1994 Q45t fuel injector help

[cyclohexanol]

Hey everyone,

I posted on here about a year ago when I got my Q, and suddenly a fuel injector went out (ohmed at 1), unfortunately it was the #3, and I had to remove the plenum I replaced the injector and it ran well until around June of this year, when another one went out (ohmed at 1), this time it was #2, so it was significantly easier to replace. I haven't really had any specific fuel injector problems since, however I had a problem today which is probably unrelated, but it led me to question the fuel system.

Today as I'm driving home in LA traffic I notice the temp gauge is way up there, so I get out of traffic and cruise around, it drops back to 3 o'clock, good. I decide to do an oil change, because I was a little overdue, then I check the coolant, etc... all is well.

Well then I decide to ohm the injectors, just out of curiosity. I've noticed that right after I replaced the other 2 injectors, the car ran smooth as silk for a couple days, then went back to being a rolling massage chair. As it turns out, all 8 of the injectors (ohmed from the connector) were registering 18-20 ohms, which is quite a bit out of spec.

So, long story/question short... Could I have some sort of injector circuit problem that is causing the injectors to short? If so, what could it be, has anyone heard of anything like this?

thanks!

[JedCoop]

18-20 is a little high, so the problem would not be a short.It seems unlikely to be consistent on al injectors. Where are you ohming the injectors? Is it as described here? http://www.q45.org/ohminjectors.html

Are the connectors clean?Maybe someone else with more experience has seen this.

[cyclohexanol]

Yes, I used the method described in http://www.q45.org/ohminjectors.html. The last time I ohmed them and I had the one shorted, the rest were all between 11-12, but now they are all 18-20... I don't get it, the connector is squeeky clean as well

[q45tech2]

Could ohmeter have changed [low internal battery?] ............buy a 10 [ 5% tolerance 9.5-10.5] ohm resistor from radioshack to check calibration].

[Q451990]

Nice to see you back Dennis! Is your old ID not working?

Heath

[3Q Jay]

first thought on the high ohmage is your meter/leads.

sounds like you don't know the root of why your temp climbed up. better not leave that unsolved....

[cyclohexanol]

Ok so here is an update --

After changing the oil, flushing the rad and replacing the t-stat, the car doesn't overheat/overwarm.

However, today I go to start it in the morning and its idling funny, like it does when an injector goes out, and it throws a code. I ohm the injectors, all of them are within spec, so I'm guessing the previous problem was actually due to a dirty contact or something.

I got home and pulled the ECU out and checked the code, 51 (Injector Analysis), but all of the injectors are within spec, almost all of them were at 12.0 exactly. So then I double-check, and verify that all are within spec. I start the car up again and its fine... wtf?

This car seems to have a history of fuel injection problems (injectors shorting, etc...), my question is what is causing that? I've replaced 2 since I bought the car a year ago...

-j

[maxnix]

Are you in CA or AZ? It helps us if you complete your profile.

Might check your injector harnesses for continuity. Presume you didn't tough the MAF Sensor, nor its connector?

[3Q Jay]

t-stat. good. secondary when system tight, but not as cool as it should be is the foam surrounds for the radiator, and the fan clutch. can do the cardboard thing and/or watch how long it spins on shutdown.

injectors: you might also get it good and hot, and then disconnect the harness and ohm all 8 every 30 minutes as it cools down [which will be rather rapid if you leave hood up]. you may pick-up a marginal injector this way as the electrical characteristics do change with temp.

[elwesso]

did you replace the spark plug of the cylinder that failed... often a failed injector leads to a fouled plug on that cylinder.

[sdkhalsa]

Have 94' Q and replaced injectors. 18 ohms is about the figure that I had when then required replacing. In my experience, once one went the others followed shortly. The number does not tell the whole story as they can fail in an erratic way. I would just bite the bullet and replace them all.