What is the most common problem on the VQ30 engine?

[Ryan Heo]

I think it is hard to start.

I have a 96' I30 which is 127k on it. The car always has a starting problem which is long crank regardless of cold or hot temp. It was cleaned between the engine block and transmission by a mechanic because the car wasn't start. The righ after the engine cleaned, the strating was good. However it is getting worse now. I replaced knock sensors, O2 sensors and spark plugs. What else I can do? Do I have to go to shop again? If I go to the same shop, can I get a warranty?

Thanks.

[huyqvu]

probably just needs a new starter.

[Ryan Heo]

The starter is the brand new one. Man...Thanks.

[flutie845]

On 2000 maxima with 136400 the only problems I have had are Ignition coils.Replace #3 & #6 I have bought two backups 1 for front and 1 for the rear.I found brand new ones on ebay for 18.00 shipped to my house. That was 18.00 for each one.The stealer wanted 105.00 a pice.Ive been looking for more but cant fine them under 60.00 each.Flutie845

[Q45tech]

Careful about low cost copies of oem coils, we have seen clones which throw [misfire] codes even though they fit externally the same.

[Ryan Heo]

I've been a infinit dealership to check the engine.They guessed bad ignition coils and POS sensors so the coils and one of th POS sensors were replaced. But nothing happens. Any suggestions to me?

[Q45tech]

If the misfire is too short [not sequential repeats] or partial burn so as not to be severe enough for the OBD2 internal diagnosis to set a code, THENyou must change 1 coil at a time and drive a few days to eventually narrow down the weak coils.

With more specialized test equipment you can view the voltage/current waveform from each coil primary and secondary to rank each coil performance and find the weaker ones.

If replacing spark plugs shows improvement you can bet it's a coil.

The way the ecu examines misfire is via O2 sensors so new O2 sensors are always a good idea every 60k...................they get slower and slower to switch which degrades highway MPG so always cost effective to maintain newish O2 the primary ones not the secondaries which don't affect MPG.

Many manufactirers and states have 3 day seminars for techs on how to find random misfires the most difficult diagnosis problem in the industry today.

No wonder the dealers just change all the coils instead of charging you all day 8 hours for diagnosis.

Gasoline especially E10 is not so homogenous and this can cause misfires until all the gasoline in tank warms up [doesn't happen with new returnless fuel system in winter].

BG44k will clean injectors, sparkplug tips and piston crowns and intake valves of deposits and carbon...........if this product helps as long as it is in concentration in fuel you have another clue............bad gasoline for the coils ability to fire plug.

[Ryan Heo]

When the engine temp. gauge is on normal degree, the hard staring problem came up mostly. In the mornig when the engine is cold, the start is almost good as normal. But after sitting 5~10min., it need a long crank time. Also when the engine is hot, the start is good to 1 out of 20.

Nobody has the solution for the hard starting problem. I wouldl like to tell about the history of repair.

My I30 had the starting problem before I bought.Only what I knew about the problem, the problem was started after the transmission was rebuilt. Right after the A/T was rebuilt, the car won't started at all. So it was repaired to the problem on the another shop. It was the labor description at that time.

CRANKS BUT WILL NOT START ------------ $192HAS SPARK AND INJECTOR PULSE. HAS GOOD FUEL PRESSURE. INSPECTED SPARK PLUGS AND FOUND PLUGS GAS FOULED.REPLACED SPARK PLUGS WIHT O/E STYLE.CARBON BUILD UP CAUSING HARD START WHEN COLD.NEEDS TO CLEAN MOUNTING SURFACE BETWEEN ENGINE AND TRANSMISSION. REROUTE GROUND CABLE TO THE STATER BOLT.

CLEAN MATING SURFACE BETWEEN TRANSMISSION AND ENGINE.INSTALLED GROUND CABLE TO THE STARTER BOLT. AFTER CLEANING VEHICLE NOW STARTS AND RUNS. -------------- $352

When the repair was done, the start was good like normal. However after one month, it was getting worse. Like three times every 10 times was hard to start.

On two months later I've infiniti dealership and import car specialist but they just told me that

1.the error code P1320 even though the car haven't show up the CEL. (I don't know how did they get the code.) So it might be needed to replace all of the ignition coils -$950. 2. Also the ECU could be malfunctioned. It should go to dealership. 3. The carbon could be accumulated inside the engine.

After that, I replaced the ignition coils and crankshaft sensor but nothing. I spent about $1000 to try to fix the problem. But I'm missing now.

The list of parts which were replaced.1. an alternator2. a starter3. spark plugs4. a PCV valve5. a coolant temperature sensor6. an ignition switch7. a fuel pump relay8. a knock sensor9. a fuel filter10. a valve cover gasket11. spark plug tube seals12. a battery13. an air filter14. oxygen sensors15. five ignition coils (one is left)16. cleaned IAV valve and throttle body17. cleaned the engine grounds18. put the fuel system cleaner

I found someguys who have the similar problem and fix that. They made new groud wires to fix the problem. So I tried that way but nothing happens to me. Unfornately the solution is for a M/T model not a A/T. I'm just full time student with a small budget to fix a car.

If someone know about the problem and guaranty to fix a solution, I would like to go to get rid of the problem anywhere. I want to know how to do it and inform to all other guys who have the same problem.

Thanks.

[maximaman]

wow you really did alot of work on that car. only advice i could offer you is that it may be a few things.

1- your ecu is bad ~you should get one off of a donor car and have it tuned to your cars specifications. year/model

2- fuel injectors~remove and soak them

3- battery terminals corroded~i would say clean them but in all actuality you should just replace them and cut a fraction of the wires off before reconnecting terminals

4- car running too lean ~clean and relocate IAT closer to the MAF and maybe install intake(cant hurt!)

5- bad fuel pump and or fuel filter~buy and install new one

bro... if i had to take a wild guess from what you have posted i would say go with the battery terminals first and check the starter connections. not just the connection but follow the lead and see if there are any kinks or sharp bends in the connection. a chiltons manual will help you with routing the starter wires. maybe even go as far as buying a OHM/VOLT meter and back probing the starter connections to see if the current is running the specified amount (chiltons manual will show you how). if not... the problem lies within the electrical connections. also... when did you last change your belts?

hope that was helpful buddy...

[Ryan Heo]

Hi.I already replaced the negative battery wire by OEM and made 4 new grouds wires with 4~8 gauge wires. But it has still a problem. So I doubt about ECU. When I checked the price of a used ECU, it just is $75~$100. I like to try replacing the ECU. If you know how to check ECU, would you let me know?Thanks.

[maximaman]

your local nissan dealership. dont get it confused with wide range car dealerships... go to NISSAN specific dealership. they can run codes quicker and have it installed back in your car with the quickness as the other places like performance shops you gotta send it to them and you get it back when they are done which totally imobilizes your car until they get around to it. thats not a good idea if thats your daily driver. oh... and i think your year has the engine check light trouble flash code. basically you turn your key 3 clicks without starting it and take a flat head screwdriver and turn the screw on the drivers side of the ecu one full turn clockwise(very gently until it stops), wait 2 seconds then turn it back one full turn and the check engine light will flash trouble codes to you by sequential blinks- long then short. example- 3 long blinks followed by 4 short blinks. there will be a slight pause inbetween the codes if you have more than 1. it will repeat itself indefinitely so count them correctly then use the chiltons manual to find out what blink sequence goes to what trouble code. it took me a little while to catch on but it works well especially if you are constantly tuning your car or trouble shooting and dont have an OBDII. good luck kid. click my screen name and email me if you need additional help.

by the way there is no trouble code for the ecu to my knowledge so if everything seems to be in order... it might the the unit itself. they're really moisture sensitive.

[Ryan Heo]

As I told you, I've been in a infiniti dealership. They didn't find at all.Thanks.