Iv got a 98 gmc 1500, just put a new jasper 350 in the other day and cant get started. i have fuel, compression, and spark, i know i have to time it with the computer once its started. but i cant get it started. any ideas? im sure i have it timed right, but also this distributer does not have the timing markings.


Asked by Aug 09, 2017 at 09:17 AM about the 1998 GMC Sierra 1500 K1500 SL 4WD Extended Cab LB

Question type: Maintenance & Repair

1998 GMC 1500 sierra 5.7 350

11 Answers


That right, you need to bring up number 1 on TDC then drop in the distrubutor to align with number 1 on the cap, this should get you close enough to get it to run, but it will still have to be synced with the computer for it to run properly and to turn off the check engine light for cam/crank not in sync. Had to do this twice on my old Tahoe when the intake gaskets went bye bye two times in its life.


i under stand the tdc and dropping in the dist. iv done tons of these 350 engines but never a vortec, when i go to drop the distributer in it will not go all the way in i have to turn the engine over for it to drop completly in. and my understanding is that these dist caps have markings on them, but this one does not im stumped


Then you will have to follow the number 1 plug wire back to the post on the cap. Scribe a little mark in the metal of the distributor in the number 1 position. I turn the engines by hand to get the distributor to drop in then you can turn it back to TDC to make sure your on number 1.


alright I had already ordered a new distributer by GM and its on the way. will let you know


so the dist came in with the 8-6 markings on it. popped her in and she fired right up. but now with this being a brand new engine everything is plugged in and the thermistate guage seems to go from 160 to 260 vary fast, and the oil pressure guage is also all over the place


Recheck for a missed ground wire. I would be concerned about the temp. maybe install a regular aftermarket gauge for both, temporary if need be until you get all the bugs worked out. Your sure you got all the air out of the cooling system?


have ran it a couple times with the cap off for air to bleed. is there a better way to bleed? and both temp and oil sensors are new from napa, OG temp sensor was one wire and the new one is 2 wires they donts make the 1 wire anymore, so im asssuming its power and ground beacuse thats the only way it moves the guage, and i put a pressure guage to the oil sensor and the guage also reads 70-80psi


I have always had the front end up about a foot, that really helps get the air out. If you can't get the right senders then you would be better off with a set of aftermarket gauges, you may still be able to find a nice Pillar Pod setup for your rig to put the gauges into so you won't drilling in to your dash.


i will try breing up the front up to bleed but i called jasper to ask if it had a high volume oil pump and it does so that solves the high pressure problem.


Ok one down, now onto the coolant temp, your gauge will not work with a two wire setup sender, the ohm ratings are all wrong. So you either have to find the correct sender or go aftermarket, seriously I think the pod is the way to go I had that setup on my old 3/4 ton big block, and it was way more accurate then the factory setup, and it was also an automatic so I added a tranny temp to a three gauge pillar pod, just loved the setup.


i found the Temp sensor that its suposed to have, so i have it coming

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