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Barnfind 1987 740 GLE On-going Resto Thread

Idk if its been mentioned yet but you can cause a running issue by falling for marketing and putting laser platridium super ultra mega spark plugs in redblocks because they have higher resistance than the coppers or nickels the old style ignition system wants
 
RAPTOR479 said:
Idk if its been mentioned yet but you can cause a running issue by falling for marketing and putting laser platridium super ultra mega spark plugs in redblocks because they have higher resistance than the coppers or nickels the old style ignition system wants
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The only issues I've ever had with specialty spark plugs was the fine wire platinum ones. The other platinum plugs like Autolite makes with a large electrode were good in my old 93 classic.
As far as Iridium I have only tried the Denso ones which worked well after regapping.
But yeah gotta be wary.
 
Moyni said:
Well, we might have had a breakthrough

View attachment 35147

When I first got the car I put some cheapo aftermarket distributor in chasing a no start condition. Well we pulled it back off and compared it to the OEM one I had. The alignment of the hall affect ring is off, at least enough to throw the timing off a few degrees. Once I get some more water pump gaskets and re- install it AGAIN. I will test with the OEM Bosch one back in.
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I was thinking, the only thing left is the distributor. But then I was like, "I don't see how that could be off."

You can run an engine without the cooling system hooked up. It isn't gonna hurt anything unless you get the engine hot.

This may end up being and an example of why you don't just shotgun aftermarket junk at these old bricks.
 
Good find. It's a great feeling.

Random diag story:

We fixed a 2025 truck this week that had problems with a LIN bus. We scoped out the LIN bus waveform and found it was shorted to ground. We then found a module in the back of the vehicle that was shorted to ground, taking down the bus. This short also took out another module. We replaced both modules and couldn't get the vehicle to start. After a couple of days we found a third corrupted module. Three modules later, the vehicle is now running.
 
Yet again.... nothing destroys troubleshooting machinery like "bad NEW parts out of the box". Forces us to look into the wrong areas, as "the NEW distributor cannot be bad....BTDT". I used to tell my Maint. Techs when they were stumped by machinery trouble.... "something you believe to be TRUE is actually FALSE".

Glad you found it. Nothing will grind your gizzard like defective replacement parts.... you exacerbate the situation as the work proceeds.
 
I guess the benefit of this whole wild goose chase is that it forced to me to do all the maintenance items that would have been needed anyway on the front of the motor (belts, tensioner, seals, water pump, etc).

I feel like I reached a peak and now see all the rest of the trail I have to take lol. (Suspension is still all original, most of the interior lights dont work, temp gauge is inop (top priority now), trans and rear gear fluid)
 
dl242gt said:
Well done. That's the second bad head mount replacement distributor from over there now. QC has evaporated in our society.
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It was from RockAuto too, not like some Amazon seller but I have enough parts cars with OEM Bosch ones to keep em ticking for a while...

I think my bad one could be fixed just by re-aligning the reluctor(?) wheel to where it should be compared to OEM. But first order tonight is adding more coolant and doing an oil change since I'm sure the 15 y/o oil isnt in the best shape.
 
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Went for a ~20 mile drive into town today to get a burger at the drive in spot and made it back in one piece.

Need to get a new oil cap gasket and fix the rear end leaking but otherwise a decent drive. My exhaust is rattling on the cat/heat shield.

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leaking from around the speedo cable. Probably going to pull a cover off another parts car and sand blast it at work and re-install with new fluid since mine is super crusted up.


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My knock sensor was completely destroyed too, thankfully my 400k mile parts cars one was in perfect condition. Also getting the old temp sensor out of the head was NOT fun. When putting one from a parts motor in I realized I needed a cut down and shaved 19 to really get in there, and by some miracle my grandfather had made one years ago and had left it in the drawers of the Mac Tools toolbox he gave me 10+ years ago. Worked perfect lol

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Speedo wires starting to chafe, easy enough fix. Might re pin the plug so I can fix it missing the clip that holds it in place.

I saw a video where a guy replaced a steel diff cover with an aluminum one from a turbo / lsd car. They claim that its plug and play despite being a slightly different style speedo pickup. Is this true? As you can tell my stock steel one is shot and that lock ring for the speedo cable is big $$$$ from Scandix. I feel like all my parts cars are steel as well.

In other news, got the sway bar off and brought it to work today to sand blast since its also very crusty. Ordered new hardware for the dif cover and a 7/16s 8 point socket for the drain plug (the one size I didnt have of course). I dont trust an open end or adjustable on these super rusty square drive drain plugs.
 
IDK if you can put the aluminum one on there without there being an issue with the air gap for the speedo sensor. I know I tried to do it on my 240 and was having issues and could never get the G80 tone ring to read correctly.

There is no reason to "upgrade" to aluminum. You may want to consider putting a whole 940 axle in there with a G80, but you will have to solve the speedo issue. 48 tooth g80 vs your 12? window open diff reluctor.


You can get new leads from Volvo or dbarton sells them. You could also get a new connector from his site. I used to just go to the junkyards and cut em off donor cars.

That parking brake cable looks ready to let go too.
 
Yeah I have 3 donor cars in my back yard. A 87 740 GLE wagon with ~160k, an 88 740 GLE wagon with ~450k and then an 89(?) 760 GLE turbo with ~180k on it. Both my parts wagons are from the Carolinas so they are relatively rust free. I am pretty sure the o ring around the sensor is the leak or a pinhole from the rust on the cover.

I have just seen that the updated rear diffs have the sensor connected with a bolt rather than the lock ring in my older style (which I do not trust to come apart without a serious emotional event).

I am trying to think where else in those cars they usually those 2 pin bullet connectors I could pull from that it hasnt been subjected to serious environmental damage. Have various new bolts on order to refresh all the suspension and dif hardware. Cant stand rusty parts, especially down here where we dont really "do" rust lol

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Well confirmed the rear cover had a rust hole. The 1/2in drive 7/16 8 point socket was well worth the investment. I had to use a breaker bar to loosen the drain plug.

This rear axle is so crusted up, definitely refreshing one on a stand in the barn this winter for sure. Hopefully a cover from a parts car is in better shape so I can pop it on.
 
From the looks of the rusty open diff, yours is a speedometer version and not ABS. I know the latter vehicles with ABS use a cast aluminum cover to mount the speed sensor. My 90 also has that cast cover I believe, while it doesn't have ABS.... an oddball transition year. All the 92-95 vehicles I have viewed do have the very fine pitch ABS pulse wheel attached to the diff. housing.
 
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Speedo cable redone. Grabbed a random not rotted pigtail off a parts car and then spliced it with Deutsch connectors since it was easier than trying to solder with those crusty old wires.

Also sand blasted and primed the dif cover off my parts car. Still need to clean up the gasket surface on the dif itself for when the gasket arrives. Speaking of which, finding one is not so easy anymore. Thankfully Amazon of all places had the MTC one
 
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