Timing belt replacement now intermittent start?

Caseys71 · Jul 10, 2014

Ok long story short had a timing belt pop on my '94 thank god these little 2.3s are non interference motors! Anyways followed through with replacing my belt new belt and tensioner, everything in time minus oil pump being one tooth off started up first try though and ran excellent. Drove it twice that day both short trips then it wouldn't start in the parking lot. 5 hours later back up and running fired first try drove home and then again would not start? Starting doing a little electrical trouble shooting led me to the icu if the procedure was written correctly grabbed another one and no start, found some missing insulation on crank sensor harness wire upon further inspection so attempted to remedy that from the back of timing cover to the icm no beans. Thought what the hell timing belt popped maybe the crank sensor was damaged won't hurt to replace anyways got through that procedure triple checked timing fired first try, and again a second time. After that no beans. Runs flawlessly minus a light tick I believe to either be oil pump or oil weight related whenever it runs and will run until I turn it off and it decides not to run again. Strong cranking, tried jumping the fuel pump relay with hopes of maybe intermittent ground issues as I've had before on another vehicle no luck. What gives? Any ideas? Don't see how it can run perfectly one minute then just not fire the next I'm stumped and exhausted work 2 jobs and have been chasing this issue for 4-5 nights now thanks for any help guys!

RonD · Jul 10, 2014

CKP(crank position) sensor is the ONLY sensor that tells the computer it needs to start the spark and fuel injectors.
Computer doesn't even know you are cranking the engine until CKP sensor sends it a pulse.
i.e. the ICM is a block of plastic until the CKP sensor tells it to WAKE UP.

You want to disable someones car, reach under it and unplug the CKP sensor

That's the "new rotor" on distributorless cars, lol

Anyway next time you have a no start, check for spark, exhaust side spark plug wire is where to test, intake side plugs don't get spark until engine starts, just FYI.

If no spark then you will need to spend more time looking at that CKP wire, and the CKP sensor alignment.
There is a special tool used to align these sensors after timing belt change, most don't use them and everything works fine, but...................yours may not be fine

This is the tool:
http://www.mechanicstoolsandbits.com/otc-tools-23l-crank-sensor-positioner-tool-for-ranger-otc6466-p-1944.html

Caseys71 · Jul 12, 2014

Okay so this is really driving me nuts, understand the troubleshooting process on fuel/spark should have mentioned that. Here's what I don't get, used the tool to correctly position sensor last night no go. Can jump the fuel pump relay and hear the fuel pump engage however the Scrader valve isn't emitting a lot of pressure and don't hear the pump engage with the key when it won't start. However it runs flawlessly when it does crank? Spark is there obviously when it does run however trying to spark test the other day couldn't get a spark I'm not sure what to look for at this point? Any ideas? Will try swapping coil pacs around but doesn't sound likely being that when it will run it runs well. Also tried both new and old icm to no avail (new one is a used one from junkyard granted). Could my inertia switch be faulty? Reason I ask is this is all following a light front end impact however switch seems to be disengaged but I can't reset it? Any suggestions greatly appreciated need to get this truck running soon for work

Caseys71 · Jul 12, 2014

Also tried running seperate ground on fuel pump relay thinking maybe a short? No go. What's really odd is last time it cranked yesterday I was rotating the motor by crank pulley heard an electrical sound as if a wire was shorted but got contact the fuel pump relay clicked hit the key and it immediately fired up ran great soon as I turned it off no beans. What gives?

*edit found that the EEC fuse was almost blown couldn't detect it the first couple times I looked at the fuse but upon very close inspection there was just a sliver of contact left on either side. New fuse starts first try, started again second try however took the fuel pump a longer than average interval to engage and prime then started ran great now nothing? Grounded the fuel pump relay ground to battery to no avail, swapped relays around could I have harmed a relay swapping them and cranking? Still hear the click of the relay when I turn the key Key on engine off. Almost certain it's an electrical bug at this point but what could it be?

RonD · Jul 12, 2014

This tech article has a diagram of the VIP connector in the engine compartment:
http://www.therangerstation.com/tech_library/OBD_I.shtml

Fuel Pump slot is labelled.
This slot is a secondary Ground for the fuel pump relay.
So if you put a jumper wire in that slot and then hook the other end of that jumper wire to a ground, the fuel pump relay should close when the key is on.
With this jumper in place, and fuel pump on, try tapping on the inertia switch or fuel pump relay, or just move wires around to see if you have an intermittent contact some where.

Timing belt replacement now intermittent start?

Caseys71

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RonD

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Caseys71

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Caseys71

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