Need help on 94 ranger either short or bad alternator or something else

[pentode]

I agree the 42V thing is probably a red herring, although I would think it should regulate itself down to 14.4 or whatever even with no load.

What we're left with is that something in the system is failing with a very small voltage increase. I think mechrick's suggestions of looking for shorts/intermittent shorts is the right approach. Given his example with injectors earlier in the thread, I'm back to wondering: has anyone seen a coil pack fail this way? Seems plausible though unlikely. However, we're obviously dealing with something strange here.

 

[pentode]

I should have asked this sooner - do schematics for the computer exist? I feel like I've looked for them before and failed. I'd really like to take a look at the regulation and I/O circuitry.

Edit: can I get someone with good eyes to look at IC13 in the computer photos above? Does it look to anyone else like there's a chunk blown out of it? Should be flat on one side and round on the other. Might be a trick of the light, might just be conformal coating, looks different from picture to picture.

 

[dean94]

All Injectors ohm at 7.4 ohms

 

[dean94]

I don't see an evap canister solenoid or wiring for it i disconnected egr valve still won't run tried unplugging tps sensor still won't run and also tried unplugging Grey metal box on passenger firewall still won't run. Could the coil packs have anything to do with problem i know they are old but don't know how old they are

 

[dean94]

Ohmed both coil packs on connector side of both coil packs i get 0 ohms on wire side of one i get 11.39 ohms and 12.12. on wire side of other coil pack I get 12.96 and 13.02 ohms

 

[pentode]

Where exactly are you measuring 0 ohms? Between which 2 points?

 

[dean94]

Middle pin and either side of middle pin on connector/harness side of coil pack