1997 disco 1 auto learning curve 2

joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
Well it did happen, bought a second disco , relative rust free it came from Louisiana. After digging on the inside under the carpet a bit still more rust then I expected when I was looking from the bottom.

According PO disco had been sitting for 8 yrs, I believe that because he was now for 8yrs in a wheel chair.

Another reality check that you better enjoy each day you are above ground.

The story was that 8 yrs ago he brought to a shop to get fitted with a winch and trail stuff but the shop did not do anything. Disco came back not running, po thought that because of their conflict that the shop had cut the immobilizer out.
And so it was advertised with electrical problems.

I bought it without hearing it run, in general stupid but a good sales story ,low rust for PA standard , same color as my disco 5 spd.. ( this is an automatic) did the trick..$900.

It turned out the imobilizer was there, some relay were out.
When it arrived it became clear that the ignition switch was not making good contact..
Took the switch off and with some fiddling dash lights came on.. fuel.pu.p kicked in.

And there I eFfed up. At some moment the starter engaged and really bad sounds came from the engine, like a broken piston, loud knock.. did not start and I stopped cranking.

I felt bad, next day I took the plugs out thinking that maybe I had a hydrolock from leaking injectors

Well that was indeed the case.. when I cranked with fuel pump fuse out lot so fuel came out cylinder 1 and 5.. sparkplugs did not look to bad but wet.
Cranked the engine for a while without plugs and it sounded smooth.
Then put the plugs back in and cranked again, still sounded ok.
Checked for spark , spark ok..

And indeed it ran, oil light went out. Cylinder 1 is missing. Tomorrow will do a compression test to see if I broke something. The ignition switch is damaged so it does not keep the power on when you release the starter.

So that will be my next exploration.

Johan
 

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joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
Took the covers of around the steering wheel to get access to the ignition lock. Someone was in there before and had dremeled a slot in one screw and the other was a bolt.
The cylinder mechanism came out and after I removed the lock from the car it showed that the drift pin was buggered up.. got the small Phillips out of the switch itself and did test with that.. run contact did not stay on after releasing the starter engagement.

Decided to take it apart. Worked on the hollow rivets a bit with side cutter , later with the Dremel.

It has to be angled open, there is a protrusion into the side of the housing under the middle power input wire. Open slowly and controlled to not loose the springs.

Very dirty and some wear on the silver plates contacts..

Cleaned the old grease and corrosion of the silver and it seems to work again. At least on my multimeter.

There must be another ball and spring under the contact discs that supports the distinctive switch positions and return after start..

I did not check how that worked.

The real operational test is tomorrow.

Johan
 

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joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
So today compression test. Mainly to see if I blew a hole in a cylinder because of hydrolock, in my case gasoloc.

All cylinder had compression.
Cyl1 is 9.0.. tested with all plugs out 4 compression cycles dry.

9.0 8.5 10.8 7.5 left driver side

8.0 10 10 10 right passenger side

Not great but for a car that did not run for 8 yrs and had gasoline sitting in a couple cylinders it might be not that bad.

After this car fired up but ran real rough and would stall.

While under there I noticed that the knock sensor next to the starter was broken. I guess someone tried to bypass the starter and was a bit rough or frustrated?

It sounds like the car is missing .
Idle drops to 300rpm and sometimes stalls out.
Oil pressure light goes out.
Engine check light stays on.

I pulled the plug from the air bypass valve but it had no effect.
I pulled the injectors from bank 2 .
Except for cyl 4 , engine would stall but the others had no effect.

When letting throttle go from higher rpm I have explosions in the exhaust.

Cat converters are gone and bypassed with straight pipe. Exhaust all looks very good.

So my question,, can a missing knock sensor cause above issues?

Thanks
Johan
 

joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
Thank you, I think I found it, lots to read.

Put some new gas in the disco.. hard to start, stalls out misfire.. only two of the injectors drop rpm when I pull the connector..
When I pull the air control valve it makes zero difference. Air filter clean.

So I get a code reader and see what it says

Found a crack in right side exhaust manifold..

Both knock sensors are broken off. Are these piezo sensors? 2 wire it seems.. does coolant come out if I unscrew them?

Alternator get super hot. Shorted winding or shorted diodes? It is a 100 amp version.

Happy if ran but a bit frustrated , to many sensors.
 
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joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
Had a bit of time and hooked up an elm 327 with the torque app on my phone.

P0158...o2 sensor bank 2 sensor 2 circuit high

P1193. Post catalytic fuel trim bank 2

P1508. Idle speed control valve

P0113 pending..Intake air circuit high

It fired right up. Still runs rough with some shaking.

Will take the iacv out and clean and see if it comes back to life.

Johan
 

joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
Took the iacv out and cleaned it out, then I thought of put it on contact while it is out maybe I can see it move, did not see it so I turned contact off and it came apart.

Put it back together but the valve was sticking so far out that it did not fit so I put it on it's location but did not tighten the screws. Car on contact nothing happened, car off and it pulled the valve spindle in ,then I was able to tighten the screws..
 

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joeblack5

Well-known member
Sep 12, 2023
98
46
State college usa
Today, I putzed around a bit more..the iacv does not seem to react very fast.
If I loosen the screws from the iacv and physical move the iacv 1/8" out of its air intake manifold then air rushes in and the rpms increase. I would expect the iacv trying to correct that and move the plunger out to close of the hole.. nothing seems to happen.

If I turn the car off and engine is dead then a couple of seconds later the plunger comes out. If the iacv is out then the plunger comes loose..

When the iacv would be mounted then the plunger would come to a hard stop against the valve seat in the manifold housing and the stepper motor would just skip and this be mechanical calibrated ..

In me not completely understanding why the iacv did not move all the time I decided to check the ECU for water damage . No damage visible.

Put everything back together and suddenly a nice stable 750 rpm..
But still ot even on all cylinders.

Decided to buy a new iacv.

Allowed engine to cool down and did another compression test.

Sparkplugs 1 was wet and oily .

Compression numbers did not change a whole lot ,cyl 8 was still lowest at 7.5 right next to 10. May be exhaust valve.

Decided to get new spark plugs.
Decided to get moly additive for cleaning valves ???

Then dissected the old iacv for the sake of knowledge.

I pushed the three small pins more inside with a nail and hammer and then tried the assembly out from the back.

In the process I broke the electric wires and also the plastic nose of the stator that has the counter spline that prevent the plunger from rotating.
There is one ball bearing on the backside of the permanent magnet rotor. The rotor has a square thread inside that matches with the thread on the stem of the plunger.
There is a plastic bearing at the front side that could gather crud and wear out.
The plunger does not rotate . It has to splines that slide in the front plastic section of the stator coil assembly.

The tube that holds the spring somewhat protects this from dirt entering the iacv inners..
 

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