billbranch Posted September 16, 2010 Report Share Posted September 16, 2010 This morning, five miles from my house, I slowed for a toll booth, and, on acceleration, the car would not run above 2,000 rpms. It would rev freely from idle to 1,800, then sputter up to 2,000. I had changed the oil yesterday and set the timing and throttle potentiometer, so I checked under the hood for the last place I was. Nothing seemed to be amiss. I turned off the engine for a second, and it was fine when it restarted. Any theories on this one? While I'm at it, the detonation sensor flashes whenever the engine is hot and I accelerate. There is even a small stumble at 75 under load. There is no code flashed at idle. Might improperly adjusted valves cause this? Bad sensor? Thanks for any help. Bill Quote Link to comment Share on other sites More sharing options...
nick@nite Posted September 16, 2010 Report Share Posted September 16, 2010 Something similar on the race car, it would start a misfiring @ 2k & all the way through. turn out to be the ign. relay located on the firewall, could also be knock sensor.... Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 18, 2010 Author Report Share Posted September 18, 2010 Something similar on the race car, it would start a misfiring @ 2k & all the way through. turn out to be the ign. relay located on the firewall, could also be knock sensor.... Could be anything. there's no misfire involved here. I doubt there's an expert on this engine in this country. Quote Link to comment Share on other sites More sharing options...
geo Posted September 18, 2010 Report Share Posted September 18, 2010 I've had this happen to my car, but I always got a fault code on the LED afterwards. I would check the overboost sensor and wiring - long shot, but worth a look. When you see the LED flash, do you ever hear the engine knock? The cutout at 2,000 RPMs could have been excessive knock that couldn't be stopped, so the revs were limited. How is your fuel? I am having a terrible time with my Saab because of the lousy ethanol gas they sell nowadays. Ethanol absorbs water and reduces the octane of the fuel, so the Saab is shutting down from excessive knock. Wonder if that could be the same problem you're seeing. I'm very optimistic about an additive I put in the Saab - Startron - that so far has been working like miracle juice! Before Startron, I tried all kinds of additives first with no help, because most of them are alcohol-based and make matters worse. -George Quote Link to comment Share on other sites More sharing options...
JunktionFET Posted September 19, 2010 Report Share Posted September 19, 2010 You're describing a pretty common condition and 99% of the time it's caused by a sticking throttle microswitch. Try slightly loosening the two little bolts that fasten it to the throttle body. Also make sure that the switch is adjusted properly--It shouldn't be used as a throttle stop, i.e. the closed throttle shouldn't be resting on the switch, there is a set screw on the TB for that purpose (though admittedly it is a pain in the ass to get to). The adjustment should merely allow the switch to electrically close when the throttle is shut, if that makes sense. What's basically happening is the Jetronic ECU thinks the throttle is closed when the microswitch sticks. The ECU is designed to cut the fuel injectors when coasting (deceleration mode) and you cross through the threshold RPMs for the injectors to be disabled and then re-enabled. If it happens on the road and won't clear itself, you can temporarily get around the issue by disconnecting the throttle microswitch. Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 20, 2010 Author Report Share Posted September 20, 2010 That makes sense. Thanks. Quote Link to comment Share on other sites More sharing options...
bill Posted September 21, 2010 Report Share Posted September 21, 2010 That very thing happened to me one time. With the understanding of the microswitch's function (where it cuts the fuel to the injectors on deceleration), I was able to diagnose and fix it quickly. I hooked up the meter measuring continuity, and yes, it was sticking. -Bill That makes sense. Thanks. Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 21, 2010 Author Report Share Posted September 21, 2010 That very thing happened to me one time. With the understanding of the microswitch's function (where it cuts the fuel to the injectors on deceleration), I was able to diagnose and fix it quickly. I hooked up the meter measuring continuity, and yes, it was sticking. -Bill JunktionFET is 100% correct, because the syndrome occurred again this morning. I was able to listen for and not hear the clicking of the switch as I opened and closed the throttle. I disconnected the switch and it ran satisfactorily. Now, if only loosening the bolts will solve the problem. I see the price at WH is about $158. I have also heard of replacement switches being fitted. Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 24, 2010 Author Report Share Posted September 24, 2010 JunktionFET is 100% correct, because the syndrome occurred again this morning. I was able to listen for and not hear the clicking of the switch as I opened and closed the throttle. I disconnected the switch and it ran satisfactorily. Now, if only loosening the bolts will solve the problem. I see the price at WH is about $158. I have also heard of replacement switches being fitted. There will be no self-congratulatory bs, but I loosened the mounting bolts and douched the thing with electronic parts cleaner and haven't had a problem since, although this post will certainly jinx that. However, another possible situation has arisen. I am looking through the old ignition parts interchange page from peugeot-l, where it says that on the ignition ECU the last three digits of post -89 wagons should be 153. Mine is 033. Maybe that is why my codes are not reading correctly? Or, is this info wrong? http://www.505turbo.com/forum/index.php?ac...=post&id=28 Quote Link to comment Share on other sites More sharing options...
bill Posted September 24, 2010 Report Share Posted September 24, 2010 I used a Radio Shack switch replacement for the microswitch. I don't have the number, but I think it is a stocked item for under $10. There are in the drawer with other switches. It took a slight modification to fit- there are two mount holes. The one hole accepted the bolt, but the other hole has a slight offset. I ended up wrapping a thin piece of metal wire around it tightly, and then adjusting. It has been working for 2+ years now. Bill There will be no self-congratulatory bs, but I loosened the mounting bolts and douched the thing with electronic parts cleaner and haven't had a problem since, although this post will certainly jinx that. However, another possible situation has arisen. I am looking through the old ignition parts interchange page from peugeot-l, where it says that on the ignition ECU the last three digits of post -89 wagons should be 153. Mine is 033. Maybe that is why my codes are not reading correctly? Or, is this info wrong? http://www.505turbo.com/forum/index.php?ac...=post&id=28 Quote Link to comment Share on other sites More sharing options...
billbranch Posted September 24, 2010 Author Report Share Posted September 24, 2010 I used a Radio Shack switch replacement for the microswitch. Bill Thanks for the info. Quote Link to comment Share on other sites More sharing options...
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