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vacuum advance


smegun

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some members tell me I got no advance because I got no vacuum ...old school I believe em but I got a newer booster and newer silicon tubes were needed at points and its a new lower manifold gasket (newer head job) new injectors ….were can I find more vac the modulator ? shifts ok ... looking for common errors
 


rusty ol ranger

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Since you posted this in the explorer forum im assuming you have a 4.0...

No 4.0 ever had a vaccuum advance distributor, or any distributor for that matter.

The ignition timing is controlled by the ECM
 

adsm08

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The transmission vacuum modulator (What I assume you were trying to ask about before autocorrect got ahold of it) is on the transmission, at the rear on the passenger side.
 

smegun

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I know my mix isn't right I cant excellerate there is bog it idles fine and drives fine without any or minimum pedal can even get to 65 miles an hour but dam slow and any pedal is bog with roughness and possible top end noises like lifter flutter

the mix isn't right

I was told removing the spout takes it away from pcm control and vacuum advance and lets the edis modual figure it out im no expert ...but was told no response would come from the experiment because the advance is wrong ??

same boat im in before head work (recessed valve and rocker and rod wear ) no pedal at mid speeds or passing speeds Im looking at no pedal but good sounding motor at low speed wrong destinations
 

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How is your fuel pressure. If you can, test it while driving down the road.
 

smegun

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I suppose I could some how did you ever notice on the fuel rail besides the shrader valve is an indent for another inlet like someone had the idea to connect something there was there another model that had an active fuel pressure gage? like the manufacturer projected something for that there is not much to go like a drill and a tap
 

smegun

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it was a project that I was going to do but the hardware store order 1/4 I don't like the look of one of my quick connects but there quite lengthy seated I ignored it 3/8 to 5/16 …….when doing the fuel rail last time the shrader gave up good and so did the back feed on the rail so I think im good but ill check it again I was looking for a unappreciative injector maybe I got a stuck return line or vent valve or something ive done the back seat mod new fuel pump I should of made the hole bigger the vent valve is under there somewhere :/
 

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The 1994 4.0l uses the EDIS-6 system which is self contained and only has RPM advance on its own

The engine computer, the PCM, is connected to the EDIS-6 module to get the PIP signal(Crank sensor signal) so it can time the fuel injectors, and so it can calculate "vacuum advance" or Engine load advance, and it sends this "advance" to the EDIS-6 on the SPOUT wire(SPark OUT), on the EDIS setup the SPOUT signal is called SAW(Spark Angle Word), same idea, its the computers(PCMs) signal to advance, or retard, the spark based on engine load

If this SPOUT/SAW wire is disconnected then you would have slow throttle response, so no reason for you to disconnect it, but maybe someone else did or its broken

Diagram here of the wiring: http://sideways-technologies.co.uk/forums/uploads/monthly_2018_02/IMG_0545.JPG.58e4c3c055ea42d52513fbacc34f38e1.JPG

The VR sensor is the Crank sensor
The 4 pin connector is the Coil Pack

The 12 pin connector is the EDIS-6 module
Pin 3 runs to Pin 36 on the PCM(computer) see if there is continuity on that wire, if not replace the wire
 

smegun

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recently on last run I noticed some lengthy gear switching into od but run before was typical even a slight up hill downshift into 3 ive got two brains and a few of the edis moduals ill do that its good stuffing

do you know how the cam sensor interacts with the crank also? like someone told me its just used for starting the vehicle

I tested the top harness had it completely out of the truck black tape beeping it out seemed good to the connectors got a new crank sensor also a replacement from advanced to put in ….. clean run bad run..... like I drove 20 miles to the junk yard with my dpfe nut loose off the threads hangin on the pipe but pretty good run steady highway no passing power..... the last run was no good at all surging and lifter noise so something smells fishy bad connection or something on the verge of failure

the top harness looks easy compared to the one that travels around the engine bay but nothing moves it and its tucked under radiator front clip pretty good the bottom of the vehicle ???
 

adsm08

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The crank sensor can only tell the computer when cylinder 1 is coming up to TDC, which is all you need to know for a batch fire injection system. To do sequential you need to know where the cam is as well so you can find the compression stroke.

The cam sensor tells the computer where the cam is so that compression stroke can be determined. If the signal is missing the computer has the ability to revert to a batch fire system. The problem is that the computer often doesn't notice the signal is missing until the engine has been running for 10 to 15 seconds, so during cranking it has to guess about where the engine is. This will result in erratic starting or poor running for the first few seconds until the CEL comes on and it starts doing batch fire.

When I first 4.0 swapped my 87 I had a 94 harness and computer but a 92 engine, so no cam sensor. I dealt with that for about six months before I was able to get a cam sensor and install it.
 

smegun

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good stuff I wonder if that is happening sometimes around start up the truck sounds right but later fades on a stiffer throttle …. doing the cam sensor thing I was trying to decide what was in that package the sensor has magnets the vane passes through somewhat invulnerable but there was something in the plastic housing? I don't know? I imagined a circuit or piezo stack or something ? I replaced mine since I broke the connector I tried to soldered it but turned out kind of messy it didn't test out right at all it was 12 volts all the time so I replaced it with a yard sensor and backprobed it the syncro /drive itself felt great I just replaced the sensor .. another note the assembly didn't seat at tdc but would at atdc a few revolutions seemed right the arrow on the glass and vane seemed to be in the right spot at atdc (pic) ill have to check it again if I continue to hear lifter noise after my electronics testing I am going to check if I got any grit in the rocker oil passages after my electrical testing is over ... being very helpful its interesting to know why performance is on a day to day ... I had this problem with no throttle before I did a head job you can live with lifter tick :/ what would be the error codes for batching the sequential? ive seen some 17x codes
 

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smegun

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I got it together with what I had (extra pcm , new crank sensor) I got all kinds of skematics from oriely's regarding the power distribution box informative but lacking a relation to ground on a component basis I asked the tech at the parts store about if there was a sams to step through but he didn't think so as non automotive ...from what I can tell from diagrams is the power distribution box is just what it states mostly relations to power so color codes are relations to relays and power bus bar connections …...I had every connector practically disconnected : / …. I gave in a little trying to beep it out so I changed the crank sensor and put in the fresher pcm put her back together... also I possibly found a missing vacuum line to the heater core valve that may have been dangling …. testing it has never run better since I did the head job : ) initially I had some lifter clatter though maybe I woke up a cyl or something isn't right with oil flow or ? so im not all the way there yet but it settled down again and acted more like a normal vehicle that is trying to get into its power band which I havnt felt for years out of this truck ..... still may be some component problem connection hesitation or improper fuel pressure but like were stating above the default mode is probably a default operating no power mode
 
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smegun

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very intermittent 3rd run its back to crawling along I think I got a fuel pressure problem or still and electric problem like the pcm needs a driver and wants to detune and there is flutter at valves on fuel delivery looking for the the power transistors for the pcm anyone now of a good service to get a pcm tuned up
 

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