Help please vacuum routing problem

TOOFAST87

Registered User
hi new on here but ive got an 89 5spd sc had to pull motor to work on it and didnt mark vacuum lines now that ive got it back in supercharger isnt working i think i rebuilt it too it was running close to 16 according to gauge but now it barely gets up to 5 then drops off it isnt whining or anything runs like a n/a 3.8 ported heads, scorpion roller rockers, arp rod bolts, head studs, racer walsh supercharger pulley i think 5%, oem ported manifolds way slower than when i got it with blown head gaskets, and cracked oil pan. 190k miles thanks im guessing and kinda hoping its a vacuum line in wrong spot any help would be awesome. Diagrams, pics, anything that would help.
 
The is a line that goes from the inlet plentum after the throttle body to the supercharger bypass valve on right rear behind the SC. Is that hooked up?
 
Check to make sure the bypass valve linkage isn't hung up on the back edge of the supercharger top. If it isn't closing all the way you won't get much boost.

David
 
only way I can think of that you wouldn't make boost is like David said, also major belt slip like a bad tensioner or too long of a belt. If you dont have the bypass valve vaccum hooked up properly, the valve will keep the plate closed which would force air through the blower at all times. Does it run ok, and what kind of vaccum do you see at idle?
 
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Have you checked that the cats aren't plugged?

Compression check?

Fuel pressure?

Timing light advance check?

Did you check the lifter preload when putting it back together?
 
Check to make sure the bypass valve linkage isn't hung up on the back edge of the supercharger top. If it isn't closing all the way you won't get much boost.

David

Its hanging up but if you tap solenoid that lines coming from it moves back open. I did some pin out tests because my mad isn't showing to be working on a scanner and it keeps setting code for it. Everything check out last step said voltage between. 20 -1.50 volts. Yes replace processor no replace mad sensor. It had. 10 v. So I think I need an eec . 89 sc5 speed
 
Its hanging up but if you tap solenoid that lines coming from it moves back open. I did some pin out tests because my mad isn't showing to be working on a scanner and it keeps setting code for it. Everything check out last step said voltage between. 20 -1.50 volts. Yes replace processor no replace mad sensor. It had. 10 v. So I think I need an eec . 89 sc5 speed

What is an MAD sensor? You mean MAF sensor?

Just letting you know - EEC failures are very rare. So I would pursue all other avenues first.

The boost bypass solenoid isn't really needed. It was deleted after 1989. To rule that out, just bypass it.
 
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What is an MAD sensor? You mean MAF sensor?

Just letting you know - EEC failures are very rare. So I would pursue all other avenues first.

The boost bypass solenoid isn't really needed. It was deleted after 1989. To rule that out, just bypass it.

Its got new maf. Tps cam coolant switch and sensor. Oil press switch. Keeps setting code 66. Wont run right. Still has hesitation problem like before. Wont turn cooling fan on unless coolant switch unplugged. Checked wiring harnesses for proper connection and ohms. Harnesses are good. Dont know what else to try that will get rid of sputtering hesitation problem.

Also if you could assist me on how to bypass solenoid. That would be great. Thanks
 
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Its got new maf. Tps cam coolant switch and sensor. Oil press switch. Keeps setting code 66. Wont run right. Still has hesitation problem like before. Wont turn cooling fan on unless coolant switch unplugged. Checked wiring harnesses for proper connection and ohms. Harnesses are good. Dont know what else to try that will get rid of sputtering hesitation problem.

Also if you could assist me on how to bypass solenoid. That would be great. Thanks

The bypass solenoid is by the clutch fluid reservoir. It has vacuum lines that go across it. Simply remove it and reconnect the vacuum lines. It serves no purpose. Make sure the vacuum line from the fuel pressure regulator is Hooked up to the return plenum which is the one that is bolted to the lower intake.
 
The bypass solenoid is by the clutch fluid reservoir. It has vacuum lines that go across it. Simply remove it and reconnect the vacuum lines. It serves no purpose. Make sure the vacuum line from the fuel pressure regulator is Hooked up to the return plenum which is the one that is bolted to the lower intake.

Thanks you mind telling where the other lines go to n from so I can be sure there correct
 
The bypass solenoid is by the clutch fluid reservoir. It has vacuum lines that go across it. Simply remove it and reconnect the vacuum lines. It serves no purpose.

Well, it serves a purpose, but the purpose of the purpose is questionable. It's supposed to keep the blower out of boost in reverse gear, for example. But it's really not very necessary.

TOOFAST87 said:
Its got new maf. Tps cam coolant switch and sensor. Oil press switch. Keeps setting code 66. Wont run right. Still has hesitation problem like before. Wont turn cooling fan on unless coolant switch unplugged. Checked wiring harnesses for proper connection and ohms. Harnesses are good. Dont know what else to try that will get rid of sputtering hesitation problem.

Ok, I see. Code 66 is MAF sensor voltage out of range (too low). There are a number of things that could cause that. Faulty wiring is one. Faulty sensor is another. A vacuum leak that means the car isn't drawing enough air through the MAF sensor to trigger a reading might be a third. Faulty EEC is also possible.

I am leaning away from the EEC because it's a pretty specific failure. Why would it have trouble reading only one sensor?

Does the car idle okay? If so, at what RPM? What happens if you unplug the wires to the IAC (cylinder attached to the throttle body and then start the car? Will it still idle?

So ... Can you walk me back through the pinpoint test you did on the MAF?

Also, check the radiator support on your car for a sticker with a vacuum diagram.
 
Every sensor is new except iac,baro/map, and crank sensor. Have to have maf unplugged or itll consistently keep dying. And have to leave coolant switch unplugged for Radiator fan to come on. Three day's ago it wouldn't start and checked it out fuel pump wasn't coming on. Also new. Went back out an hour later it started right up hasn't done thats again. Bypassed that solenoid now Its running10- 12psi now still lower that the 16 it was running. And way less than it should be with pulley kit on it. It's the intermittent problems making me think it's the eec. And do u have access to alldata its the pinout test for code 66. Everything read right except last step and according to test it's the eec. Thanks. And I still think ive got vacuum line swapped somewhere. Also it's using alot of gas and blowing black smoke like its running crazy rich. And isn't idling worth a damn 900-1100when its not dying and 500-700 when it's on its dying craze. Missing stuttering problems always there.
 
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Every sensor is new except iac,baro/map, and crank sensor. Have to have maf unplugged or itll consistently keep dying. And have to leave coolant switch unplugged for Radiator fan to come on. Three day's ago it wouldn't start and checked it out fuel pump wasn't coming on. Also new. Went back out an hour later it started right up hasn't done thats again. Bypassed that solenoid now Its running10- 12psi now still lower that the 16 it was running. And way less than it should be with pulley kit on it. It's the intermittent problems making me think it's the eec. And do u have access to alldata its the pinout test for code 66. Everything read right except last step and according to test it's the eec. Thanks. And I still think ive got vacuum line swapped somewhere. Also it's using alot of gas and blowing black smoke like its running crazy rich. And isn't idling worth a damn 900-1100when its not dying and 500-700 when it's on its dying craze. Missing stuttering problems always there.

I don't have access to Alldata, no. But, okay, I'll assume you followed the test correctly. Maybe the EEC is bad. I can say that, if the only way it runs is with the MAF unplugged, then the mixture control is off somehow. (But you knew that from the plume of black smoke!) I think it could still be a vacuum leak. Why not try an intake smoke tester or use an air compressor and a rubber plug in the TB bore to check for leaks? A few psi should do it. I have some spares that will fit a stock throttle body. Or if you have a larger TB, you can get rubber plugs of various sizes at www.McMaster.com. Also, try checking the timing with a timing light. It might help you figure out what the EEC is commanding, to understand if it is trying to keep idle down or trying to keep it up. (If there is a vacuum leak, it will retard timing to try to keep idle down, and it will be stuck somewhere near 10 BTDC, I would think.)
 
Only code is 66. And it's new. New coolant switch and sender. New oil sender. New maf. New tps. New cam sensor. New fuel pump. New dis module. New plugs. New wires. Checked for vacuum leaks had missing vacuum line to t in PVC pipe. Capped it off can't find line that goes to it. That's why I'm trying to figure them out 188k finally blew headgaskets. Pulled engine went threw it had original gaskets timing chain rod main bearing everything pretty amazed being supercharged. Still has original waterpump couldn't get one threw auto parts stores with pipes in correct spots. Reused it wasn't having issue. Rebuilt supercharger had snout bearing bad. It had Been redeemed before tho. But bearing and seal where ford. Put new coupler in it and a pulley kit while I was there. It would max gauge out before blew head gaskets now it'll go up to around 10-12 psi then drop off to no boost. Ran awesome even with head blown Now with pulley kit. Roller rockers. Crap load of new parts. Potted polished heads, intake & exhaust manifolds. Its slower now than with blown heads and running low boost. Only problem I found with harnesses while apart during inspection was two of the tps wires had been chewed in half by rodent. But previous owner only fixed one. I purchased new harness tps end and soldered in. Tested connection and ohmed fine. Then retaped harnesses. Oh I guess it's still got the original knock sensor and low oil sensor also. When ever it starts idling low and lopey oil gauge starts going nuts and car doesn't want to go anywhere when giving throttle. Just falls on face. I need to regap plugs according to forum on hear. I put then to stock gap. I never noticed fan quit I think that's when I blew head gs. And I can't find a motorcraft Pcv any other brand known to work proper? I'm going to get a new iac and see what that does with the idle problems and dying at idle and when cruising and let off gas.
 
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