JHZR2
Staff member
Hi,
My 98 S-10 ZR2 has 56k miles. It has been great, really reliable, and very useful, while being a perfect off roading vehicle, and a lot of fun.
Since about 2002, Ive not used it regularly. It has been for reasons ranging from fuel prices to needing to drive a LOT. Anyway, since about then, Ive noticed that the idle, while not rough, is a bit "shaky", i.e. I can feel the engine shake at idle.
Ive tuned the truck up in ~2003, it has MSD wires, the correct spark plugs, I even swapped another OE coil, it gets good mileage, etc. But yet at idle the engine shakes a bit more than I remember.
I got a blue point spark tester - the gadget that you put onto a spark plug wire and it flashes a lightbulb when the wire has current running through it. I noted that some of the wires had a much higher frequency of flashes, and one of the wires had a noted slowdown of flashing that was well correlated to when I feel the engine shake.
The question is, are these spark testing tools reliable? Is a variation in the reading from cylinder to cylinder normal? I have no CELs, never have. I pass emissions testing with flying colors, I dont think it is a big issue, but then again it was alarming how well the change/pause in flashing of the tester correlated to the engine shake.
So, question #2, what could it be? As I mentioned, I have MSD wires, they are in great shape. Delco platinum OE plugs, correct gap, etc. Could it be the distributor? Some of the positions are dirtier/eroded more than others? The plug wires are all either parallel or at 90 degree angles. They are all on really tight. Could one connection being marginally "looser" than the rest cause such behavior without a misfire or notable issue?
Any thoughts? any tests?
Thanks in advance,
JMH
My 98 S-10 ZR2 has 56k miles. It has been great, really reliable, and very useful, while being a perfect off roading vehicle, and a lot of fun.
Since about 2002, Ive not used it regularly. It has been for reasons ranging from fuel prices to needing to drive a LOT. Anyway, since about then, Ive noticed that the idle, while not rough, is a bit "shaky", i.e. I can feel the engine shake at idle.
Ive tuned the truck up in ~2003, it has MSD wires, the correct spark plugs, I even swapped another OE coil, it gets good mileage, etc. But yet at idle the engine shakes a bit more than I remember.
I got a blue point spark tester - the gadget that you put onto a spark plug wire and it flashes a lightbulb when the wire has current running through it. I noted that some of the wires had a much higher frequency of flashes, and one of the wires had a noted slowdown of flashing that was well correlated to when I feel the engine shake.
The question is, are these spark testing tools reliable? Is a variation in the reading from cylinder to cylinder normal? I have no CELs, never have. I pass emissions testing with flying colors, I dont think it is a big issue, but then again it was alarming how well the change/pause in flashing of the tester correlated to the engine shake.
So, question #2, what could it be? As I mentioned, I have MSD wires, they are in great shape. Delco platinum OE plugs, correct gap, etc. Could it be the distributor? Some of the positions are dirtier/eroded more than others? The plug wires are all either parallel or at 90 degree angles. They are all on really tight. Could one connection being marginally "looser" than the rest cause such behavior without a misfire or notable issue?
Any thoughts? any tests?
Thanks in advance,
JMH