Intermittant Concerns

Can we get a thread going about how to find and troubleshoot intermittent concerns? It seems that is all I do day in and day out.
I understand heat/cold, vibration, wiggling harnesses, but honestly simply duplicating the concern is often the hardest part. Maybe its because I deal a LOT with warranty items.

I spend (waste) a lot of time trying to duplicate concerns but its getting old. No one else in the shop has my (stubbornness) work ethic to try. Unfortunately, I don't get the time I should get paid. Looking to do it faster and easier. Often times I can duplicate the hard ones but its such a PITA.

We do NOT have to limit ourselves to just driveability but noises, rattles, etc...are all open territory.

Thanks

I don't think there is any easy answer for intermittent problems when they cant be recreated. I had one the other day, Ford f150 with lean codes and o2 sensor stuck lean codes. I did everything I could to get it to act up, even at different temps etc. I ended up clearing the codes and told the customer to come back if it acts up.There is only so much you can do. I feel your pain. seems like that's all I get too. I get a lot of newer cars from auctions (we service 4 or 5 used car lots) and most have so many codes it can take you down the rabbits hole if your not careful.

Yeah, it's always tough to know how long to chase stuff like this.

I'll do limited swapnostics at times, if the issue is so intermittent that I'll never catch it. I had an '09 Accord that would throw a P3100 for the cylinder deactivation system every two weeks or so. I suspect the bank one oil pressure switch is failing, but can't prove it. Ended up swapping the switches bank-to-bank, cleared the codes, and gave it back. Weeks later, the code moved with the switch. I chased that code for MONTHS before I thought to move switches.

Swapping stuff is OK but often you cannot do that especially in a warranty environment.

I had a customer with a intermittent P0101 MAF code on a 2011 Titan. Came and went at random. Another tech had thrown a MAF in it, with no change. Customer did not have any drive-ability complaints just the light.

I looked at all the data, etc...all seemed normal. Checked out pin fit, wiggle tests, etc....all OK. I discussed this issue with Techline and they agreed it was likely a skewed sensor or software issue. We double checked for any skewed sensor IAT/ECT and MAF. All tested OK.
I mentioned could a dirty throttle body causing air flow difference be a cause? They said it could, this one was not bad but they do NOT have a recommend method to clean the throttle body. So they told me to put a new one on the truck.

So I did on Thursday. Customer has extended warranty (Nissan in fact) they did not want to pay for it because the carbon was "environmental." Yet, Nissan does not recommend cleaning it so how do you fix it? The throttle body is a covered part. Long story short, Service manager had to call Techline and have them forward the documentation to the bean counters and then spend a good part of an hour arguing with them. Politics and BS at its finest. IMHO, extended warranties of any sort are a ponzi scheme.

One thing I have found with noises specifically is get the customer to drive/ride in the vehicle with you. If the car does it, great. If it does not, the customer cannot be pissed at you. Seems a lot of people think we are magicians and can just magically hear the exact noise they do based on a crappy description.

I also love with Nissan the fix everything with a TSB, a recall, or a reprogramming. I bet some days I reprogram 10+ modules. Heck, I did a two ECM's, a ABS unit, and a couple OCS units just today.

I've ran into some driveabilty issues that showed NO codes, no data issues, NOTHING. In both cases that i can think of, I flat told the customer I bet its the way the vehicle is programmed to operate. Then to call Techline and talk to them and they say. Engineering is aware of the issue and is working on a solution. So your telling me you on PURPOSE programmed a vehicle to act that way and released it to the pubic? I'm pretty sure the OEM's are more focused on fuel mileage and emissions and could give a rats about drive-ability. The new Nissan Titan's 7 speed auto shifts like CRAP. The throttle response is CRAP. Normal operation. GM's old 4T60E was WAY WAY WAY better at shifting and being responsive.

Anyway I'd love to see Danner do a special on intermittent just to keep us on our toes. I actually get excited when I have a hard fault or a constant issue. No more chasing my tail.

Perfect example of these intermittants occured the following two days. 2005 Nissan Sentra. Customer complaints that at times it has a long crank and poor acceleration. CEL is on.

So I took the ol trusty Consult 2 out and pulled the codes. P0455 and P0128. Neither of which is going to cause a long crank at least in a normal world.

Customer said it is random does not matter on weather or time of day or hot or cold.
Started just fine and test drove fine. I ran some basic data just to look for anything obvious. Went to do a WOT pull in 1st gear and I noticed the throttle pedal could not depress the whole way. Floor mat was in the way. Fixed on area of concern. Keep in mind 1.8L with 171K, its a not a rocket at any rate....fuel trims, etc...all looked perfect. Let it sit till the end of the day and it fired right up. We let it sit over night, fired right up. Sat all day today. Fired right up this afternoon......there is a bulletin for a long crank, you basically replace the in tank regulator but its about $370 just for the pump and ironically you can put a Nissan fuel pump assy. in for only a bit more. How can you "fix" a car you cannot verity other than showing the customer the bulletin and asking them to pay $500+ dollars for something that MIGHT fix it?