Low Vacuum
Baja
Joined: Mar 2010
Posts: 5,584
Likes: 7
From: Pittsburgh PA suburbs.
Are you talking about the Y pipe to exhaust Manifold? There should be a nice metal gasket there or you will have an exhaust leak.
I have seen a couple of different configurations for the exhaust manifold to the block, either a group of connected gaskets or individual ones.
I was wondering how your efforts were progressing.
I have seen a couple of different configurations for the exhaust manifold to the block, either a group of connected gaskets or individual ones.
I was wondering how your efforts were progressing.
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Three Wheeling
Joined: Mar 2012
Posts: 59
Likes: 0
Hello all,
Just read post on D1 plugs fouling all plugs. His adventure sounds identical to mine with as much frustration and a slightly different logic tree. Same symptoms, wait...not the same but identical. Low vacuum, no leaks, . After months of work came down to ECM. That's where I am today, maybe it'll work. Danny, You posted many times with him as with me, shoulda remembered that adventure and pointed it out sooner, I'm still trying, i know it's physics and not emotion, That's why I have persevered. I think I'll go back to the 70 chevy pickup.
Just read post on D1 plugs fouling all plugs. His adventure sounds identical to mine with as much frustration and a slightly different logic tree. Same symptoms, wait...not the same but identical. Low vacuum, no leaks, . After months of work came down to ECM. That's where I am today, maybe it'll work. Danny, You posted many times with him as with me, shoulda remembered that adventure and pointed it out sooner, I'm still trying, i know it's physics and not emotion, That's why I have persevered. I think I'll go back to the 70 chevy pickup.
Baja
Joined: Mar 2010
Posts: 5,584
Likes: 7
From: Pittsburgh PA suburbs.
Didn't he post something on here regarding the ECM. I remember he was going thru a set of plugs and a tank of gas almost every time he cranked his engine up.
I don't remember his having the high pressures you were focused on.
When you remove your old ECM, hang onto it. Do not toss it. O[pen it up nd see how bad it is. I have avoided dealing with mine so far, but I want to pick up a spare an open it up.
Long term mods I want to do would include moving the ECM from the engine bay to insude the cab. Maybe even put it where the glove box is now. I just have not addressed rerouting that much wiring yet.
I don't remember his having the high pressures you were focused on.
When you remove your old ECM, hang onto it. Do not toss it. O[pen it up nd see how bad it is. I have avoided dealing with mine so far, but I want to pick up a spare an open it up.
Long term mods I want to do would include moving the ECM from the engine bay to insude the cab. Maybe even put it where the glove box is now. I just have not addressed rerouting that much wiring yet.
Thread Starter
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Three Wheeling
Joined: Mar 2012
Posts: 59
Likes: 0
No joy. ECM and Security ECU replaced. Engine fires right up, runs Smooth, I mean smooth idle, 15" vacuum. 3k rpm cuts out. Stalls when returns to idle. Thought maybe out of fuel? Waited 2 minutes identical conditions. Fires right up no missing at idle. cuts out at 3k rpm.
Any new ideas?
Any new ideas?
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
here's a blurb from the RAVE about the TPS, which can limit higher RPM, poor idle, etc. If yours is bad, or "noisy" (like volume control on old radio), might be part of the problem.
light (MIL) on North American specification vehicles.
The throttle position sensor is mounted on the plenum
chamber and connected directly to the throttle shaft.
The sensor is a variable resistor, the signal from
which (0 - 5V) informs the ECM of the actual position
of the throttle disc. As there is no default strategy,
failure of the sensor will result in poor idle and lack of
throttle response. If failure occurs in the closed
position the engine will only reach 1750 rev/min when
the ECM will initiate overrun fuel cut off. The fault is
indicated by illumination of the malfunction indicator
chamber and connected directly to the throttle shaft.
The sensor is a variable resistor, the signal from
which (0 - 5V) informs the ECM of the actual position
of the throttle disc. As there is no default strategy,
failure of the sensor will result in poor idle and lack of
throttle response. If failure occurs in the closed
position the engine will only reach 1750 rev/min when
the ECM will initiate overrun fuel cut off. The fault is
indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.
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Three Wheeling
Joined: Mar 2012
Posts: 59
Likes: 0
Thanks for continued thought application Savannah,
So if it's tps that could explain dead after 3k rpm and possibly manifest at lower speeds by being wonky. How can it be diagnosed? And I should have a MIL light.
So if it's tps that could explain dead after 3k rpm and possibly manifest at lower speeds by being wonky. How can it be diagnosed? And I should have a MIL light.
Pro Wrench
Joined: Sep 2011
Posts: 1,526
Likes: 18
From: Oregon
Make sure O2 sensors are working using OBDII scanner with live readout.
Remove inspection plate on front of bell housing to gain access to flywheel. Check for bent reluctor tabs. Tabs should be spaced 4.5 - 5 mm.
Check CKP for correct placement, not hitting tabs, and no metal debris on tip.
Remove inspection plate on front of bell housing to gain access to flywheel. Check for bent reluctor tabs. Tabs should be spaced 4.5 - 5 mm.
Check CKP for correct placement, not hitting tabs, and no metal debris on tip.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
Should have a MIL but who knows if that function is working as planned. Another possibility is that "new" ECU is "learning" the existing sensors. The TPS is just a variable resistor, linked to the "butterfly" valve. If it gives the wrong info the the ECU, the ECU has a hard time making adjustments. On models with an OBDII port the throttle % is provided for a scanner. It does not go all the way to zero, the minimum is usually in the 9% range or so. The ECU is supposed to have a fallback plan if the TPS is out, so if you unplugged it, may see things get worse (because sensor was actually good); or stay about the same (sensor was bad). Can also read with a volt meter or ohm meter, you are looking for smooth and steady changes. Here's a page with voltage readings for various TPS found on D1 and early Rover fuel injection systems. Your probably looks like #2 or # 3.
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Three Wheeling
Joined: Mar 2012
Posts: 59
Likes: 0
Ok, disconnected the TPS, immediate start, 18" Vaccuum, Fuel pressure 36, Runs smooth about 1500rpm guessing. Depressed throttle, engine skips and sputters. Reconnect TPS, after 10 seconds engine returns to idle 10" vacuum, disconnect TPS idles fast 18" vacuum, disconect, normal idle 10" vacuum.
How do you access the pins to check the voltages with the plug engaged? Mine looks like the GEMS unit pictured.
How do you access the pins to check the voltages with the plug engaged? Mine looks like the GEMS unit pictured.