Bang blow suck: non Olds
August 15th, 2018, 07:40 PM
#1
Bang blow suck: non Olds
Guys this has nothing to do with An Olds engine but I have a lot of respect for the experience on this site and the problem is petty basic stuff to any 4 stroke engine. I would appreciate any comments.
The problem I am having is with a 1988 AMC 360 in a Jeep Grand Wagoneer I am restoring. ( the online Jeep,forums do not compare to the experience and advice on this site for Olds enthusiasts.). Here is a little history. The Wagoneer sat for several years before I purchased it and the owner stated that there was an intermittent problem with the engine running/not running. The odometer reads 140k but I do not believe this is the original engine, so mileage unknown. After I purchased I found a cracked fuel line on the suction side of the fuel pump. I repaired the line and he engine started relatively easily. Although I did not run it for long periods of time I started and ran the engine on and off over the coarse of 1 year as I performed other restoration work. It started and ran fine. There was some blue smoke I attributed to valve seals that would clear up after the engine warmed up. The engine ran well and idled fine but seemed to lack power. After some resto work I turned my attention to tuning the engine. I replace all maint. Items like plugs, wires, filters hoses etc and took it out for a test drive. Low power deteriorated to missing and backfiring within 1/4 mile and I barely made it back home until it died and would not restart.
Since then I have:
replaced ignition with HEI due to no/weak spark. Also chased various wiring gremlins associated with this problem. Ignition problem is resolved and now have consistent 12 vt to Distributor and good blue spark at the plugs.
checked and rechecked timing and firing order/ distributor orientation. With #1 piston at TDC verified. distributor is firing #1 and dampener timing mark is @ 0*.
engine will occasionally start and run but get erratic shut down and not restart. Verify fuel and spark.
Ran a compression check today with horrible results. 70-90 psi on all cyl.
my initial though was that it jumped time when it backfired on the test drive. The backfire was caused by the ignition failing. But.....there is not a lot of slop in the timing chain and the dampener timing mark was at TDC when the piston was TDC.
Any thoughts would be appreciated.
Steve
The problem I am having is with a 1988 AMC 360 in a Jeep Grand Wagoneer I am restoring. ( the online Jeep,forums do not compare to the experience and advice on this site for Olds enthusiasts.). Here is a little history. The Wagoneer sat for several years before I purchased it and the owner stated that there was an intermittent problem with the engine running/not running. The odometer reads 140k but I do not believe this is the original engine, so mileage unknown. After I purchased I found a cracked fuel line on the suction side of the fuel pump. I repaired the line and he engine started relatively easily. Although I did not run it for long periods of time I started and ran the engine on and off over the coarse of 1 year as I performed other restoration work. It started and ran fine. There was some blue smoke I attributed to valve seals that would clear up after the engine warmed up. The engine ran well and idled fine but seemed to lack power. After some resto work I turned my attention to tuning the engine. I replace all maint. Items like plugs, wires, filters hoses etc and took it out for a test drive. Low power deteriorated to missing and backfiring within 1/4 mile and I barely made it back home until it died and would not restart.
Since then I have:
replaced ignition with HEI due to no/weak spark. Also chased various wiring gremlins associated with this problem. Ignition problem is resolved and now have consistent 12 vt to Distributor and good blue spark at the plugs.
checked and rechecked timing and firing order/ distributor orientation. With #1 piston at TDC verified. distributor is firing #1 and dampener timing mark is @ 0*.
engine will occasionally start and run but get erratic shut down and not restart. Verify fuel and spark.
Ran a compression check today with horrible results. 70-90 psi on all cyl.
my initial though was that it jumped time when it backfired on the test drive. The backfire was caused by the ignition failing. But.....there is not a lot of slop in the timing chain and the dampener timing mark was at TDC when the piston was TDC.
Any thoughts would be appreciated.
Steve
August 15th, 2018, 09:52 PM
#2
Registered User
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 13,757
Does it have a catalytic converter? I once had an ignition module failure that caused fuel to get into the cat, melt the substrate, and plug the exhaust. Engine would barely run and bogged down easily. When I unbolted the front of the cat from the manifold pipe the engine ran like normal.
Last edited by Fun71; August 15th, 2018 at 09:55 PM.
August 16th, 2018, 02:41 AM
#3
ph_ckstick1
Join Date: May 2017
Posts: 450
Check the converter, and for vacuum leaks, Is the egr valve functioning as it should.
Is this 88 360 topped with a holley efi tbi? like the dodge trucks of the era were?
I'm finding it hard to believe that you can't find a good jeep/amc forum.
Is this 88 360 topped with a holley efi tbi? like the dodge trucks of the era were?
I'm finding it hard to believe that you can't find a good jeep/amc forum.
August 16th, 2018, 04:11 AM
#4
Registered User
Join Date: May 2011
Location: Pontiac, MI
Posts: 142
Lot of possibilities here but 70-90 cranking compression is too low. If you are certain the cam timing is correct you can try the old squirt oil in the cylinders and see if it raises. If not, run a leak down test. If it's carbon build up causing the valves not to seal you can try some Mopar combustion chamber cleaner, don't have much to lose at this point.
August 16th, 2018, 04:42 AM
#5
Lot of possibilities here but 70-90 cranking compression is too low. If you are certain the cam timing is correct you can try the old squirt oil in the cylinders and see if it raises. If not, run a leak down test. If it's carbon build up causing the valves not to seal you can try some Mopar combustion chamber cleaner, don't have much to lose at this point.
August 16th, 2018, 04:45 AM
#6
Does it have a catalytic converter? I once had an ignition module failure that caused fuel to get into the cat, melt the substrate, and plug the exhaust. Engine would barely run and bogged down easily. When I unbolted the front of the cat from the manifold pipe the engine ran like normal.
August 16th, 2018, 04:55 AM
#7
I installed a new EGR. And have plugged most vacuum. This engine has a Motorcraft 2 barrel carb. Actually the International Full Size Jeep Association (IFSJA) site is pretty good. I am having some tech problems accessing them right now. They still do not compare with The folks on here.
August 16th, 2018, 10:35 AM
#8
'87 Delta 88 Royale
Join Date: Dec 2010
Location: Margate, England
Posts: 2,513
Checking the lifters only need the valve covers removed, the cam timing is a bit more involved and need the valve cover off anyway.
Roger.
August 18th, 2018, 06:02 PM
#9
So the problem lies with the valvetrain. I would rule out head gasket as all cylinders are affected. Either the valve timing has jumped, or the lifters have pumped up and won't bleed down.
Checking the lifters only need the valve covers removed, the cam timing is a bit more involved and need the valve cover off anyway.
Roger.
Checking the lifters only need the valve covers removed, the cam timing is a bit more involved and need the valve cover off anyway.
Roger.
thanks for the input Roger.
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