Q45 What the cluck did I do? Need help

[DAEDALUS]

So long as you have the plugs out, run a compression check just for grins.

Only the injectors fire simultaneously. The plugs still need to fire at the optimum time for power.

[Walnuts]

The drivers side bank has no spark either. I' don't know where to go from here. Could it be as simple as a fuse that I have yet to find?

[Walnuts]

My wife is cranking the engine and I'm about 6 inches away from the plug and see no spark nor can I hear it. I don't have a compression tester but the car has allways run strong.

[Th4rg0r]

Sounds like my car when I swapped out the fuel pump/filter. 20/30 sec cranking is too long in my opinion, just do a 4-8 sec crank and let it sit for a while before trying again. I have a friend come by to help me past time talking crap in between the "rests", heh heh.

On second thought, it really sounds like mine just before it started, though I have to give it some gas to catch it, and a little constant gas till it warms up a little and idles somewhat by itself (urm, it's sat for a long time before I swapped out the fuel pump to revive it).

Also, when flooring the pedal, my has a slight clicker to tell me it's all the way down. When this is not done right, plus your 20/30 crank, it'll just make matters worst. Plus the drain on your battery/starter, not good.

Good luck,

Shang

[Walnuts]

I'm going to suurond the grounded plug with dark plastic and a towel and place my digital camera in movie mode under the dark cover to record the plug. Hopefully in a dark environment I would be able to prove that the its not creating a spark. Besides my "assistant" has left so I need to do this on my own. I'll post again in a few

[Walnuts]

My recording in as close to dark as I could get didn't show a spark but it's a very grainy image. I think at this point I need to proceed as if its not generating a spark on either bank. Are there specific electrical connectors that I should check or is there something else that I can do asside from have it towed 40 miles and rent a minivan for our week vacation starting Saturday? I can only guess how expensive that would be.

[DAEDALUS]

Verify the connections on the ignitor boxes on both heads.

[Walnuts]

I have disconnceted and cleaned with an elctronics cleaner all electrical connections that I could find. Still sounds the same. How does the anti theft system work? Is there anything that prevents a car from starting and if so how? I even checked the connections on the computer. It seems like there can't be too many things that would prevent a spark.

I'm up for any suggestions. I' verify once it gets dark that there is in deed no spark.

[elwesso]

when the anti theft goes off, it prevents it from turning over... it cuts the starter relay.

[Qgrappler]

When testing for spark, Need to make sure you're getting contact between the top of the plug and the contact in the coil boot. You need to have a little pressure there, as there would be if it were installed. Also, if you're using the bottom of the plug as tne contact point to ground, that has to be clean, as does the place you're touching it to. The plenum may be a little isolated from ground in the engine since there are gaskets, etc separating it from the block. Try touching the clean bottom of the plug to a (clean) metal bracket nearby.

BTW, I'd be careful how I held it. There's a lot of voltage to create that spark.

Its hard to believe you lost the spark entirely, but it certainly would be consistent with your symptom. I had a similar problem after replacing my injector, which was caused by me replacing the fuel pump fuse that I had pulled in the wrong slot, leaving the actual fuel pump circuit with no connection. IF YOU MOVED ANY FUSES, LOOK CLOSELY AT THE DIAGRAMS AND COUNT THE SLOTS TO MAKE SURE YOU GOT IT RIGHT.

[RobertsnewQ]

The weird thing is, there doesn't appear to be a common feed to the two power transistors so I can't see how both could die at the same time?

Maybe one of the more experienced Q techs knows what could cause both banks to die (other than a bad ECU, but you have injector/fuel pressure).

[Walnuts]

Thanks for all of the responses. I't really helps to have you all on the other end of this.

Tonight, in the dark, I again tested for spark with no success. I've done this four times now and the funny thing is after each time I say to my self "yep no spark", a few minutes later I begin to doubt my testing method.

Here is what I did tonight, Left the coil connector connecter per the FSM and inserted the plug into the boot. The coil wire only has about 3" of play so there are not alot of grounding options. I held the threads with a rubber mechanics glove to apply pressure so that the plug would remain in contact with the spring\coil thing inside the rubber boot. I grounded the side of the plug to a bolt near the plenum, then the plenum itself. I also took a 2' section of 14\2 wire and wrapped the ground wite around the threads of the plug and had the other end making contact with the hole that the plug is placed into. Even in the dark I saw no spark or heard anything either as the engine was cranked.

I'm now upstairs and having read the post by Qgrappler, am again for the fouth time doubting that my method was correct. I couldn't see the copper ground wire after I turned off the lights so it's possible that it wasn't making contact and maybye I was somehow grounding to a bolt or plenum section that was insulated by a gasket. So yet again I'll test for spark tomorrow night.

Let's assume that I'm not generating a spark on either bank, what would be the next thing to check? Thanks again for following the saga.

Amazing that 30 cents worth of carb cleaner has cost me 20 hours of time.

[CGB]

Man, I feel your pain. This is probably a shot in the dark. By your posts, it appears that you have good fuel pressure, but no "spark".By looking in the FSM, there are two ignition relays. If they go bad, she won't start. The reason that I say this... it happened to me, although it was a different car, yet, with the same problem running fine before then.Go figure.

Good luck!

[elwesso]

Just FYI, when the ECU is out, it will start but it will not fire.... Kinda sounds like that.... If you want ill send you my ECU so you can try it, then send it back...

I tried to duplicate your problem today on my car by removing fuses and I accomplished nothing (except how to disable HICAS ).....

[DominickJ30]

Get a known good spark plug and test it out that way. If the 'good' plug has spark then its your plugs(most likely fouled by all the carb cleaner you dumped on em). If not then its might be a number of things starting with the coils.

[DAEDALUS]

What is the groundpath from the head to the battery? I know there's a harness groundwire under the plastic head cover, and another between the head and the shock tower.

[Qgrappler]

I reread the entire thread and it would seem that the fuses have been pulled and replaced at least once in this process.

My distant diagnosis is that this is a case of flooding compounded now by a fuse being in the wrong spot---or more likely missing from the correct spot. Its just a guess, but I really don't think you could've screwed up the spark or fuel delivery any other way...

As I said in my prior post, I did this to myself when replacing an injector---I pulled the fuel pump fuse and put it back into the wrong slot, leaving the proper spot empty and with an open circuit. Couldn't figure out why it wouldn't start at all. Finally got on hands and knees with a flashlight and a llittle more patience and found my mistake.

Isn't there something called Occams Razor---that the simplest explanation of something is usually right. Look at the fuses again.

[elwesso]

I reread the entire thread and it would seem that the fuses have been pulled and replaced at least once in this process.

My distant diagnosis is that this is a case of flooding compounded now by a fuse being in the wrong spot---or more likely missing from the correct spot. Its just a guess, but I really don't think you could've screwed up the spark or fuel delivery any other way...

As I said in my prior post, I did this to myself when replacing an injector---I pulled the fuel pump fuse and put it back into the wrong slot, leaving the proper spot empty and with an open circuit. Couldn't figure out why it wouldn't start at all. Finally got on hands and knees with a flashlight and a llittle more patience and found my mistake.

Isn't there something called Occams Razor---that the simplest explanation of something is usually right. Look at the fuses again.

I agree..... I really think we're spinning our wheels (sorry) by doing the spark testing......

[RobertsnewQ]

I agree with both of you guys. It's flooded and/or something knocked loose during diagnostics.

If you absolutely NEED to get the car running today, call one of those travelling mechanics and just cough up the $100 or so for them to diagnose. How much is your time worth? I'm one to avoid paying someone else for something I can do myself, but even I would give up at this point. Sometimes it just needs a fresh look.

[elwesso]

I agree with both of you guys. It's flooded and/or something knocked loose during diagnostics.

If you absolutely NEED to get the car running today, call one of those travelling mechanics and just cough up the $100 or so for them to diagnose. How much is your time worth? I'm one to avoid paying someone else for something I can do myself, but even I would give up at this point. Sometimes it just needs a fresh look.

Even more impressive.. The car would have been parted out by now if I had been dealing with it!!

[Q-less]

I have been following this since you started and am curious if you got it fixed?

[metaverse3]

you cleaned your intake and let it sit. loosened the gunk and let it float somewhere..idle air valve ?

Hook up a battery charger and charge the battery. If possible, get/put the battery charger in jumpstart mode so it delivers crank power to the battery.

Car will always start hard after a TB cleaning. It might take around 20 tries..sometimes..

This might sound crazy, re-clean the TB. Find a can of 2+2 carb cleaner. This can also double as starting fluid. Clean the TB. Then Find a can of PB Blaster and lubricate all moving parts in the TB.

Crank away. Pedal down or no pedal.. Post back with results..


Modified by metaverse3 at 9:49 PM 7/17/2005

[Walnuts]

Hi Everyone, Thanks for all of the great advice over the past week. I ran out of time and was lucky enough to have my parents off us a car for the week. When we get back from Nags Head North Carolina on Saturday I'll be back at the troubleshooting. Looks like we have some new suggestions for me to try. Thanks again for all of your help. We'll get this car running again one way or another.

[Q-less]

So....what happened? I am curious as to what the culprit is/was.

[Walnuts]

After a nice relaxing vacation last week, I began the troubleshooting process again last night. This time I was very careful to test for a spark by applying a lot of force to the plug as it is inserted into the coil boot and made sure that I had a ground that was not insulated in any way. Low and behold I had spark, so it was my testing method that was at fault.

Now I was back at square one: Fuel pressure was fine, spark was fine, injectors were fine, compression I assumed was fine, but my Q still would not start. I decided to look through the TSBs that I had downloaded a while back and guess what I found? One entitled "ENGINE CRANKS, BUT WILL NOT START OR IS HARD TO START". I read through and decided to try the suggestions. I unplugged the primary TPS connector, the secondary TPS (my Q has TCS) and the MAF connector. Turned the key and she started right up although I had to keep some pedal pressure to keep her from stalling. I held the RPMs to 1200-1500 for a few minutes to warm her up then turned her off. I reconnected all three connectors and started her again. My Q fired right up and idled and ran fine. I drove for a few miles to make sure everything was OK and now plan to change the oil to remove any unburned fuel and carb cleaner before really taking her out for a ride.

I trully appreciate all of the help that I received on this topic. Now my question for the techs is what did disconnecting the TPS sensors do? Could it be that I really didn’t have good compression? A quote from the TSB says:

"Use this bulletin if the engine cranks over normally, but is difficult to start or will not start at all. This situation may be caused by small carbon deposits falling onto the intake and exhaust valve sealing surfaces, which results in loss of compression."

Here is the TSB in case someone in the future has a similar problem.

Thanks again, You guys are great!

[elwesso]

Very good.. I was going to suggest unplugging the MAF connector, but I guess i didnt remember at the time....

Too bad you didnt get to take your Q on the vacation, but at least its running now!

[RobertsnewQ]

Unplugging the sensors forces the engine to fire the injectors blindly

I think your car was just flooded and it took the week to evaporate all the gas/carb cleaner.

Good to hear it's running again.

[M30 Steve]

Hey Walnuts,

Glad to here you are up and running, my wife always calls me a dumb arse for playing with my old cars too, so don't feel bad. I have learned a trick or two at the Nissan Online Mechanic site. One of the greatest posts is by a moderator who is Nissan tech it says "don't take something apart if you don't know what it does" I think this is great wisdom for guys like me who are novice mechanics. So tell your wife how lucky she is you are not the guy who pays $500/ month to drive the latest leased car. You have the extra cash to go on vacation and take her out to dinner!!