Cascade Crew

DBL_TKE · Posted: Thu Sep 01, 2011 10:20 pm Post subject: Codes 32, 42, & 43

So I'm working on a car with a speed density LB9 and and having an issue with a code 32 (EGR), 42 (ICM), and 43 (ESC). It's also having drivability issues. It will run fine when everything is cold, however in hot weather or when the car gets hot it will lose nearly all power for a second or two, then pick back up again. It's not a misfire but it completely loses power. If I push in the clutch while this happens the car will die. It will start back up the first 2 or 3 times but eventually it won't start and will just crank. I have to let it sit for 20 minutes or so until everything is cool for it to start again.

Obviously this is not EGR related, so it has to do with code 42 and 43. It has a new knock sensor, yet the code still stays. I checked all the wiring and connectors for the ignition and everything looks ok, even has a brand new Ignition control module. I just put a new distributor in yet the problem persists. What else could cause this? Bad ECU/memcal? Bad coil?

Dv8 · Member Joined: 05 Mar 2010 Posts: 108 Location: Ruston WA

Check your TPS(throttle position sensor) on your throttle body. Do you have a scanner?? Or just counting the flashes?? Also could be a lack of fuel problem. check your regulator vacuum line for gas, and check your pressure if you can. If your running low on pressure you can run lean and throw codes. If there is gas in the vacuum line, your regulator is bad

My .02

DBL_TKE · Posted: Fri Sep 02, 2011 7:11 pm Post subject:

I replaced the ECU with a new AC delco unit, no change there. Checked TPS operation via DVOM, readings were steady and within spec for both idle and full throttle. Checked Fuel pump relay by swapping with the fan relay, no change there. I pulled a spark plug wire when I cant get it to start and it was getting spark. I also checked fuel pressure at the fuel rail and its getting a full 50psi during the crank/no start, straight to 50psi with key on and while cranking. I'm baffled, it's getting fuel and spark yet wont start.

kurfbird · Posted: Fri Sep 02, 2011 7:40 pm Post subject:

DBL_TKE · Posted: Fri Sep 02, 2011 8:24 pm Post subject:

I pulled the codes again after I put in the new ECU and the only code present is the 43 (Electronic Spark Control circuit), in other words, the knock sensor. I followed the diagnostics flow chart from ALLDATA and i get 4.88V at the ECU side of the circuit and 4.88V at the connector, so theres no wiring issue there. I then checked the ohm reading for the knock sensor by connecting the ohmmeter between the sensor terminal and the engine block and got .0003 ohms, which is definitely a far cry from the proper operating range of between 3300 and 4500 ohms. This leads me to believe that the knock sensor is bad. Can a faulty knock sensor cause a no start issue? I was under the impression that it only caused drivability problems.

DBL_TKE · Posted: Sat Sep 03, 2011 7:21 pm Post subject:

So I replaced the knock sensor, tightened it to approx 14 ft/lbs, cleared the codes. Started it up and still died after about a minute on a cold start and still showed a code 43. I decided to just replace the ignition coil anyway (aftermarket). It started up and idled for about 10 minutes, SES light came on for a few minutes then went away. Test drove around for about 10 miles or so with multiple ignition cycling and hasn't dies yet. I'll pull the codes tomorrow to see what it's still throwing but at least it's driving. (fingers crossed) I'm still stumped as to why I still have a code 43. I've tested everything that I know of on that circuit. Can something else be causing a false code 43?

kurfbird · Posted: Sat Sep 03, 2011 7:42 pm Post subject: parts

Doe sit have a ESC module. had one on a manual TBI I parted. Not sure it applies though

DBL_TKE · Posted: Sat Sep 03, 2011 7:45 pm Post subject:

No, on speed density cars the ESC is taken care of by the ECU, which led me to think the ECU was faulty, which apparently it wasn't since I had replaced it. However, there's the possibly that the EPROM could be bad...

Twilightoptics · Posted: Sun Sep 04, 2011 8:13 am Post subject:

Doubt the e-prom.

If it doesn't have a knock module..... could have swore it still did.....

I'd find a schematic and check the pin on the ecm to the knock sensor if it's just the one wire.

Also make sure you get the right knock sensor.

DBL_TKE · Posted: Sun Sep 04, 2011 10:02 am Post subject:

I've double checked and triple checked about the ESC module and the 90-92 speed density PROMs have the ESC circuitry onboard, and that cannot be changed.

And I already checked the the continuity from the ECU pin to the connector, both read about 4.88V (on a 5V signal) so all is well there. I will try to double check the part number for the knock sensor. If all is in order than I'll talk to one of my Service Advisor, I found a TSB for 91-92 LB9 cars about intermittently dying and loss of power due to the 305 knock sensor being too sensitive. The fix is an updated knock sensor and an updated CALPACK.

DBL_TKE · Posted: Thu Sep 08, 2011 7:36 am Post subject:

So I checked the timing, it was dead on at the factory spec of 6* BTDC with the EST wire disconnected. I got some insight from another tech at my dealership and he brought up the fact that had gotten an EGR code too. I haven't looked into that yet simply because it isn't causing any drivabily problems which leads me to believe that the EGR is stuck open. However that also means that this is essentially a vacuum leak, causing the engine to run leaner than what the computer thinks it's at, possibly inducing a little detonation resulting in the knock sensor code (43). So I'm going to cap off the vacuum line at the EGR to see if maybe that's causing an issue.

Twilightoptics · Posted: Thu Sep 08, 2011 9:15 am Post subject:

DBL_TKE · Posted: Sat Oct 01, 2011 6:24 pm Post subject:

While I had the car on the lift today I tested the knock sensor again. This one was at 100.2 ohms. Looks like it was a faulty part out of the box. I'll replace this one and test again.

DBL_TKE · Posted: Sun Jan 22, 2012 3:12 am Post subject:

Recently my car had started running worse and worse. To the point were it always felt like it had a lack of power and at times would hardly accelerate, similar to when you've run out of gas. Well I already knew that my knock sensor was bad so I just double checked and threw in an AC Delco replacement and cleared the codes (32, 43). After installation, my car ran like a champ. Full power and not a hiccup. However, twice now in the past three days, I've had a little episode where it almost felt like the car was going to die under acceleration throughout first, second, and third gear. The feeling was again similar to running out of gas. The biggest issue is that this is intermittent, so it makes it hard to do any tests because this only happens under acceleration. Now I've checked and adjusted fuel pressure at idle with the vaccuum line disconnected and took the fuel pressure down from 55psi to 45psi (stock: 43.5psi). I've tested the connector at the knock sensor and it's getting 5 volts which is perfectly in spec.

Another thing I should throw in here is that I've been having a undercharging issue (10-11volts) ever since I got the car. It's never caused any issues (dead batteries, etc) so I've been brushing it off. But I wonder if it can screw with the fuel pump if it's not getting the full 12 volts? I really need to find a way to be able to see what happens with my fuel pressure when this happens. I'm also beginning to wonder if maybe I have a loose connector for the knock sensor or a broken wire.

aaron_sK · Posted: Sun Jan 22, 2012 8:24 am Post subject:

DBL_TKE · Posted: Sun Jan 22, 2012 11:41 am Post subject:

iansane · Posted: Sun Jan 22, 2012 1:45 pm Post subject:

Where did you check to see that you were only putting out 10-11 volts? Battery? Alt charge stud? Have you checked the reference wire to make sure the alt is "seeing" the right voltage?

Twilightoptics · Posted: Sun Jan 22, 2012 6:02 pm Post subject:

chevymad · Posted: Sun Jan 22, 2012 7:00 pm Post subject:

While I check things just like Paul just mentioned, you can also check it out with a lab scope if you have access at work. Scoping the fuel pump circuit can show all kinds of things if you know how the read the wave form. From burnt out field circuits to worn pump bushings.

Here's a basic video, the guy show's what a pump with a bad field circuit(brush contact or winding) looks like. Better yet he also shows what a good pump looks like. If you don't have that nice sawtooth pattern the pumps messed up.

http://www.youtube.com/watch?v=pEdMhfbw69M

DBL_TKE · Posted: Sun Jan 22, 2012 9:52 pm Post subject:

I was going by the factory voltmeter in my gauge cluster and my radar detector also has a voltage readout. The lights get brighter and windows roll up/down faster when I raise the RPM as well.

Unfortunately, my dealership does not have a scope or even a Tech 1 for that matter. I think it's kind of rediculous personally but it is what's it is.