Boost flutter

[Joe Lemay]

Got a 87' turbo/intercooled 2.3 t-bird stick in a 'half-the-weight' 37 chevy P/U.
Used stock wiring harness and stock LA-2 computer. Modifications are: Wisco dished turbo pistons, 2 1/2 " ex system, no Cat, and I un-shrouded the combustion chamber around back of the intake valve in the head.

The problem is I get a flutter, almost like a MSD box rev limiter around 2500 RPM, boost gauge at this point is 10-15 psi. If I squeeze it off softly I can get though it, but it definatly does not like to be stomped on. Using Boush platinium plugs I closed gap to .024. This helped alot but not fixed.

I have a Tweecer chip that I have not loaded yet for I wanted to get it running stock first. Is the chip the fix due to the freer flowing engine trait?

I'm and old carb guy and this EFI stuff is all new to me(but fun!). Hope one of you younger guys can help.

Thanks for your time ,
Joe

 

[Str8sixfan]

sorry wish I could help, but I will say I like the concept of your build, even though it's a Chevy! I'd love to see more pics. You might also try the "forced induction" sub-forum on this board, as there might be more people who have turbo2.3s that frequent that area over this one. That's where the mods prefer most of those questions are asked.

 

[Hahnsb2]

Kinda sounds like it's blowing out spark. Got a wideband on it?

 

[Joe Lemay]

As in wideband , do you mean an O2.? It does have an O2. Wideband or not , couldnt tell you. And yes it does feel like it s blowing out

 

[Hahnsb2]

Wideband as in aftermarket wideband O2 with gauge to monitor AFRs. Boosted engines without them can be hard to tune and diagnose. it would be nice to know what the AFRs are doing when it does this too. Perhaps try different plugs, like some plain jane copper Autolights or NGKs. Not very familiar with the 2.3T but I know a lot of older engines don't seem to care for fancy plugs.

 

[AllanD]

Ok, LA2 computer... Factory Knock sensor installed?

What camshaft? ("Sled" follower turbo camshaft or ranger roller cam?)

I'll prempt some answer by telling you that flat follower camshafts in
the 2.3Ford Lima engine tend to grind a groove in the face of the
cam followers from the "base circle" of the camshaft.

When this happens it causes a bit of valve chatter as the lobe tip
runs across this transverse groove in the follower and that in turn causes several things to happen...

1)It crachs the hard surface of the case tip of the camshaft lobes.
2)It creates a smaller transverse band across the face of the follower.
3) IF the factory knock sensor is installed and connected it "Hears"
this noise and interprets it as spark knock and then the worst thing happens...

The PCM pulls timing in 3degree steps until it doesn't hear the noise and it dumps the boost
through the Boost control solenoid.

The problem is that the computer also turns the timing back up in 1/2degree steps....

The first "fix" is to install a 1988-94 Ranger camshaft with it's roller followers.
(no noise, no "phantom knock" symptoms.)

The second is to eliminate the factory boost control solenoid and replace it either with a "fishtank bleeder" (ample descriptions can be found on the web)
OR installing the stand alone APC system robbed off of a 1982-1/2-1994 Saab 900 turbo.

AD

 

[scotts90ranger]

Back when Dave R was around here, he used to say the Autolite 764 spark plugs were the ones to use, so that's what I use. What Allan said is good too, since I was starting with a '89 2.3L ranger I stole the cam when I did my swap, now I have two sliding follower cams sitting gathering dust... I haven't even been able to find a buyer at $20 per cam with followers...

 

[--weezl--]

i've always been told to stay away from platnium plugs in fords... not sure exactly why, but heard it from more than 1 person...

autolite are definately the brand to go with, IIRC, that's what ford uses from the factory

 

[alwaysFlOoReD]

It just so happens I was reading the back of the Champion spark plug catalog last night, serendipity or what.... OK, or what, my wife's on holidays, what can I say other than I'm really not that boring in person. Anyway, there was a blurb about DIS and wasted spark systems and how hard the spark traveling in reverse was on platinum plugs. IIRC the fix is double platinum plugs, something about less wear when both the giving and receiving ends on the spark plug are platinum.

Richard

 

[scotts90ranger]

If he's using a stock '87 setup, it's still TFI with distributor

 

[Joe Lemay]

Wow Guy's!!! thanks for the great input. Plugs are a cheap start and I'll keep my eyes open in the yards for the Ranger.

 

[--weezl--]

It just so happens I was reading the back of the Champion spark plug catalog last night, serendipity or what.... OK, or what, my wife's on holidays, what can I say other than I'm really not that boring in person. Anyway, there was a blurb about DIS and wasted spark systems and how hard the spark traveling in reverse was on platinum plugs. IIRC the fix is double platinum plugs, something about less wear when both the giving and receiving ends on the spark plug are platinum.

Richard

doesn't change the fact that ford (vehicles) still dislike platinum plugs

 

[Joe Lemay]

Thanks again guy's! Thanks to you , you got me on the right track. Got the Autolites, set them at .044 no change. Reset @ .025 along with a new coil ALL BETTER! Truck fly's!