'92 Q45a--Not running on all cylinders!
'92 Q45a--Not running on all cylinders!
I've been up all night reading many of the earlier posts, searching for info relevant to my problem. Lots of great info on this site! Still have questions:My 1992 125K mile Qa is not running on all 8. The engine shakes at idle, a couple dead cylinders from the exhaust note...sounds like a race car with a big cam (LOL!) It also seems to be pinging quite badly during moderate acceleration. At idle the tach seems to hold steady but reads low. WHether it's ignition or fuel I don't know. I pulled the plugs. They still looked okay after 65k miles (from vehicle history info)...whitish tannish colored tip...no evidence of fouling and I ordered new NGK Iridium IX's (in lieu of the Platinums--I hope this is ok! After pulling out the plugs I noticed that oil is leaking into the the spark plug holes on both heads...indicating bad valve cover gaskets. Can this oil soaking in the holes be the cause of the ignition misfiring? With respect to the fuel system, is there a relatively easy way to check and test all the injectors without having to remove the plenum...or is this best left to the dealership with their CONSULT device?Also...The car is not smoking, or backfiring or leaking anything visibly...and the I performed a vacuum test reading with a steady needle (approx 18-20 Hg at idle). Any suggestions? I just bought the car and put a transmission, an external cooler and inline filter in her...also a new radiator. I haven't even been able to fully experience the power of this car that everyone in this forum has gotten me so excited about! I'm really looking forward to solving this dilema. THanks for your advice!
Also....I Checked all the coil packs for resistance. All read 1.4 ohms. However-I have the 1994 FSM that specs approx .7 ohms, but I assume there is not a problem here due to uniformity across the board. No check engine light/trouble codes stored but the main battery had been discharged from sitting prior to my purchase of the car. Is there a way to trigger the ECM to show a code again if there ever was one?
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
That's what the misfire codes do in OBD2 [96-04] give you the cylinder that is misfiring. Up to you to decide if injector, or coil, or plug...............or valves.
You swap a known good coil because impossible to ACCURATELY test [coil transistor zener assembly] other than having it feed an external spark plug and observing .
You swap a known good coil because impossible to ACCURATELY test [coil transistor zener assembly] other than having it feed an external spark plug and observing .
So I am beginning to assume that the problem is more likely to be a multiple injector failure rather than spark plugs shorting due to the oil pooling in the spark plug hole from the valve cover leak. Has anyone ever heard of that happening? I spoke with NICO recommended tech Scott from Euro Imports in Scottsdale. He said the Q's had reliability issues with injectors...especially with the west coast (AZ and CA) gasoline. Is it possible to check all the injectors without having to pull the plenum? Any one care to offer any assistance or comment?
Duck3986...I checked resistance on each coil pack with an ohm meter between terminals 1 and 2 on Cylinder # 1 and #2 , and between terminals 2 and 3 on cylinders #3-#8. I have been told that the coil packs themselves seldom fail. Your car being a newer model probably has a different procedure.
Duck3986...I checked resistance on each coil pack with an ohm meter between terminals 1 and 2 on Cylinder # 1 and #2 , and between terminals 2 and 3 on cylinders #3-#8. I have been told that the coil packs themselves seldom fail. Your car being a newer model probably has a different procedure.
I replaced all the plugs w/ NGK Iridium IX's...car is running better but #4 is definitely out...cold exhaust manifold downtube. I can hear the injector clicking but not as loudly as the others. I will try to pull the #4 lead off and check resistance (10-12 ohms). Any other method or area worth checking/testing? What are the chances that a professional "on the car" injector power cleaning will cure this problem? Could the injector just be dirty/clogged since I can still hear a clicking? This car has 124K miles on her. As always, thanks for any advice!
Pugs all looked decent...tannish white. No apparent fouling or damage. I will try a resistance check across the injector if I can access it. depending on the reading, I'll do a can of injector cleaner drawn in through the intake vaccuum method--probably beneficial for all the other injectors at the very least! Then I'll probably end up replacing the injector. Thanks again.