: Cranks, but won't start



Luey357
04-12-06, 05:32 PM
Replaced engine. We're not getting spark. We're not getting any voltage to the coil pack. Tested the wire from PCM to coil pack and it is good. My friend (from GM tech) came over with his $3000 tester and came up with nothing. We swaped the ignition coil module with the old one with same results. All connecters seem to be hooked up. We have no codes either. Does anyone have any ideas on what to check? :confused: We may jump the coil pack with a direct 12V supply just to see if it starts, but my friend didn't suggest it.

zonie77
04-12-06, 10:35 PM
Are you getting any voltage? How are you checking?

CHeck for a ground wire not hooked up. Do you have the FSM?

eldorado1
04-12-06, 11:20 PM
Well, the obvious suggestion is to check the fuses.

Then I'd suggest connecting the module to the battery directly, through a fuse. You want that fuse in case the module has some internal short to ground. (and is the reason it blew out to begin with)

Luey357
04-13-06, 12:36 AM
We are checking voltage with a multimeter. Checked all fuses. I'm not very good with electrical, just mechanical. My brother is pretty good and my buddies are better, and they work for GM tech support and write manuals or something, but they don't have the time to hang out and help with everything. I don't know what a FSM is. I just thought maybe someone on here with experiance with cadi's might have run across the same problem or might have a good idea what to check. Next, I'm going to check some of the "hard to get at" connections/grounds. We have all the manuals, schematics etc., I just don't know how to read them that well. I'm sure we'll figure it out, it'll just take time.

Eldorado1, I will try bypassing it tomorrow after I check a few connections and will let you know.

Thanks

Ranger
04-13-06, 11:48 AM
FSM = Factory Service Manual

Luey357
04-13-06, 12:03 PM
FSM = Factory Service Manual

OK, yea... we have three books from GM and one from Haynes. The GM guy just sent me a sheet of the most probable causes according to the tech support records. I'm getting out there now to check everything.

Luey357
04-14-06, 01:28 AM
Good news, figured it out. On the sheet my buddy sent me, said to disconnect one of the crank position sensors and see if it starts... and it did. Apparently we reversed the upper and lower connectors. IMO, it's pretty stupid to have two connectors right next to each other that can be plugged in to each other. Oh well, It works and the cadi is on the road.

Next project is to repair head gaskets (timesert) the original engine.

eldorado1
04-14-06, 11:25 AM
What happened to "it's not getting any voltage"? :thepan:

Luey357
04-14-06, 10:08 PM
What happened to "it's not getting any voltage"? :thepan:

Apparently, If you have the crank pos. sensors reversed, the PCM cuts off voltage to the ICM.

eldorado1
04-14-06, 11:00 PM
I think the power plug goes straight to the fusebox. Sure you were measuring the right connector? It would be the outer pins of the 3 pin connector on the driver's side(?) see pic.

Luey357
04-15-06, 02:59 AM
I think the power plug goes straight to the fusebox. Sure you were measuring the right connector? It would be the outer pins of the 3 pin connector on the driver's side(?) see pic.

Yes... that's it. I personally didn't test them, but I saw them check all the pins and they had no voltage to them. They checked all fuses and then they checked the white wire from the ICM to the PCM and the wire was good. The next day he sent me an email (see below). We unplugged one of the crank pos. sensors and it started. We then switched the connectors and it started, so there was no need to check voltage at the ICM anymore. I don't need to insert frying pan thing do I? I have great resources, this site is one of them.

This is what was sent to me:

(GM manual writer writes)
I need you to do a search for me.
1997 DTS with a 4.6L

they put a new engine in the vehicle and now they have no spark.
the vehicle ran before they changed engines.
Now they don't have power on ckt 423 ignition control (IC)
ckt 423 is a ignition voltage that comes from the PCM and feeds the
Ignition module.

(GM tech. support writes)
As far as cases go I see some with ignition relay issues, I see a couple
crank shaft sensor concerns, corrosion in wiring for crankshaft sensor to
ICM as well as crossed wiring, and a few theft deterrent related concerns.

I also found the following PI information:

MODELS:
1993-98 ELDORADO, SEVILLE, SLS, STS, CONCOURS, ALLANTE' WITH 4.6L

CONDITION:
ENGINE WILL CRANK BUT NOT START AFTER REPLACEMENT OF ENGINE OR
CRANKSHAFT, OR AFTER UPDATE OF 1993-94 ICM TO P/N 10477276 OR LATER.

CAUSE:
POSSIBLE MIS-MACHINED RELUCTOR RING ON CRANKSHAFT GIVING IMPROPER
SIGNAL TO ICM. P/N 10477276 AND LATER IGNITION CONTROL MODULES
(ICM) ARE PROGRAMMED NOT TO ALLOW AN ENGINE START. THIS PREVENTS
A VEHICLE WITH A FAULTY RELUCTOR RING FROM BEING FROM THE VEHICLE
ASSEMBLY PLANT. SERVICE ENGINES AND CRANKS HAVE NOT BEEN CHECKED
FOR THIS CONDITION PRIOR TO SHIPMENT.
AN ADDITION CAUSE MAY BE THE CRANK SENSOR WIRES BEING REVERSED AT THE
SENSOR OR THE ICM.

DIAGNOSIS:
1) DISCONNECT EITHER OF THE TWO CRANKSHAFT SENSOR CONNECTORS.
2) IF ENGINE STARTS WITH ONE SENSOR DISCONNECTED
VERIFY CRANK AND CAM SENSOR WIRING AS FOLLOWS;

CRANK SENSOR A (TOP)
CIRCUIT 574 - PURPLE WIRE - CRANK SENSOR PIN A TO ICM C1 PIN B
CIRCUIT 573 - YELLOW WIRE - CRANK SENSOR PIN B TO ICM C1 PIN A

CRANK SENSOR B (BOTTOM)
CIRCUIT 1800 - LT BLUE/WHT - CRANK SENSOR PIN A TO ICM C1 PIN E
CIRCUIT 470 - BLACK WIRE - CRANK SENSOR PIN B TO ICM C1 PIN F

CAM SENSOR
CIRCUIT 632 - PINK/BLACK - CAM SENSOR PIN A TO ICM C2 PIN B
CIRCUIT 633 - BROWN/WHITE - CAM SENSOR PIN B TO ICM C2 PIN A

3) IF WIRING IS OK, THE LIKELY CAUSE IS THE CRANKSHAFT RELUCTOR RING.

CORRECTION:
REPAIR WIRING IF INCORRECT, OR REPLACE ENGINE OR CRANKSHAFT,
THE CRANKSHAFT RELUCTOR RING IS NOT SEPERATELY SERVICEABLE.

eldorado1
04-15-06, 02:25 PM
Hmm... must be an OBDII thing. My OBDI manual shows it going straight to an ignition feed.