Help diagnosing a no start. ive done everything

[2GEEZEY]

First off with out dsmers and this website I wouldn't be building my 3rd dsm and this one being a drag build so its a big deal, you guys are awesome and have helped so much so thank you all, now I can help others with the same problem.

So for diagnosing my no start after wire tuck and push button,

RPMS don't move while cranking
CEL only while trying to crank then shuts off
properlyECU is working properly, boots up and cel goes away as it should ( factory beep beep beep still works

MFI/fuelpump relay works, fuel pump is getting power via toggle switch ( stm rewire wally 255)


just when I go to push the button to crank it will crank kind of slow and wont start or act like its starting. No spark at all. my coil pack did get really hot at some point Im going to test them and see

 

[2GEEZEY]

coil packs test out fine, still no spark, rpms don't move while cranking, re did the whole harness and still no start...

 

[c2ypt1c]

Sounds like the cas or crank sensor.

 

[2GEEZEY]

that's what im thinking, I checked the wires to them and they seem fine..how about hardwiring the crank sensor to the ecu?

 

[c2ypt1c]

I can tell you from my own experience, when my crank sensor went out, I was not getting any spark and I would get a cel (p0335) while cranking but it would stay on, which made it pretty easy to diagnose. Since your cel is turning off after cranking, I'm leaning more toward your cas.

I've never had a cas go out on me so I'm not 100% sure this is the expected behaviour, but this post describes something similar:

(car DOES crank), CEL comes on and goes off after 7 seconds

turned out to be his cas and/or cps being plugged into the ac connector:

After getting a new cas and installing it, I rechecked over everything the previous owner did. Turns out he had the cps plugged into like the ac compressor harness (or one of the other triangle plugs down there)... got it to crank and start, idles horrible but that will be fixed soon!

 

[2GEEZEY]

alright so I think I got lucky and found the problem! I was squeezing around the power transistor wiring and when the car is off, key out the of the ignition and all doors close the factory alarm ( beep beep beep) was going off...? so leads me that one of the ignition wires is making contact with that causing my ignition fuse to keep blowing in the first place. last time im every using liquitape and heatshrink over my soldered connections.

So I may have found the problem, the thick Blue/Red wire coming from the coilpack/powertransistor I cant tell is not connected to anything...what pin in the ecu does this connect to?

 

[c2ypt1c]

the factory alarm ( beep beep beep) was going off...?

WTF

So I may have found the problem, the thick Blue/Red wire coming from the coilpack/powertransistor I cant tell is not connected to anything...what pin in the ecu does this connect to?

The power transitor has two signals that go to the ecu - black/blue (pin 10) and brown/red (pin 23).

Are you sure it's not the blue/red cas wire? Can you post a pic?

EDIT: I think I know which wire you're talking about. The blue/red wire from the coilpack?

 

[2GEEZEY]

Yes it is not the cas wire, its a thicker gauged Blue wire with red tracer its connected to the coil pack harness

yes its that wire, but were does it connect to? I dug deep into my harness and don't see any wire like that, no wire to the ecu is that big, the only similar wire is going to the fuse box along with other smaller blue wires with red tracers

and btw, no more CEL while cranking, the CEL comes on and shuts off when ecu boots as it should, go to crank and no spark due to that wire im pretty sure. just need to know where it connects to

 

[gofer]

These are worth their weight in gold, print them off or save them to your laptop because I refer to these often.

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[2GEEZEY]

You are the man. I don't know where you find that stuff but you are considered a dsm god in my book, Im checking these out and hopefully Ironman will be up and running shortly! thank you again gof.

 

[c2ypt1c]

These are worth their weight in gold, print them off or save them to your laptop because I refer to these often.

Ah nice post Gofer!

Yeah from the looks of the diagram, that blue/red wire goes to the engine speed detection connector. Check it out:
52. Engine Speed Detection Connector

I think you found your no-start problem

 

[2GEEZEY]

wow fcuk!!! that's exactly what I cut cause I thought it was part of emissions, I was thinking random blue connector? it was on the emission harness so I cut it. now down to tracing the black and white wire

 

[c2ypt1c]

wow fcuk!!! that's exactly what I cut cause I thought it was part of emissions, I was thinking random blue connector? it was on the emission harness so I cut it. now down to tracing the black and white wire

yeah the black/white wire goes from the engine speed connector to the power transitor:
7. Ignition Power Transistor

There are two black/white wires going into the power transistor connector. The one you want is on the end, in the #8 spot. It's on the left:

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[2GEEZEY]

thank you so much, that helped out so much

I want to smack myself, I was looking at that connector wondering what it was, guess I learned the hardway and should have looked through the electrical connections thread (BEFORE) wiretucking , so tomarrow should be a easy fix, got brand new plugs and wires cause the car needed them not cause I was throwing parts at it but hopefully shes up and running shortly and then its hx40 and e85 time!!!

once again, thank you all this site has helped so much in my career as a tech and not only with these cars but all cars so I cant thank you guys enough

 

[c2ypt1c]

Oh btw, you can just solder the two wires together where you cut the connector off. There's not really a need to go hunting them down...

 

[2GEEZEY]

yeah that's what I was going to do

bad news, soldered the two together and still no start...

 

[gofer]

They arent electrically connected in the connector, thats not your problem. Lol. Thats why i posted that diagram so you could see that wire does nothing. Check voltages at the CAS and CPS.

My fault for not being more to the point.

 

[c2ypt1c]

They arent electrically connected in the connector, thats not your problem. Lol. Thats why i posted that diagram so you could see that wire does nothing. Check voltages at the CAS and CPS.

there is some conflicting information

The wires are joined inside that single connector; it is not two connectors coming together.

The wires that run into this plug must stay connected. You can chop the plug off, but you must make sure the wires are securely connected (preferably soldered) or the car will not start.

Also, if they were not joined together inside the connector, I would expect the diagram to show numbers next to their inputs on the connector.

 

[gofer]

To my knowledge the engine speed detection connector is an additional unused connector that allows you to connect a aux. tach to set idle speed or test for a tach signal. I've been known to be wrong but I can't imagine a test point carrying a signal that's vital to engine operation.

You're correct, they do look electrically connected at the connector but the signal they carry appears to make it from the IPT to the coil pack whether they're contacting each or not.

 

[2GEEZEY]

I am getting fuel, I pulled the plugs and smell like gas and have some residue on them, after cranking so many times with no start I may disconnect the mpi relay and crank to clear that up but the problem is theres no spark ( that red and blue signal wire) I don't believe is hooked up to the right wire. I soldered it to the black/white wire pin 8 on the power transistor and still no spark. CAS and CPS are getting proper voltage I already tested those. Is there a wire in the ecu that I can solder the blue/red wire coming from the coil pack to know that it IS getting proper signal to send the spark?

 

[gofer]

Take a multimeter and ohm out the harness, pin to pin. You just did a wire tuck so depending on how extensive you went it could be anything. If it were my car Id pull the harness to do it and use those pin-outs I attached above.

You said somewhere in there you kept blowing the ign. fuse? How are you cranking the car if the fuse keeps blowing?

 

[2GEEZEY]

the ign. switch kept blowing due to a bad ground( the thick black and white wire with the connector on it) so I basically cut that and grounded it underneath the dash and that fixed the problem with the fuse keep blowing, car cranks and everything with the push start, im getting fuel, rpms don't move while cranking and sometimes it will throw a code for ect malfunction but I checked the wire and its soldered properly, put the sensor in boiling hot water and still no start, the only thing is that I saw is the thick connector on the t stat housing by the head has two black wires going to it, blk/white and black, and they are kind of frayed at the connector could that be the problem? yes next step was to pull the harness and re wire everything...again

how can I test the power transistor to make sure its working properly? I have the red and blue wire soldered to the black/white one and still no spark.

 

[gofer]

Don't pull the harness apart, just pull the harness out of the car and use a multimeter to check the wiring for any breaks. Just twist a thin paper clip around each meter lead, set the DMM to measure Ω (ohms), and look at that pin-out I posted testing each connector from sensor to ECU. If you put the leads on the pins and it reads open you know you found your wire, you even know it's ignition related so you can narrow it down to just a few connectors.

IPT Testing

 

[2GEEZEY]

thanks for all that info I saved the link but to late in a good way, check out my new thread..its practically half a part and a build I planned doing in a year but mind as well finish it, the right way.

a mod can delete this I don't know how to delete it unless someone needs the info in this thread from two awesome DSMers that have helped me with my knowledge so I can help others as well, you guys rock