Definitely an easily overlooked cause.
Rare but possible.
Grounding the secondary won't hurt a thing, but then there will be no spark observed anyway (no gap), open circuit on the secondary is absolutely a bad idea.
No fuse on the coil feed other than the fuse links down by the starter, but since it cranks, ruled out.
I know it is different as it was first generation (they are on third gen now) but even the modern replacement parts for it are more relaible than those parts made nearly 25 years ago.
----------------- TheSnoMan.com
I meant to say.. Never check for Spark by holding the ignition wire next to a ground
There is an ignition Fuse in the BOX
Well, okay, if it's humid enough, the 'holdee' might get a bit of a jolt. Other than that, I see no ill effects.
Circuit #39, pink wire(s) with a black tracer, basically any accessory circuit that goes live with the key in "on" or "accessory." It does NOT feed the ignition coil.
Well there you go then!
Silly me. Spent the whole day working on a Nissan Maxima, I guess I forgot my GM basics.
Wait...
... no I didn't.
No, the newer -designs- are more reliable, not to mention that your 89 has no mechanical fuel pump to contribute noise into the knock sensor circuit and uses a serpentine belt instead of the (vintage 85) vee belts which would get hot and stretch in the G vans and contribute enough racket into the knock sensor to cause power loss and poor fuel economy. The term "couldn't pull cotton out of a Kotex" was frequently used back in the mid 80s WRT 305 trucks and the way the ESC [didn't] work.
You know I have been driving since late 60's and have been around and dirven most of the vehicle discussed here or ones like them. I saw some reliable ESC systems. Also the knock sensor has a quarts crystal in it and it listens for a certain frequency that a knock produces and it is a lot different than fuel pump noise in this regard. Van generally were more prone to knock because they had higher underhood temps which increase tendancy to knock on lower octane fuel and would make them appear more troublesome at times. BTW, the reason they went to a electronic pump is because TBI fuel injection needed a stead fuel presure supply not because the pump was interfering with knock sensor. I know all about those pumps because my dad rep'ed for a company that did prototype work on the pump motor for GM in mid 80's and provided them for a while too. I could tell you all about those motors. I used to have one of the prototypes years ago but it is long gone now. It was a bit of a challange at first to make them work and last but they worked it out before production. My 89 still has original pump too. (one of my "dad's" motors so to speak)
----------------- TheSnoMan.com
Driving does not make you a mechanic.
"Been around" and "dirven" hardly beats factory training.
Not in the late 60's.
'Quartz' "Quarts" is how they sell booze.
Wow, you know more than the engineers at GM. Did I perhaps meet you at some time at the GM/ Delco engineering facility on Port Washington Rd. in Milwaukee?
The TSB applied equally to vans and pick up trucks.
Pathetic that you would imply that I said anything remotely close to that.
And this proves what? (other than you like to go off on irrelevant tangents)
By Passed worked fine. Although Timing is off the scale, it seems to be runnig fine so far. As for the knock sensor...I just gotta start putting in premium gas. Thanks all for the tip...saved me a few hundred for sure.
Yes... You'll need to retard your timing a bit is all. Basically, treat it as a 1st generation HEI distributor (non-computerized). You may want to check the timing specs of an older van to find a good starting point for your initial timing. Remember, non-computer-controlled distributors don't have a way of self-correcting for spark knock.
You can further compensate with an adjustable vacuum advance module and a different set of weights and springs in order to get the timing curve that works best for your application. If you tow things, or carry heavy loads, you may need to tweak it to avoid pinging. I'm not sure, but it would seem logical that the weight and spring requirements may be different for a distributor that can electronically regulate itself. The parts are cheap and readily available, so experiment as needed.
Either way, I'm very happy to see that you're up and running again! :-)
~jp
General wrote:
Did you disconnect the vacuum advance before you checked he timing, was the idle speed all the way down to curb idle? Did you take the cap and rotor off and check that the mechanical advance isn't seized?
Ah-hem...
Nor does being an engineer,
U can TRAIN a Dog or animal to do anything BUT they Still know NOTHING !
Doesnot mean u Know anything, We remember that GM engineer's Created all those parts that NEEDED to be RECALLED !! And a TRUE MECHANIC had to change them!
THe bottom line is though that with todays and tomorrows fuel prices you want maximum possible efficecny from engine not having to run it retard to prevent knock under load. On my 89 4x4 burb I run 8 BTDC and
93 octane and it will ALWAYs get 18 to 19 MPG on trips (it has a 40 gallon tank and will cruise 600 mile between fills with a good reserve) best it ever did with 87 and stock timing was maybe 15 and usually less and it was a slug on hot days and wanted to ping even with spark control under load. Now it never makes a sound and runs really well. Been running it this way for many years too and plan to for at least another 6 years until kids finish college. It is not a daily driver and is still pretty cherry. It will never see another tank of 87 as long as I own it no matter how high fuel prices get.----------------- TheSnoMan.com
I only run 93 octane and have for years. For vehicles equipped with knock sensors, it makes even more sense, as the engine will allow more advance for better power and efficiency. So I do believe (unsubstantiated) that running 93 octane fuel will get me better mileage and performance.
My girlfriend's 2006 Tahoe runs *much* better on 89 than 87...we can both tell a difference. She hasn't tried 93 in it yet. She still sees the cheaper priced 87 and thinks cheaper must be "as good".
An experimental Saab engine had variable compression, and produced more power and did so more efficiently as octane rating increased. In fact, it reportedly ran the best when E-85 was used.
Ja, Ja, did the vacuum advance....its an older van...stationed here in
-40C Winnipeg, Canada....the battery been frozen over at least 4 times. First time I started it in nearly 2 years. Still has that old gas from two years ago....but I might need to adjust the Carb because there was an issue about it before the tear down.
I guess you know that I share these veiws but I have seen MPG gains from it in several vehicles. And yes today 93 octane is 5 to7% more tops here and even 89 is maybe 3% more and even a 3% gain in MPG (or about from 20 to 20.6 would break even on the cost of 89 orver 87. In theory it would be possible to run very high compression if you used only E85 (around 12 to 1 or so) because of its high octane. Modern engine are really hamstringed by the need to "tolerate" 87 octane because of John Q. Public's affinity for it. If it was removed from market and only 89 and 93 or only 93 they could build engines with a lot higher compression in new vehicle and this would improve their thermodynamic efficency and therefore their MPG too but this cannot happen as long as 87 octane "tolerance" is needed. WHen direct injection for gas engine makes it main stream it will allow for even higher CR's because injecting it just before ignition cools the mixture some and reduces octane requirement a bit for a given CR.
----------------- TheSnoMan.com
Heh... Sno, buddy, you're preachin' to the choir.
If E-85 were actually widely available, I'd rebuild the K5's engine with that fuel in mind. More power, emissions-compliant, cheaper gas...what's not to like about that?
I thought it'd be fun to build a high-compression, E-85-burning
4-banger or small Buick 231 V6 just for kicks...and stick it in something tiny, like an MG or Fiat.It's exactly as you say. If we could bump up the compression to get more power with the E-85 gas, we could then build smaller, high performance engines to do the same task using less fuel.
What happened to the days when REAL engines were built with high-octane fuel in mind??? Remember the label next to the shifter on the real monster Corvettes in the 60's?? It specified that it *had* to use high-octane gas!
~jp
SnoMan wrote:
On 16 Aug 2006 19:10:08 -0700, "Jon R. Pickens" wrote:
I grew up street rodding in the late 60's and into 70's and I had a
1972 GMC 3/4 ton 4x4 with factory dual tanks and a SM465 that I got when it was about a year old and souped it up some too. It was a trip because 4x4's were really very rare then and powerfull ones were even more rare. I almost put a warmed up 396 in it and I wish I had to look back on now. I had a 69 Implala SS with a 396 that I was kinda of fond of for several years until the frame started to rust out where control arms for rear axle hook to frame. I beefed it up before it failed and then sold it. (that was the engine I was thinking of using in my truck and scraping the car) Back then you knew who the cheap skates were when it came to buying gas as you could hear them rattling away from lights. Some modern engines have some good power but it still nothing like a old BB with 11 to one CR and a nice intake and cam. You try and tell that to someone that never saw them in their prime though and they think you are BSing them. I drove and road in some down right scary cars back then HP wise. I knew a guy that had a 67 GTO with a blue printed 421 tripower and a 4.56 rear axle that could run 12's all day with street slicks and a bit faster with race slicks. Those old tripowers were scarey stock and even more so souped up. He was untouchable on street by all except a guy that had a 67 camaro with a roots blower on a warmed up 427. It was a 10 second machine wearing track slicks and could easily pull front end on street. Oh the good old days. Time to get off of soup box.----------------- TheSnoMan.com
Indeed. Seems I recall Snoball making a claim to that effect...
Agreed. A classic example would be comparing a mechanical/vacuum advance distributor with ESC in a 1985 van to a computer controlled EST/ESC system in a 1989 Suburban (or S-10) and expecting the second to behave the same as the first.
What recall would that be?
What type of emissions testing is mandated where you live?
Use to check CO,NC and NOx emissions here bi-anually until last year when they stopped doing it. That burb easily passed it every time and well below limits.. Matter of fact, none of my cars ever failed.
----------------- TheSnoMan.com
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