1990 GMC Suburban ... Cummins Powered

[greguw]

Found some time to tinker with the truck ... The Tachometer was kicking my butt ... I was using a HEI module with a magnetic pickup to trigger and thats common with ford and dodge guys .
For some reason I need to send power via a resister to the tach connection in order to get the tach to pick up the signal .
It will work from idle to around 1100 rpm then the tack goes flat and back down at idle its fine again ... I know I am in the ball park .
The biig news is I pulled her out this morning ... sucks because I had to move a ton of crap , its worked out .
I'm in a larger industrial park so I was out driving and checking everything thing for leaks and any problems ... one stupid leak to do with the autometer sender ,,, few cranks of the wrench and it was fine .
Truck rode nicer than my new dodge cummins 4x4 ... it rides like a big caddy ... brakes are perfect , shifts great but with the small tires the gears are pretty short but got the feel .
Had her running for over an hour with out any problems .,.. Hydro steering is awsome ... Its best handling lift truck I ever rode , no bump steering at all ... Its a 30k truck ...LOL
Going to move forward , still have to research the tach thing , but moving on to the body .
Going to pull the windshield and side glass to start preping for new glass and paint .

[CowboyProtectionUnit]

subscribed.... lol doin a cummins swap asap after i get my truck

[Mrtn15]

Subscribed! Those wheels are monster!
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[greguw]

I'm going for that lifted low rider look ...LOL Check page 5 for tires .

[Dieselwrencher]

Very nice. It's a nice feeling when they can back out and see the sin light for them selves! Good luck on the tach!

[greguw]

Just talked to tech at Autometer , they said they are using Dakota Digital to connect a gas version of the tach to a cummins ... I had emailled them over the weekend but just called them .
Told the what I was doing and they had a interface unit that should work ... another 80 bucks ...LOL

[Dieselwrencher]

I just purchased a tach pick up from EEP for an auto meter diesel tach I got. Yeah, and guess what, it wouldn't work either. I guess I'll be getting the dakota digital one too.

[greguw]

If your getting the DSL-1 D make sure you get the module and pickup if you don't have one ... I was just on the phone again with Dakota Digital and now another tech just told me the module will not trigger on just the 4 pulses .
I'm going to have to move the pickup to the inspection hole on the cummins bell housing .
I may have to buy there pickup also ... will see .
This tech seemed a little more with it with his answers ... I must have talked to the guy who sweeped the floors the first time .
I'll keep you posted on the tach .
Mean while I got all the glass removed , headliner and interior plastics so I can start the body work on the roof .
I repaired the rear air unit ... someone installed a new blower but put it in Bass ack words ...LOL had it all jammed up . fixed all that and installed a new switch and she purrs like a kitten .
So I also pulled a vacuum on the system ... held at 29 vacuum lbs all night and going to add some oil and R134a tomorrow ... I'll be sitting in my diesel powered suburban with front and rear air blowing ice cold with no windows ... picture that ...LOL

[Dieselwrencher]

I picture that will be super bad azz! Thanks for the update on the tach. I just remembered that a buddy of mine used an isspro tach I think and it could run off 6 pulses. He just drilled a hole in his TC bolt cover on the bell housing and it read off the TC bolts. But, that won't work in your situation.

[greguw]

Just about done for the day ... took off my probe and poped out the access plug , does not look too bad I am going to try and make up a mount for this probe ... nice thing is I have another cummins motor plate sitting around so I can do most of the work on the bench .

[flomulgator]

Hey Greguw,
thanks for answering my questions a page ago. Just to clarify, my 1991 is the old body-style, looks near identical to 89-90 on the surface. 1992 is the first year of the new bodstyle. Hope that didn't sound patronizing; you clearly know your stuff very well. Thanks for the info though; since I won't be trailing it it sounds like I could get away with leaving the frame as-is if I pull the trigger on the Cummins swap.

As for your tach problems, I recently installed a TinyTach. Latches right on to the injector line of any diesel and requires no setup or calibration. Not a huge fan of the digital display but if your headaches continue maybe you could buy that and convert how it's being displayed?

Also, I wish I didn't know enough to appreciate how good your wiring looks. Unfortunately I've had to replace most of the wiring in my truck so I now know what good wiring looks like. Someone was wondering why all the wiring under the dash is molested? here's why:

On a -15 degree night in WY once my truck nearly caught fire while parked in the middle of the night, with a lot of wiring fusing and melting together behind the dash.. My guess is the very dry air had something to do with it. Had to get it towed and a shop did a quick fix for me, rewiring what was necessary. Years later on my second rewiring trip behind the dash I figured it out. After about 20 years all of the electrical connections on the truck will have corroded, and if you still own one of these and haven't yet, do yourself a huge favor and clean all contacts on the truck. The problem is the amperage keeps going up as the connections get poorer. The worst offender, by far, is an aluminum ground bus that anchors only to the thin body sheet metal. This is the ground for most of the wiring behind the dash, and the cause of all my headaches. It was in atrocious shape, and it appears others out there in internet land have had this experience. I chopped off all the GM style clips and rewired everything to a giant gold bus station with ring terminals, and then grounded the terminal directly to the battery via a long wire. I literally saw a difference in my stock IC voltometer. This bus is located up the left wall above the parking brake; you'll have to pull the dash and instrument cluster to get to it.

/rant, hope it helps someone.

Also, I feel ya on the cost runups. My latest fixes and 3/4 ton axle swap w/ wheels/tires was only supposed to run me about $3k. I'd guess I'm double that. How'd that happen?!?

[greguw]

Had some time yesterday to experiment with the new Dakota box ... I use the magnetic probe I bought from Autometer 5211 ... The 3/4 nut just fits inside the plastic plug access hole so I fabed up a piece of steel to recess it and bolt thru the closest hole .
I had another motor plate to all the jig work , took my measurement for depth and allinement .
It was really close and I also had to machine off material off the locking nut to get my clearance ... I used some molding clay to get my depth then fine tuned it from there .
It works ... Proble got a little to close but did run the tack just fine .
I also redesigned my spot sand blaster ... works great for all the small areas plus I'm not getting sand all over the shop .

[greguw]

Got the sensor all mounted up in place ... seems pretty happy so I am going to leave it in place . Started to strip the truck down to the bare body , looks like I am doing window motors and track gaskets .
Roof has a little bit of rust ... sucks but I will deal with it ... some dumb ass fill the roof rack holes with body filler so the water must have migrated in over time .
I'll get everything all sand blasted up and make some repairs as needed .

[Dieselwrencher]

That's great you got your tach working! That stinks about the rust you have to fix. There's always something though.

[greguw]

Sucks that could have been prevented ... thats like the worst of it ... Just chasing a few small spots ... I am going to add some reinforcing plates to the inside for my custom roof rack so it all will work out .
If I get the roof done by the end of the summer ... paint and the rack done I will be happy .
Just keep humping !

[y5mgisi]

That dash looks pretty!

[greguw]

The roof is coming along , got most of the rust sand blasted out ... I was going to lead everything but am going to weld patches in and going to use all-metal instead .
Not a big fan of Dyna-Hair but the all-metal is some good stuff , I should not have much filler to use at all ... maybe a quart at the max on this truck .
The worst is the passengers rear corner and thats half way repaired yesterday .
I used screws from the inside out and just ground them down and welded them up and not much distortion to the metal at all ... you won't be able to see them any way with the custom rack I'm building and the rood is going to be painted white .

[y5mgisi]

Moving along!

[Dieselwrencher]

Great looking rust repair!

[greguw]

Been busy with regular life but did find some time to finish the roof , a little more work than I planned , took 8hrs to prep and primer the roof , my luck a bad rain storm blew thru and halfway thru applying the prime the power went out ... so I'm on the scaffle with no lights and the roof half primered ...LOL came back on and I was able to finish .
I used DP40 epoxy primer , I had some urethane white paint sitting around , so I preped and painted the visor last night to make sure the paint and hardener was still good ... worked out well ... I'm doing the roof white .

[greguw]

We got the Storm ... I managed to get the roof painted yesterday morning before the rain hit ... Looks pretty good for a go truck ... its got the FJ cruiser roof .
Still have to finish prepping the rain guards and the roof rack parts for paint . Going to try and get that stuff painted so I can start assembling my roof rack .

[thirdstreettito]

Judging by those roof pictures a burb roof is a single layer of metal?

[WarBeard]

Yup all the way front to back. Not like the blazers or Pick-up's

[thirdstreettito]

Damnit. I have to take out my headliner to weld up my roof holes, DAMNIT! Oh well...

[greguw]

Its double on the ends but single in the middle ... that made for a pain in the butt with the rust , seems when the water leaks lays in the seams where its double ... I sand blasted and welded the holes .
Nice thing about rack area I was able to run large head screws up from the inside and just welded them up with minimal metal distortion ...
I'm going to work on the roof rack and cleaning all the sand and dirt from the inside ... the roof was the worst as far as any rust on the truck , now it will be just strip the delaminating paint ...