Fuel Injectors in Nissan Murano 2003

[dilipdeka]

My Nissan Murano (2003 model) ran great for 40,000 miles. On 12/20/04, while driving on a highway in Houston, Texas, at 70 mph, it suddenly surged forward and the engine died. On restarting the engine would not hold. The car was towed to the nearest Nissan dealer, Robbins Nissan. The mechanic replaced the fuel pump but that did not solve the problem. Then he checked fuel pressure at the injectors that was found to be at recommended 50 psi. But fuel was not going through the injectors (all six). He tried to clean the injectors by applying gasoline with cleaner directly to the fuel rail. He even increased the fuel pressure to 70 psi. This effort did not produce any result. Then he used a set of injectors from another Murano and found that the engine runs. He blames bad gasoline in the tank of my car to be the culprit and Nissan technical advisers agree with him.However I do not agree with them and think there is some inherent problem with the injectors or the EFC (Electronic Fuel Control) system is malfunctioning intermittently. 1. There was no indication prior to the engine shutting down that injectors were getting clogged. The engine was running smoothly like in a new car. Fuel economy number was running at 18 mpg.2. The fuel tank was at ¼ full. The car ran fine on the same tank of gas till the incident.3. The dealer hinted there could have been some contaminant like sugar added to the tank. This does not seem possible since the Murano fuel tank has a lock on it. Also the car is parked in a garage at night.4. We use the same gas stations to fill gas tanks in three other cars in the family (Jeep Wrangler, Jeep Grand Cherokee and a Ford Cobra) and none of them has had a problem with fuel injectors.Has any Nissan car owner had a problem with fuel injectors? I’d greatly appreciate any input I can get.Thanks,Dilip DekaHouston Texas

[DAEDALUS]

Sorry to hear. Is the car under warranty? Are they trying to get you to pay for the repair?

I agree with you. If the gas was bad enough to clog multiple injectors, you would have known long before reaching 1/4 tank. Besides, how would the contaminants get past the fuel filter? Anything dissolved in the gas would stay dissolved until reaching the combustion chamber.

[navysnail]

and on top of that, say they somthing did get past the filter, no way it would clog all injectors at once

[Richard Petersen]

I take it they never even took ohm meter readings. Must have known what happened before on other cars. ECM thru a FIT and flamed the injectors. The surge is the injector coils being held on continously and ALL of them burned out due to the 100 % on, duty cycle. NO other way can all go bad at once. Smoked by the ECM. You know the drill now. New ECM and injectors next time. Good luck

[navysnail]

richard- i thought about that, but it seemed that somthing liek that has such a low occurence from what i see........ but if that happened, it would explain everything

[dilipdeka]

The mechanic told me that the injectors were clicking when voltage is applied.They are going to put the old injectors back in tomorrow to make a final decision whether the injectors are bad.I also told them that I suspect there is something unusual in some common part that feeds all injectors. Apparently the fuel pump is not the problem. So it has to be in the ECM (intermittent problem?)The mechanic told me that the injectors won't pass gasoline even when 70 psi was applied. Why is that if the coils are clicking?Any thoughts?

[s13sr20chris]

he applied 70psi? for what? is that in the fsm?(i know the answer and its no) would techline ever reccomend that sort of goofing? i doubt it. i wonder about some guys. please dont quote me directly as nissan is my boss, but...

that dealership is screwing with you!

i have seen one vq35de with bad injectors. it was in an 04 quest and it ran like poo but it did run. the tech replaced them all and it went away. if you are at all not satisfied with the repair call nissan and complain. any service manager worth his shoes will give you the number.

now, i pray that i dont eat those words at my dealership!

[damn240]

Did they use a noid light? that would of determined if the injectors were getting a signal from the pcm.

[DAEDALUS]

How do they know the injector's not flowing gas? Did they remove the fuel rail?

[s13sr20chris]

How do they know the injector's not flowing gas? Did they remove the fuel rail?

i would hope, but id say its a heck of an assumption here. removing the plenum is cake but how many times does a tech feel like doing that for one diagnosis. surely she wont run without it.

[Richard Petersen]

The ECU flamed all the injector coils. Injector coils have very, very short duty cycles. Thousandths of a second ON. The power surge you felt just before the engine died, was the ECU turning on all the injectors at once and burning them all out at once. There is no way to test for a random failure like this. Just replace the injectors AND THE ECU next time.

[Richard Petersen]

About the clicking injectors. Ask them if clicking false teeth means they are chewing food or just clicking.

[Q45tech]

Actually injectors can operate at 100% duty cycle for a while as the gasoline cools them quite effectively..........13.4 volts at 1 ampere is 13.4 watts x 3.14=~~ 42 BTU/hr of heat generation.......not much.

At idle true the duty cycle is 2/150 =a few %.

Since returnless rail pressure is higher than old [33-43psi on loop back designs] ~~ 55 psi..........wouldn't think 70 psi was excessive to try to blow the crap thru the filter screens.

Do it all the time.

US gasoline has become even more horrible than it was a few years ago.

High Sulfur compound levels in some fuels fries the injectors.

New returnless fuel injection systems are quite different from older designs in that the fuel is filtered only ONCE not constantly filtered and refiltered.

Since 3.5 returnless system is only 3 years old not a lot of higher mileage [life history]......pattern/mode failure info YET.

[s13sr20chris]

Since returnless rail pressure is higher than old [33-43psi on loop back designs] ~~ 55 psi..........wouldn't think 70 psi was excessive to try to blow the crap thru the filter screens.

Do it all the time..

i stand corrected. i will have to remember that.

[Richard Petersen]

That may explain why my Nissans up to the 2000 all went +120,000 miles and never had a injector problem. Now I am sure a carb and a distributor goes in the boat V8. A spare carb and distrib. cost $500. I can change both in 20 minutes if I had to, and have it running for the dock. This is a fantastic forum, Thanks for having it. Rich

[dilipdeka]

This is what happened finally on my Murano Injector problem. After the dealer told me they wanted to replace all six injectors, I told them there was no way all six injectors go bad at the same time and the engine just goes dead as it happened with my car. The mechanic offered to put the old injectors back and try again. Well, the car started running. The dealer claims whatever crud there was in the fuel rail probably got cleared when the mechanic was playing around with high pressure etc. I am not convinced.

The dealer charged me $350.00 for four hours of labor. What bothers me is that the mechanic did not find anything wrong with any part in the fuel system and spent four hours or more trying to diagnose a problem that truly wasn't there.

Isn't there anyway to check pressure in the fuel rail before declaring that the fuel pump is not working or that the injectors are not passing any gas?

I hate to say it but it looked like either the mechanics at Robbins Nissan in Houston are not factory trained or they tried to scam me into replacing injectors at $1300.00. Any thoughts, anyone?

[DAEDALUS]

Very sorry to hear that. I have had my run-ins with shady independents, but I would never expect that at a dealership.I'm not sure how there could be enough crud in the rail to block fuel flow--that's what the fuel filter's for. It's easy to check fuel pressure (past the filter) and whether each injector is firing. It's a little more difficult to verify fuel is actually flowing through the injectors, but if you have pressure and if the injectors are firing, all but impossible to not have fuel flowing through them.