Just recentely my 1992 Q has had a hesitation issue.....the same problem happened last month for one week, but went away until today. After examining the engine the #8 piston is not getting fire or gas. I noticed this after un-plugging the #8 coil pack and the car ran the same as when plugged in. How can I test the coil pack to find out if it is the coil pack or the injector?
The spark plugs were replaced after the first time this happened....but the problem did not go away for annother couple days when for no reason just went away, until now.
Any help would be appreciated.
Q45 engine hesitation?
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Q45tech
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- Joined: Tue Apr 30, 2002 3:19 am
- 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
Ohm the injectors at the connector on the passenger side of engine......easiest.Look at the common injector current with an oscilloscope, to make sure they are all drawing 1.0 ampere and the pintle openings coincide ......66% up the ramp.
For techs: Think about the fact that the fuel pressure regulator vacuum port will reflect the fuel pressure change when the injector opens. Those cheap MAP sensors from GM can be rigged to show air vacuum/pressure on a scope by watching the changes on a line disconnected from plenum [what was a vacuum line will show a tiny pressure as the regulator diaphram moves].
Many expensive scan tools have a manometer attachment option.
Swapping coils when you don't have a GOOD spare is time consumming.
For techs: Think about the fact that the fuel pressure regulator vacuum port will reflect the fuel pressure change when the injector opens. Those cheap MAP sensors from GM can be rigged to show air vacuum/pressure on a scope by watching the changes on a line disconnected from plenum [what was a vacuum line will show a tiny pressure as the regulator diaphram moves].
Many expensive scan tools have a manometer attachment option.
Swapping coils when you don't have a GOOD spare is time consumming.
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Q451990
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- Car: 1990 Q45 - 118K, 2022 Toyota 4 Runner, 2004 Frontier M/T - 108K, 2012 Xterra (Mom's), 2023 Rogue (Inlaws)
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I'd say injector failure would be far more common than coil failure. My local dealership just assumes (or did in 1998) that it's the injector when there's a dead cylinder! I certainly don't advocate not investigating everything fully, but that's how common the injector failure is vs. the coil pack.
Heath
Heath
1) 12 ohms2) Not running3) Yes, but not as good a measure4) About $142 from one of our wholesale sponsors, such as http://www.infinitipartsusa.com5) Not the easiest, but definitely not the hardest either6) *Usually* best not to throw parts at a problem, especially expensive ones
