Slow Cranking and No Start

mazdaverx7 · 05-12-2014, 03:26 PM

85.5 that I just got is having some issues. First off, it sat for 10 years. No good. I got it home and have been toying with it. With a good battery, the engine cranks very slowly, even when using my Corvette to jump it. Here's what I've done so far:

Cleaned all of the starter connections and the battery cables. I removed and cleaned the negative cable and mounting point on the engine. I cleaned the battery cable ends.

I also cleaned the starter and the points on the starter where the cables and trigger wire connect.

Made not much of a difference. I pulled the plugs to do a compression test and when the plugs are out, the engine spins quickly as one would expect it to.

Here's a video:

20140511_222111.mp4 Video by mazdaverx7 | Photobucket

In the video, it looks as if the battery is dead. It is not by any means. I'm kind of at a loss here and any help would be appreciated.

9FF · 04:47 PM

These cars turn over slow anyway, yours is a little slower than normal but could be corroded old wiring, it should still start at that speed if everything else is ok. You don't have any tach bounce as far as I can see in that light, check your speed/ref sensors, DME relay, then see if you have fuel & spark. I take it your compression is good. All details on Clark's.

Btw this was not a good idea:

Quote:

Originally Posted by mazdaverx7

...even when using my Corvette to jump it.

mazdaverx7 · 05-12-2014, 05:40 PM

/I cleaned all of the battery cables and engine bay grounds. I removed the starter and cleaned it and the contact points.

I do have tach bounce and can always take another video to verify.

Why was it a bad idea to use my Corvette to jump the battery when it was weak? Never had a problem doing that.

9FF · 05-12-2014, 07:39 PM

Jump starting these cars leads to DME failure, put the battery on a charger overnight if you think it's drained.

Have you swapped out the DME relay?
Do you have spark?
Do you have fuel at the rail?
Have you gone through the Clark's "turns but no start" checklist?

If you have compression, fuel & spark it will attempt to fire-up regardless if anything else is at fault.

mazdaverx7 · 05-12-2014, 08:22 PM

I have gone through quite a bit at Clark's.

I have spark but getting 'I'm getting no fuel. I verified that the pump is not operating properly by applying 12V directly to the fuel pump's connector.

I have not swapped out the DME relay yet but I did attempt to bypass it per Clark's Garage's method of using a jumper to actuate the fuel pump. That procedure led me into applying the 12V directly to the pump.

Glad to know that jump starting can lead to DME failure. I wasn't aware of that.

mazdaverx7 · 05-12-2014, 08:25 PM

I did a compression test and it was between 135 psi and 145 psi on each cylinder. I forgot what it was exactly. I tried using starting fluid to start it and it did not start. I even went as far as putting a small amount of gas directly into each spark plug hole on the head. It did not start with either method.

I'm stating to suspect the speed or reference sensor or both to have failed.