Fuel Injectors - where did I $$$ up???

[Wade Nelson]

Two years ago I had a fairly decent running car, but it occasionally had hot restart problems. Assuming it was due to injector leakdown and loss of fuel pressure when parked, I replaced the injectors. That's when the problems began.

I purchased a set of new injectors from eBay. I immediately experienced driveability problems including a loping idle, horrible gas mileage, etc. A mechanic friend pulled plug #1 and it was fouled suggesting injector #1 was stuck open. Listening with a stethoscope it wasn't ticking like the others. The vendor sent me a replacement injector and I thought I was good. Just to be sure, I installed a new fuel filter. If crud had clogged my new injector, I sure didn't want it to clog a replacement.

Drove the car almost daily till November, when it seemed to develop a problem starting in bitter cold weather. Thought I had diagnosed it down to an electrical problem, but perhaps I'm wrong. It sat parked over the winter until a few days ago.

I've been driving it all week, despite some cold morning starting problems that were usually resolved with a blast of starting fluid. Been through a tank and a half of fresh gasoline.

This morning it turned into a complete no-start. I've got spark, I've got fuel, the fuel IS gasoline (my first thought....diesel? water?). It seems to be flooding BADLY. So bad it won't start.

I disconnected the fuel line entirely and started it on ether (after drying out all the cylinders with compressed air) and it actually ran for 30 seconds or so -- I assume on gas fumes being sucked out of the crankcase by the PCV system.

I reconnected the fuel line, re-cranked, and it wouldn't start. It appears it can't build sufficient fuel pressure because of a stuck open injector.

I seem to have traced it down to the #5 injector, and possibly #2 as well stuck open. I can hear the #5 pissing down fuel pressure after I quit cranking, and the cylinder is full of fuel. So is the oil.

What I'd like to know is where I screwed up? Buying cheap injectors? Not flushing and perhaps brushing my metal fuel lines before installing new injectors? Not installing a fresh filter the FIRST time around? Leaving stale fuel in over the winter? How can I have so many failing injectors? The fuel filter ought to have caught any rust in the tank, no?

I simply don't have time to work on this car endlessly. I may have to sell or give it away and just go buy something reliable. I have a busy life outside of a Z-car hobby. But I'd like to know what YOU think I might have done wrong, if anything. I'm so frustrated I could scream. I love driving this machine but it's just one thing after another! I already shot the hood full of holes just as a warning to it not to mess with me, but it hasn't helped...

[Zed Head]

Are you sure it's not electrical? You could check for voltage drop to see if something is grounding the injectors. Or you could disconnect the injector electricals, repressurize the rail and look for pressure drop. If it's mechanical they'll leak down, electrical, they'll hold.

The stock filter should reject most of any crud, and a bit of water since the element is paper. It would be odd for new injectors to crap out so soon. I have a set of original 1978 280Z injectors from a car that sat dead for ten years, that flow-tested on my home made tester within a couple percentage points of each other. Ran great on the engine.

[Darrel]

Get your old injectors cleaned and tested. cruize performance(?)

When I had my zxt, I bought new injectors from napa, they were for turbo. But I had nothing but problems with them. Mainly lean running. I decided to get new inj from nissan and never had a problem after that.

[Classic83owner]

Wade, you probably have crappy injectors. Disconnect as Zed said and do a pressure drop test. My experience has taught me to always buy quality injectors. I got some spare ones I can send you. Just give me a call if you need a few. By the way, how's the tranny working for you?

[rcb280z]

Wade, you didn't say what condition your fuel filter was in after you changed it....was it full of crud? Have you thought about pulling the fuel rail and pressurizing it to look for leaks. That's how I found out ALL of mine were leaking. Maybe you'll find more than one injector leaking.

You definitely have a cold start issue which is another problem. But Im curious what you find on the "flooding" issue.

[sjb15316]

I agree with all the suggestions above... I've got a erratic "miss" in mine that is/has absolutely drove me nearly "postal" on mine too.... Anyway, you're going to have to weigh the pros and cons and decide if you really want to put that much time and effort into the car or cut your losses and let it go to another. I will tell you from personal experience.... there is NO GREATER feeling in the world than finding the cause of your problems and driving the car YOU fixed. Good luck.

[Wade Nelson]

I really appreciate all the suggestions given. Several are excellent.

I will tell you from personal experience.... there is NO GREATER feeling in the world than finding the cause of your problems and driving the car YOU fixed. Good luck.

I'm gonna give you a big AMEN on that. And the deeper and darker the problem the greater the feeling after finally diagnosing it.

Seeing if the injectors ARE somehow getting grounded seems very worthwhile. Other possibilities I've thought of:

1) Sugar in the gas tank, causing a carbon'd up injector

2) An ECM with green crud on the connector holding an injector open

3) Having the fuel filter connected to the return line by mistake so fuel's flowing the wrong way?

[Wade Nelson]

Wade, you didn't say what condition your fuel filter was in after you changed it....was it full of crud? .

No more than normal. I blew it out into a paper towel and didn't see anything of concern.

[Wade Nelson]

I've got a erratic "miss" in mine that is/has absolutely drove me nearly "postal" on mine too....

Years of being in the business taught me that everyone has a "blind spot," even the very best mechanics. They get so focused on where they think the problem lies they overlook the basics, or have incorrectly ruled something out based on false evidence.

The answer is almost ALWAYS to get someone else to look at it, starting with the basics, and NOT "contaminate" them by telling them what you have or haven't already checked, ruled out, etc. Just

tell them the symptom and walk away.

On rare occasions there are two overlapping problems and you can't find the second until you diagnose and repair the first. Those are the problems that sometimes make customers sue the shop since a

shop seldom re-tests the vehicle after finding a clear and unmistakeable primary cause.

As for your erratic miss, have you posted about it here?

[sjb15316]

I just did an update on "My '83 tale"... Bottom line, a mechanic friend of mine who works on anything ("but your damn Datsun"...), told me when he pulls a motor out of the junk yard to put into a car/truck/van/etc., the last thing he does is pull the "original" fuel lines and injectors from motor he removed and use them. After time, lines (and injectors) can rust, varnish, and whatever that "white crap" is, you find after gas dries up and clog up the fuel system. So he installs the original ones on the "junkyard" motor and says it saves him hours of problems later on... so I put a set of injectors in and as much as it pains me to say it... "He was right!"... So I'm sending mine to be rebuilt/refurbished (if it can be done) to a place the next town over so I'll have a spare set. Oh, and I immediately changed the oil & filter just in case I got some gas in it as I don't want it "washing" the rings. Good luck.

[Wade Nelson]

I found out where I screwed up today. I smashed the wires to the #2 injector underneath the valve cover after checking the valve clearances. It made a nice ground causing that injector to squirt anytime the ignition was on. So it A) Wouldn't build fuel pressure, Consequently wouldn't start C) filled the cylinder / crankcase with fuel causing hydrolocking / very difficult cranking.

I still may have one other injector occasionally sticking open. Need to put a stethoscope on it. Otherwise car is running fantastic.

[Darrel]

I hate it when that happens.