Engine Back in : No start : So Close!

[ae1969]

Re: 86 turbo

Well my winter long project is almost complete!

THe engine is back in and to give you a brief update. EVERYTHING WAS OUT OF THE CAR. Now half of the car is back in.....

Just the engine and dash.

SO after rewiring everything.........double checking all connections, fluids etc. I figure I would prime the oil pump first.....

So pulled the DME relay .... and cranked her over a couple of times...... HOORAY OIL PRESSURE.

So now I hook up the dme, check the plugs.... get ready to fire...

Crank ............ uhmmm something doesnt sound right....

Looked at fuel pressure guage looked good.... open up bleed screw air pocket and gas comes out. OK we have gas...... but Injectors are not firing.... (your ear gets used to listening for them)....

....do some quick checks.

With ignition swith on:

1. Pressure regulator still reads 30 and while I crank it creeps up ..... gas is there... Check... next
2. PUll plugs out..... can't smell gas... No good... injectors not firing... next
3. Voltage at all injectors 12.5 one side 10.5 on the other...... so wiring harness is ok.... next
4. Check Coil. Voltage on both terminals with ignition on. Check...so we have power to the ignition....
5. Ground out a plug and crank..... UHmmm no spark. DME or reference sensors uhmmmmm
6. Check reference sensors..... BTW. They are new. The readings on them are ~930ohms. On both sensors...
7. Checked power on DME ..... 18 power to 5 ground and 35 power to ground 5.......... both show battery voltage.

So I am still leaning toward my reference sensors?...... I set the friggen things on an engine stand with a friggen feeler guage.... but I am going to try and see if I can read the 2V spike of the reference sensor.........

Is their anything else I am missing ????

Thanks

[SoCal Driver]

Change the connectors to the sensors. You may have them plugged in to the wrong sensor.

[ae1969]

hehehe..... no kidding... Socal!

SOmetimes its the obvious........ I will check that after supper!

Socal..... the rpms should jump up while I am cranking right ???? I didnt even look at the dash....... I was so fixated at looking at oil pressure...

If no rpm then the signal is not getting through then maybe the gap is too big?

Has anyone ever tried to determine what the max distance the sensors will pick up at?

[AFJuvat]

They will pick up around 1.2mm but the signal will be weak and the car will run like crap

AFJuvat

[ae1969]

Uhmmm well hopefully I installed it too far...... and not too close.

augggh....

WIll let you know what I find.

[SoCal Driver]

Please keep us posted. I did the cross plugs to the sensors a long while back. Didn't have Pelican to confess too. Had to figure it out myself.

[ae1969]

Well.........

Switched the sensor plugs.... no difference.... pulled the reference sensors and set them again.............. no difference....

OMG does that hurt the hands. Where can you rent someone with small hands.........

SO .... I ran out of time today..... (had to fix a fuel leak as well.... I must of crushed an injector o-ring when tightening the fuel rail down.... it was starting a small leak)

I will ponder this overnight........

[ae1969]

Well........... On my way home I am picking up an oscilloscope just in case..... (i really want to see if the signal is there from the reference sensors)....

Any suggestions what I should test first.... or start from the beginning.

[Brando]

did you put the right relay for the DME in?

[Brando]

did you put the right relay for the DME in? Try jumping the connection on the relay socket if you think the relay might be bad.

[ae1969]

Brando ... I have 3 dme relays that I have been swapping....

Now.... extra things tossing through my head...

Socal and AF... Doing some thinking at work.... (trying not to hurt myself)

The speed sensor must be picking up a signal......since the fuel pump is firing up as I crank the engine.... but If the other reference sensor were not to be picking up a signal... what symptoms would that show?

[SoCal Driver]

As I understand the logic; the speed sensor is what keeps the fuel pump running. But, there is an over ride when you are cranking the car. The signal to the starter is split off to the DME. The DME will close the fuel pump contacts in the DME relay. These contacts can only close if the first set of contacts are closed. We know the first set are closed because you report 12 vdc at the injectors.

The reference sensor is what fires the coil and the injectors. If you have spark you should also be seeing injector pulses. Do you? If you have spark and no injector pulses then I would be suspicious of the DME and/or the wiring from the DME to the injectors.

If you take the injectors out and lay them on some rags and crank the engine you should see them spray. Don't get carried away.

The AFS may keep the injectors from firing if it's not reading right. The temp sensors regulate the injectors but I don't think they stop them completely.

The throttle switch can stop the injectors if set wrong.

Too many beers can give you a head ache.

[AFJuvat]

Not to insult your intelligence but....

Now it is time to go through and check all of the electrical connections to your sensors - Airflow Sensor, all injectors, boost switch, etc.

AFJuvat

[ae1969]

Originally posted by AFJuvat
Not to insult your intelligence but....

Now it is time to go through and check all of the electrical connections to your sensors - Airflow Sensor, all injectors, boost switch, etc.

AFJuvat

Hehehehe...... insult me all you want....... I will take a boat load of insults from you and Socal any day of the week !!!! It couldnt come from a better pair....

You are both totally right..... I think I left something unhooked or swapped around ..... there is so MUCH extra wiring in the car now...... EGT, AVC-R, Wideband, SMT6 wiring, MAF setup........ we are talking A LOT OF rewiring it almost feels like a 928 with all this extra wiring..... but it just feels like I am missing something....


So I am just sitting back thinking if I want to go and aggravate myself in the garage tonight or not............

.... I dug the oscilloscope out and I am playing with it in the kitchen. The kids think its a big fancy etch-a-sketch.........

I will go back and verify some numbers and let you guys know what I find.

See you later......

[AFJuvat]

If you have a MAF installed:

Verify that you tapped it in to the correct wire and that it is indeed getting 12 volts with the key turned on.

ask me how I know this one....

AFJuvat

[ae1969]

Ok...

Went and tested sensors...........

1. Speed sensor............

see image...



GOOD SIGNAL

2. Reference sensor..........

Not near 2V spike needed..... maybe 0.5 v

So.... I need to get the sensor closer.............

Background: Fidanza flywheel...........with which I thought was a properly aligned mark on it.... guess not......... It looked right to the eye....

SO what now?

[88_944]

Crank ............ uhmmm something doesnt sound right....

Is the engine runing bad?

[AFJuvat]

Hey AE,

The measurement you are looking for on the reference pin is:

5mm +\- 0.1mm

AFJuvat

[SoCal Driver]

You really need to identify ALL of your modifications when reporting problems. The aftermarket flywheel has to be set up like the stock flywheel. You have to have the set screw for the reference signal the same height as the stock set screw. Measure off of the starter ring teeth. If not then you don't get any signal OR you take out the set screw (pin) and the sensor when they hit.

Here are the signals from the factory DME Testing Plans:


Reference: Set Screw-Pin


Speed: Starter Ring Teeth

[ae1969]

So ...its 5 mm from the pin to the sensor ..........awesome AF! I will check ..........

Socal......

1. yup the wave I posted... is for the speed sensor..... and I stretched it so it would be more noticeable.... otherwise to spec.... I was getting easily a 3 Volt swing.... So it was reading the ring gear nicely.

2. The reference set-screw.
When I ran the oscilloscope on the reference sensor.......I would get a 0.5 volt spike as it read the set screw........... Now 3 things..... that I havent ruled out.....but hopefully will determine today.

a. set screw not at the right height (AF just gave me the number to check). The Fidanza wheel came with the set screw in place........ oddly enough the fidanza wheels circumference is maybe 2-3 mm less than stock..... but the pin sticks out further......... so it look dead on.

b. the harness has a short or craked wire.

c. the new sensor is bad.


I will get back to you guys after I check the above.

Thanks!