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Discussion Starter · #1 ·
I have a 98 5.7 vortec (spider injection) motor. The motor turns over very slow and at times even needs a few turns of the key to crank at all(as if it's frozen for a sec). It seems to be a huge strain for the starter to crank the motor. I have two fully charged/tested 875 CCA batteries I tried and I have triple checked all wiring connections to ground/batteries/alternator and starter. I also tried a new starter. I have also done my best to get the distributor correct by putting the #1 to TDC and mounting the distributor rotor pointing to the #1 marked on the cap. I'm starting to think that the motor which was recently rebuilt by a friend may have had the timing chain put on wrong or off. I want to rule out every other option before I go pulling things apart to check the chain. On this motor I would have to drop the oil pan as well as remove everything up front. Two questions:

1. How would I know and what would I do if my dist? is 180 degrees off. Could that cause a slow crank?
2. Any ideas on what else could cause a slow crank?
 

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Wrench Turner
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IDK which version of the spider you are using.If you are using the older poppet style,they are bad about leakin gas into the cylinders.The stiff balck hose used on the earlier style also gets brittle over time & leaks gas in between the upper & lower intake.I also don't know if you are using the stock controller & wire harnes for engine management.If any rewiring has been done,the injectors could also be firing @ the wrong time.Just some things to ck for besides timing.Mine started out being hard to turn over also.Followed a few days later by excessive gas consumption & smoking.When I pulled my upper intake,I had a pool of gas 1/2" deep in the lower.It can get bad enuff that if the plugs get 2 wet to fire,it can cause hydrolock if you try to force it.You will usually get some kickback tho & notice a strong odor of gas.Just thought I would mention tho.
 

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Discussion Starter · #6 ·
Hmmmm- I'm using a Howell harness and ECU so I have to assume it was made correctly(direct plug in). As for the injectors leaking that's def something I may look into. It is the poppet style as far as I know. The entire set up was pulled from a Chevy 98 K2500 (HD I think because it had 8 lug axles). I'm an idiot for rebuilding this thing. It ran perfect, 98000 miles, but I figured I should do it while it's out.
 

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Wrench Turner
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I pulled my original engine @ 250K.It wuz runnin good.Just low oil psi.I replaced it with a Goodwrench crate & it now has 284K & still runnin good.Low oil psi again tho.534K on the truck.I'm currently rebuilding the original motor to put back in.You probably had another good 150K left on it.LOL.With the work involved tho rebuilding was prolly a good decision.You know for sure what you have now rather than just what a previous owner said.Let me know whatcha find wrong.
 

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Discussion Starter · #9 ·
why is it cranking slow>?

The starter is not painted at any of the contact points(where it bolts to the block). Also, by voltage drop-are you referring to just taking a reading?

I'm leaning towards two possibilities at this point.
1. The actual cam and crank gear were not aligned properly during the timing chain install(hard to believe with the clearly marked dots).

2.The Jeep fuel pressure is not enough to fire the poppet style injectors. With that said the motor doesn't start when you spray carb cleaner in the throttle body either. I ordered the upgrade MPI units regardless and I will get an external fuel pump as well. My understanding is that I won't need an external regulator because it's already on the MPI unit.

This all still begs the question.....why is it cranking slow>? If the timing is not off and the motors not hydrolocked?
 

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Discussion Starter · #13 ·
I appreciate all the answers. Because this motor is out of it's element between the frame rails of a Jeep it seems I underestimated the need of a solid ground. I had grounded the motor to the frame and the battery to the frame as well. Well, I ran a ground from the frame rail to the starter motor bolt and then from the starter motor bolt back to the battery neg as well. Now the motor is spinning just fine.
It starts for about a second and then immediately stalls and it will do this over and over again. I'm almost certain its not getting enough fuel. although the pump on a Jeep is capable of about 90 psi it is regulated to 49 PSI back at the in tank regulator. I have to figure out how to bypass that. Supposedlyt 05-06 TJ's came with stock pumps that could put out 60 PSI so I may look into swapping the regulator or the entire fuel pump from my 04 for an 06. Not sure whats compatible yet. My other option is Novak(1997-2004 TJ, XJ Fuel System Integration for GM Gen III+ Engines) but the CNC part I need to bypass the regulator is on back order until they get their lathe up and running.

Thanks for putting up with my Jeep banter on a hot rod page but I figured if I have Chevy SB questions this is the place to go.
 

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Wrench Turner
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Gonna hav to get that psi up.You need to get a minimum of 58 to the spider.More would be better cuz the regulator on the spider is gonna control the psi.I had a pump that puttin out 55 psi.It would do just as your describing except sometimes it would run but would have a really bad stumble when I would accelerate from a steady speed.Low psi will also cause you to run lean & create even more problems.IDK if your runnin a cat convertor or not,but,a lean condition can even cause the media to get hot enuff to melt & stop the convertor up.
 

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Wrench Turner
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I had a brainfart.Since I know absolutely nuthin bout Jeeps,just thought I would throw this out there.What about possibly swappin an entire fuel tank from a GM vehicle into your Jeep so you could use the GM sending unit,pump & all??? As I said,I have no idea how a Jeep tank is made,or,how it is fastened in.Or........adapting the sending unit into the Jeep tank??? Just a thought,or,a really stinkin brain fart !!!!!LOL.
 
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