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93 Northstar stalling

2K views 8 replies 3 participants last post by  boricuacaddy 
#1 ·
I just bought a 93 Eldorado with the 4.6 Northstar motor in it.After about 20-40 mins.of running it hesatates,and stalls.It useally restarts but runs ruff and stalls again right away.It has codes P071,P105,and IO52.I replaced the ign.control module,coils and plug wires(no help)Can anyone help me?I hear that the Northstar is known to have problems with the crankshaft pos.sensors?Does this sound like it might be the problem?Thanks,Bruce
 
#4 ·
so you took off top cover of plenum to access the MAT sensor???Did you measured the kpa reading PD02 on the onboard compute using a vaccum pump? yes they had problems with the CKPs but with your descripion of problems and codes it leads me away to check other things, those codes just dont come up to throw you off the trail..it wont give give you codes for low vacuum unless the engine has a serious problem in that area, it would give you a near stall code maybe...Also check fuel pressure..
 
#5 ·
I think your right about a vaccum leak Cad Tech,Its funning when the car has set for along time when first started it runs fine for 20-30 mins.the engine temp was 223 and it was still running fine,then it started fluxuating up and down.I checked the PD02 and it was going from 10-35 at 1000 rpm and 10-55 at 2000 rpm.as the engine fluxuated.So it sounds like I'm going to pull the plenum cover,I don't have a vaccum pump to check the MAP,is there another way to check it?Also were would I look for a cracked plenum(sides,top,can't really see the bottom)Thanks for the help so far,I feel I'm getting closer to the problem!
 
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