Fuel Injector Failure another ethanol victim

[texasoil]

Had another early (tan body) Q45 fuel injector fail Saturday afternoon up at Texas International Speedway at College Station. Was running fine on shutdown, DEAD on restart an hour later. Ohms went from 14.9 that morning to ?? Infinity) that afternoon. Fortunately, when I reinstalled the set after Deutsch service,4 months ago, I found this 1 a little high (13.5 ohms) and installed it passenger side front, so replacing it was very easy. Fortunately I had brung some spares with me to the weekend of track driver education (translated how to go fast around corners, slow down rapidly, and do things in the right order at the right time.)

[Mint Q45A]

Is the injector's resistance a definitive test to tell whether the injector is good or not? Or can an injector with a resistance within specs still be "bad" - i.e. leaking gas after shutdown?

[elwesso]

Is the injector's resistance a definitive test to tell whether the injector is good or not? Or can an injector with a resistance within specs still be "bad" - i.e. leaking gas after shutdown?

Injectors dont typically leak through the pintle, they usually would leak from the O-Rings (possibly dissolved by ethanol)... So in that case, that could happen. A leakdown test would show that.

Weird that the injector would do that, maybe it was just on its last legs?

[3Q Jay]

way to plan ahead and perform emergency repairs.

gee- i'll bet tech doesn't even carry spare fi in his trunk i know he won't let his Q get within 100 n mi of ethanol though just to be safe.....

[qship96]

Not so sure ethanol is the cause of all the injector issues-I have now been forced to use ethanol for the last 36,000 miles in my Q,and MTBE before that since new...now at 205,600 and no injector issues ever...

[maxnix]

gee- i'll bet tech doesn't even carry spare fi in his trunk

Need to check the old post on what members carry in their trunks. I think he included a couple of fuel injectors.

Yes, a dirty injector, for instance, can ohm out within specification but not perform correctly.

I am not so sure about MTBE as it was in WA gas regularly. I think associated water inclusion with ethanol is the big problem. But ethanol does reduce performance.

[texasoil]

The problem is the 'plastic' body of the early FI (tan) is attacked by ethanol and swells enough to rip apart the electrical coils imbedded in it.

[Q45denver]

How old are your injectors? Later purple body ones are reportedly more reliable.

[3Q Jay]

Keith, that seems consistent with i've never heard of a purple injector ethanol failure.

qship do you have the purple injectors (m.y. 96?) black (my 95) has the tan, but so far so good. of course the first 107k were on new mexico gas which i don't blve is ethanol blend (yet).silver (my 94) came with tan, now has all 8 purple oem replacements. california girl from day one.

[Q45man1]

FI with purple color body were put in when replaced 10K miles ago. Just ohm it last week with reading at 12.5 Ohms each.

[1990Q45'r]

I just replaced #6 injector. Ohms were 8.1 ? Never had one read below 10 ohms. The one before, the pintle cap was broken interrupting the spray pattern!

[Q45tech]

Low resistance is obviously an entirely different TYPE of failure mode!

The insulating varnish on the copper coil has failed and some turns have shorted to lower the resistance.... even 1 turn shorts can badly affect the strength of magnetic field.

Funny after 317k [18 years] of use my injector caps are still perfect but I've hand cleaned and polished then 3 times, when I had the rail off for hose replacements.