A vexing Bosch problem
03-27-2005, 03:31 PM
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A vexing Bosch problem
About a month ago, I was followed home by a 90Q20V, it is safe to say that it has not led a sheltered life.
I have a bunch of problems, no idle when cold, high idle, sometimes it diesels when shut off, it is very slow to drop down to idle after you "blip" the throttle.
Here is what I have done and obseved.
1. I immediately assumed it was "that old rascal" ISV (early build, Hitachi). I took it off and dismantled it. It didn't look dirty, but I cleaned it anyway. I bench tested it with 9V and 12V. Seems to work.
2. I can't find any vacuum leaks, but I notice that if I take off the oil fill there is no change in idle. The crankcase breather tube looks pretty tired to me, but I haven't played with that yet.
3. A little short of nomenclature here, but bear with me. I notice that the arm under the throttle body does not contact the idle switch, in fact, it stops at rest about a 1/4 inch from the raised stops on the idle switch. I assume that the throttle arm should rest on the stops at idle? I assume that the ISV is therefore not activated? I notice that the "plunger" on the idle switch does not extend beyond the "stops" on either side. I assume that it should, is that correct? I also notice that the cap on the idle adjustment screw is missing. I assume that the PO has made some adjustment. Would this move the arm that activates the idle switch?
4. Today I Gunked the engine down to get a better look at things. Somehow this killed the battery (or apeared to, the horn still blew and other accessories worked) I had to jump it to get it started. IT STARTS FINE.
I let it idle for 20 minutes to dry off. When I blipped the throttle to 3000, it just stayed there and would not come down to normal idle.
Any guesses? I haven't started making adjustments without a clear objective in mind.
I have a bunch of problems, no idle when cold, high idle, sometimes it diesels when shut off, it is very slow to drop down to idle after you "blip" the throttle.
Here is what I have done and obseved.
1. I immediately assumed it was "that old rascal" ISV (early build, Hitachi). I took it off and dismantled it. It didn't look dirty, but I cleaned it anyway. I bench tested it with 9V and 12V. Seems to work.
2. I can't find any vacuum leaks, but I notice that if I take off the oil fill there is no change in idle. The crankcase breather tube looks pretty tired to me, but I haven't played with that yet.
3. A little short of nomenclature here, but bear with me. I notice that the arm under the throttle body does not contact the idle switch, in fact, it stops at rest about a 1/4 inch from the raised stops on the idle switch. I assume that the throttle arm should rest on the stops at idle? I assume that the ISV is therefore not activated? I notice that the "plunger" on the idle switch does not extend beyond the "stops" on either side. I assume that it should, is that correct? I also notice that the cap on the idle adjustment screw is missing. I assume that the PO has made some adjustment. Would this move the arm that activates the idle switch?
4. Today I Gunked the engine down to get a better look at things. Somehow this killed the battery (or apeared to, the horn still blew and other accessories worked) I had to jump it to get it started. IT STARTS FINE.
I let it idle for 20 minutes to dry off. When I blipped the throttle to 3000, it just stayed there and would not come down to normal idle.
Any guesses? I haven't started making adjustments without a clear objective in mind.
03-27-2005, 03:39 PM
#2
You wish you had a BOSCH problem
Isn't that the ol' Hitachi system on that 20V.. I could be wrong.
On to the TB: from the sounds of it someone has screwed with the throttle position via adjusting the stop (NEVER do that, btw) It was most likely done to compensate for a faulty ISV, you mentioned testing it and it was ok, narrow down your sticky/misajusted throttle first.
The Breather tube: if it's the same as the 7a tube it was superseeded by a Metal version of the same tube to solve the colapsing problem. There are part numbers on 20v.org I think, if not email me, I think i have them.
If you have a Bentley, start by testing those throttle switches and position. Get those right in order to give yourself a good base line. Then fix that pesky breather tube, then move onto other electrical possibilities.
Paul
On to the TB: from the sounds of it someone has screwed with the throttle position via adjusting the stop (NEVER do that, btw) It was most likely done to compensate for a faulty ISV, you mentioned testing it and it was ok, narrow down your sticky/misajusted throttle first.
The Breather tube: if it's the same as the 7a tube it was superseeded by a Metal version of the same tube to solve the colapsing problem. There are part numbers on 20v.org I think, if not email me, I think i have them.
If you have a Bentley, start by testing those throttle switches and position. Get those right in order to give yourself a good base line. Then fix that pesky breather tube, then move onto other electrical possibilities.
Paul
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