Update on '92 Q45 fuel injector problem

[kdkrone]

I had posted a few weeks ago about an intermittent problem I had with missing either on starting the engine or within a few blocks. Initially it was intermittent, then it became constant. Replacing the #4 injector solved the problem. (the coils were OK and my mechanic replaced the plugs while he was there) Or it solved the problem for a while.

Within a few days, the problem recurred. This time replacing the #6 injector solved the problem. My mechanic thought the battery seemed to be the problem, and checked the alternator, which was charging at almost 17+ amps. He replaced the battery, the charging rate fell to under 16 amps, and I have not had a problem for 2 weeks now.

He mentioned something about the injectors in that year having only 4 Ohm resistance or something like that, leaving them susceptible to problems of frying. Does that sound reasonable to you gurus out there? If so, is there anything I can install to protect the injectors from frying again?

ThanksKen K

[DAEDALUS]

That's a first. All 1st gen injectors should ohm between 10 and 14 ohms. Assuming the engineers did their job, it shouldn't matter what they ohm at, as long as they're within factory spec. I've replaced 2 injectors on my Q with 220k. Based on service records, those were the only 2 to be replaced in the vehicles life, so injectors don't seem to be a high-failure-rate item. The fact that we have 8 just increases the odds.

[Q45tech]

California and parts of Arizona [which use CA fuel] are the worst on injectors. The failure rate is 5-10 times what it is in the Southeast. Where it is so rare that we don't even stock injectors vs Scottsdale AZ who might keep 24 on hand everyday.

There are other locations which have varying failure rates. Injectors were only designed to last 100k on conventional gasoline anyway.

Those of us who have gotten 200-257-295k are on borrowed time......the next tank of Quasi Gasoline [with water] could do us in.

The 10-14 ohm range is too broad almost every good injector we measure is 11.8-12.8 ohms with an accurate ohm meter [the wide range probably was there for cheapo ohmmeter].

You must measure cold and hot to be sure.

I have been saving up and now have 4 new injectors just in case.Used ones are suspect as you don't know where/what diet of gasoline they were exposed to.

The recent reformulation of CA fuels will set off a new round of failures.

Use BG44k to wash the nasty stuff away from the injectors, and isopropyl alcohol to absorb any moisture that is transported with the ethanol [say every 100-150 gallons]. Frequent fuel filter changes and check the inside of all your fuel hoses.

[szh]

...isopropyl alcohol to absorb any moisture that is transported with the ethanol.

This is sold commercially in auto-stores as ISOHEET. Avoid the more common HEET because it is methanol, not isopropyl alcohol.

Z

[kdkrone]

Daedalus,

Followup to my problem with the idle that was solved by replacement of two injectors. 3 more were found to be faulty when the problem recurred, so I had them all replaced.

I spoke with Jerry Tucker when I took my Q to him to have the timing chaing guides replaced at 88K (cracked but no loose fragments!!!) and he said that the Nissan folks think it is related to MTSB additive (or whatever it is that they put in the gas here in CA. How you have avoided the problem I do not know but the dealer in Fresno stocks the injectors).

CheersKen K

[Q45tech]

MTBE is/was the accused problematic oxygenate additive.However it is/was used elsewhere:http://www.epa.gov/otaq/consum...e.pdfh ... y-area.pdf