My headers interfered with the oil dipstick. Just left it loose.

”327” is the last three digits in the GM part number for the LT1 block. 10125327

 

Thank you for these details.

I have the headers back on, the plugs routed w/heat sleeves, steering linkage hooked back up etc. Not ever having much time in one session while working on this has almost totally kept me from getting frustrated with the plugs/wires/headers, which involve lots of limited hand/arm space. I found that a flying Superman position on top of the engine (perpendicular) made the worst parts of the job 90% easier.

I ran into one problem/question to run by you. The last header bolt on the driver's side, closest to the firewall, will not thread in. I removed a bolt from this spot and did not notice, at that time, that it was any different than the rest. Looking in the hole with a mirror and flashlight, I can see that it looks shallow; the threads also seem faint. Was this hole drilled from the factory? I seem to recall from a big project on my '95 Roadmaster wagon that I read that factory heads had bolt holes on the far ends that were not always drilled. I might be wrong. There was one bolt that had a thicker washer, plus the lock washer, unlike all the others. My guess is that it might have come from this spot, but I did not pay attention at the time.

I know I am going to have an exhaust leak here, but I am definitely not going to remove the head or anything right now. I want to see if the coolant system issue has been resolved before that. Is there anything to be done to address this without removing the head and drilling/installing a helicoil?

 

I finally wrapped up the work on the cooling system and putting the car back together a couple of weeks ago but have just been too busy to post about it. The car idles for extended periods of time now without any coolant bubbling out of the overflow tank or any other apparent issues.

I didn't spend the money for the Airlift vacuum tool, but I did buy a different brand/type (Robinair maybe?) for less money. It's pretty cool. Pull a vacuum, make sure it holds, then let the hose that is in a bucket of coolant (in my case, distilled water with radiator flush mixed in) suck it all into the system. In my case, the vacuum gauge registered that there was no more vacuum left even though the radiator was not full to the top. I thought that it was supposed fill the system with exactly as much as it can hold. Still, after topping it off, all seems well.

I also installed a Tefba coolant filter on the upper radiator hose. I picked this type of filter because you can open it up and clean out the mesh filter and the sludge basket without having to do anything more than unscrew a cap, and no air is introduced into the system. It comes with a fine mesh screen and one that has larger holes. I'm starting with the fine mesh. I only found one place online in the US that sells these, a Jag performance site down in I think Texas.

As of today, after jacking the back of the car up to make it level with the front to do a more effective oil change, the car is struggling to idle and stay running. The exhaust also smells very rich. I'm not sure what's wrong. The fuel level is pretty low, a lot of the vacuum lines on the intake look pretty questionable, the fuel filter is old etc. Time to start digging into it. I have a cable and a program for an older laptop that will let me plug into the diagnostic port and get some data, so I think I will try that, too.

 

I found an older laptop with Windows 8 on it that I will use to run a datalogging program. The car will start now but dies after just a couple/few seconds. I installed WinALDL and Tunerpro. Both seem to open, though Tunepro also gives me an error message saying that no "XDF" file has been selected or something to that effect.

I identified the port that the cable is communicating with as per the instructions. I see that I also need to tell the program which ECM my vehicle has. Where do I find this information?

I opened WinALDL and plugged the cable into my laptop and the OBD1 port but no data was being transmitted.

 

I'm not familiar with either of those programs.

You mention “the OBD-1 port”, but while the 95 has an OBD-1 PCM, the port is a 16-pin OBD-2 style. How are you addressing that - correct 95 cable, or jumper wires to an 12-pin cable?

http://shbox.com/1/xraycable.jpg

 

After a long hiatus caused by the demands of life, I have returned to my project.

I purchased an older Actron scanner that will read codes and at least some data for the '95 cars with the OBD1 computer but OBD2 plug.

The scanner is showing an 015 DTC, which seems to point to the coolant temp sensor, I think the one in the water pump.

 

Yes, the sensor in the water pump feeds the PCM. The gauge is fed by a sensor in the driver side head. DTC 15 usually indicates an open circuit. Use Shoebox's guide:

4th Gen LT1 F-body Tech Articles

 

I had a new water temp sensor on my workbench that I had meant to install when I was doing all this work. Inexplicably, I forgot to do this and left the old sensor in. I replaced it today hoping for a quick fix. It did not solve the problem. The car is very hard to start and dies once it does start.

I printed out the directions from the shbox site to test the wiring and will try to do that next. It seems rather challenging to get alligator clips on the two terminals on this sensor. They are tiny and pretty far into the plastic housing and I have no line of sight to see what I am doing.

I plugged the Actron scan tool into the car again. It still shows the 015 DTC even after I cleared it previously. I noticed that it also displays the water temp as being 57 degrees, which seems exactly accurate given what the thermometer in my shop says the ambient temp was today. If the sensor is sending this temperature to the computer, doesn't that suggest the sensor is working properly?

 

Is it possible there is a minus sign in front of the CLT sensor reading? Usually with an open circuit (= infinite resistance = very low temperature) you get a -40 something reading.

Check for the 5 volt reference by taking the connector off the sensor, and (key in “RUN”) measuring the voltage across the two pins in the connector. On my multi-meter, the alligator clips unscrew leaving thin, pointed probes for easier access.

 

I've got the battery on the charger for the night because it got so low the car wasn't cranking anymore. I will hook the Actron up tomorrow the recheck the temp reading and also measure that voltage on the unplugged connector as you describe.

 

I performed this test last week. If you don't have a set of Pomona leads, you can use a flashlight/good lighting and a mirror to get a reference to put your leads into the connector housing until you make contact with the terminals, slightly angling up or down to maintain stable contact. You'll know you're making contact across the terminals when you see the resistance value displayed on the multimeter stabilize.

The voltage check on the plug is a bit easier because you can angle it to get your leads to contact the terminals while your key switch is on.

Regardless I struggled with both lol, but got the measurements I needed.

-Eric

 

Okay, so I tested the voltage at the connector when it is unplugged from the sensor with the key in the "run" position. 5 volts. I hooked up the scanner while the sensor was unplugged and it showed a coolant temp of -40 degrees. I plugged the sensor back in and checked the coolant temp again using the Actron: 55 degrees. I cleared the 015 DTC from the system and in my limited time out there today, trying to crank the car over, the code did not yet come back. The car cranks for a long time without starting or starting and running for a short time before dying.

I'm not convinced that my gauges work (I know the dash coolant gauge does not) so I actually don't know how much fuel is in the tank. I started thinking about that today.

I used the Actron to record data while I cranked the car. I am attaching pictures of what the data shows. I'm not experienced in interpreting these numbers. so I'd appreciate it if you could let me know if anything seems off here.

 

I found the little Schraeder valve on the fuel rail and depressed the plunger with a screwdriver a handful of times. Each time, fuel came out. It didn't dribble, there was pressure behind it and it shot up, though I don't have a pressure gauge to measure how much we are talking about. It seemed aerated and not just a solid stream of liquid; I also don't know if that's normal. Should I invest in a fuel pressure gauge?

Maybe for hah-has I will add a jerry can of gas to the tank.

Now that the Actron scanner isn't showing any error codes, I'm not really sure what direction to be troubleshooting in. if it were the Opti, I'd be getting codes, wouldn't it?

Edit: I should also maybe mention that I have no idea how old the gas in the tank is.

 

I've currently got varnished fuel in my tank (until a couple more parts come in, then I'm pulling it). When it gets lower on fuel mine sputters. Pour in fresh 93 gas and it runs fine. I'd get ahold of a pressure gauge to check what you have if good fuel doesn't bring it around. Shoebox has the steps to check if you're getting spark.

 

Looking at the photos of the Actron, the temp sensor is OK. You have agreement between the CLT, IAT and A/C Evap, all showing what is likely your ambient air temp where the car is sitting.

I went back and looked at some older data logs that showed the engine cranking. but not yet running. The things that I looked at specifically:

-Barometric pressure looks correct assuming you are located near sea level elevation. But I wasn't sure of the MAP reading - seemed like it might be high. That came back mixed. In one log the BAR was 30.5" Hg and MAP was 29.7 to 27.2, similar to yours. The IAC was 115 and the injector pulse width was 11.8 milliseconds. In another, BAR was 30.6 and MAP was 19.2, IAC was 118 and pulse width was 15.6 while cranking. This gets complicated when trying to compare because one was a cold start and the other was on a warmer engine.

Your IAC is 137, open more, and the 53/58 millisecond pulse width looks excessive. After you check the fuel pressure, try and start it, let it crank for a few seconds, and pull a plug and see if it is soaked with fuel. Also, on anith3r try, before turning the key to "START" put the accel pedal on the floor and hold it there while you try and start the engine. That puts the PM in "clear flood" mode and cuts the pulse widths.

I notice the MAF reading was "0", but that is consistent with the other data logs. PCM doesn't read MAF until the engine starts.

Your TPS volts are a bit on the high side for closed throttle, but won't cause a problem until they get closer to 1.0 volts. But not related to current roblem.

Other data looks OK.