91 Q45 Timing Question

[photographybytmc]

Newbie here guys..

Got a 91 Q45 192K miles. Have been having some sporatic fuel injector issues so got hold of the third party Consult software and interface to the ECU.

I am noticing that my ignition timing is never dropping to less than 29 BTD at idle RPM's and averaging 45-50 BTDC at 2200 or crusie speeds.

Knowing that it times to 15 BTDC when set up...Question: Is it normal for the ECU to run it that far advanced?

O2 sensor voltages seem low too (0 to .5 V..)

Is there some good data available on what I should be seeing.

I am getting readouts on:

Ignition Timing ..MAF ..INJ Pulse length ..O2 Sensor V ..Water Temp.. RPM .. MPH.. AAC %

Any help is greatly appreciated !

[Q451990]

Great work getting the Consult software and interface working! There is a known issue with the timing numbers and those software packages... so the numbers you're seeing are not correct. If I recall correctly, you're probably getting 40 degrees BTDC at idle - so you should be able to subtract 25 from the indicated number to see what you're actually running assuming your base timing is set to the 15 degrees BTDC spec.

I'm not sure on the other numbers, but there are several people here using the interfaces now - so we should be able to get you some numbers.

What software pacakge are you using?

Welcome to NICO!

Heath

[photographybytmc]

Hey Heath..Thanks for the "lightning fast" Reply :-)

I got Cable and Nissan DataScan v 1.52 from BlaZt.

Haven't got the DataScan to report right yet..but the Free ver of Consult reports well.

NICO rocks!

TMc

[Q45tech]

Always use a timing light to double check free to low cost software.

We alwyas use a timing light to check even the $6,000 Consult II.

Because the ecu uses CAS offset and ASSUMES the CAS is always set at 15 degrees. You can misset CAS and the Consult and others will still read 15!!

or in your case 40.

Hope I am being clear as ecu has no way to check what you do with CAS.

[photographybytmc]

Ok..got that. Will check it on the weekend.

THANKS

TMc

[photographybytmc]

Upda

Ok..got that. Will check it on the weekend.

THANKS

TMc

e..

Got the Nissan Data Scan v1.52 working with OLDER Laptop using direct Serial port connection without the USB converter.

Amazing amount of data being relayed. WIll try to log a 400 mile trip tommoro fo later analsys.

TMc

[photographybytmc]

Got the Nissan data Scan working on a new Vista x64 laptop ..but using the USB cable from BlaZt. Just in time too. Getting a code 45 (injector circut leak) and I am trying to identify which bank..and then which injector.

reviewing log data my RH O2 seems to be running higher than driver side at idle and around town. The sensors are old..never replaced? with 195K on the vehicle.

at crusie speeds the O2's seem to run on par at 88 or 89 in the log data. Arround town the RH O2 seems to run @ 33-35 & other @ way down 20-30 pts lower.

Is this a sign of a weak/old O2 sensor? as well as leaky injector?

Please & Thanks guys!

[Q451990]

That injector code is a catch-all for any rich/lean fuel issue. Assuming you have the CA ECU, it will probably be more sensitive.

If you have the original O2 sensors, I would replace them first. It's very possible that they're getting sluggish, causing the injector code - but not stuck in a lean or rich mode - or sluggish enough to throw the O2 sensor code.

We typically recommend replacing the sensors at about 80-100K for optimal performance - so if these are the originals, you "got the goody out of 'em."

Heath

[photographybytmc]

Ok got that. Actually bought the sensors last month for that reason..and the special sockets too.

Was listining to the fuel pump tonight. Same age issues....listening to it whine..up..down....wondering if that was controller board or the pump. Changed one of the fuel regulators on the injector rail two years ago when I did the #3 injector. Thinking the fuel pump is a time bomb. Ont he subject of injectors ..fuel pump.. seals...are the replacements more resistanht to the Ethonol in our CA gas?

Again..Please & Thanks!

[maxnix]

No mention of timing chain guides in all of this?

Have you read the trunk of your car recently? Ever?

[Q451990]

Was listining to the fuel pump tonight. Same age issues....listening to it whine..up..down....wondering if that was controller board or the pump... Thinking the fuel pump is a time bomb. Ont he subject of injectors ..fuel pump.. seals...are the replacements more resistanht to the Ethonol in our CA gas?

If, by chance, that's the original fuel pump it is absolutely a time bomb. I would say the average life of a fuel pump is somewhere between 80-100K miles. The noise is from the pump, not the controller. I would replace it ASAP if it sounds like there's a hive of bees hanging behind your back seat while you're idling with less than 1/2 a tank of gas. Check the controller for melted connections and components at the same time. It's still working at this point, so you might be able to avoid replacing it...

I don't know that anything is more resistant to crappy modern gasoline... there's some speculation that the 94-96 injectors could be slightly better, but no real long-term data yet.

Heath

[photographybytmc]

Yup.. got the "bee hive " sounds for sure..and it will go up..and down.. at idle when it's struggling to idle. Recomendations for source of new pump? ..and how many hours to replace?

At the risk of airing one's ignorance "read the trunk.." not a clue as to what this is.

Thanks Again!Looks like I got my work cut out for me.

[photographybytmc]

Ok..got the Fuel Pump ordered. $284 delivered to CA ..not bad. Hope it comes with necessary gaskets.

I have read the chain guide warnings. Probably should pull the oil pan and see what lurks in the bottom.

[maxnix]

At the risk of airing one's ignorance "read the trunk.." not a clue as to what this is.

Just stand behind the car and read the writing on the trunk lid.

Hint: Where is the letter y?

You must order the new O ring also. It is not included.

Have you read the timing chain guide article?

[photographybytmc]

Thanks Brian..just ammended the order to include that "O"ring.

made me go look at that trunk lid. No "Y" ? Just Q45 on right side.

opened it..nothing. What am I missing?

TMc

[Q451990]

opened it..nothing. What am I missing?

The car brand Infiniti is spelled with an "i" at the end, not a "y" ...

Heath

[photographybytmc]

ROFLMAO..just relized I misspelled Infiniti in my NICO profile..you really had me going there ..

No ..got pump from:

sewellparts.com 6421 Lemmon Avenue Dallas, TX 75209

it was linked somehow off the NICO site.

and they added the "O"ring.

Thanks!

TMc

[goody90q45]

Recomendations for source of new pump? ..and how many hours to replace?

Replacing the pump is a pretty simple DIY. Both pieces of the rear seat and then the rear speaker deck will need to be removed. From there you'll be able to see the top off the gas tank with the pump and sending unit mounted in the center.

Be careful about stripping screws when unfastening the sending unit (use the proper sized screwdriver) and don't bend any arms on the sending unit when removing it from the tank (take your time). The new fuel pump will plug into the FPCU so you want to examine both connectors for signs of burning. We (and Infiniti) recommend that you replace the FPCU at the same time or at least have the know-how to inspect and repair any burnt solder connections inside the FPCU. Your call.

There's lots more detail on fuel pump replacement using the search function. Good luck.

[goody90q45]

Got the Nissan data Scan working.......Getting a code 45 (injector circut leak) and I am trying to identify which bank..and then which injector. Is this a sign of a weak/old O2 sensor? as well as leaky injector?

I second everything Heath said and will add that replacing the oxygen sensors will clear the code. When I was a NICO noob I had the same code on my 90Q and it wouldn't pass smog. It's fortunate since two oxygen sensors are a heck of a lot cheaper than eight fuel injectors.

[maxnix]

sewellparts.com 6421 Lemmon Avenue Dallas, TX 75209

No knock on Sewell, but Joe is our friend, and yours too.

http://www.infinitipartsusa.com

[photographybytmc]

Umm..so noted. Do we have a a URL for Joe?

TMc

[Q451990]

Having the gas tank down to 1/4 tank or less makes replacing the pump easier, or at least not as messy.

Joe is the internet parts manager at Infinti of Scottsdale... url is http://www.everythinginfiniti.com or http://www.infinitipartsusa.com will get you there too.

Pricing is probably the same as Seawell. Joe and his guys are awesome to work with - not sure about Seawell, because I haven't tried them. I've been ordering from Scottsdale since the late 90s except for one order from another place in Lisle, IL once.

Heath

[photographybytmc]

Thanks Heath..made a note of the URL.

TMc

[photographybytmc]

I just got a "heads up" note from the supplier of the pump. RE: no warranty if I don't replace the FPC module at same time. It's pricey at $400+. I am fairly comfortable in the electronic arena so I will follow "goody's" lead and do a close inspection of the module before making a decision to replace.

Thanks for the great info there "goody"

[Q45tech]

It's usually the converse, no warranty on FPCU without replacing pump.