Shark Attack

I have a starting issue I have been chasing for over a year. Sadly it has come down to one of two issues.

God forbid, Vapor Lock
or Crank Position sensor.

Please take my word that the issue is not high current electrical at this point.
I have replaced EVERYTHING from starter to battery, cables. ground straps and trust me. Sadly its not that simple.

I have a slow/ to no crank when hot. It always "tries" but then the computer shuts of the starter after hearing a 1/2 hearted crank.

So I pulled the crank position sensor. At 70*F the sensor reads 910 ohms. (in tolerance according to a friend of mine that works for a dealer)

So I put the sensor in the oven and brought it up to 220*F and the resistance goes to 1200....

Now I Don't think this would give me the issue. Because when the car cranks resistance should go down on this sensor not up and I am not getting any CEL codes. So if the senor starts out high, it would think the car isn't turning....... I don't know.. Im so out of ideas at this point.

when I pulled the sensor it was caked full of crap and shavings.

Sensors are pushing $300.00 I don't want to just "try one" I want to approach this with a little more knowledge.

Thanks for your input.

Ahsai

The computer does not shut off the starter. As long as power is supplied through the ignition switch, clutch switch, etc to the starter, the starter should keep spinning.

The DME will shut down the fuel pump if it doesnt like the crank sensor signal but it wont shut down the starter.

Is the issue a slow spinning starter or normal spinning but then cut off or wont fire?

Ahsai

Btw, the resistance test of the sensor may not be conclusive. To fully test it, you need to use a scope to check its waveform, per the service manual. E.g., if one of the teeth of the flywheel is bent slightly, that will throw off the sensor.

If your starter is "cut off" during cranking, I still highly suspect it's an electrical issue.

What does you voltmeter in the instrument cluster show when cranking. It should not drop below 9v.

Shark Attack

I'm sorry to argue with you. But yes, when the car starts, no matter if you hold the key in the start position or not, the starter shuts off when it see the engine is running. It does tell this by the CPS.

Ahsai

First not arguing. More like discussing. Just trying to help here. You verified when the engine is hot, you can hand rotate it and all the other accessaries and pulleys?

Macster

Whenever someone posts something like this:

"Please take my word that the issue is not high current electrical at this point."

I strongly suspect the problem is related to exactly what the poster believes it is not related to.

My info is the engine will crank with a defective/non-functioning crankshaft position sensor but the DME will not trigger the fuel injectors or spark plugs as it does not know when to trigger these.

Clean the crankshaft position sensor and be sure you install it with the proper gap/clearance and the sensor is secure.

Then look elsewhere for the source of the problem.

Where to look? Well....something in the high current electrical system would be my WAG.

Oh to comment on your most recent post I can't confirm what you say is true regarding the DME shutting off the starter once the engine begins to run, but if it is true then look at this circuit from the DME to whatever the DME talks to (electrically) to turn off the starter when the engine spins up from a start.

A relay perhaps is failing and mimicking a premature "shut off the starter" signal.

thedugger1

I know nothing about electronics, but perhaps buying and installing a used CPS might at least allow you to rule it out, no? If it's still an issue, you can just resell it and only lose the cost of shipping.

extanker

i do not think vapor lock is an issue here. a dvom at the starter when it quits cranking will tell you if you have voltage at the starter .does this type of starter have a solenoid on it ? cranking voltage testing,starter draw [amps] ,battery load tested ?

Shark Attack

-I thank everyone for their inputs.
-I've replaced the starter
-I've replaced the battery
-I've removed the new starter and took it an had it tested
-I've replaced the cable that goes from the alt to starter to jump post
-I've cleaned the orig ground strap
-I added a ground strap
-I cleaned the ground connections at the battery
-When I shut the car off an then hit the starter RIGHT AWAY. It starts, lazy but starts
If I wait 15 seconds it gives a 1/2 hearted crank and stops
-I pulled the CPS cleaned and re installed.
-I have to start to look at other possibilities.

Again open to all input
I've also noticed I'm running warmer than I used to according to the dash gauge.

Again thanks for input cause I'm out of ideas.

Shark Attack

I will do a hand crank test later tonight.

Macster

When you wait the 15 seconds and then the engine gives a 1/2 hearted crank then stops how long do you have to wait before the engine starts normally?

Also, about the dash gage reading... do you have an OBD2 scan tool that you can use to view say intake air temp, coolant temp, fuel trims, etc. at engine start? I'd also be interested in having a voltmeter and seeing what the voltage does and amperage too as the car manifests this behavior.

Macster

Other things you have to consider and yet I do not believe you have are the relays. For instance the DME relay, the ignition relay and the fuel pump relay.

That the engine stops cranking vs. just cranks and doesn't fire suggests to me the DME relay or the ignition relay should be at the top of the list of things to be considered.

Imo000

If the engine is slow to spin, then its either the starting system is fhe issue or the engine is siezing up. It's one or the other. Fist step is to check the engine. Try to turn it with a breaker bar, while the seprentine belt is on and then when it's off. Then report back.

Shark Attack

I'm posting from my phone please excuse typos:

Ok, how long do I have to
Wait: it's getting longer and longer, I'd say at this point 1/2 hour.

I did the hand crank test, the engine is about the same to turn over by hand no matter cold or hot. So that puts me back to electrical. I have to be missing a connection point somewhere.

Some other posts talk about a point somewhere above the transmission. Any one know where this one is and if it is on my car? Very early 99 c2

Ahsai

One quick test. When it cranks slow, jump start it with another car idling at the engine jump start terminal and the airfilter bolt.

If it starts fine, your problem is electrical between the battery and the starter (since you already eliminated the ground strap with a jumper cable before.

Very difficult to believe the engine is running fine then seize tge next second after it stopped. You hand crank test just verified that.