Computer just stopped working

[TURBOZ]

I just got the computer back from fast and had it configured for a magnetic pickup. Everything was working fine, then I go to start the car again and there is no spark. Also the computer is reading a constant 125rpm which is not right at all. The motor is spinning fast enough to produce 35psi of oil pressure. My guess is the rpm is roughtly 500ish.

I also tried moving the rpm before start to 100rpm and that is nothing. Anyone know what might be going on here?

 

[bobc455]

That doesn't sound right!

Are you saying that it shows 125 RPM even when the engine is off?

-Bob Cunningham

 

[TURBOZ]

No it will drop to 0 when the engine is not spinning. Cant seem to figure out what happend?

 

[TURBOZ]

What would you say is an average cranking speed for the motor? I thought probably in the 300-400 range?

Also any reason why the fast would not tell the MSD box to spark if it is seeing RPM ? Also its spraying fuel so I would figure everything else would work???

 

[TURBOZ]

Just for the hell of it I tried reversing the polarity on the distributor, and the results were the same. 125 rpm. From my understanding the polarity must go one way or the results will be incorrect. Dont know if this info helps at all.

I also pulled my distributor apart and everything still looks new. The distributor is brand new, just bought it. At this point I can only think that something happend to the FAST? I have checked fuses, any new wires that I just installed, etc. Nothing wrong. The fast still comes on line..

 

[bobc455]

Pretty sure that switching the pickup will give you the same RPM, but mess up your advance.

I would guess most engines crank around 200-250, but that isn't very scientific. Most ECMs have crank-to-run set at 400, so I would think most cranking is well below 400. It doesn't take a lot of RPM to build pressure with cold oil, but every engine is different.

It sure sounds like the FAST is not telling the ignition to fire, although it is hard to tell the real problem without looking at the car. When you say "magnetic pickup", are you sure that is what you have (not an inductive pickup or something)? If it was running before, why did you have it reconfigured?

-Bob Cunningham

 

[TURBOZ]

Originally posted by bobc455
Pretty sure that switching the pickup will give you the same RPM, but mess up your advance.

I would guess most engines crank around 200-250, but that isn't very scientific. Most ECMs have crank-to-run set at 400, so I would think most cranking is well below 400. It doesn't take a lot of RPM to build pressure with cold oil, but every engine is different.

It sure sounds like the FAST is not telling the ignition to fire, although it is hard to tell the real problem without looking at the car. When you say "magnetic pickup", are you sure that is what you have (not an inductive pickup or something)? If it was running before, why did you have it reconfigured?

-Bob Cunningham

This is a new setup. I just put a distributor in the car, sent the fast out to have it configured for a magnetic pickup. I got the fast back wired everything up and started it. It fired on the first crank but died 5 seconds after that. I realized that my factory computer was cutting power to the fuel pump because it no longer saw a signal from the optispark. (The fast and factory computer are both used. The factory computer only runs the assesories.) I thoguht that maybe the computer was cutting power to my msd box so I ran a direct wire from the battary to the "key on" location on the box. The car did the same thing started, then died 5 seconds later. I then ran my fuel pump directly to the battery and then car never sparked again I tried putting it back and still no spark. I didnt change anything else, no fuses blew, im just like WTF! Everything else on the FAST works, it just will not tell the MSD to spark.

 

[10SV6]

You've changed the crank ref angle to 50 ? You need to line the mag pickup point for the #1 cylinder at 50 BTDC.

If the box is firing the injectors it's getting a cranking rpm signal.

125 rpm is probably just about right for cold cranking rpm.

On the MSD pickup wires, you should have them twisted like you would on a HEI.

The distributor should be wired to the crank trigger inputs on the FAST Box. You've got the white points wire from the FAST going to the MSD box ?

 

[TURBOZ]

Originally posted by 10SV6
You've changed the crank ref angle to 50 ? You need to line the mag pickup point for the #1 cylinder at 50 BTDC.

If the box is firing the injectors it's getting a cranking rpm signal.

125 rpm is probably just about right for cold cranking rpm.

On the MSD pickup wires, you should have them twisted like you would on a HEI.

The distributor should be wired to the crank trigger inputs on the FAST Box. You've got the white points wire from the FAST going to the MSD box ?

I think we concluded that I have a dead ECU.