My Q failed emissions on inspection Help!

[pjq45]

Hello I took the car in for inspection the car failed emissions. the car right now is 230 miles to a full tank of gas on the highway. It use to get 350 on highway. Here is the test results. HC 1.30 gpm. CO 38.48. Nox0.39 gpm. NYS limits are. HC 0.80 gpm. CO 15.00 Nox 2.00 gpm.

I've had the car for years and it's all ways been running real clean. Way below the limits. Last winter I put in new spark plugs NGK, o2 sensors. knock sensors and hoses under the plenum. now two ago the car has a hesitation off the line. Were should I start to fix this

[Unnatural1]

Your engine is running rich, burning the air/fuel mix incompletely, or your catalytic converter is dead...or maybe a combination of those.

Have you checked the ECU for trouble codes? Are you still on the original injectors? Did you use Nissan O2 sensors or aftermarket?

Have you noticed sluggish acceleration lately? Vacuum leak? Dirty or dead MAF?

Pull a spark plug and examine it's condition.

[pjq45]

I know the cats are good. The o2 sensors and not nissan they are made by NGK last year it passed with them no problem. some injectors have been changed one new from infiniti. And last winter i Was in a jam so i had to put in used injectors i put in three of them. could one of them leaking into the cylender. I was thinking of sending the fuel rails and injectors to deatschwerks to see whats going on with them

[goody90q45]

How many cranks of the engine before it starts? (More than one?) You're only getting 11-12 mpg and that's pretty low under any driving conditions. I'm leaning towards a leaky injector lower o-ring. Have your shop do a fuel pressure leakdown test and depending on the results a power balance test looking to shut off one injector at a time. If it's a leaker these two tests will find it.

[pjq45]

It cranks at least 3 times before it starts cold or hot. I thinking you right about the lower o-ring. And also I did smell gas when i was stopped at light the other day. The car is hitting 200000 soon so I think the injectors need some attention anyway but I don't think i can afford OEM ones from Infiniti. I was thinking of sending the rails/injectors out to deatschwerks.

[goody90q45]

The engine shouldn't labor at all on start up in normal weather conditions. Both my Q's start on the first turn of the engine. When I did have a leaker in the 94Q it took 3 or 4 rotations for her to fire up.

Deatschwerks is a great idea and Dave Deatsch and crew always provide great customer service. I've used them 3 times. Their turnaround time will be quick so the Q wont be down more than 10-12 days. Ship the rail out in Saturday's mail and you'll have it back to install the next weekend. For about $15 X 8 they remove the injectors from the rail, clean, flow test, reinstall in the rail with new orings, and leak check. They also make sure the flow rate is balanced (within family) and if one FI is bad they charge $60 for a replacement IIRC. With shipping in both directions budget about $200 for their service. Deatschwerks is listed under NICO sponsors on the right side of the screen.

If you're engine is running decent you should get 180-210 miles (14-15mpg) on 3/4 of a tank with 100% city driving. On the highway (350-380 miles/tank (20-22mpg) is not unreasonable. I just did it on a drive to Monterrey last weekend. By my estimates the repair will save you at least $15-$20/tank and will pay for itself very quickly. Do it. Good Luck.

[Q451990]

I agree on the Deatschwerks idea... those guys are very good!

Heath

[Unnatural1]

It would appear that we all agree on a possible leaking injector. That's why it was my second question behind, "Have you checked the ECU for trouble codes?" Which you should still do if you haven't done so. Before you tear the fuel rails out you need to try to be sure that a leaky injector is the problem.

The easiest way is to do a bleed down test of the fuel system. You need to attach a fuel pressure gauge (can be had at Sears and possibly in an auto part store's tool section) to the fuel supply line from the fuel pump. Start the engine and let it idle. You should have good fuel pressure at idle. Turn off the engine and watch the gauge. It should hold pressure and not bleed down. The fuel pressure will bleed down over an extended time but right after you shut off the engine it should hold as long as all your injectors (and your fuel pump) are doing their job. If you can watch the needle steadily fall to 0psi after you shut off the engine then you have a problem.

[pjq45]

Today I checked the fuel pressure with a gauge. I did the test a few times. I first times it held pressure. the second time it dropped from 40psi to 25 psi quick. I did it few more times it was fine. I did it one more time and it was dropping again. So I pulled out the fuel rails with the injectors. 4 out of the 8 were spotless the other 4 were dirty. I had them all out last winter and cleaned all of them So I thinking the clean ones are leaking ones. Plus on one of them the plastic is cracked on it. So I now know that one is bad to. I didn't check for trouble codes because I have the battery out recently. Fuel pressure was 34PSI idle.

[Unnatural1]

Cool...it sounds like you've found the possible problem. A leaking fuel injector will kill your fuel mileage and any chance of passing an emissions test. Definitely fix the leakers and get that test rerun. Keep us posted.

[Mint Q45A]

A leacking fuel injector can also flood your engine with gasoline and cause it to hydrolock - you may very well kill the engine (bend a rod) simply by attempting to start it

[pjq45]

Today I got the call from Deatschwerks. They told me that I have four bad injectors. They are going to replace them and service the rest. The car ran pretty good even with the bad injectors. It was a little ruff when first started and it smooth out after a few mins. Now it should run good.

[pjq45]

Hello I got my fuel rails and injectors back. But I had a question should I replace the rubber rings ( the lower injectors insulators) that sit in each intake tube.

[Q451990]

You mean the insulators that sit in the runners? If so, they are probably fine if they are not visibly damaged. I assume the injectors came back from Deatschwerks already mounted in the rails?

If so, I wouldn't mess with those seals. They are in a better position than most anyone to test those seals with their test equipment.

Heath

[pjq45]

I took the car back for inspection and it failed again. the results were better but still did not pass. now HC 0.90 CO 22.80 gpm Nox 0.31 gpm. The First the results were HC 1.30 C0 38.48 gpm Nox0.39 gpm. I got the car back and checked for codes. I got 13 and 46. Are their two coolant temp sensors. I see one by the thermostat housing and looks like theirs one under the plenum