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Topic: Boost coming in late (Read 3446 times) previous topic - next topic

Boost coming in late

OK here I I'm again with and issue let me go through rundown of what I've done. In March intermittent shaft broke some teeth and stripped if some teeth on dis. So I ordered the shaft from Esslinger racing and installed it with the new  brass dizzy gear. I went ahead and installed a new fuel pump because I had to change the tank year ago which it came of a v8 sport tbird which didn't have the right fuel pressure. I got car I think in time all my markers r gone so I adjusted to the best of my ability car cranks and runs good has a rough idle but it's been doing that since I've owned the car. I know I probably have vacuum issues thats something I'm going to get to soon but my big problem is my boost is coming in around 2500 and pulls good but only building 6lbs of boost according to boost gauge the gauge didn't work when I first bought car but it ran whole lot better them b4 the gear broke it was only building 6lbs boost so I assumed it was fuel pressure but now it's still only 6lbs but that don't bug me as much as it coming in later in rpms it feels sluggish. I wonder if maybe my cam is advanced a tooth and maybe I should retard it a tooth the car is stock no mods just air cleaner. I also thought maybe my timing is out a tooth it took me a little bit to get it right with no markers but it cranks pretty good not as good as last time but it's not running as good as it was b4 gear broke. I just wonder if I should move the cam to retarded side but I need to know which way to go so I don't get it to far of then drive see what happens then go to dis and try timing again. I just want it to run better than it did. I've read on the forums that the cam is 9.5 degrees a tooth thats y I'm thing it could b advanced a tooth I don't have no spark knock like I used to but my power band sucks. I drive n town and up 25-35 mph hills and car lags bad. Any help any better than none. Thanks

Boost coming in late

Reply #1 –
Well, first...please break up your wall of text next time. Tedious to sift through all of that.|

Second, if you don't have your timing marks, and just guessed at the cam alignment, I'll bet that it is not correct.

Simple check. Set the engine at TDC. Use a straight edge or piece of string and run it between the centers of the cam and auxiliary (not intermittent) shaft bolts. The index mark on the cam pulley should line up with that line. If not, your cam is out of time with the crank.
Long live the 4-eyes!  - '83 Tbird Turbo

Boost coming in late

Reply #2 –
OK don't know what talking about a text wall this ain't the first time I've discussed things on this forum.
This ain't the first time I've had to retime this car it's about 4th time  but I do think it's out but I've moved it both ways a tooth at a time and it cranks and runs I'm going to try moving distributor again
As far as cam I just need to know which way to move to retard or advance
The last time I timed it fired as soon as I hit switch so I can time it ( just trial and error)
It's just a few other things I need to know

Boost coming in late

Reply #3 –
Check the cam timing. Don't just randomly move it.

Get a timing light to check ignition timing after that.

Don't guess. Know.
Long live the 4-eyes!  - '83 Tbird Turbo

Boost coming in late

Reply #4 –
Thanks. I wish I knew that awhile back lol. I'll check the cam but I do think it is
I would like to get it back to where it was b4 I the it broke, it was a little lean and spark knocked b4 boost but it ran pretty good now it feels sick.
Hopefully do some adjustments and it be right

Boost coming in late

Reply #5 –
Helpful article can be found HERE.
Long live the 4-eyes!  - '83 Tbird Turbo

Boost coming in late

Reply #6 –
OK let me give the run down on what I did today
I got it up on tdc and made sure by pulling plug and using a screwdriver
The cam lines right up to the auxiliary using a piece of wire it's not dead on but it's real close,it's nt even one tooth out so don't think that's problem.
I pulled distributor cause were it was set at it wasn't quite right,so I pulled it out and moved it down one tooth.
Car starts up good but when I drove it my spark knock was back,but power came n decent right around 3k+rpms.
So I got back home move dis.just enough that spark knock went away but now my power has fell off a little.
How much boost is the 88 TC supposed to build n stock trim?
Unless my guage ain't right or I got vacuum leak I'm still only building about 6lbs of boost.
I'm wondering if I have another problem, like tps or vam.
The next thing is when I got the new fuel pump I couldn't get the fuel pump filter for that pump I had to get one for a v8 fuel pump. Is there any differences
The car has new motocraft plugs and wires, new dis,new fuel pump,new fuel filter.
I replaced 2 bad vacuum hoses going to turbo and no difference.
Any thoughts

Boost coming in late

Reply #7 –
A 1988 5-speed should make 15Lb boost, ones I've owned were all in by 2500-3000 RPM(one was making full boost at 2K but it was modded turbo, found out from buddy who bought it hot side had extra vanes)... A automatic will make 8-9Lb at approx same RPM range...

AFAIK there is no difference in turbo & V8 strainer... I used 5.0 kits in several TC that I repl pump, other than hose connecting pump to hanger was different, those were otherwise identical...

Boost coming in late

Reply #8 –
OK thanks
If this car make that much ten I can't figure y my don't.
My car is a 5pd swap but I when I swapd it I used all parts off door including the ecm.
I've had some issues like rough idle and erratic idling when u first crank it.
Boost comes in 2-3k rpms but only 6lbs full throttle.
I'm trying to figure this out, I don't know that much about turbo cars I know they r kind of temperamental.
I didn't think that the fuel pumps had same pressure, if I knew that I wouldn't have changed pumps the other was working,but I was told they had lower pressure and when I swapped the tank a couple of yrs ago car started running lean so I just assumed it was fuel pump.
Right now car feels sluggish then boost comes in and it goes but it still don't feel right.
It doesn't really run rich and it is little bit lean spark knock does persist b4 boost and my mpg isn't that bad but not that good either.
I haven't changed tps yet.
I know I need to have timing set by timing light but I ain't got one, so I play it by ear and smell.
Just wondering if there something I'm missing.
Maybe some ideas. I just don't know what else to do.
I did swap vam and tps and a couple of other parts from donor car and car runs the same.
Right now I'm at a loss.
If it is timing or cam timing I could understand but if I move the distributor a 1/4 inch it goes from lean to rich so I try to dial n to where it's not to rich and it response good, but I still got spark knock like it to lean.
I'm wondering if I should get an adjustable cam pulley, cause my cam isn't dead on the mark but it's to close to want to move. Maybe I alt to to c what happens.

Boost coming in late

Reply #9 –
You need a compression test, and you need to inspect the wastegate.  I dealt with an XR4Ti (same engine) some years back that had a leaking wastegate and it boosted late and low, 5 or 6 psi, I don't remember exactly.

Boost coming in late

Reply #10 –
The wastegate bleed fitting on turbo is different for stick vs automatic, you'll never get same boost as a stick...

Disconnect the BCS and jumper a short piece of hose between ports on turbo, with auto turbo should get approx 12 psi boost... At least my white Bird would when it still had the four banger...

Boost coming in late

Reply #11 –
Ok .. I do think my waste is leaking. I can hear leaking while its n full boost. I've checked all my vacuums and replaced a couple of bad hoses. What I need to know now is where can I find a waste gate. Can I use a aftermarket one and if so what will fit. Car is running better but still not right and I think I need to replace tps

Boost coming in late

Reply #12 –
OK thanks. Is the BCS that round thing on fenderwall that has two hoses and and wire connection going to it. If so u say take the two hoses off and jump the two ports together and just completely in hook the bcs

Boost coming in late

Reply #13 –
Yep that's the deal...

If wastegate diaphram is leaking it will overboost... If W/G door isn't closing completely, boost will be late and/or low...

Boost coming in late

Reply #14 –
Ok..thanks..I'll do that tomorrow b4 work was going to do today but wasn't actually sure. Where can I find waste gate