swapped explorer intake on, runs rich/bogs, please help!

[v8only]

--------------------------------------------------------------------------------

progress.....perhaps.

I haven't had ANY time due to being on call this week, I've already put 70 hours in, and this weekend isn't even here yet.

however for a friday treat, I went straight home after work and disconnected the brake booster line from the vacuum tree and stuck that puppy in mouth and sucked like Ginger Lynn.

First observations is that it seemed to be a lot easier to suck in than sn boosters I've tried this with at the junkyards. (no I couldn't find a vacuum pump just yet. My bro has ours, and autozone doesn't have any to loan). I then sucked sucked sucked using my tongue as a sort of wratchet to build up extra pressure, then held for a moment. Moments later I tried sucking even more and could.

Unofficial observations lead me to believe my 186k mile oem booster has gone south.

I went ahead and fired her up with nothing connected to vacuum except pcv, map sensor, and fuel pressure regulator, and let her idle and revved the hell out of her. absolutely no popping and no bogging whatsoever. This is good news. I then stuck my nose up the tailpipe and got no wiff of rich fuel whatsoever, even during cold operation.

Unfortunately the tanks is just about dry and I can barely keep my eyes open, so a test drive will have to wait for tomorrow or Sunday. I will keep you all posted. FYI, this is the best this car has ever run yet with this intake, so I'm just about postive it's nearly dialed in to at least drive and play with now. I'll update further this weekend after the test drive.

If it is a bad booster, my guess is going to this bigger ported gt40 style intake had less vacuum than the oem intake, thus making a slightly leaking booster a much bigger deal.
__________________

 

[jrichker]

The rubber grommet that holds the booster vacuum check valve is a known leak culprit.

 

[v8only]

yea, I am worried about that. It's new, but it's an autozone replacement generic one size fits all. I'll have to see if it's coming from there.

 

[tmoss]

your getting close to solving this thing - then it will drive fine.........good work!

 

[v8only]

very close, finally. I'll drive her tomorrow and update. Once I get it to the point where everything is on that I want on, I'm gonna get it dyno'd and a tune so I know where I need to be with timing and fuel pressure etc.

Here are a couple of pics. Ugly engine bay eh? Just as soon as I can stop concentrating on the motor, engine bay cleanup and restore will commence, polishing and clear powdercoat of accessory brackets too. Something I should have taken my time with before I dropped in the motor.

it's not coming along too badly for being broke.

 

[v8only]

I'm contemplating what to do now. I went out there with an official vacuum pump and squeezed the hell out of the handle, and couldn't get any vacuum at all. Either the plug on the booster (new from autozone) is bad, or the booster is. I'm leaning toward the booster.

50 proof gave me his oem one from his 86. although it's got 200k on it, it does hold vacuum. I'm not sure I want a huge project with hogging out firewall holes and knocking the strut tower, as my brake swap won't be for some time.

decisions decisions. Ironically, this was likely the problem all along, I just didn't notice it with the smaller intake, who would've thought eh?

never took it for a test drive the first time, so I never had to step on the brake pedal and never found out.

 

[v8only]

Well, I finally took it for a test drive! (with no brake booster)


First thing I did was pump the timing up to 15 degrees. I then turned right on our empty street a few blocks from my house. Not expecting much (as usual) I nailed her to the floor. First gear lit up like the house from lampoons christmas vacation. the rear end got squirly and she spun it right till 6k. It spun so damn bad, the car wasn't moving too quickly.

I shift her into second with the speed of a kid going after an ice cream cone and nail her. MY GOD, she pulled and pulled and pulled. Shifted into third gear, well now, what is this we say, I"VE GOT A THIRD GEAR. This car has NEVER pulled like this ever. It feels like a literal 100 horsepower over last test drive.

guys, thanks so much for your help on this one, this motor is actually beginning to exceed my expectations for once.

 

[gruvee87vertgt]

subcribing.

 

[OrLackThereof]

That sounds more like it.... There's a lot of power to be found between fixing problems that you think are only little....and dialing things in. Keep tinkering with it and be patient and you can get that sucker dialed in reaaalll good.

 

[v8only]

I at first was convinced the speed density and stock HO cam were holding me back. I've gone from that to deciding to hold off on the mass air swap, keep the HO cam for some time, andkeep dialing it in. I've got a BILLION touch up things to address, then I'm going to have to dyno it so I can see where I'm at. I do feel, like TMOSS did for himself that I'll need an adj fuel pressure regulator so I can bump up the fuel pressure. That stock 200k 4 catted h can't be helping too much either.

Perhaps the biggest thing to overcome though is traction issues. My bro, with the same combo (but gt40 heads and unported explorer intake) couldn't best 15.3 at the track because he did nothing but spin em.

 

[OrLackThereof]

Perhaps the biggest thing to overcome though is traction issues. My bro, with the same combo (but gt40 heads and unported explorer intake) couldn't best 15.3 at the track because he did nothing but spin em.

Well if you want to ET, youre better to bog a little and pedal it. I can't hook up for sh-t on the street with my combo, if I'm in it hard I will be sideways through all of first gear, and still sideways through second gear up to about 70 mph before I hook.....but I can still manage high 13's on street tires. Just leave the hole conservatively, at maybe 25 psi rear, 40 psi front, for street tires....and slowly ease down on it....the drivetrain shock from hammering it, ESPECIALLY in a manual, has a LOT to do with traction loss. Get some nice sticky street tires and play with it for a few passes, you'd be amazed what you can drop off your time.