Engine GT40 Tubular Intake Install Problems....

Mustang5L5

Put lubricant all over the balls
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None of that should affect how the car runs significantly.

I still suspect vac leak due to manifold gasket.

Dunp codes and perform the cylinder balance test procedure. See if you actually have a misfire or dead cylinder.
 
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daredevil95

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Feb 20, 2011
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None of that should affect how the car runs significantly.

I still suspect vac leak due to manifold gasket.

Dunp codes and perform the cylinder balance test procedure. See if you actually have a misfire or dead cylinder.
Yep, car is at the point that it stalls at every stop, feels like a misfire (timing?) & surging idle. This car is driving me crazy! lol I gotta get the car back to the garage tomorrow, check for codes, no light on so? IDK. I'm probably going to pull it apart tomorrow, check for slipped intake gasket? I can't find any vacuum leaks other then the TPS center and the TB butterfly at bottom of TB? I'll rip it apart one more time, if this don't fix it, either stock intake or carb setup. This is the 4th week working on this here and there so, one more try! Wish me luck.
 

Mustang5L5

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The CEL light being on doesn't necessarily mean there aren't some codes present that might give us a clue as to what is going on. The cylinder balance test procedure is also a good thing to try to see if you get a passing code for all cylinders. I think only 11-13 of the codes actually turn the light on, but there are something like 50 or so potential codes. It's not like OBD2 where every little thing turns the light on.

A slipped intake gasket won't necessarily show as an external vac leak. It's possible for the gasket to slip in such a way that the leak path is into the lifter valley where the hydraulic lifters are. That wouldn't show during a smoke test.
 
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daredevil95

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The CEL light being on doesn't necessarily mean there aren't some codes present that might give us a clue as to what is going on. The cylinder balance test procedure is also a good thing to try to see if you get a passing code for all cylinders. I think only 11-13 of the codes actually turn the light on, but there are something like 50 or so potential codes. It's not like OBD2 where every little thing turns the light on.

A slipped intake gasket won't necessarily show as an external vac leak. It's possible for the gasket to slip in such a way that the leak path is into the lifter valley where the hydraulic lifters are. That wouldn't show during a smoke test.

Tomorrow, If i could get the car to idle, I will do the balance test. Then, I'm pulling both intakes off, check gaskets and check lower intake surfaces with a straight edge. I'm getting pretty quick at removing the intakes! lol Basically start over amd see what I find? Hopefully find something obvious?
 

Mustang5L5

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What lower intake gasket set are you using?

One tip for install. Get 2-4 bolts that match the intake manifold bolts. Cut the heads off. Install them in the corners. Use that as a guide to drop the intake down into place. Should help with alignment issues and preventing a gasket from slipping.
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
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While the car is running wiggle the salt and pepper shakers...the white and black 10 pin connectors at the back of the intake. They cause similar issues. The pins inside loosen up. If you notice a difference unplug them and use a pick or small screw driver to close up the female side of the pins a little. It's happened to me more than once working on these cars over the years.
 

daredevil95

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Feb 20, 2011
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We made some progress, I replaced the distributor and a new TFI module, those changes got the car to idle decent but, still has a stumble? Next I ran the codes, KOER and I got 2 smog codes plus, the EGR....vacuum line off EGR. So, that is expected until tune with EGR delete is delivered to me. Next, I did a cylinder balance test, this was inconsistent after doing 3 separate tests, different cylinders failed? IDK. Next i removed the computer, opened computer and did a visual inspection, nothing noticeable? My last idea was removing the lower intake to see if gaskets slipped skewing the balance tests? No, problem with gaskets, they were good and in place. So, I'm thinking the new injectors might be causing a issue? Went from single nozzle hole to the 4 nozzle hole 19lbs injectors? IDK? I might try a different intake, a Explore GT40 with no EGR provisions. IDK? Anyone have suggestions? I attached a video I made yesterday during all these tests, it's actually pretty good if your into this kinda stuff....of course monetization is turned off / no ads. I'm not looking for views as to I could use some advice? Thanks, Gene


View: https://youtu.be/9zStq_FV8MA
 

rednotch

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Aug 14, 2000
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So many little issues with that car, Speedo not working and the brake light cutting off and on would drive me nuts. But the speedo can contribute to stalling and idle issues in closed loop if its not seeing the vss signal the a9l uses this info to hold a higher idle when stopping and shifting..., idk if the Speedo gear is still spinning it.... .

But most of your issues seem to be during cold start in open loop, does it calm down a bit when warmed up an goes to Closed loop? if it does I would still check for vacuum leaks, all those vaccum lines off the tab/tad and egr selonoids should be capped if not being used. Capping the egr itself does nothing, that's a vaccum diaphragm that opens the valve. The lines running to it need to be sealed. Wiring in these cars is old as hell these days I all way go over them very carefully, broken clips get zip ties to reinforce connectors etc, until I can source new ends, make sure all the connections and factory grounds are good especially the injector harness. I would make sure its sealed up, no possible vaccum leaks, throw a stock Maf on it if you still have it for now since there stock injectors, set the base timing to 10 then do a base idle reset on a cold engine, your chasing your tail if you have a open loop idle issue and let car warm up and go into closed loop. When the engine is cold Unplug the IAC and crank the throttle screw a few turns and start engine. Idle should be high 1500rpm or so..... Back the screw down until the engine is barely idling.....around 600 rpm, then plug in the iac an note the rpm it jumps to should be above 1200 on cold idle. Disconnect the battery and let the car get cold, reconnect it and restart to see if it will pull a cold idlle. if it does adjust the throttle for loaded conditions, AC, lights etc.. Them put some miles on it. The eec applies adaptive to both open and closed loop.


Don't chuck the distributor... Rebuild it, $40 worth of parts from eBay using old stock standard motor products and its good as new... current motorcraft tfi is just a smp 218lx, 223lx is the same as the old 5spd motorcraft part number from the early 2000's before they consolidated them.. Pickup up was actualy the t series mold made in mexico...
 

FastDriver

My dad had a bra
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Sep 5, 2001
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Don't go further away from the way you had it. Go back!

Change one thing at a time. Before you put on the upper & lower manifold, you said it ran. I would restore everything the way you had it, except the manifold. Then, start chasing your issue. You're running the risk of creating a multi-variable problem and confounding your diagnosis.

If everything goes back how you had it, you've re-installed gaskets, and you still can't find the issue, then go back to the old intake, too. You're missing something that putting the old one on may shine a light on.

This probably started as a vacuum leak and has morphed into several problems. You mentioned the new throttle body. If it really is new, then, swap your old one back on. Its settings for idle matter.

The car is obviously not getting enough fuel (vacuum leak, faulty MAF/TPS signal) or enough air (Throttle adjustment).
 
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Mustang5L5

Put lubricant all over the balls
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The CBT showing multiple cylinders is interesting but could help I’d the cause.

What cylinders showed the misfire? I’m curious because if it’s a group of cylinders in one area of the engine, then that could point to a slipped gasket.

If it’s jumping to all cylinders, then there is potentially an issue that causes misfire on all cylinders.
 

kgrier

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Jun 20, 2022
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Change one thing at a time. Before you put on the upper & lower manifold, you said it ran. I would restore everything the way you had it, except the manifold. Then, start chasing your issue. You're running the risk of creating a multi-variable problem and confounding your diagnosis.
Great advice. Simplify a complex system to the base components that should work together, i.e. as close to stock / OEM as you can get.

I am noob here, but just went through a similar deal with the 5.0 in my 1967 Cougar over the past month or so. When she idled it was either high, hesitation off idle, very slow dashpot return holding high idle, or like it had a B cam. So many "missed it by that much".

Long story short, 02 sensor readings were very helpful once I confirmed they were real - "how can she be that lean and still have some wet plugs !?!? And why no O2 computer codes??" But after a 30-year IT career, I don't admit defeat readily. There is a reason, I just don't know it yet.

Returning all but the GT-40 to stock (removing Accel dist / injectors, BBK TB) and then troubleshooting led me to: breaks in EFI harness, leaking FPR, worn OEM injector seals.

Car is running well with re-capped stock A9P, stock dist, stock TB, stock injectors and GT-40. Well enough to go downtown on date night with my bride :)

If I could buy only one of the many tools I now have (Quarterhorse, 02 simulator, among them) it would be the EEC-IV breakout box. It was invaluable. Mine is an OTC 3225. Prices vary on ebay, as does quality. Jakemart has one they are asking $225 for. Make them an offer. Search for "jakemart 3225-12508". If you need a manual, message here, and I'll scan mine. It's pretty simple but the manual does have a pin map and expected values at KOEO, KOER includes ID'ing all the grounds. It installs inline to the ECU and can be left in place while operating the car.

EDIT: There is the Thexton flavor of the EEC-IV Breakout Box on ebay now at $65 bid with a day or two left. Search "THEXTON 126 FORD EEC IV".
 
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daredevil95

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Feb 20, 2011
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Update: replaced lower inatke gaskets, installed old set of fuel injectors, I cleaned and tested injectors with cheap amazon injector kit, EGR removed and installed Bama 4 Bank eliminator chip with EGR delete.....car now runs perfect! Put about 40 miles on it and all is good. Finally!! Thanks for all the advice!
 
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