Car cranks but will not start. Fuel is there.

[kidwiththelaser]

I crashed my old laser, and then bought a talon shell, and swapped everything over.

I crashed the laser about 5-6 months ago, so it hasnt ran in awhile. Everything worked beautifully on the laser, so I know that everything I pulled off the laser is good.

Now heres my problem:

-The car will not start, it turns over but it will not start up. I know its getting fuel because there is fuel pressure at my FPR, and it should be getting spark because I pulled everything off of my running laser. And I know that it has good compression.

I think it could possibly be leaky ECU caps, but im not sure, im going to go check as soon as im done with this post. Or maybe I forgot to plug something in, what do the pros think?

thank you very much!

-Charlie

 

[femmeDSM]

We'll add one more member to the ECT sensor club. It's hard to believe that this sensor will keep the car from starting but it does.

Yeah, ironically I need to be added to this list as well now. Haha. Except my car actually runs *better* with the sensor completely unplugged WTF ...I don't get it.
http://dsmtuners.com/forums/showthread.php?t=214117

 

[steve]

Sounds like it's time to put that datalogger cable to work.

Steve

 

[femmeDSM]

Sounds like it's time to put that datalogger cable to work.

Steve

Yeah, it's been getting a workout lately. If it weren't for my handy logger, there's no telling when I would have figured out that the ECT had taken a nosedive.

Everything else on the car looks good, though, log-wise. I haven't been able to take it out on a hard run yet to really get a thorough reading (due to a sticky transmission problem ) but the car seems to be responding well to all the "little" adjustments I've been making, and I haven't hit any major problems with knock, timing, or O2 readings.

I picked up my new ECT sensor today, and will install it tonight. Hopefully this will mark the end of my sensor troubles, and I will finally be able to clear that ECT CEL for good

 

[90dsm]

Ok, i didnt want to start a new thread for my one simple question so i figured this would be the best thread to attach it to. I am currently having the same problem with my 90 tsi. I bought a new CAS and installed but still nothing. I was wondering if there is any specific way to install them or can you just bolt them in and plug them in. I no they control the injector pulse so does this mean it has to be at TDC for install?
Thanks in advance for the help

 

[steve]

I bought a new CAS and installed but still nothing. I was wondering if there is any specific way to install them or can you just bolt them in and plug them in.

The CAS can go in one of two ways. The way to make sure it to set the engine to TDC and line up the marks on the CAS. Once it's installed correctly you need to use a timing light for final adjustment.

http://www.dsmtuners.com/forums/showpost.php?p=1199823&postcount=19

Steve

 

[kidwiththelaser]

Ok, i didnt want to start a new thread for my one simple question so i figured this would be the best thread to attach it to. I am currently having the same problem with my 90 tsi. I bought a new CAS and installed but still nothing. I was wondering if there is any specific way to install them or can you just bolt them in and plug them in. I no they control the injector pulse so does this mean it has to be at TDC for install?
Thanks in advance for the help

You can check the CAS by unbolting it, and turning the key to on position.

And then manually spinning it, you should hear the injectors ticking, and should get spark.

I suppose that its a bit late to test the CAS, but if someone searches for CAS TEST hopefully they will see this.

If you dont hear anything, then time to replace it with a known good CAS. And then test that one, if you still get nothing then check to see if its getting voltage. If its not getting voltage and the EFI relay doesnt turn on, then suspect either a bad ECU or the MPI relay fuse on the (+) battery terminal.

 

[90dsm]

thanks for the help guys i will be replacing the CAS properly tonight and let you know how it goes

 

[RichL19]

Oh my god iv been racking my brain for like 2 days trying to figure out why my car won't run and this was the peoblem my coolent temp sensor wire broke just like this guys. I never thought that this would keep the car from starting . Add me to the list CTS For Life

 

[AL92]

Ok guys..have similar problem...Car turns over has gas in tank..car has spark .Car seems to have fuel coming out the return line.
She runs for second and then dies.or tries to run its sort of hard to tell.
Now a few things will change out coolant sensor and will try to check cas.the car was worked on by idiots so mabye the cas is 180 out? Also I hear a clicking evertime turn key by the ecu..the ecu was swapped with a supposed good one.the ecu looks fine,no smell and no evidence of any cap leakage.
I think that relay by the ecu is the fuel injector relay..isn't that under the dash.that would be my first suspect.So it that it near the ecu or what..I keep hearing about mpi relay but no one is clearly saying where it is or what it looks like..car is a 91 laser.
Anyone got a pic of it.don't seem to show it in the haynes book..or maybe just can't seem to find it..
That relay is injectors and fuel pump?
Help please guys..!!!

 

[femmeDSM]

Ok guys..have similar problem...Car turns over has gas in tank..car has spark .Car seems to have fuel coming out the return line.
She runs for second and then dies.or tries to run its sort of hard to tell.
Now a few things will change out coolant sensor and will try to check cas.the car was worked on by idiots so mabye the cas is 180 out? Also I hear a clicking evertime turn key by the ecu..the ecu was swapped with a supposed good one.the ecu looks fine,no smell and no evidence of any cap leakage.
I think that relay by the ecu is the fuel injector relay..isn't that under the dash.that would be my first suspect.So it that it near the ecu or what..I keep hearing about mpi relay but no one is clearly saying where it is or what it looks like..car is a 91 laser.
Anyone got a pic of it.don't seem to show it in the haynes book..or maybe just can't seem to find it..
That relay is injectors and fuel pump?
Help please guys..!!!

The clicking you're hearing is likely the MPI relay. The MPI relay is the big relay right next to the ECU - it's actually 2 relays in one box, and controlls the fuel pump and the MPI circuit (fuel injection). It's easy to spot it - just look around near the ECU for a small square gold box. That's it. If you're having trouble locating it, I can give more specific instructions if you want.

The MPI relay normally clicks ON when you start cranking the car, and OFF a few seconds after you turn the car off. If this is the clicking you're hearing, this is normal. But if it's a rapid clicking, that's a problem.

You said you "seem" to be getting fuel out the return hose - you need to positively determine whether you're getting fuel before we can go any further.

Does the fuel pump turn on? On a 1g, the pump will not turn on until you crank the engine or energize the fuel pump check connector on the firewall, FYI. If the MPI relay is bad, you will not be able to get the pump to come on. But let's start there to get a good basis for the rest of the testing, etc.

 

[VisegripMech]

The 1G DSM has two main circuits for the engine. The MPI circuit and the Ignition circuit.

The ECU is connected to both but powered from the MPI circuit.

Power for the MPI circuit comes from the MPI fusable link on the positive battery terminal to pin 10 on the MPI relay and should be present all the time even with the car off. Power for the Fuel Pump and the rest of the ignition circuit comes from the Ignition fusable link on the positive battery terminal and for the fuel pump winds up on pin 3 on the MPI relay.

The MPI relay has two actual relays inside, one for the MPI power and one for the fuel pump power. The fuel pump relay has two trigger inputs, the MPI relay one. Pin 10 in the input for the MPI power and pin 3 is the input for the FP power. When one of the control lines to either relay is activated the relay switches the power from the input to the outpin pin(s)

The ECU receives backup power on pin 103 from fuse 19 (room) in the drivers footwell fusebox. This is used to maintain the RAM in the ECU's CPU and allow the ECU to power itself up. Like MPI relay pin 10 the backup power on ECU pin 103 should to present all the time even with the car off.

The ECU sits dormant in a powered down state waiting to see pin 110 (IG1 from ignition switch) go high (to battery voltage). When pin 110 goes high the ECU pulls its pin 63 (MPI relay pin 8) low (to ground). This causes the the relay to activate and switches the MPI power from MPI pin 10 to MPI pins 4 and 5 providing power to the ECU on pins 102 and 107 along with various sensors, solenoids, injectors, ISC, and O2 Heater in the engine bay.

Shortly after battery voltage shows up on ECU pins 102 and 107 the reset circuit in the ECU wakes the ECU up and if it boots up you'll get a heartbeat on ECU pin 1, the CEL will come on for about 5 seconds, the boost gauge will display 0 (Stock ECU software on turbo cars) and the ISC on the throttle body will move in and out to rehome.

The next interesting condition is when ECU pin 108 (indirectly START from the ignition switch) goes high (to battery voltage).

The START signal also goes to the Fuel side of the MPI relay to power up the fuel pump, and to the ECU causing the ECU to do the things it needs to do the start the engine. Once the engine is running the ECU pulls it's pin 56 (MPI relay pin 8) to ground and continues to hold it low until you turn the car off or the engine stops running, to keep the fuel pump powered after you release the ignition.

The first thing you should do if your ECU doesn't power up (CEL on for about 5 seconds, the boost gauge displays 0) is check the two fusable links and the room fuse. Measure the fuses for continuity (0 ohms resistance) rather than look at them. Then check for battery voltage at the ECU and MPI relay pins. Remember that the ECU doesn't get power on pins 102 and 107 until the MPI relay is activated by turning the ignition key to RUN or START. If the MPI relay doesn't activate try grounding its pin 8 and check that power shows up on its pins 4 and 5. If that works then either the ECU isn't seeing the IG1 signal or the ECU is damaged.

If power is present on ECU pins 102 and 107, the ECU grounds are good and the ECU doesn't power up it's damaged.

Steve

I have been searching for this exact info for so long, and only found it by sorting all the posts in this forum by "number of replies". I'm gonna print several copies, and tape one to my monitor, one on the inside my hood, and one in the bathroom, next to the buttwipe. Thank-you, thank-you, thank-you.