[jdfromla]

Hey Guys,

Infrequent poster - sometime lurker here with a newly rebuilt GA16I that refuses to start. I checked the archives but could not find anything like the problem I'm having on a brand new engine. Let me lay it out for you.

I built this engine out of a NOS NIB factory short block and a rebuilt head after my friend lost his timing chain and bent the exhaust valves. There are many new parts including a new oil pump and cover so nothing was spared.

The problem is fuel-related. The distributor/ crank angle sensor is brand new, indexed properly and functioning. Pouring a little gas down the throttle body makes the engine run instantaneously for ten seconds or so.

What I tested thus far:

This is a TBI engine. The only code I got from the ECU is 55. The Haynes Manual shows 44 to be the "no problem" code for the TBI motor so what's up? There is no 55 code except for the multi-port FI engine which is the "no problem" code.

The Central Branch of the LA Public Library has the shop manuals for almost every car ever built so I have access to a factory manual. That means I have a good schematic. I forgot to note the proper trouble codes from the manual because I thought Haynes would at least get that right.

The fuel pump and relay are operating. I bypassed the relay with some jumper wire and tried a start that way. No go. Verified fuel flow for the 5-second pre-start and when turning the key to the start position by running the fuel filter output into a gas can. Also took the fuel filter out and pumped the bare fuel line output the same way. No difference.

Fuel injector impedance: 1.7 Ohms (good)

Continuity of both wires to injector verified

Test for battery voltage at pins 101, 110 of the 16-pin ECU connector passed.

Test for continuity on the ground side with pins 107, 108 and 116 passed.

Injector was tested and cleaned by RC Engineering to new specs.

Verified fuel at the injector itself by pulling the injector back out and seeing a quantity of fuel in its housing.

Made and remade every harness connection and ground.

Without any set trouble codes (other than 55), I have nothing to go on. One thing I do not know is the actual fuel pressure when cranking or with the relay bypassed and running the fuel pump. If necessary, I will cut up my Bosch K-Jetronic rig to tee into the fuel line.

This is my 17th engine. Usually they start right up and run. This is really the first time I've had a problem that couldn't be solved in a few minutes.

Other than that, I am at a loss. Hopefully, someone here can help. I'm sure I missed something stupid.

Thank you in advance,
Jerry

 

[bob89sentra]

Does the oil light ever turn off while cranking?
Code 55 is for the 89-90 GA16I the all clear code, not 44
The computer on the GA16I is rather dumb, it monitors a very small amount of the engines systems, and usually takes quite a big thing to set a code.
I am thinking you should also check the spark plug wires and verify they are in 1-3-4-2 order. Also check under the distributer cap, and make sure the rotor is firmly bolted in place, there is a screw that keeps it in place that if it were to be missing or come loose would cause some of those symptoms.
There are more things to check after theese, but this is a good place to start.

 

[jdfromla]

The oil light goes out. I spun the motor without the plugs to prime the oil pump and pre-lubed everything when I built it.

I found the "real" fault code list on the AutoZone website. the haynes book omits codes and juxtaposes them. What a mess.

I would think not starting would be a "big thing" for the ECU. Ha-ha.

The firing order is correct. The rotor screw is tight. As I said it does run when I pour a little fuel into it. Actually, it runs quite well that way. This thing wants to go!

Thank you for responding so quickly.

 

[jdfromla]

Problem Solved

The problem is solved. I did check the fuel pressure and it was exactly what it was supposed to be with no vacuum at the regulator. So after all these tests, everything pointed at the fuel injector.

How could it be a problem? I just had it serviced (cleaning and calibration) by RC Engineering in Torrance, CA. Anyway, I pulled the injector again and also found another injector at the local Pick-Your-Part, just in case the first one was Tango Uniform. I explained my problem to the tech at RC. He took the injector he serviced originally back to the test stand. Turns out the injector was stuck shut.

Evidently, injectors will stick if you don't install them right away after servicing. Residual cleaning or calibration fluid dries out and jams the injector. Since we had the original service done on January 29, the injector had almost two months to petrify. Also, old injectors will do the same thing after a period of inactivity if they get too varnish-y

Our tech said if I dropped the injector and installed it, that might've cured it. All he did was give it a couple of love taps while it was on the test stand and it started working.

That was yesterday. Today, I installed the injector, retested the resistance to make sure I had continuity, and the engine fired right up, settling into a high idle just as soon as I remembered to plug the wiring harness back into the injector housing. Oops.

Thanks to RC Engineering for fixing the problem so quickly. They're a really nice bunch and their work always makes a satisfying improvement. I was unaware of the sticking injector potential so the next time I do a motor, I'll have the injectors serviced just before the motor is ready to start.

The new engine is running beautifully. Very flexible as it will get the car moving from 5 mph in third gear with no pinging or lugging. Nothing like the torque of a brand new motor with excellent compression.

It's still a thrill to hear them come to life for the first time.

Jerry