ThomasBorchers Posted November 2, 2016 Author Share Posted November 2, 2016 Hello again, well, in the meantime I am a bit more familiar with the DFI system. As Larry told me, I have checked the TPS adjustment. The voltage was too high for the idle speed. To adjust, I had to remove the TBI body, drill out this small welding spots which block the “adjustment” screws of the TPS. There I found out, that the cam of the throttle cam has a bit too much clearance in the TBI body. But I have replaced the TBI housing as it was. Then I tried to adjust the engine at 400rpm but this was not possible. The lowest speed I can set is 600rpm. Under this, the engine shuts off. Perhaps this is the result of the throttle cam play, don’t know. So I set the voltage of the TPS at 600rpm at 0,6 volts which should not be too much. So actually from this view, the mixture should not be too rich. I tried to do the adjustment as described in the shop manual with ISC and TPS. But the ISC is not moving. Since I know, that the motor can work, if it has voltage, I think the actuation from the ECM is not working as it should. Probably… I removed then the plug of the ISC, set the plunger to an idle speed around 800rpm. The idling was ok now, the exhaust was perhaps a bit black but not that much as before. Then I accelerated the engine and the was a “hole” in the acceleration, was not really possible to speed it up. When I went slowly back to idle, it run again rough and with more black smoke as before. At this point I decided to order a new MAP sensor since this part is also responsible for the mixture. Today a have installed the new MAP. Well, actually it is like before but I mean, that it now accelerates better as before. But going slowly back to idle, I have than again a too rich mixture and the engine shuts off. When I then shut of the ignition, wait some seconds, start again, the engine runs again better with good idling and just a little bit black smoke or perhaps it is just blue from oil. At the moment I come to the result, that the ECM could have a malfunction and need to be replaced. ( again… ). What do you think? It shows no codes, the ISC is not working and then the rich idling… I am sorry for my English but it is hard to say all this in a foreign language. Kind regards Thomas Link to comment Share on other sites More sharing options...
JGNZM Posted May 9, 2023 Share Posted May 9, 2023 Hi have you figured out your problem? It is most probably MAP sensor due to your low vacuum source at idle. I have the same problem, engine have low compression too.. Link to comment Share on other sites More sharing options...
ThomasBorchers Posted May 13, 2023 Author Share Posted May 13, 2023 Hi, well, I changed the MAP but made no difference. The solution was a broken ECM. Then it was ok but after a short while I had no ignition spark. A nightmare... Finally I bought a new distributor. But I have still to adjust it, seems that the ignition is now too late. The car is running but the display shows again nothing and when I switch the ignition on, the blower is on the highest level. Seems that there is again a problem with the ECM or wiring or so... Kind regards Thomas Link to comment Share on other sites More sharing options...
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