1989 Nissan Sentra GA16i No-Start Dilemma

Hey guys,

I just rebuilt a really nice Nissan GA16i motor for a friend of mine but now it won't start. 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 (related to the fuel injector) 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.

Bad air flow sensor? Just a guess.........

I would think the motor would still start, then run crappy. There is no combustion at all. Not even one hit.

I got nothing. I was thinking Coolent Temp Sensor, but I think it would at least run really rich. You rechecked all of your grounds and stuff, right? I wish I could be more help. It's been a few years since I had a nissan. Maybe we'll get someone here shortly that can help.

Will

You can try to unplug the MAF, for some reason they will run without it, but not with if it is defective.

AllData isn't giving me the DTC's either, only for the ABS computer.

Thanks guys. I pulled the "real" list of trouble codes off the AutoZone website. Turns out Haynes has half of them wrong or transposed. The 55 code is in fact the no problem code for a GA16i.

Tomorrow I should have a fuel pressure reading both with vacuum at the regulator and without. Then I will pull the connector on the MAF and see what happens.

Jerry

Okay, xci_ed6, 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 by a GRM advertiser, 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.

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.

Jerry