Finished 3.2 running rough... advice needed.

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COliveira95

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Hey everyone. I've got the 3.2 swap together finally on my 95 MTX and am having some issues with it not running properly. I'm going to try and describe all of the details to the best of my knowlege and the steps I've taken to try and troubleshoot it.

I had a 3.2 motor stripped down to the block and sent to the machine shop. It was honed, new piston rings, main bearings, thrust bearings, and polished crank. They assembled the motor and painted the outside of the block.

DSCN2515

We finished assembly with new 3.2 head gaskets and the 3.0 heads (still with the untouched 3.0 cams in them). We put the timing belt on and such, new spark plugs, and new plug wires. The intake manifold was powdercoated along with the valve covers. ...and for the record, the Taylor plug wires were tossed and I used factory motorcraft wires instead.

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8

I buttoned up the motor mated with the quaifed tranny. I dropped the tank and installed a 190 lph fuel pump. While under there, I replaced the fuel filter. When reinstalling the fuel pump, I reused this piece here:

Fp9

...per the instructions to do so. When installing the 190 lph fuel pump on my old 93 SHO, I did NOT use this, but instead I used the supplied rubber hose it came with. (side note, good feeling this may be my problem)

So it goes on, I start the car and prime the motor... it doesn't want to run... finally it runs and idles fairly smooth. I go through the first break in stage and then change the oil as you should with a new motor. After idling for a long time and running through quite a few fan cycles, the car begins to run extremely rough where we can't even put any stress on the motor. A touch of the throttle and it bogs down and wants to stall. Playing with the throttle can get it to rev up. If I punch it, the car revs to the secondaries and does not pass the 4k RPM mark, it gets bogged there and stays there. If I slowly ease into the throttle, I can get it into the secondaries (which are opening and closing as they should) and all the way to redline fairly smooth. (meaning, no misfiring or bucking). This tells me I may have a fuel issue rather than a timing issue.

I'm not getting a CE light (and I verified that it is working). Although, tomorrow I will run the codes for any hidden codes and I will also run a fuel pressure gauge on it.

I guess my question is if these symptoms sound familiar to anyone, and maybe that can help narrow down what to look for. I have come to the conclusion thus far that if it were a timing issue, it would be running much rougher than it is.

FWIW, troubleshooting I have already done:

-I've checked the routing of the plug wires to confirm they are correct and they are

-I've looked and listened for vaccum leaks with none to be found, including all the runner donut seals on the manifold

-I've checked for leaking injectors or such, but cannot seem to see any fuel around them or smell any for the matter

I hope I clearified my situation enough to be understood. Tomorrow I will run the codes and check the fuel pressure. I will add my results to this thread. Thanks in advance people.
 

DavidT

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wow! Congratulations on performing every 3.0's dream :dribble: and for all your hard work. It will pay off in the end :thumb: when the bugs are worked out.
I have very little input... but this was my experience with the rebuilt motor dropped in my rough running sho:
ECT sensor broke off (which will throw a code)
spark plug wires at coil pack not making perfect contact
Good luck.
btw, is your intake plenum polished? It is sweet! :dribble:
 

masho95

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That piece that you reused from the old fuel pump assembly is a fuel pulse dampner. When I installed my 190lph I also left it out like you did before. I don't quite remember if there are seals at each end, but there might be. If there is a seal and one of them isn't sealed right you're not going to have all the fuel there is supposed to be coming out.

Check your fuel pressure like you said you were going to do tomorrow. I'm betting that it's not quite up to par. If it's not I'd go ahead and pull the fuel pump assembly out again and take out the dampner and just use the rubber hose.

Edit: You put the sock back on the end of the fuel pump before you put it back in too, right? :D
 

COliveira95

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David, my intake plenums are not polished (I wish!) they are powdercoated silver.

MASHO, yeah I bet that's the issue, I don't think they sealed properly. We'll see when I check the fuel pressure tomorrow but I'm betting that's my issue.

Thanks guys!
masho95 said:
That piece that you reused from the old fuel pump assembly is a fuel pulse dampner. When I installed my 190lph I also left it out like you did before. I don't quite remember if there are seals at each end, but there might be. If there is a seal and one of them isn't sealed right you're not going to have all the fuel there is supposed to be coming out.

Check your fuel pressure like you said you were going to do tomorrow. I'm betting that it's not quite up to par. If it's not I'd go ahead and pull the fuel pump assembly out again and take out the dampner and just use the rubber hose.

Edit: You put the sock back on the end of the fuel pump before you put it back in too, right? :D
 

AutoSHO

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With as much flow as a 190 provides you wouldn't think that could be the problem, but it is possible. I would check the intake to head bolt torque, along with anything between the MAF and heads (clamps, electrical connections, etc). Stock MAF? New TPS?
 

COliveira95

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I double checked the head to intake bolts and all the hose fittings. It is using the stock MAF and I didn't change the TPS.
AutoSHO said:
With as much flow as a 190 provides you wouldn't think that could be the problem, but it is possible. I would check the intake to head bolt torque, along with anything between the MAF and heads (clamps, electrical connections, etc). Stock MAF? New TPS?
 

AutoSHO

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I'm definately curious as to what your fuel pressure looks like. I'll wait on that before making any more guesses. :)

Is it a defined, constant miss, like losing 1 cyl or 2? or is it just running really rough and (obviously) very low on power?

Last, did it give any codes?
 

COliveira95

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UPDATE: Car is all set.

I connected the fuel pressure gauge and got a whopping 20-25 psi... (if I was lucky.) I dropped the tank and pulled that dampener out and replaced it with rubber hose. That solved my issue. 40 psi and a great running 3.2 now! :thumb:
 

DavidT

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and I was wrong. Imagine that. hehe


btw, I am jealous! Is the 3.2 MUCH MORE exciting than the 3.0?
Congrats!
 

COliveira95

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MASHO: yeah I knew from the beginning that was probably my issue. That's the last time I ever follow directions :D j/k.

David: the 3.2 has a much more noticeable torque difference from the 3.0. As far as horsepower wise, I haven't gotten on the car enough yet to tell, but so far so good. Gotta get the motor all broken in first.
 

DavidT

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I just noticed your sig. Wow! You wanna trade sho's?????

Did you install the quaife yourself?
 

COliveira95

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DavidT said:
I just noticed your sig. Wow! You wanna trade sho's?????

Did you install the quaife yourself?

Trade SHO's, no thanks, install quaife, yes, but I had Beth go through the entire tranny afterwards.
 

shojuan

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FWIW the 89's don't have a pulse damper and they run just fine without it. Just an example of adding more parts to the toaster that can break and lead to bad toast!
 
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