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Topic: Exhausted over HCI swap problem (Read 4377 times) previous topic - next topic

Exhausted over HCI swap problem

A while back I built the following:
Stock re-ring, reman crank, file fit rings, new oil pump...etc
World Windsor JR heads
Stud mount roller rockers
New lifters
New Double Roller timing chain
TFS-51402000 cam
A9l mass air conversion stock mass air sensor
T5 conversion.
ARP Head bolts
Cheapie Professional Products Typhoon Intake


Clayed the PVC, checked all the tolerances, file fit the piston rings for perfect clearance.  The bottom end runs smooth and runs quiet.

New FPR and filter.

But I cannot get the  thing to idle below 1100.  It runs strong in higher RPM bands.  Sometimes when its cooler outside, it wants to idle around 1900....very annoying :mad::mad::mad::mad:  It will also try to idle high after a good WOT run. Turning the car off and back on will have it settle down to 1100 again.

Codes deal with the emissions stuff that is not hooked up.

Things I have done:
1. I have checked a million times for vac leaks, I am certain there are none. 
2. Removed the IAC, cleaned Installed.
3. Removed IAC disassembled, cleaned, reinstalled.
4. Swapped IAC with one from another engine
5. Installed new IAC
6. Set TPS voltage.
7. Swapped TPS with another.
8. Installed TPS
9. Reset the Idle per multiple methods about 1 million times.
10. Readjusted the valves (I am about to try this again using my dial gauge).
11. Checked IAC Voltage

If I disconnect the IAC, and adjust the idle, the computer will compensate the timing to kick up the idle and wont go below 1000.  If I pull the spout it will let me adjust it down to around 900.  Any lower and it starts to surge or tries to stall.  Once I plug the spout and the IAC back in it shoots back up to 1200 or so.

Is there anything I have missed?

EGR is attached but is ornamental (no vacuum source) but it seals good and would probably work if hooked up.

I will pull codes again tonight to see if there is anything new as my girlfriend has been daily driving the car lately.  Maybe I will get a vid.  I am starting to think about pulling a whole harness from the Junkyard.

Thanks.
My car is a gravity hybrid.  The gasoline engine gets me up the hills, and gravity gets me down.

Exhausted over HCI swap problem

Reply #1 –
Codes?
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Exhausted over HCI swap problem

Reply #2 –
Put up what codes you have. Also have you done a cylinder balance test after running codes?
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Exhausted over HCI swap problem

Reply #3 –
Could the timing be off?  I am having a similar problem but not as extreme as yours.
'88 'bird, 10.9:1 306 w/TFS top end, forged rods/pistons, T-5 swap & bunch of other stuff, 1-family owned, had it since ‘98, 5.0tbrd88 on Instagram and YouTube

Exhausted over HCI swap problem

Reply #4 –
How about the screw in the TB.Or binding in the throttle linkage. also what injectors and maf,are they matched?
Just throwing some things out there. "Possible bad vac. leak." Lower intake spray it down running, see if it changes rpm.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Exhausted over HCI swap problem

Reply #5 –
Quote from: Kitz Kat;338703
How about the screw in the TB.Or binding in the throttle linkage.

that seems to be the #1 problem when the IAC and TPS check out fine

Exhausted over HCI swap problem

Reply #6 –
I'm thinking more a vac leak, check it it sure sounds like it.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Exhausted over HCI swap problem

Reply #7 –
Specially the ends of the intake, A vac leak will cause a idle issue. Not sure how you put the lower intake on, everybody has there own way, I know I have mine and never had a leak.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Exhausted over HCI swap problem

Reply #8 –
I will check again for air leaks.  Ive spayed around with brake clean before to no avail.  No binding in the throttle linkage...nice and smooth.

I did try this however.  I removed the screws for the tps and let it hang loose.  Then i started it and set the base idle.  I was able to get the base down into the 800 range without surge.  I notched the tps holes and reinstalled it at exactly  .89 v.  Started it and it idles pretty reliable at 1000ish. 

I will check timing but i think i had it set at about 14. 
Stock maf and 19#ers.
My car is a gravity hybrid.  The gasoline engine gets me up the hills, and gravity gets me down.

Exhausted over HCI swap problem

Reply #9 –
I'm still leaning vac. small hose disconnected. Cam timed right? like I said throwing it out there. It's not hard to overlook the simple things.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Exhausted over HCI swap problem

Reply #10 –
Man these things can be so frustrating.  Hope you figure it out soon!
'88 'bird, 10.9:1 306 w/TFS top end, forged rods/pistons, T-5 swap & bunch of other stuff, 1-family owned, had it since ‘98, 5.0tbrd88 on Instagram and YouTube

Exhausted over HCI swap problem

Reply #11 –
Codes...
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Exhausted over HCI swap problem

Reply #12 –
Quote from: Haystack;338839
Codes...


Followed by a vacuum test....

FWIW -- Swap out that MAF and injectors for a matched set using 24 pounders for that combo and use at least a 155 LPH pump.....

WIth a stock HO MAF and 19's at stock pressure I'll bet you'll see a code that says the adaptive fuel strategy lean limit has been reached......
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Exhausted over HCI swap problem

Reply #13 –
Welcome to the world of performance cams and stock electronics, mine has had some surge on cold start from day one, but has never increased in idle...

What is the TPS voltage???(.999 I bet) If so reduce it to around .9 and no higher to see if it helps with the hanging idle, do so after setting the base idle... I use around 900-950 RPM in gear, but mine is AOD...

EDIT

Paul may well have something, I didn't realize you had a stock MAF on it... But thinking back, I don't remember having any more/less of a idle problem when I ran the stock meter and 19lb inj...

Exhausted over HCI swap problem

Reply #14 –
Just a shot in the dark but how are your grounds? Bad grounds will cause some strange problems.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.