No vacuum at idle
#1
No Sleep
Thread Starter
No vacuum at idle
Just as the title states engine is pulling zero vacuum at idle and even builds boost with no load. Car is a 1986 6 port turbo, street port, and freshly rebuilt. Ive verified no vacuum in ESP and on my boost gauge. The vacuum line is plugged where the old factory pressure sensor. I’m not sure if this is an ecu setting problem, timing, etc. I’m using the base map for the FD. The car starts and idle fine at around 1300 rpm but wont rev past 3k then sputters and dies when put into gear. Has anybody seen no vacuum at idle before? I tried to search but only found nothing for rotaries. Any help will greatly be appreciated.
#2
Restoration expert
Maybe?
Possibly a big vacuum leak? Or the vac line to the gauge is going to a plugged vac port one he mainfold? Your saying to are able to spool up the turbo and build pressure? How much?
#3
No Sleep
Thread Starter
The boost got up to 4 psi but could probably build more since it didn’t go above 3500 rpm. I rechecked timing just to be sure and with the timing locked in ESP and its spot on. I switched the nipple with the fuel pressure regulator and same result, no vacuum. The engine is running rich and when I adjust the setting in ESP it seems to have no result. I will look for vacuum leaks and report back.
#4
No Sleep
Thread Starter
Ok so looks it no vacuum leaks but my mechanic says it may be a problem with the tune. Possibly too rich and timing retarded. Ill have him look at it. If this doesn’t fix it I think ill have to sell the car.
#5
Senior Member
Slow down a bit. Can you show us some pictures of your setup? How about a picture of where you are measuring vacuum from? Maybe some other pics of the engine bay so we can see your setup and get some clues. A high idle and lack of boost are usually (almost always) a vacuum/boost leak. If it's a turbo setup, the location of the leak will change the effect the leak has on the engine as well as change how you can detect it. Smart money usually get placed on the most obvious solution. Please give us some more info and we'll see what we can do.
#6
No Sleep
Thread Starter
Slow down a bit. Can you show us some pictures of your setup? How about a picture of where you are measuring vacuum from? Maybe some other pics of the engine bay so we can see your setup and get some clues. A high idle and lack of boost are usually (almost always) a vacuum/boost leak. If it's a turbo setup, the location of the leak will change the effect the leak has on the engine as well as change how you can detect it. Smart money usually get placed on the most obvious solution. Please give us some more info and we'll see what we can do.
Found it! It’s was the tee that I used to split the vacuum for both the ECU and gauge. After replacing the tee even during cranking I can see the vacuum reach to about -5. Nothing like a cheap fix but unfortunately the fuel pump went out again. I have already ordered a new one and am anxiously waiting. It’s weird to me that with a vacuum leak the car would produce boost in neutral though. I hope this is the last part in order to get her back on the road.
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