[JML77280Z]

Hi folks,

Thanks for the generous responses I have been getting on my questions about my new 77Z. I have had some problems with it running reliably. Sometimes it runs well, the next time it smokes, runs like crap, quits, won't restart then fouls out the plugs. Someone suggested replacing the ignition module. I was not aware that a 77 had one. The person recommending it said it was tied into the F.I.

Could someone please explain this a little more to me. I priced one today and it was $164. I don't mind spending the money but I would like to know what I am buying.

Also, my parts replacement plan to rid this gremlin out of my 77 is as follows:
1. replace the water temperature sensor and thermotime sensor
2. replace the ignition module
3. replace the mass air flow sensor
4 replace the ECU

I plan on keeping this car for a long time as a daily driver and I do not want to hesitate about taking it anywhere for fear of it being unreliable. Any other suggestions? Thanks again. I look forward to your responses. John.

 

[yo2001]

try thermotiming sensor too. when its faulty, it'll run the cold start valve at the wrong time and the engine run too rich. to check to see if that's the problem, unplug the cold start valve connector and let the car warm up. Then try to turn the car back on right after shut down. Could be weak ignition wires too

 

[monsterdog]

The replacement list you talked about are critical system items. In my quest to refurbish my Z car I replaced may of the items you listed because I wanted to have a reliable car. However, to save money I found some of the parts in the junk yard. Too my suprise most of the items on your list were still in excellant shape after 22 years. The good thing is that I have back up parts that i put in the trunk for added security.

What you are describing is that your Mass Air Sensor might need replacing.. or the connector is loose or corroded. I forgot to reconnect the connector on the Mass Air Flow Sensor and the car ran like crap and fouled out all the spark plugs before I found the problem. Also the water temp sensor might be going bad. The water temp sensor is connected to the Thermostate Housing. There are three sensors. The most critical one is the water temp sensor. This could make you Z car run really bad.

I hope this helps. Many of the parts Im replacing have been with the car 22 years and they are still good...


Good Luck

 

[Zuber]

Re: Back to basics

You need to look at your troubleshooting methods.

If you have an intermittent fault, more than likely it is not a failed component. In all likelyhood, you have a bad connection.

Instead of buying an ignition module, which rarely ever fails in the 77, spend half/third as much and buy a factory service manual. It's chock full of good information.

If you haven't done it already, take all the connectors off one at a time, and clean them. Clean the sensors too. Then put some dialectric grease on the connectors to keep them from corroding again in the future. Do all the fuel injectors, all the sensors, your AFM connector, your fusible link connections, everything. Also, check the lines that come from the front sensor pod. There are some inline bullet connectors that are hidden from view. When dirty or disconnected, the car will run badly.

If you've done all that, start replacing vacuum lines. Don't judge them for quality, just replace them. Your goal is dependability, so get rid of the 25 year old vacuum lines. This means the big ones that come from the valve cover, fast idle device, and throttle body.

If you've done all this, and the car still runs poorly, then you can take the FSM and troubleshoot it properly. It has a test for every sensor and system. You should be able to find the problem.