I got rid of the 96 as soon as I found out you could not do the upgrades. I will call you next week to see when we can get together.

Thanks

[maxnix]

No it's a 94, I got rid of the 96 as soon as I found out you could not do the upgrades.

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