Car Turns But Doesn't Start

SuperSleeper · 10-15-2004

So jpretz's car isn't starting. First found that the fuel pump doesn't turn on when he turns the car on. (And he heard a sound like the pump killing itself when it died, so we thought it was bad) But upon running power directly to the pump, the pump turns freely. So tear the dash up and take the ECU and MFI relay out (he has EPROM! :bounce: ) Discover there's lack of continuity (or continuity--don't remember which) in one side of the relay. So it's toast. Going to replace that today, but wondering if there's anything else we should look for in the meantime... Just wanna make sure we aren't lookin over anything, cuz if this isn't what's wrong, I'm stumped.

npaulseth · 10-15-2004

How do you know it's EPROM?

A//// Guy · 10-15-2004

Might want to replace the ECU caps while you have it out. That can cause starting problems.

john · 10-15-2004

Check timing, spark, and fuel.

1QUICK4 · 10-15-2004

Did it turn over abnormaly fast? Did it sound higher pitched than normal while cranking?

jpretz · 10-15-2004

This is Dane:
Know it's EPROM because I opened up the ECU and saw the chip. I'm being led to believe it may potentially be the ECU that's bad. I gotta go take it back out to smell for rotten fish.

I still have to check for spark, but the valve that came on the fuel filter sprays not an ounce of fuel. So it clearly doesn't have that.

It cranks about normal speed--but I guess it'd help to hear how a normal car cranks over to compare.

Anyway, as you may have assumed, replacing the MFI relay didn't solve the problem. When I apply power directly to the fuel pump harness in the hatch, it spins. But when I apply power to the check terminal in the engine bay, it doesn't. So there's clearly a break in the line somewhere...

A//// Guy · 10-15-2004

My ECU didnt smell and it was close to junk. Replace the caps anyway if they havent been done. They will go bad no matter what.

Also if you have any clicking behind the dahs and under the hood while cranking thats a sure sign of an ECU problem.

SuperSleeper · 10-15-2004

Didn't hear any clicking. We tried starting it, and got a couple quick pops of exhaust, but that was it. Tried it another time, and got a very loud pop. Don't know if it was combustion or not... (sure hope it was)

Anyway, probably will replace the caps soon. Guesstimate on cost for that, and where to go?

The MFI harness had power at two places when key was at the "on" position, and power at one position when it was off. I really don't know if that's how it's supposed to be, but at least it has power to that point. So it's somowhere between the ECU and the fuel pump....

Any other suggestions appreciated. Thanks.

niterydr · 10-15-2004

If the signal is leaving the ecu to the mpi relay, usually the ecu is fine. Replacing the caps is a very good preventive measure however.

tsiawdspeed · 10-15-2004

After seeing the car, I would say that the when the starter turns over, it seems faster and more high pitched but the speed is actually slower. The battery does have 12 volts so its not dead. I don't really know what else could be causing the problem.

Raptor · 10-15-2004

I have a good ecu you could swap in to check it with, also if you get too stumped, call Enes and have him grab it on the trailer, we can figure it out for you

Enes · 10-15-2004

does the engine spin at all or is it just the starter that spins?

when i put the trany back in i forgot to hook up a connector on the starter, the one that tells it to actually engage...

make sure that is hooked up..

-E

520Talon · 10-15-2004

Don't forget to check you cam angle sensor. There are tiny wires in there that can break and leave you stuck. I had the same problem and I changed all the stuff you described and it ended up being the cam sensor. If its not working it won't tell the motor when to spark.

SuperSleeper · 10-15-2004

These are all good points, but keep in mind there is not a drop of fuel at the fuel filter.

Enes, yes the whole motor spins. We have juggled with it being a starter issue, but we have heard some signs of combustion, and it appears to be a fuel-related (and maybe electronics too)

Thanks Mike. I feel at this point that's probably the best way to handle this, but Jayme is understandably concerned about costs.

john · 10-16-2004

Timing??? Did it all of a sudden happen or was the car bought this way? I bought one that way and the timing was off. Another kid on here bought a 2g fuel pump from me ($5) having the same problem. Turned out he smashed his valves. Have you done a compression test? If I remember correctly, the laser sounded high pitched and like it didn't have much power due to loss of compression.

niterydr · 10-16-2004

My question still wasn't answered.
Is the ecu sending power out to the mpi relay?
Does the relay send power to the pump?
Do you have power at the pump?

SuperSleeper · 10-16-2004

Quote:

Originally posted by niterydr@Oct 16 2004, 03:39 AM
My question still wasn't answered.
Is the ecu sending power out to the mpi relay?
Does the relay send power to the pump?
Do you have power at the pump?

The MPI and MFI relays are the same, correct? (Mulitiport Fuel Injection or just Multi Port Injection)... If so, then yes. The ECU is sending power to the relay. I detected two 12v sources in the relay's harness... one that was continuous, and one that was switched power.

As I mentioned in the first post, the fuel pump doesn't have power. We disconnected its harness in the trunk and checked with a multimeter. Nothing. But it spins when supplied direct power from the battery.

I'm gonna try to convince him to just bring it up to QPR... we lack the expertise and tools to do a proper diagnosis and repair. This is all very foreign to me.

SuperSleeper · 10-16-2004

Quote:

Originally posted by 92tsiawd84@Oct 16 2004, 01:07 AM
Timing??? Did it all of a sudden happen or was the car bought this way?

Have you done a compression test? If I remember correctly, the laser sounded high pitched and like it didn't have much power due to loss of compression.

All of a sudden happened... and compression was tested two weeks ago. It was good enough to be driving...

tsiawdspeed · 10-16-2004

I think he was saying to check the compression now to see if the timing skipped a few teeth and smashed the valves.

A//// Guy · 10-16-2004

I would just take the cam cover off and manually see if the marks line up, first. And try another ECU....

Then take it somewhere.