Missing Calpak

[mdsbch]

On my 85 coupe, I am getting a code 52 (CALPAK missing) as well as other intermittent codes 53 (System over voltage) and 54 (Fuel pump voltage low). The last two are intermittent and don't always come up, but every time I do a scqn with my AutoXray, the code 52 shows up. I know it is there, because I replaced the ECM and had to swap the PROM and CALPAK over to the new ECM. The previous ECM was throwing the same codes. If anyone knows of a way to test the CALPAK or even where I can get another one (prefferably new, but a used one that is known to be good would work) would be greatly appreciated. I already talked to RockAuto since they had one listed for an 85 with manual trans, but I have an automatic and they say the one they have will not work and the one for the automatic has been discontinued. :ugh

Mike

 

[MPoore]

Is RockAuto a dealer? I would think you could still get a calpak from the dealer. If not, check NAPA. Check the salvage yards specializing in Corvettes. Maybe Hypertech? TPIS does a lot of ecm stuff too.

If you are having voltage variances, that could cause phantom trouble codes and memory problems. Make sure your alternator is working properly.

I burn chips, but I don't have the binary for your calpak. My 1985 is a manual transmission. I checked the EFI websites and no one has it posted. Most people who tinker with the ecm focus on the prom. The calpak is only used for "limp home" mode.

You could take the calpak to someone who has a chip burner and they could attempt to read the chip and burn a new one for you. Check around with the computer geeks in your area to find someone with the equipment. Most people are using flash memory now, so the equipment is not as ubiquitous as it once was.

Mike

 

[77-85]

Wow, your 85 is behaving exactly like mine is. Although I have not had a chance to debug the problem (I just drive the car and it runs fine), I will be looking into the issue this weekend.

Here is what I see:

1 - Start the car, car runs fine, Check Engine light is off
2 - Drive around for 30 minutes or so, Check Engine light comes on
3 - Shut off car, and next time I start it up, Check Engine light is off

If I scan for codes after the engine has been shut off, there are none stored.

So I drove the car with my scanner hooked up, and the next time the Check Engine light came on, I scanned the codes, and I got:

Code 54
Code 53
Code 52

The really strange thing is that I did not have any problems at all with the car until I rebuilt the engine. I pulled the engine, rebuilt it, and put it back in. As soon as I started driving the car with the new engine, I started seeing this problem.

My guess is that I messed up the wiring harness or pinched a wire during the engine installation, and somehow it is throwing these codes as a result. Aside from the codes, the car runs fine.

It has been like this for 3 months now, and this weekend I will finally have the time to dig into the wiring and see what I can find. If I figure out what is wrong I will let you know.

 

[mdsbch]

77-85 are you using an AutoXray 5000 to scan the codes. That is what I used and I'm beginning to think that it may be giving eroniuos error codes. On another corvette web site someone else was getting the same, but no codes when reading them the manual way (paperclip and check engine light). I wonder if anyone knows for sure if the AutoXray has a bug in it?

Mike

 

[MPoore]

The really strange thing is that I did not have any problems at all with the car until I rebuilt the engine. I pulled the engine, rebuilt it, and put it back in. As soon as I started driving the car with the new engine, I started seeing this problem.

My guess is that I messed up the wiring harness or pinched a wire during the engine installation, and somehow it is throwing these codes as a result. Aside from the codes, the car runs fine.

Your post reminded me of another thing to check. Check the ground wires. A bad ground could cause erratic codes. If you rebuilt the engine, everything was probably painted and it could have caused one of your grounds to have a bad connection.

Mike

 

[mdsbch]

Thanks for the information, but the engine has not been rebuilt and I've already checked the two grounds at the ECM as well as all the voltages at the ECM connectors with the key on and the engine off. Everything looks Ok, but I,m not sure how to check them with the engine running as per the Helms Manual.


Mike

 

[77-85]

As I said before I too was getting the same codes:

Code 54 - Fuel Pump Circuit (Low Voltage)
Code 53 - System Over Voltage
Code 52 - CALPAK Missing

I was scanning these with my AutoXray scanner as I drove, since every time I shut off the engine, no codes would be stored.

Today, I had some time, and I looked into the issue a little deeper.

Code 54 will set if the ECM does not see a signal on circuit 120 for 1.5 seconds after the car is running. I checked the wiring and it was good, so I then replaced the Oil Pressure switch which operates the fuel pump when the engine is running.

Took the car out for a test drive, and within 30 minutes the Check Engine light goes on again. Had the scanner ready, and checked the codes.

Now I only get 2 codes:

Code 52 - CALPAK Missing
Code 41 - Cylinder Select Error

Since the codes are not hard (not stored), the manual says to carefully check circuit 450. So now I take MPoore's advise and carefully check my grounds. Circuit 450 uses ground G103 according to the manual. I checked G103, and it looked OK, but just in case I clean it up and make sure it is tight.

I then take the car out for a test drive, drive around for about an hour, and the check engine light is still off. I'm feeling pretty good about myself and head home, 5 minutes before I get home, the Check Engine light comes on. I check the codes, and I get:

Code 52 - CALPAK Missing
Code 41 - Cylinder Select Error

I guess I will need to check the grounds again tomorrow.

So as far as your problem goes, check circuit 120 (oil pressure switch for fuel pump) as it seems to have cleared up my code 54 and code 53.

You may also want to check your grounds as MPoore suggested as it seems to be related to the Code 52 I am still getting.

 

[mdsbch]

Thanks for the info 77-85. Is the Oil pressure switch the same as the Oil pressure sensor or is it something else, because my Oil pressure sensor did go bad on me about a month or so ago and I replaced it. I will check the ground and see if that helps any.


Mike

 

[77-85]

The Oil Pressure switch is the smaller of the two, and it has 2 wires going to it. This switch supplies voltage to the fuel pump when the engine is running. If you lose Oil pressure, the switch opens, which shuts off the fuel pump and saves your engine from damage. (prevents your significant other from driving with no oil pressure).

The Oil Pressure sender (gives you reading on gauge) is the larger unit, and only has 1 wire going to it.

You may want to simply check that the connector to your Oil Pressure switch is tight, I replaced mine because it was cheap (only $ 13), but it probably was just a loose connector (the connector has a rather bulky design meant to lock it in place). When I rebuilt the engine, I remember that I hooked up the connector with the distributor in place, and it was hard to do. This time I removed the distributor.

 

[money pit]

same problem

i know this is old thread iwould like to know if the problem ever got fixed
i have the exact same problem