Page 2 of 2 FirstFirst 12
Results 26 to 49 of 49
  1. #26


    I have a slightly parallel thread over in v8 but maybe moving this might make sense since cfi isn't 350 specific.

  2. #27


    Just to end this on a sad note. Oil was thick with fine metal bits after 10 miles. Pretty sure cam bearings are gone. Going to have to pull and rebuild. My problem now is how "built" should I go? I kind of want to try keeping my cfi for a while but most of the easy stuff I would have the shop do in the rebuild would likely mess that up. Feels silly to pull the motor and not do more than just bearings.

  3. #28


    When they did your intake, they cleaned up the head surfaces with roloc abrasive fills the valley with sand. Seen it many times. Motors are junk In just a few miles. Usually just long enough for the customer to get almost home. Understand, this is a guess based on reading your thread and the symptoms. I do not have a crystal ball.

  4. #29


    I have my suspicions too. I am hoping to guilt them into a cheap engine pull.

  5. #30


    You could magnet up the pan and do a quick flush, filter, refill, and see what it's going to do. A 15w oil isn't going to hurt

    Ive had pressure pickups go bad. Carries great pressure at start then tanks to 0.

    I'm not saying throw caution to the wind, but just to be certain.

  6. #31


    Yeah, the oil was full of bearing material. Just as an update (since nobody has posted anything in the gt350 forum for so long I don't want too much dust to settle), the guys have pulled the engine, it is now at the engine builders (they normally just do race engines, but since winter is slow here in upstate ny...). I have a set of gt-40 heads at the shop and so far they are planning on some hypereutectic pistons (boring as appropriate, I want to shoot for 9.5 - 10:1 compression), and a 35-255-5 cam plus full kit. Balance etc. I am not rushing them since it is cold and nasty outside but I hope to have it out again in a month or two.

    I purchased an AEM AFR gauge so when it comes back together I am hoping to get the CFI going 'right' and seeing what it can do. If that is just sad and depressing I will put a sniper on it and gut the CFI material. I just really, really want to know what the ford CFI can do if you turn the car into what it should have been from the factory. Good manifold, good heads, good cam, good exhaust. Nothing crazy, just good.

  7. #32


    Well, they took apart the block. It was crank bearings. Crank is badly scored so that is getting replaced. Going 30 over and flat top hypereutectic pistons too. Should be done in a few weeks. Here is a picture of the old heads for posterity. They have Cleveland forge markings.Name:  IMG_20180116_105722.jpg
Views: 225
Size:  107.4 KB

  8. #33


    Just an update. Engine is complete, installed, and still throws a 41 (lean) code but the AFR gauge is not showing anything too lean, particularly at open throttle. Running real good. After I get the engine broken in I will do another 0-60 and see how it goes with the CFI. The CFI appears to be dealing just fine with the new cam, gt40 heads, 3721 intake, and shorty equal length header combination. However, I suspect it has become the real bottle neck and I don't think I could do any more to make it go to the next level. The 'bending' I did on the stop tab on the throttle appears to have been harmless. The throttle now opens completely and the car responds wonderfully to it, no oddness/bog or anything. The car now pulls evenly all the way to red line rather than giving up at 4k. It doesn't pull particularly hard but I blame that on the CFI, you can tell it does a much better job 1-3k than 4-5k, after the shift the car surges (like it always had, particularly when I bought it and somebody put a non-ho cfi on it).

  9. #34


    Amazing the things that happen when an engine is allowed to breathe. Code 41 isn't just about the (right) oxygen sensor, but about it's circuit, meaning it, it's mounting, and every connection and wire between it and the brain box. Varying amounts of resistance or sporadic open circuit etc can do it...
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website --->

  10. #35


    I don't like the wire that hooks to the o2 sensor, it is about as brittle as every other wire in the car. That is part of why I got the AFR guage, so I could actually see what I was running. I wonder if I could run a fresh wire down to the O2 sensor, where does that puppy start from? I probably won't be able to make much headway on the ratio if the car is always trying to richen the mix. Although the variation I see in the AFR makes me think it is not really a continuous rich condition.

  11. #36


    I posted this over in the V8 forum but for posterity on this thread I am going to put it here too.

    Dropped the timing advance down to 11 to be safe. Just did a 0-60 run, didn't push it too hard and a soft start. 7 seconds. So I am guessing 225 horsepower with only 140 miles on the rebuilt motor. I hope we get up to 230/240 as the motor breaks in. Very happy with that. Not bad at all for a CFI and an automatic transmission.

  12. #37


    I was just thinking, this is pretty cool: The engine is basically a 1993 engine minus the multiport fuel injection and the roller cam and I am coming close to the same output with the CFI system compared to the MPFI. I suspect I am losing out at high rpms but when the engine is broken in I will give a higher rpm run at the quarter mile a shot.

  13. #38


    Just got a friend's gas pressure gauge... I had it at 47, I brought it down to 45 just because it is a hair rich at WOT but it runs so good I saw no reason to go lower.

  14. #39
    FEP Super Member JTurbo's Avatar
    Join Date
    Jan 2006
    Western MA


    Glad to hear that you got the car back on the road after the engine mishap. I've always heard horror stories with CFI, looks like you have your's spot on. Congrats!
    1979 Indy Pace Car Mustang 302 / 5spd
    1982 Mustang GT T-Top 302 / 4spd
    1986 SVO Mustang - 1C

  15. #40


    Took it out for a spin in the higher RPMs today since it has 300+ miles on the rebuild. Took it up to about 5500 at WOT before letting it go to second. Pulled strong all the way to 5.5k and was picking up steam but I didn't want to push it with a new motor. Before the rebuild and before the 'issue' it ran out of steam around 4200 rpm. Cool that it wasn't the CFI limiting it, but rather the heads and intake most likely. It had the headers and full duals when it would just kinda give it up at 4.2k (0-60 in 8 seconds). Too bad the intake install killed the crank, would have been nice to know what just the intake was up to. I did run a 0-60 with just the intake replaced (and new exhaust) but the engine was toast so I can't really count that (it was awful, 10secs, the engine just laid down and died at 4k). The new cam in it is meant more for torque so it is nice that it is still strong up there.

    46 pounds on the regulator ended up being the sweet spot.
    Last edited by emerygt350; 04-19-2018 at 03:41 PM.

  16. #41


    glad to hear its running! just in time for spring, if it will ever get here!

  17. #42


    It is now getting its last upgrade for a while... 3.73 gears for the rear and a full rebuild back there. Hope to get it back tomorrow afternoon but I am sure Wednesday will be more like it.

  18. #43


    Nevermind, didn't read through the whole post.
    Last edited by Haystack; 04-09-2018 at 10:28 PM.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  19. #44


    Just finished the gears. I will try another 0-60 tomorrow.

  20. #45


    Just did a run to 60. Let the transmission shift as it wanted (4800? 4600?). 6.7 seconds. I think holding it till it was in the high 5k would probably take another bite out of it. Had plenty of omph building when it shifted.

  21. #46


    I am not sure how much I trust this but

    Estimates 290hp at the flywheel. I found a local Dyno so after I break the engine in more I will go fo a Dyno run. I suspect 230 maybe at the tires.

  22. #47


    Hah. Well. I don't trust those hp calculators, either that or the mustang is a very very efficient machine. I will post this under the V8 thread too for people that don't muck around in the specialties.

    I went and dynoed the car today. What a ball. Tuned it best we could using the fuel pressure and a hair more advance (was at 13, now higher, but just barely). First run is in blue, last run is in red. The car was really leaning out and just dropping dead lean at 4.1, you can see the dip in the first run. Jacked up the fuel pressure gradually and added more timing a hair. We lost 4 or 5 lbs of torque when we bumped the timing but picked up that much horsepower. I may bring it back down since the torque is more fun for my driving. Not that you would feel 4 lbs but I feel better about potential detonation. No sign at all of that by the way. Here is the dyno sheet. I was hoping for more but I think I have done all I can do with the CFI and not mucking with the computer. That was the technicians opinion too although he did say that the numbers I got are what he tends to see on mild build 5.0s. Next summer, holley sniper time.

    Name:  1984 mustang.jpg
Views: 71
Size:  150.8 KB

    Oh, and on the way home I did a 0-60 clocked at 6.34.
    Last edited by emerygt350; 04-21-2018 at 04:12 PM.

  23. #48


    Sniper's a joke... even if you just put a Holley 500cfm 2 barrel on there, the bottom end and average torque would perk right up significantly, and the high end horsepower would extend up beyond 5000rpm and be at least 50 horsepower more.
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website --->

  24. #49


    just to update (also posted this in the v8 forum) this gt350... new dyno today after fixing all kinds of sensor related stuff.
    Name:  84mustang.jpg
Views: 27
Size:  133.8 KB This is at the rear wheels of course.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear.
    Firehawk A/S 225/55/16 on LMR TRX r390 wheels (street)
    Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts