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Guest Message by DevFuse
 

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fuel injector problems...


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3 replies to this topic

#1 heartless

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Posted 11 June 2008 - 07:21 AM

1990 Legacy LS wagon - the Snow Queen...

last week Thursday, while driving to work the car suddenly started running rough & the CE light came on - acted this way for a minute or two, then just as suddenly "corrected" itself and ran fine the rest of the way in. Ran fine going home that evening.

Next day, Friday - happens again, longer this time - was still running like crap when I arrived at work and shut it down. Tried restarting right away - still running like crap. Had to get to work, so left it. Get ready to head home, start car - still running like crap - called the other half to him know I was heading home & car was giving me fits just in case I needed a "rescue". On the drive home it suddenly straightens up again and ran fine the rest of the way home.

Saturday - dug out the FSM, pulled codes...
had codes for:
#2 injector
#4 injector
Knock Sensor (new about 2 mo ago)
02 sensor

obviously if the injectors are not working correctly it will set of the knock and O2 sensors, so wasnt overly worried about those right off...

after reading further in the FSM I attempted to diagnose the problem w/the injectors.

Checked power at the plugs (FSM says min. 10v) - 12.5v - check
Check resistance on the injectors themselves (FSM says between 10-11 Ohms)
#2 - 56.2!! :eek:
#4 - 13.something...

OK - not ideal readings. Went to the parts car (91 LS sedan) and checked the injectors on it - no reading on #2 at all, but #4 was reading around 12.5 - much better than 56+ (and more in keeping with what #'s 1 & 3 were reading on the wagon)

Got #2 injector swapped out on the wagon, hook everything back up, and fire it up...seems to be running better. Decided to go for a test drive "around the block" (country block = about 12 miles)
Seemed to be running fine till a little better than 1/2 way it started to act up again - crap! then, suddenly, the temp guage spikes!!:eek: :( ah, he-double toothpicks!!!

pulled over, popped the hood - the overflow bottle's cap was open & antifreeze all over - WTF??? closed that up - get back in - guage is down closer to normal - take off again - still running like crap - temp starts going up again - switch the heater on to help cool things off - runs fine for about a minute, then no heat - uh-oh!!

managed to creep her home ever soo slowly - temp guage pretty much pegged all the way. pulled in the drive, shut engine down, but turned the key back on to run the fan to cool her off.

I should mention that timing belts & related, water pump & thermostat were all replaced late last summer (07) by a friend at the local Community college Auto shop class (I should have known better... :-\ )

clear out the garage to get her pulled all the way in (had to move the motorcycles) pull the car in and commence pulling the lower radiator hose - only got about 1 gallon of coolant out... pulled the thermostat and find it is a Stant w/o the jiggle pin/bypass hole....:banghead:
OK, problem known there...had to order the correct thermostat (no dealers close to me)

Next recheck the injectors - #2 is reading 12.4 Ohms - same as it was when installed - #4 is reading nothing now, no change on the meter at all, not even a flicker.
OK, problem known there now, too...

So - do I go for another used injector reading in the 12+ range (as all seem to be now - keeping in mind that the FSM says spec is between 10-11 ohms) or do I replace them all to avoid further problems?

FiveOmotorsport has a complete set of 4 correct for my vehicle for about $200 + cores, with a 3 yr/unlimited mileage warranty...

Sorry this was so long....

#2 Gloyale

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Posted 11 June 2008 - 11:00 AM

Did you get a CEL again???

I would try replacing the #4 injector and see what you get. Obviously Zero Ohms means a problem.

After a new thermostat of course.

Check the overflow bottle for bubbles in case you have a HG leak.

You may also want to check you're fuel pressure. Low Pressure would mean running lean, which increases cylinder temps. It would also put a high demand on the injectors(staying open longer per shot) as the ECU trys to balance the mixture.

After that it would be time to Unplug the ECU, and the injectors. Then measure resistance end to end on the Injector signal wires. Check for full continuity (0.x ohms) Also check for any continuity to ground or any other wires on the connector(should be infinite, no continuity).

#3 heartless

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Posted 14 June 2008 - 07:07 AM

Gloyale - Thank you for the reply and the added info. especially this tidbit...

You may also want to check you're fuel pressure. Low Pressure would mean running lean, which increases cylinder temps. It would also put a high demand on the injectors(staying open longer per shot) as the ECU trys to balance the mixture.


Finally got my new thermostat, and did go ahead and order the injectors...

Will be putting everything back together this weekend and see how things go - and will definitely be keeping an eye out for headgasket symptoms (hoping no problems, but with my luck...:rolleyes: )

#4 heartless

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Posted 16 June 2008 - 05:57 AM

Got my "new" injectors on Friday.
Got them, and the new thermostat installed over the weekend - WOW, what a difference!!! Car idles so smoothly now that you can barely tell it is running - especially with the radio on. :)

Quick question about the type of bubbling i would see if there is a HG issue...i would be seeing more or less a steady stream of small bubbles if there was a problem, right??

I get an occasional larger bubble, but it is infrequent, and no real pattern to it...assuming it is still burbing trapped air here and there yet. (i did jack up the front corner when refilling the radiator, ran car to operating temp w/heat on, etc)

so far, so good - took her for a couple of shorter runs yesterday (20 miles or so) and she ran perfectly, temp was perfect...keeping the fingers crossed!




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