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Summer will be upon us soon! Make sure you check the Meets subforum to see if there's a get-together near you!

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 on: March 16, 2018, 09:03:29 PM 
Started by boomingbeetle - Last post by jdp
I just changed the thermostat and coolant temp sensor for the fan today in my 94 turbo.  In doing so, I too realize that the stud the ground wires are bolted to are twice removed from the block via the cruise cable bracket and thermostat housing.  I would not have thought it necessary to pull the bolt on the thermostat housing to look for corrosion, I would have just cleaned the stud the ground wires were bolted.  my 92 is having the same stumbling issues that Boomingbeetle was having....I might have to checkout that thermostat housing bolt too on that car.   Thanks Boomingbeetle for keeping us updated on the final outcome.

 on: March 16, 2018, 08:24:39 PM 
Started by Rocketman - Last post by azgtx
And collector's items these will be for sure.

 on: March 16, 2018, 06:18:13 PM 
Started by boomingbeetle - Last post by SHOwn
See, that kind of analysis is priceless to those of us who just stumble along. It would take me days to begin hunting down that path. Thanks for documenting that in this thread. It helps to know where to start when you have a symptom. All I knew about grounding was what I read in an article in the RockAuto newsletter Tom Taylor wrote a few months ago.

 on: March 16, 2018, 04:43:53 PM 
Started by boomingbeetle - Last post by chrispoe
Seems logical to me

You said the engine ran fine when first started (below operating temp) or when you unplugged the TPS sensor and created an operating fault which forced the ECU to run back in open loop mode. In this mode the ECU pretty much determines the amount of fuel to provide by the barometric pressure sensor, coolant temp sensor, Vaf(flapper door and air temp), and the RPM.

When the engine gets to operating temp and there're no major faults, it goes into closed loop mode. In this mode and the engine running at a steady RPM, the ECU will use the feedback of the O2 sensor to help adjust the fuel.

Those ground wires that connect at the thermostat housing run directly back to the ECU to provide the ECU with an engine ground reference point.  This is important for the proper operation of the ECU to determine the true state of the O2 sensor. The O2 sensor only has a range of 0-1 volt, if it's below .5V the ECU read it as lean, above and it's rich.

With the engine reference ground disconnected, the ECU ground started to float a little and created a bias that made the ECU interpret the O2 sensor's signal as being higher than it really was.

 on: March 16, 2018, 10:16:54 AM 
Started by boomingbeetle - Last post by boomingbeetle
IIRC, the darn thing gets sealed in place so you donít have a leak through the bolt hole like you experienced.

It was actually leaking at the t-stat gasket seal at the block, not the bolt hole. Even with half a turn on the upper bolt, the thermostat housing started to separate from the block. And Iím sure part of the problem with the ground is corrosion of the bolt threads because that sucker is TIGHT

 on: March 16, 2018, 05:20:36 AM 
Started by boomingbeetle - Last post by SHOwn
Man, I hope it stays good. If so, your persistence paid off. If it comes back you might look for other grounding locations to try or maybe replace the thermostat and gasket- maybe the housing as well. Iím just wondering that if it is that touchy, why should they have ever used that bolt in the first place. IIRC, the darn thing gets sealed in place so you donít have a leak through the bolt hole like you experienced. How is that actually supposed to ground well, through the coolant?
Anyway, that will be great if it keeps purring.

 on: March 15, 2018, 11:12:55 PM 
Started by boomingbeetle - Last post by boomingbeetle
Like, delivery next week??? Iíve tried emailing rocketman at his site address a couple of times this last month and PM, but he must be tied up with other commitments. Iíll be going on a road trip 3/22 if anyone wants to sell me theirs, or even rent it for the week so I can feel the difference?

 on: March 15, 2018, 11:01:12 PM 
Started by boomingbeetle - Last post by boomingbeetle
Well... if itís stupid, and it works, it ainít stupid! 

So I decided to try taking the whole grounding bracket off of the thermostat housing (the thing that the grounds bolt to and the O2 sensor harness clips onto).  I only got the bolt about half a turn out and coolant started to seep out of the top of the housing, so I wiggled the bracket and retightened the housing. Then I connected the grounds to the negative battery terminal with an alligator clip. NO STUMBLE / MISFIRE / HESITATING / POWER LOSS for two days of driving. I donít understand it, but Iím happy about it. I took the alligator clip off and it still works, so maybe I scraped through some oxidation or helped the connection by messing with the t-stat bolts. I might try just un-grounding those wires to see if it starts acting up again, but honestly Iím too afraid I wonít be able to reverse it!  I promise Iíll post some more pics including TPS diagnosis this weekend.

 on: March 15, 2018, 12:35:12 PM 
Started by BiPoBro - Last post by SHOwn
Great tip Ronald! Good to know.

 on: March 15, 2018, 12:10:57 PM 
Started by BiPoBro - Last post by Ronaldhoff
I recently had to replace the left outside door handle on my 1992 Capri.  I found that they interchange with the 90-94 Mazda 323 and 90-95 Mazda Protťgť.  Dorman 93853 which is the right side is available from Auto Zone and Advance Auto.  The left side is Dorman 93854 which seems to be hard to find.  If you need a left, just switch the plastic holder for the actuator rod as right and left door handles are the same.  The Dorman handle seems to be made better than the original in that it has two springs instead of one. 

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