Randy, I'm sure this is not the problem.
cylinders 1 and 7 are cold
- Thread starter OC_
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Randy, I'm sure this is not the problem.
John,
Did you build the MS2 ECU or buy the plug and play version?
FWIW, I found two injector drivers, a transistor, and a resistor with cold joints on my MSPNP. Two of the 4 injector drivers would drop on my batch fired SBF. Cyl #1 injector would drop intermittently in steady state driving or if you hit a bump on the road, were the first symptoms. Hooking up a noid (LED) verified it.
I know you have swapped injector wires already but I would suggest a close inspection of the MS circuit boards and injector drivers for cold solder joints. If you have the old factory ECU go ahead and swap it with the MS and see if you're firing on all cylinders.
Did you build the MS2 ECU or buy the plug and play version?
FWIW, I found two injector drivers, a transistor, and a resistor with cold joints on my MSPNP. Two of the 4 injector drivers would drop on my batch fired SBF. Cyl #1 injector would drop intermittently in steady state driving or if you hit a bump on the road, were the first symptoms. Hooking up a noid (LED) verified it.
I know you have swapped injector wires already but I would suggest a close inspection of the MS circuit boards and injector drivers for cold solder joints. If you have the old factory ECU go ahead and swap it with the MS and see if you're firing on all cylinders.
I don't have the cam card in front of me, but I have one of these Comp Cams XFI cams with 280ø of duration. No exotic firing order.
I'm thinking because I have checked pretty much everything 10x, its got to be some huge electrical snafu.
I'm thinking because I have checked pretty much everything 10x, its got to be some huge electrical snafu.
Ron Earp
Admin
Me, and most of the guys I know that mess with electronics have them. They're a lot different than the old phosphor dot on a screen jobs though. Mine looks like this:
Except mine is black and white, not color. Invaluable for this sort of thing, still made new, and you might find a deal on Ebay. Mine is a Techtronix unit and it has come in very handy in diagnosing problems with EFI systems like you're having.
My MS2 is a prebuilt unit with a TPI adapter board. Its not a PNP version though. I don't think my factory ECU would run the engine, I have different injectors and a cam and the tune on the factory unit is not set up for that.
I'll have to look at a schematic on how things are wired, but how are yours wired up? I think there is only 2 injector drivers in my unit (or im just using 2 right now) to run an entire bank.
Me, and most of the guys I know that mess with electronics have them. They're a lot different than the old phosphor dot on a screen jobs though. Mine looks like this:
Except mine is black and white, not color. Invaluable for this sort of thing, still made new, and you might find a deal on Ebay. Mine is a Techtronix unit and it has come in very handy in diagnosing problems with EFI systems like you're having.
Ron, that does look like a nice unit. I'm a little hesitant about dumping more money for stuff for the car, you can guess how much its consumed already. Poking around on ebay though, they do have a lot of old scopes on there. I have never run a scope before, would something like this work? Tektronix 465M Oscilloscope Militarised Scope An USM 425 V 1 | eBay
Seymour Snerd
Lifetime Supporter
If you insist that your scope be implemented using a cathode ray tube it's still possible to buy used examples of very high quality scopes like a Tektronix 465 that mere mortals only dreamed about owning in the day, for quite reasonable money. See: Tektronix 465 & 465A Model Oscilloscope | Used Oscilloscope But Rons shows by example it would be a strange thing to do given the advances in digital scopes in the intervening years, including those at hobbyist-level pricing.
Tektronix Oscilloscope
Hitachi V-665 Oscilloscope
What do you guys think of these? What should i be looking for?
Hitachi V-665 Oscilloscope
What do you guys think of these? What should i be looking for?
If this engine is running on 8 cyl but running poorly I would probably move my search back over to a vacuum leak of some sort...disconect the pcv and try spraying some starting fluid into the oil fill cavity and see if the idle fluctuates if so there is a good chance somewhere on the bottom of the intake there is a leak.
The starting fluid will work its way through the crank case and oil galley into said vacuum leak..
The starting fluid will work its way through the crank case and oil galley into said vacuum leak..
I think at this point, i believe i have extinguished all possibilities of a vac leak. I have had this intake of more times i can count now looking for a leak and have never found anything.
The plugs come out wet and sooty.
I have tried the started fluid thing too with no effect.
I have tried the started fluid thing too with no effect.
Gas - oil would be a dead giveaway.
Yeah, I have checked the distributor cap and have even run 2 different distributors.
Yeah, I have checked the distributor cap and have even run 2 different distributors.
Mice. I am still thinking that the engine cannot breath (exhaust)... Pop the header loose on that side and see if you then have fire coming from ports 1 & 7.
Mice have been known to plug up exhaust systems before and these tubes are on the same side. Bottom of the collector? Doesn't really matter.
I would not spend anymore money on high tech or expensive replacement parts until you verify that those two cylinders can breath..
Once you have fuel to the cylinders, it's really pretty simple...
Suck-squeeze-bang-blow
The car does have a CAT, they would have to make it though the cat to get up in there. I guess it wouldn't hurt to check, but if there was any mice in there, they should be pretty roasted by now. Even the cold cylinders are about 300ø.
What a hilarious pun btw.
Seymour Snerd
Lifetime Supporter
I'm not sure I can advise you if your budget is really only $100. A $100 '70s Tektronix scope is like a $1,000 rolls Royce. It may run now but if it has the slightest problem it goes straight into the trash.
Take a look at the Velleman kits, and at some of the USB-connected units that use your laptop as a display. You might be able to do it that way.
If all you want to do is visualize noise on an EFI or ignition line, anything will work. But investing any money in 40-year old electronics is basically crazy.
There was a paradigm shift when low-cost oscilloscopes went digital (due to fast cheap A/D converters and memory) so buying into the era before that is (IMO) a waste of money. It's a real shame not to take advantage of that. This is an area unlike automobile technology because it is subject to Moore's law, eg., (roughly) performance vs cost doubles every couple years. So old stuff isn't obsolete and cute like an AMC Gremlin. It's just worthless junk and always will be.
Seymour Snerd
Lifetime Supporter
Those "USB connected" units I was talking about are called "PC scopes."
