2seater

Dave, I know what you mean, but Mc had given a good solution days ago and I missed it also. For a movie reference, I feel like Kahn in the "Wrath of Kahn", as Spock observed "He is thinking in only two dimensions".

In my best Homer Simpson fashion, DOH! MC, I knew you knew what you were talking about and had posted the diagram earlier, but I skipped right over it, while pursuing the elusive yellow wire. Blind to what you were trying to communicate so to speak It makes perfect sense when my eyes are open to all input. The most elegant solution is also the simplest.

That is what I thought when I first read the post, but if wired in conventional manner, power in on terminal #30, is routed to #87 when energized and #87a when not. Since the power fed to #30 is always "hot", when the relay is inactive, #87a is now "hot", energizing whatever is connected to it? I wonder if maybe wired backwards, with power in on #87 and out on #30? The power would then be prevented from flowing out #30 or #87a? I'm too fuddled to make a better guess, but I just don't see how it would work unless the signal to the HDM is relocated. I just can't get a handle on how that would work? I think the OP solved his issue by leaving a the fog lights engaged creating an alternate path the HDM likes. Edit: I do like the idea of repurposing terminals, or replacing, but I think there will be splices somewhere anyway and the factory apparently did so for no apparent reason. Done properly, they shoudl cause no issues.

I will admit upfront that I am a little slow as to what others may take for granted. I must be misunderstanding. If anything is connected to the NC terminal, 87a, and terminal 30 is connected to an unswitched B+, won't that function be active with the power removed? I am having difficulty getting my head around this but I don't see how you can avoid using a power enable relay to feed the beam switching relay, and relocate the yellow wire connection point? The separate hi and low relays would work as well, but the yellow wire still needs to be relocated.

Not to ignore the detail discussion, but I believe I asked about a direct headlight switch power feed to under the hood, but couldn't see the forest for the trees. The yellow wire IS the power direct from the headlight switch. On the '90 without the upgrade, the yellow wire runs from the headlight switch to supply the power to the hi-lo relay in the console, which comes out as the tan and green wires to the headlights. Along the way from the headlight switch to the relay, s255 taps off the yellow wire and routes it out to the headlight door module. In the upgrade we are discussing, the yellow wire is cut and now becomes the signal to turn the enable relay on, and the end that was cut off becomes the signal wire to the module, connected to the output of the enable relay, yes? Perhaps this is obvious to others that tried to tell me that, and I missed it, or when tracing a circuit over multiple pages, I look where I'm going and forget about where I came from? As an aside, why on earth would the factory place a splice in a wire run less than 12" from the terminal? If it was at junction where the harness splits, it would make some sense, but in a straight run? On the '90, S255 is 9" from the relay terminal in the console. Very difficult to unwrap the harness to find it inside the console. It would be very simple if connected at the terminal since the relay center slides right out for access to the rear. It seems plain to me that a more efficient way would be to split the wires at the terminal, just like is done at the left headlight socket. Edit: I found that splice where the yellow splits for the headlight module. It is inside the 1" diameter split loom between the fender and the relay center. It can be accessed by releasing the harness clamp on the fender and pulling it upwards. I also have the giant harness connector that is just to the rear of the relay center unbolted from the fender. Since my engine air intake is not stock, access is probably easier than stock.

No doubt the splice will be where most difficult to work with I keep flip-flopping back and forth and have decided that it just isn't worth the time to do a halfway measure. The best is to have the relays up front and the power feeds as short as possible, as the OP did and Mc has also suggested. The only thing additional I can see that I need from the inside to under hood is a feed from the headlight switch to trip the enable relay and a second relay to switch beams. The FSM shows the yellow wire to low beam filament, but in between relays is factory style and what I will do. I'm thinking the yellow wire connects to that giant connector on the fender, probably hidden by the air filter on stock cars. Still need headlight power to the original hi-lo relay in the console to satisfy the BCM and allow hi-lo switching.

Mc, thanks for adding to the discussion. I too have been debating which way to go. The best voltage drop solution is as you stated and done by the OP, short power runs direct from B+. The factory upgrade is limited to helping the switch and a bit of reduction in voltage drop, all useful. This appears to be a relatively simple change all done inside the cabin. I don't believe it to be adequate for 100w bulbs(even though it has worked for years with an 18ga. feed). I am still investigating the route I will take. I found that splice for the yellow wire in the console but no way to discriminate which way the splice goes so cutting it and reusing it for two jobs is probably out the window. A new wire from the switch to relay is probably the easiest as you mentioned.

I would be happy to write up what I eventually decide to do. I am leaning toward doing the factory relay upgrade and also run two new 12ga. wires to the headlights from the Hi-Lo relay, probably in parallel with the existing ones. I am guessing that the yellow wire will still function as originally intended. Edit: Oops, I should look at the diagram and not from memory. Since I do not presently have the upgrade, I will need to relocate the yellow wire to match the updated wiring schematic. Dave: I will call as soon as I have a chance.

Thanks a bunch. That is what I thought was the best way. I also though about pulling the connector but some are pull to seat complicating that procedure. Not sure about these. I'm thinking you mean the giant connector on the fender just to the rear of the relay center? It looks like there is a splice before the module as there are two yellow inputs to the module but only one wire feeding them both. Since the original will remain from the old style wiring, I will only be duplicating the hi-low relay in a second location. I don't like a bunch of extra splices either, but some will be required. Both headlight sockets are showing heat damage at the ground connection, particularly the right side, which has extra voltage drop due to the harness design. I don't remember seeing a circuit breaker in the OP, but will be included in this one. The factory mod would be the easiest upgrade, but I don't like the light ga. wiring feeding 200 watts of headlight. Now that I think about it, it would also be a factory upgrade "enhancement" to replace the factory wires with heavier gauge gauge to the headlights with a separate harness? Still need to connect the yellow wire to the low beam splice where they split up front? It would be little more work than pulling a headlight activation wire to the enable relay? I greatly appreciate the insight and info. Much to think about.

Are you sure it's the fuel pump you hear and not the brake pump under the hood? The fuel pump will only run for 2-3 seconds while the brake pump will run for up to a minute if it has been sitting a long time. The way to know for sure is test the fuel pressure with a gauge. Could just be a plugged filter if the pump does run and little fuel pressure. Did you mean pressing the pedal while cranking or only before and releasing before cranking, like setting a choke on a carburetor?

Thank you for that information. I'm sure mine would be worse with the 80/100 Hella's I am using. I should really have known better, so no need to kick me, I'm busy doing it myself. It would have been nice if the standard hi-low relay would have been under the hood, but that's not the way it is. In any case, it seems even the factory upgrade would be very marginal. It looks like the factory wire size to the left headlight is only equivalent to 16ga. I see why the two hi and lo relays were used, because it appears to be straightforward to trip with the hi and lo beam wiring. One enable relay and a single hi-lo relay also works, which essentially mimics what is happening in the late model upgrade already inside the car, redundant really, but should work okay. The question I guess I still have is what to trip the enable relay with? It would seem to be direct power from the headlight switch. Anything like that available under the hood? Yellow module wire connected to the input of the hi-low? I'm probably plowing old ground and apologize if I am.

I have looked at the factory diagrams and I think I understand what needs to be done to do the factory upgrade, which looks to include a small upgrade in power to the lights as well as reducing load on the switch. I am considering doing a more extensive upgrade, with direct power to the headlights, similar to what was detailed by the OP. It looks like the yellow wire to the module must have a connection to the output side of the relay so it "sees" the headlight filament. Adding one or more relays closer to the lights is really redundant but reducing voltage drop, etc. through the factory wiring is what we are after, yes? My lights are out of commission right now so I don't have a good way to see what the actual factory voltage delivery is. edit: I see there was an additional post and I will say, at least on mine, the circuit panel slides out of the console after removing the four mounting screws/expanders on the sides, so access isn't too bad.

I am curious as to the resolution to this issue. I have had two headlight switch failures in the last six months and suspect power through the switch to be a contributor. It looks like in simplest form, a relay could be added right at the headlight switch to reroute power around the outside of the switch, even more basic than the factory upgrade. The most effective as far as reducing voltage drop is detailed above. It looks like the only missing link is rerouting the yellow module sensing wire and I wonder if this was effective?

VV, I have had an odd behavior lately also, so I am very interested in what you find. I never get any codes, but twice in the last month it has refused to idle on it's own. Once was engine cold, the other with engine warm. With manual intervention, depress throttle, it idles fine. I suspected the IAC was having an issue, so I watched what it was doing, or being commanded to do. During the hot incident, the IAC was hunting all around 100 counts, trying to "catch" the engine, but failing to do so, then the issue disappeard on its own during the same drive. The following morning, it started normally, idled up and then slowed down as it warmed, as per normal. IAC counts were in the 130's and didn't drop when fully warm, but it idled fine. This was this last weekend. Now, warm idle counts are in the 50's, and no issues are apparent. I am using a TPI throttle body/MAF assembly, so actual counts may be different than what many will see. Fuel pressure is textbook perfect, and my vacuum/boost gauge shows steady and normal readings. A tap test on the MAF was negative, but I cannot be certain it is not acting up intermittantly. I still suspect the IAC, MAF or possibly the ECM itself.

Speaking of vacuum, how many pounds of vacuum is there supposed to be in each gear selection? I tested the line at the modulator and at the manifold, and every gear came back with 15 or less pounds of vacuum. Vacuum is most commonly measured in inches of mercury or Hg. At hot idle in gear, I usually see about 16"-17" of manifold vacuum, but 15" sounds okay depending on the local barometric pressure. Even though located at about 850 ft. above sea level, barometer tends to run high here, usually around 30"Hg. Should be slightly higher at idle in park.

Perhaps others have tried a tee below the sender but I never found a good way to do so. The heater feed pipes are directly above the sender, so unless some senders are shorter than others, it doesn't look like there is enough room with the sender stacked on top of the tee? It may be possible to place the sender in the side of the tee, but I was always concerned the horizontal weight of the sender wouldn't be a good thing for longevity. A steel or stainless steel fitting would be stronger than a brass type, and there may be low profile specialized tee's for use where clearance is an issue but never investigated. In my case, I have a tapped hole into the passage below the sender on the oil filter adapter to feed my turbo oiling, so I have used my turbo feed line for a pressure tap a couple of times. If really serious about adding a mechanical gauge, tapping directly into the filter adapter is relatively simple to do and a gauge could be located under the hood if not desired in the cabin. In this case, hotwiring the fuel pump and a hose connected in place of the sender would seem the simplest.

The second hose you mentioned is for the charcoal canister for fuel vapors. It isn't unusual for that line to become disconnected due to the design. That said, if vacuum is low to the trans. modulator (like a leaky or disconnected line) the trans. should shift more firmly, not less so. There is an additional vacuum line that runs from the octopus on the engine intake toward the firewall. It doesn't sound like a vacuum problem, although it never hurts to check for leaks. You could try a fluid and filter change, plus a Seafoam treatment for the trans. to see if it helps, but it does sound like the trans. may be on the way out.

Clearances are guite large inside the combustion chamber, so about zero chance of binding anything in there. Could catch under intake valve momentarily but IMHO it is not a concern.

No comment on Startron, but it begs the question, where does the ethanol go? Does up to 10% of the fuel disappear? I have used Stabil for over twenty years with no hiccups.

No, I was only mentioning what the ECM does to operate the purge valve. If you disconnect it, I am pretty certain it will set a code. I would leave it plugged in and operate as normal. If there is a problem, the ECM should set a code, but it is not self correcting.

It should be fine to drive as is, however, just plug the vacuum line coming from the engine and cap it if concerned about vacuum leaks. It runs in parallel with the trans. modulator steel line until it gets to the front of the trans. Did you have a check engine light that makes you suspect an issue? Probably a quad driver code if something is going on. Usually the quad driver circuits in the ECM just switch a ground to operate. I doubt it is damaged but the pick n pull should have lots of them.

Nicely done. Excellent photos. Thanks for the specific pics of the timing chain which illustrates what I was trying to convey. The aftermarket stuff just isn't up to the OE standard. Water over the dam now, but you could have removed the lower portion of the O2 sensor boss too, but the amount cleaned up will be fine. Thanks for the fine update.

Also, disconnect, clean and reconnect the battery terminals. Be certain the connections are clean and tight. Look for corrosion at the positive cable end. I suspect Ronnie's advice is right on, but it's good to start at the very beginning.

I think the average joe must join and get a password to link to the site? I just clicked on it and asked for authorization? I'm sure it's good test info. I only mentioned the regulator as it was brought up in a prior post. Essentially a fuel injector is flow rated at a specific differential pressure, the difference between the intake manifold pressure or vacuum and the fuel pressure. The regulator "sees" the vacuum in the intake manifold and reduces fuel pressure to keep the relationship stable. The vacuum pump can simulate the manifold vacuum. Approximate value is 1psi for every two inches Hg manifold vacuum. It also works in reverse when the manifold is pressurized due to turbo or supercharger and raises fuel pressure in a direct relationship to the amount of boost. The regulator is a separate issue from the fuel pump but if it malfunctions and keeps the pressure higher than required it does put more strain on the fuel pump. A boosted engine is even more sensitive to the ability of the fuel pump to keep up. An engine running up to one bar of boost will need to maintain flow at up to 60 psi or so, usually requiring an upgrade.

42-43 psi with key on and engine off is about correct. It should drop with the engine running in response to engine vacuum, probably to the mid-upper 30's for fuel pressure at idle. It should blip back up to the low 40's when the throttle is snapped open and return to the mid-30's when it returns to idle. If it remains at 42'ish pressure at idle, the vacuum diaphragm or line to the regulator is defective. You do need to get the vacuum line off to check for vacuum when running and also for evidence of fuel in the vacuum line. It should never drop below the mid'30's in any running condition. If so, the filter or pump is plugged or failing. The fuel filter first is a good place to start, as suggested, as well as the regulator itself.