347 running like GARBAGE

Topic: 347 running like GARBAGE (Read 1328 times) previous topic - next topic

347 running like GARBAGE

August 17, 2011, 09:56:15 PM

A few years ago i built a motor for a customer and it ran flawless in his mustang. He came to the shop the other day complaining of poor performance a high idle and all kinds of drive ability issues. A quick scan of the TPS showed 5 Volts on all the leads. I knew the ECM took a DIVE. I replaced the ecm and the car ran much better but the idle was still high and the motor was lean. Now i noticed a new intake manifold on the car and did not give it a thought?? So knowing these cars fairly well i suspected a Vacuum leak. Got out the trusty SMOKE machine and presto from under the upper the smoke poured out. I suspected this and my suspicions panned out. The person that installed The EDELBROCK manifold made the classic MISTAKE. They used rubber plugs to plug the UN used vacuum taps. Sure enough when i pulled the upper i found the rubber cap sitting on the lower manifold. That was my leak. I then proceeded to remove the candy cane vacuum setup that ford designed into this manifold. And plugged all the un used taps with pipe plugs. I cant for the life of me figure out why ford did this. With that said i made a long vacuum hard line to bring out the fitting past the upper and removed the factory candy cane hose. Car runs great and all is good in the world.

http://i740.photobucket.com/albums/xx46/proguns/002-32.jpg

http://i740.photobucket.com/albums/xx46/proguns/002-28.jpg

http://i740.photobucket.com/albums/xx46/proguns/003-22.jpg

This manifold is in my view a piece of junk. It has a hidden bolt that is almost impossible to tighten and loosen. I have a 40 manifold in stock but the customer refused to buy it. Stating the one he has is better, Well he is the customer and they are always right.

Note the sig return is opened in the ECM making almost all the sensors USELESS.

347 running like GARBAGE

Reply #1 – August 18, 2011, 08:53:31 AM

They used a rubber plug to try and seal the threaded bung under the intake?

347 running like GARBAGE

Reply #2 – August 18, 2011, 03:38:36 PM

The vac routing on that looks all wrong to begin with. Who ever did that didn't know or pay attention to where the lines are supposed to run.

Any ideas on what caused the EEC to die? I've never had one die on me......yet.

347 running like GARBAGE

Reply #3 – August 18, 2011, 04:33:31 PM

88CougarGT fixed a blown sig rtn land pattern in his ECU and shows how he did it with pictures.

http://www.foxtbirdcougarforums.com/showthread.php?31025-Fix-for-poor-idle-rich-mixture-and-poor-performance-after-HO-T-5-mass-air-swap

347 running like GARBAGE

Reply #4 – August 18, 2011, 04:57:41 PM

Thunder how goes it. Actually i have seen this many times. Now the car is a STOCK 5 speeder from the factory. So no stray voltage was applied to the ECM. I checked it and also disconnected the tranny switch along with the clutch switch for the CRUSE. I was thinking it to had a 12 VOLT feed back. But it didn't. The easiest way to tell if you sig return is missing is to try and pull codes from the ECM. You cant with an open SIG RETURN. No filtered ground at the ALDL. I spent several hours checking for back voltage on this car. Once again it was a factory 5 speeder. Not a converted car from an AUTO. Here is how i eliminate any soft hose under the manifold. I made a hard line from the rear plug and use a 3/8 brake line with a pipe adapter. I run it past the back of the upper and put a BUBBLE on the end. This way all the lines are past the upper for easy access. I use one for the PCV and the other for the Vacuum Booster. The small ones are for the regulator and blend door and EGR. Hope this is some help for some. The candy cane hose is original with a ford part#. I have no clue why Ford did it this way. Thanks for listening. TOM

http://i740.photobucket.com/albums/xx46/proguns/001-63.jpg

347 running like GARBAGE

Reply #5 – August 18, 2011, 05:03:45 PM

Soft touch i was actually considering repairing the ECM also. But nothing was BURNT when i took it apart. Now some people tell me they just ground pin 46 to the engine. I know this actually works but i normally do not redesign ECM circuits that Ford designed for a reason. I am wondering if the repair the person made actually picks up the FILTERED GROUND or just Chassi ground. Interisting post. But for 75 bucks i bought a rebuilt ECM and just swapped it in. Thanks

347 running like GARBAGE

Reply #6 – August 18, 2011, 06:15:46 PM

The guy that had the blown sig rtn back in February was pulling codes. He was jumping STI to ground instead of sig rtn. There is a write up on another Ford forum that uses this method. Turned out to be a gottcha for him.

347 running like GARBAGE

Reply #7 – August 18, 2011, 06:57:19 PM

It was a very interesting article. As the matter of fact i have a 9 ECM in the shop with a blown SIG RTN. Actually came out of an auto conversion. I am going to bust it open and look for the burnt circuit board. Thanks

347 running like GARBAGE

Reply #8 – August 19, 2011, 03:19:01 PM

Let's make it a sticky. I thought it was? I also looked at a few ecu's for that problem, only 1 had that problem ,and then some.
That story has been out there for a while. about the auto stick thing. Ive been around this for awhile, I wish I could see it.

i

347 running like GARBAGE

Reply #9 – August 19, 2011, 09:01:22 PM

Quote from: TOM Renzo;365397

This manifold is in my view a piece of junk. It has a hidden bolt that is almost impossible to tighten and loosen. I have a 40 manifold in stock but the customer refused to buy it. Stating the one he has is better, Well he is the customer and they are always right.

x2!

The performer MAY make slightly more power than the gt40 unported. Even then it would be very close and there might be tests with the gt40 on top. However, that stupid bolt, upper to lower gaskets that are not readily available and unparalleled looks make the gt40 far superior.
Good catch on the vac leak.