MH77280Z

I thought this was metal. Seems like this is plastic and getting very brittle where the old iron rusted screws were. I suppose this cannot go in the heating oven after powder coat? Do they sell reproductions of it?

I am able to drop the RPM in P to 1K with closing the idle screw. System looks really good at the moment. Plan to continue driving on HW for the next week or so. I think i need new suspension now (creating new post)!!!

One final thing on this topic: my idle RPM in D mode are around 900 and in P (parking) they are a bit higher about 1200. Is P mode idle OK or high? Manual says to check idle in D mode and it is within range. We did change the thermal coupler on the fan as well. Temp was climbing at idle a bit but now it is stable a little below 1/2.

@siteunseen guys problem solved. I tracked the green wires for the thermotime connector and it was hooked in the temp sensor!!! Car started beautifully. Appreciate all the responses.

Thanks guys.

Hi, So my ignition issue is fixed (new ignition module). I tested the temp sensor today according to manual at cold. At coolant temp of about 58-59F the resistance across the temp sensor terminals was very slightly above 3K Ohms. This is in exact range mentioned in the manual. How can you test the continuity of the wiring harness for the temp sensor? Also, I have cleaned the bullet connectors and can someone confirm the temp sensor connects to the two GREEN wires through these bullet connectors? (I mean the other two wires are black and both connect to the thermotime switch via bullet connectors). Trying to make sure I have not done it reverse?!!!

Just for the broader community: I followed this video and was able to remove the sheer screws, the one closer to the dash for me was a bit too close and i did damage the dash a bit but my dash is already has lot of cracks. After removing the entire key and ignition assembly i realized you can probably leave the front key unit on and can remove the ignition assembly only from the back where the wiring harness hooks into - it is the round thing that screws at the back of the key assembly with 2 small screws. Also, there were two wires on the original key assembly which were not there on the new one (part of the buzzer circuit if door is left open and key is still in ignition). You might want to keep the original key slot and just replace the ignition module from the back. It is much easy without having to go through the hassle of taking these sheer screws out. Thanks.

Starting is MUCH better. The ignition relay on the passenger side do make a decent amount of clicking noise though. Is it normal or sign of going bad?

@SteveJ what i had noticed was when u start the ignition, sometimes starter solenoid engages and sometimes not. Also the current draw I can feel was low. Today I had received a new ignition switch module and have tested it. It is night and day difference in terms of how the engine cranks. Changing the ignition switch and continue to operate for few more days and see if relays have any issues. Also, I am planning to get rid of those sheer screws on the new ignition switch module, not sure if there is a specific purpose for those? I am using a dremel to cut a slot on those to hopefully take them out safely and put standard screws in the new.

The RPM needle match the rpm. When I said rpm was abrupt I meant the engine runs with a lot of hesitation during the first minute and if u don’t pump the paddle engine dies/stalls. after about 1 min while engine was still doing this it suddenly clears up and starting idling very smooth. someone suggested build up of fuel pressure and checking FPR etc. I suspect that? What u guys think?

Don’t smell any fuel.

There is one more observation today ... I cranked the car cold and rpms were abrupt and i had to keep the paddle pumping to keep it alive and sometimes it went to high RPM (as expected) but within 1 min of running and sputtering like this it suddenly smoothed out. I am very sure the engine was NOT at operating temperature. So something got corrected during that 1 min... Dont hate me for it guys ... what do you think?

@Dave WM I looked at the diagram and the pins labeled on the water temp sensor are 13 and 49 I believe. What is a 35 pin connector?

Ok let me measure that and also clean the bullet connectors and brass contacts on all these sensors like others also mentioned.

When u say 35 pin connector - where is that? Appreciate everyone’s patience 🙂

Where are those brass connectors? do I have to drain the coolant and open the thermostat housing to clean it? what will that effect?

We installed a new Standard Motors cold start valve. I can clean the bullet connectors but what does that mean? do u suspect the injector is not working due to corroded connections etc.?

I tested a second used AAR i bought of ebay which is also about 1/4-1/3 open etc. The car had same issue. Once it warms up the engine is more smooth on idle as well. Once it warmed up in 10 mins i took the AAR out and inspected and it was fully closed. After 15-30 mins at room temp it does opened up 1/4-1/3. Initially i thought the car was too rich due to AAR closed and hence the bypass. Now with the AAR as well it has same issues.

@Zed Head and all I am back to start. Today I had my AUX Air Reg still bypassed (waiting for the rebuild to arrive) and cranked the engine and had the same uneven sputtering issues. Once it warms up it runs and idles fine. But cold start is EXTREMELY terrible. I dont think i should change any settings of the air bypass screw on the AFM as the engine idles fine when it is warm. I have not pulled the throttle body for cleaning like @siteunseen has suggested. I plan to do that. What should be the logical next step?

One more dumb question: the idle screw on the throttle body, what is the default position of that screw? or how to set it to factory default?

The spare cold start valve I have is about 1/3 open at cold. Will that work or does it have to be fully opened? Planning to test that While I am waiting for the rebuild to arrive.

What is the cold start idle RPM range? I think normal engine temp idle rpm range is 700to900?

Hi Friends, Sometimes when i turn the ignition On-Start etc. the starter do not engage. It is like there is no current flowing to it. I then back off the key and turn it ON again and after 2 try or sometimes 3rd try the starter gets engaged. Mine is a A/T so there is a seat belt relay which is also involved and I have the seat belt hooked. Have anyone seen this? where can the issue be? I feel one of the relays is not getting energized? what you guys think? Starter is rebuilt and I am hoping it is not a starter/solenoid issue.

So today I took the AUX AIR Regulator off and inspected at cold, it was closed. I then bypassed the regulator and connected the hose directly into throttle chamber and the car fired up much better and no sputtering. Idle was fast though. I shut it down. Plan to get this rebuild from fuel injection corp and test it again and adjust the idle speed. Will report back in about 1 week. Really appreciate you guys hangin in there with me. There is one more question: I plan to change some of the vacuum lines coming from the vacuum reservoir. 1. There is one thin vac line going into the firewall next to the battery, where does that go? 2. Also, in front of the fusible links towards the car front there are two round switches, vacuum lines also go into those. What are those?

Guys, when i bought the car i took a risk. I knew it was overheated and also later found the head cracked. So far we have replaced the head and car seems to run decent. Took these compression readings last week and wanted to share. Cylinder 1: 130 Cylinder 2: 130 Cylinder 3: 135 Cylinder 4: 140 Cylinder 5: 130 Cylinder 6: 130 I have yet to see if it burns any oil. Not driven too much. But i expect older engine to burn a bit which is fine. I change every year and dont drive too much. What do you guys think about these numbers? Personally i expected a bit worse but I think 130+ should be acceptable? Any advises for on-going maintenance are appreciated as well?