You wrote:
>
>
>Hi all -
>
>Want to pick your collective brain on a weird problem I had with my Dakota
>last night. I was driving home from work on the highway at about 70 mph,
>and was behind someone in the left-hand lane who was traveling about 55-60
>mph. There was another car coming up in the middle lane fairly quickly, so
>I decided to use a little V8 muscle (insert appropriate Tim Allen grunt
>here) to get around the slower car. I downshifted to fourth (I have the
>5-speed), and floored it. My truck took off, but at WOT (at about 3500-4000
>rpm) I started to hear a clattering noise which seemed to be coming from the
>lower portion of the engine. I let off the gas, and the noise subsided, but
>when I tried again a little further down the road, ...downshift, punch it,
>same noise, I got a little worried. Was this an internal engine problem, a
>rod knocking or something? Once I got closer to home, I tried a couple of
>jackrabbit WOT starts from a full stop, ran through the gears, and I wasn't
>getting the same noise.
The engine load @ 70 mph and WOT is a lot greater than during 1st-2nd-3rd WOT
runs... It is definately pinging. Before the MP SBEC when I ran 87 octane, I too
would occationally have this happen. Once CA. went to the O2 type fuel, it did it
almost every time I got on it (87 octane with stock SBEC). The SBEC 'learns' your
driving habits, and if you only occationally jump on it, it might not be able to
adjust in a 'timely' fashion to the abrupt change. I found that running a higher
grade gas, driving a little 'harder' than normal with that higher octane gas, then
going back to a 87 octane...the pinging went away (even with the new O2 type
fuel). Currently my truck has the stock SBEC, and 92 octane...I have done quite a
few hard runs (3rd to 80 mph, 4th to 102 mph) to find a fault I have been having,
and the truck has been ROCK steady...no pinging... Rap out the truck with the MP
SBEC and it's a different story! (You will still get pinging above 4200-4500 rpm
with 92 octane!! You have to add a can of 104+ booster to correct this.)
>I'm wondering if this is just "pinging" (I run 87 octane as recommended by
>the owners manual) , or if perhaps the computer wasn't having enough time to
>adjust the timing when I went from loafing along at 70 mph in 5th gear, to
>romping on it in fourth gear?? There was a discussion about a year ago,
>about whether or not the higher octane gas was worth the extra
>$$$/performance, or whether it had any effect on increasing engine life, and
>it seemed to be all personal preference and/or gas company propaganda.
> Consumer Reports (I know, I know) recently did a comparison on gas
>performance, and it showed no real differences in mileage/performance
>between regular octane, and higher octane gas, nor any real difference
>between the new RFG as opposed to gas from about 10 years ago. My truck is
>only a year old, and it only has 13,600 miles on it, that's why I was a
You might want to take an hour and pull your spark plugs to check the gap too.
The plugs on my truck have been pulled every 15,000 miles (mostly clean 'em,
regap if necessary, and re-install). It helps...
>little concerned about hearing knocking/pinging already. Maybe it has
>something to do with the oxygenated RFG they use in my area (CT) in the
>winter... Hopefully, by early next spring, MP will have released some of
>the performance parts for the '96 Dakota 5.2, and I can get the MP SBEC, and
>start running the hi-octance gas. (read ka-ching!)
It's not THAT BAD! On average my weekly fill up is about $31.50; only $4.25
more per tank than a 87 octane fill up. $4.25 x 52 weeks = $221 extra per year,
divided by 12 months = An extra $18.42 per month to have a LOT of fun with your
truck!
...Sam '95 SLT
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:07:26 EDT