Gonna try again ... Need ideas about hesitation on light throttle

Topic: Gonna try again ... Need ideas about hesitation on light throttle (Read 3495 times) previous topic - next topic

Gonna try again ... Need ideas about hesitation on light throttle

Reply #15 – January 02, 2008, 12:11:04 AM

take a look at the pic and zoom in on the injector screen. Just start a screw into the top of the injector and pull hard.

Now, when i pulled mine, the screens were squished closed sort of. In addition, there was some blockage of light passing through the screen. I agree it does not make sense in your case,, and as well my case.

All i can tell you is that my slight hesitation all the way up to a full second or two of feeling like it boggs out all went away when the screens were tossed.

Now,, take a look at another thing as well. What is your fuel presure? If your cfi has a freeze plug on top, drill a hole in it and then use that hole to pop out that cap. Adjust your fuel presure to about 42psi.

You can also do an experiment like i did.

Pull out an injector and remove one screen. leave the other screen in on the other injector.

fill both injectors up with fuel or dry cleaning solvent.
hook up each injector to 12vdc and watch how quick the fuel pours out of the injector that has no screen. Now imagine what new screen filters would do?

its up to you,, you asked for an opinion and like i said,, this is what finally cured my hesitation after years of g around with other parts. As i said before, mine at wot was fine also,,it just seemed like most of the time there was a hesitation or a delay in the pedal response.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #16 – January 02, 2008, 07:36:01 AM

vacuum? Needs vacuum at idle, doesn't at high rpms?

Gonna try again ... Need ideas about hesitation on light throttle

Reply #17 – January 08, 2008, 10:31:43 PM

Quote from: jcassity;195415

Now, when i pulled mine, the screens were squished closed sort of. In addition, there was some blockage of light passing through the screen. I agree it does not make sense in your case,, and as well my case.

Didn't mean to sound argumentative. Your last post about "fine at WOT" now sounds pretty much exactly like my problem. Dead for nearly a second with a light throttle change, and surging under constant light throttle. Did yours also idle well? If mine has ever stalled, it's because I was trying to get it to by goofing around with it. When I can get it to sit still long enough (too many trips for an 18 yr old's social life) for me to yank the throttle body off, it's gonna get a thorough cleaning, and possibly new injector filters, if I can find 'em. I'll attend to the EGR then too. I'm sure it's probably full of crud again.

I'll give it a spin when the better half can let me have the car a couple days. She won't drive my F-150 cause it's a manual, so I await the inevitable pulling of the CFI. Probably wouldn't hurt to give it a good cleaning and new gaskets/o-rings while I'm at it.

One more ? What is that really nifty looking little vacuum operated valve between #5 and #6 intake runners for? Is that for warming the intake? I don't find that in the vacuum diagram (on the vehicle or in the Haynes manual). Best I can tell, it closes when the engine is up to temp.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #18 – January 08, 2008, 11:46:44 PM

I believe you are talking about the exhaust heat control valve.

Warm exhaust heats up the intake on a cold engine.

The EEC controls the vacuum to it with one of the solenoid controlled vacuum valves under the coolent expansion tank.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #19 – January 09, 2008, 08:51:46 PM

That was my assumption. It appears to be working, and it was just curiosity more than anything else. The other part of the curiosity is why it doesn't show up in the vacuum diagrams. My guess is, if the EEC controls it, that it uses either the ACT or ECT to determine if it should be open. I never really noticed it on the diagrams for the EEC either. At least not in the diagrams that are in the Haynes manual. I've found numerous other bloopers in that diagram as well, so I'm not surprised.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #20 – January 10, 2008, 10:18:53 PM

Quote from: Old_Paint;196799

The other part of the curiosity is why it doesn't show up in the vacuum diagrams.

The vacuum diagram on the fan shroud of my 84 3.8L shows the Heat Control Valve as "C/O HCV". I don't know what the C/O stands for.

Quote

My guess is, if the EEC controls it, that it uses either the ACT or ECT to determine if it should be open. I never really noticed it on the diagrams for the EEC either. At least not in the diagrams that are in the Haynes manual. I've found numerous other bloopers in that diagram as well, so I'm not surprised.

EEC pin 55 controls the exhaust heat control solenoid. This is unique to the 3.8L. Maybe those manuals concentrate on the 5.0L.

My car has the same problem as yours. In my case it will go away if I disconnect and plug the vacuum line to the EGR valve. Unfortunately this doesn't work for you.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #21 – January 10, 2008, 10:52:16 PM

I'm sure the EGR plate is plugged solid with crud. I pulled it off and cleaned it years ago, when the car was about 5 years old. The ex used to drive it all the time, and never had a trip more than 5 miles in the thing. Needless to say, that's a lotta rich sooty exhaust because the engine never really got warm.

I may take the new Mrs. Paint to work Sunday so i can have the 'bird all weekend to work on it. Gotta round up parts tomorrow, though, for certain. I may just drop two new injectors in it for gins and griggles, while I have the CFI apart. I'm sorta debating a CFI from a 5.0, for the larger venturis. Won't be a huge difference, but should make a little bump in a very anemic 3.8. Gotta try to find someone to build an exhaust for it. Ford did their homework on these things. The factory exhaust is still intact, except the ler, and no leaks (except through the gigantic holes i the ler). That's not bad for a 21 year old car.

Eventually, Mrs Paint gets a new ride (she wants a Charger or Magnum). Then, ol' Blue is mine to play with. Right now, I just have to keep it running for her daily driver. I'll have a look again at my Haynes, but I don't remember anything about the intake heat valve. I may have just overlooked it though.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #22 – January 11, 2008, 04:30:12 PM

Quote from: Old_Paint;197088

I'm sorta debating a CFI from a 5.0, for the larger venturis. Won't be a huge difference, but should make a little bump in a very anemic 3.8.

There are more differances than just the size between the 3.8 and 5.0 CFI.

The 5.0 does not have the PCV port on the back of it.

The 5.0 does not use a ISC motor like the 3.8.
It uses the carburetor type stuff:
Fast idle cam, Auto-choke bi-metal spring thing and a vacuum pull down. It also has a vacuum operated throttle kicker.

I don't know if all that stuff can be removed so you can still use the ISC motor. Maybe someone on here knows.

For sure you will have to find another way to get your PCV hose hooked up to the intake manifold

Gonna try again ... Need ideas about hesitation on light throttle

Reply #23 – January 11, 2008, 11:03:33 PM

yes the 5.0 cfi can work on the 3.8 engine.

you just have to hacksaw off the rear pass side choke pull off, toss it.
Install your ISC right where the old one was.
The 5.0 injectors deliver too much fuel to the 3.8 so your green tops need to go back in. The gain is air flow only and thats helped me out a lot.
As for the pcv port on the lower rear driver side of the CFI,, no biggie, you dont need that either. ALL the vac you need is on the vac tree bolted to the rear center of your intake.
Basically to use the 5.0cfi, all you have to do is make your 5.0 one look like the 3.8 one which is very very easy. Even the butterfly linkage on the 5.0 will work out, youll just have this stubby part sticking out past your tps.

You need to yank out the smog tube from the pass exhaust and then get down there on the header and pinch off that with your vice grips.
next you ened to undo the smog line on the rear of the intake and or remove that check valve and replace it with a bolt.
next, plug off the tan, black lines for the smog.

next, remove the pully off the smog pump and then, pry off the plastic impeller from the face of the pump.
next , run down to the napa and get a 77 1/2'' belt and install it. You are bypassing the smog.
I was throwing belts for a long time and one day i decided to check all my pullys after the car had warmed up. Sure enough, the water pump, power steering , and idler all checked out fine with the belt removed. I spun the smog and it was hard to do so it was time to decommission it.

once you do all ive said,, your egr will no longer clog up as i had perfect results of no cloggage afterward.

Yes my car hesitated from a dead stop to agressive throttle like there was no spark or fuel then suddenly came to life.
Idle was perfect, no miss or anything.

pull them screens and clean that cfi.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #24 – January 12, 2008, 04:41:27 PM

Quote from: jcassity;197272

As for the pcv port on the lower rear driver side of the CFI,, no biggie, you dont need that either. ALL the vac you need is on the vac tree bolted to the rear center of your intake.

The PCV is kinda on the oily side. Are you sure you would want that going into the vacuum tee?

Quote

You need to yank out the smog tube from the pass exhaust and then get down there on the header and pinch off that with your vice grips.
next you ened to undo the smog line on the rear of the intake and or remove that check valve and replace it with a bolt.
next, plug off the tan, black lines for the smog.

next, remove the pully off the smog pump and then, pry off the plastic impeller from the face of the pump.
next , run down to the napa and get a 77 1/2'' belt and install it. You are bypassing the smog.
I was throwing belts for a long time and one day i decided to check all my pullys after the car had warmed up. Sure enough, the water pump, power steering , and idler all checked out fine with the belt removed. I spun the smog and it was hard to do so it was time to decommission it.

once you do all ive said,, your egr will no longer clog up as i had perfect results of no cloggage afterward.

Are you saying you must remove the smog pump stuff to use the 5.0 CFI?
What do you think makes the EGR be cleaner?

Gonna try again ... Need ideas about hesitation on light throttle

Reply #25 – January 13, 2008, 10:00:38 AM

The pcv on the cfi 5.0 does not go to the driver rear side. I am not sure where ford decided to hook it up but there are no fittings for the pcv present. I wonderd the same thing, "why the 3.8 got this and the 5.0 did not". This got me to thinking about the likelyhood that the power would be reduced in the long haul due to the CFI sucking in crank case vapors and dumping it into the intake.

For the smog,, I was just babbling. If his system is broken (valve stem seals,guides ect) and new parts are nto going in to fix the problem, he might as well not keep dumping crud back into the burn cycle.
You dont have to delete smog to use the 5.0CFI on a 3.8.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #26 – January 13, 2008, 10:48:26 AM

I'll throw out one idea.

Ford used to make a split wire rotor for the distributor that came with my 1984, instead of the solid T rotor. Per shop manual the idea was to get a gap in the spark between the wires instead of holding it for the length of the T. IN FACT Shop manual says NOT to use the T type rotor.

Unfortunately, after market stopped carrying them about 15 years ago. Ever since, I've had a similar periodic problems, especially from a dead stop.

Gonna try again ... Need ideas about hesitation on light throttle

Reply #27 – January 24, 2008, 10:53:47 PM

Quote from: jcassity;197464

The pcv on the cfi 5.0 does not go to the driver rear side. I am not sure where ford decided to hook it up but there are no fittings for the pcv present. I wonderd the same thing, "why the 3.8 got this and the 5.0 did not". This got me to thinking about the likelyhood that the power would be reduced in the long haul due to the CFI sucking in crank case vapors and dumping it into the intake.

For the smog,, I was just babbling. If his system is broken (valve stem seals,guides ect) and new parts are nto going in to fix the problem, he might as well not keep dumping crud back into the burn cycle.
You dont have to delete smog to use the 5.0CFI on a 3.8.

As best I can tell, it's all still working. With the huge holes in the ler, you can hear when the AIR bypass shuts off flow to the cat, and the exhaust thumps a little from unspent fuel hitting the cat. The IAC will hold the throttle at high idle for a split second until the AIR closes, then chops to idle. Even though the termites have been chewing on the OE ler for several years, it still isn't loud. Still, it's time for a new ler. I don't recall any tube from the AIR system to the right or left manifolds. That doesn't mean it isn't there, though. I know the check valve you speak of at the back of the intake, and then the long tube going back to the cat, then the dump ler. Drop that pump, the diverter, ler, tube to the back of the engine and to the cat, and bingo, instant real-estate.

I'm not kidding myself thinking I'm going to have some sort of hotrod with a strangled 3.8 V6 in it. I'm not looking for huge gains, just a little more of what the engine should be capable of. I may do the 5.0 CFI if I can find one. I didn't figure the 3.8 was gonna digest the same amount of juice that a 5.0 needs either. I want the old girl to run until I can build up a 5.0 and AOD package to drop in. I need it reliable right now, cause the missus needs it for work. If she gets the new Charger she wants for anniversary/birthday/Thanksgiving/Christmas/MLK Day/4th of July/Australia day, then once again, it'll be my toy.

I just wonder why no one ever spent much time on aftermarket upgrades for the 3.8. I guess that's because the CFI 3.8 was relatively short lived. Didn't the 87 3.8 have SEFI? I know 84's were carbed, leaving only 85 and 86 with the CFI 3.8. It was like Ford rushed their EFI technology before they were ready to make manifolds and better head gaskets. Dunno. I really wanted the V8 when I bought the car, but insurance at the time was nearly double what it cost for the V6. I was just penny wise and dollar foolish at the time. The V6 was classed as a 2D sedan, but the V8 was classed as a coupe. Go figger.

Did the 5.0 CFI body make a significant difference in the performance? Or was the smog delete the largest contributor? Getting rid of that pump and associated plumbing on that side would sure make plug changes a lot easier. I may consider a custom exhaust on it too. I'm sure the cat's done what it's going to do on a 22 year old car. I don't intend to spend another $200 for a cat if I decommission the other smog junk. How hard is it to run true duals on these old birds? I know it's best to keep the exhaust as far away as possible from the fuel line to prevent boiling the fuel.

Is the PCV being combined in the same spacer plate what you attribute to the EGR gunking up? Never really thought about it, but I guess that makes sense if you're blasting oily vapors with hot exhaust when the EGR opens. It might make more sense to attach the PCV to the tree. The 5.0 has a different issue with PCV plumbing, but still PCV related. Don't see where it should hurt anything to relocate it to a different vacuum point, regardless of the oil vapors. My only concern is if some of the other devices want to collect that vapor, such as the MAP, vac reservoir, etc. What about a T in the brake booster line? Or is there a safety implication there? I take it you just left the TAB/TAD valves in place to keep the EEC from squawking about 'em. What about hanging an equivalent resistance across the connections at the ECM harness and delete those too? I'd like to shorten up and clean up some of the clutter in the vacuum lines, and maybe delete some of the unused wiring out there. Don't wanna lose the cruise control, though. It works very well on this old car.

She's got her problems, as any 22 year old car would have that's still running on mostly OE hardware. It's had shocks, struts and mounts, new rotors/bearings up front, and a new long block/timing cover, but otherwise, she's still factory bone stock. She's more a keepsake now (first new car I ever bought) and I just want to keep her running for nostalgic value, and fix the broken bits and pieces. The ex wasn't very nice to her, but that's a chapter best left outta the book. Eventually, I wouldn't mind adding some muscle to a very classic and classy automobile.