North American Turbocoupe Organization



Still only pulling 16" of vac at warm idle and 10 PSI max
Ryan H Offline
Posting Freak
#1
Full background..

Did a full head gasket job, replaced every gasket on the upper half of the engine. Also put an IHI w/ new center section in and braided oil line. Reused the stocker return line, it was in good shape. Replaced the lower coolant hoses also while I was in there.

I am only getting 16" of vac at warm idle now. I was getting 17-17.5 but I used some Sea Foam and it went down. Apparently whatever is leaking got more "un-clogged" from the Sea Foam.

My car was doing the "buck stutter and hesitate" dance, so here's what I did last night/today.

- New timing belt/tensioner.
- New fuel filter.
- New cap, rotor, plugs, wires. Cleaned the K&N.
- New Ranger valve cover gasket to replace the crappy FelPro cork gasket.
- New "quick fix" IC hoses.
- Added my Aeromotive FPR and adjusted the pressure to 42 with the vac hose off.
- Zip tie secured all major vac lines.
- Replaced the PCV valve and upper PCV hose with some silicone hose and hose clamps.

- Ignition timing is at 12*
- BCS is bypassed.

I'm only getting 10 PSI now. The bucking/stuttering completly stopped and the idle stays pretty steady at 1000, sometimes 1100. I took my vac gauge and hooked it to the vac tree. I then unplugged each hose, one by one and plugged them. The vac never increased. I also sprayed starting fluid on everything I can think of that holds air and the RPM never raised at all. I'd like to think it doesn't have a leak anymore since the bucking and all stopped and the computer comes up empty with codes. Of course I could be wrong and I'm open to suggestions!

On edit: I'd also like to add that I've got a few worn cam lobes. I read a previous post by Pete D stating something about shims on the followers gaining 2" of vacuum? My car never had this problem before I did the head gasket and stuff, so something had to have changed. Which forms of timing can affect the vacuum reading?

Thanks again!

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Ryan Harris

88 TC, 5 speed, B&M Ripper Shifter, Walbro 190 LPH, Aeromotive FPR, K&N, 3.73's, 88K miles

[This message has been edited by Ryan H (edited 08-17-2005).]
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Ryan H Offline
Posting Freak
#2
I have heard of the timing marks being way off before. I just checked mine and they do seem off to some degree, at least the crank cover ones do. I took the pulley off and use the cast timing alignment marks to line up the crank, and slipped the cover back on to get an idea. It was off by a few degrees just from glancing at it, which makes me question my cam timing pointer.

When I rotate the cam sprocket and it gets to the #1 intake stroke, the sprocket likes to land on the far left (passenger side) pointer, instead of the middle pointer. Is it supposed to do this and I move it backwards to the center mark, or is it supposed to be landing on the center mark? Does anyone have the answer to this off the top of thier head and/or recall having to set the sprocket backwards a little to match the marks up?

I'm almost positive that my low vacuum and boost issue are directly related to my cam/crank timing now. I literally SOAKED my engine in ether (I was scared but I had the fire extinguisher ready LOL) and the idle speed did not raise one single bit! I hit the throttle body really good, all over the lower intake and I got underneath it real good. Blasted all of the vacuum lines as well as sprayed down where the cruise control lines go. Nothing!
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Pete D Offline
Administrator
#3
Quote:Is it supposed to do this and I move it backwards to the center mark, or is it supposed to be landing on the center mark

It should land on the center mark as you rotate the crank/cam/aux shaft clockwise. You should not be turning the engine counter clockwise as far as settings go because of "freeplay" (slack).If you do turn it counter clock wise (CCW), you need to turn it CCW further than needed then reverse and go clock wise to what ever point you want to check. Going in the clock wise direction takes the slack out.

I said it should land on the center mark and that is true for an uncut head. As I said earlier, a shaved head may not line up exactly but how it lines up depends on the amount it been cut. I don't know what the ratio is. From what I can gather it should line up within 1/2 tooth. If it is off a full tooth or more, it probably just isn't set correct. See next paragraph

Each tooth on the cam/aux shaft pully represents about 9.5 degrees AT the cam/aux shaft, which turn at 1/2 speed of the crank

If I remember correctly, when I degreed my cam using the method provided by Turbo Ray at TF, It was less than 2* (at the crank) off relative to the marks on the cam belt covers. I did rescribe the crank pully to reflect this. I was surprised it was this small, given what I perceived as the slop in the covers.

Cam timing can affect vacuum. So can ignition timing. So can all the subsystems connected to the vacuum tree. You can eliminate the susbsystems by disconnecting the big vac feed line from the upper intake to the vac tree and plugging the port on the upper. Connect you gauge directly to the upper intake (you can use the FPR port for ease of connection). If the vacuum does not change, you know the cause is the actual engine itself, either due to cam or ignition timing or due to a leak(s). Since you had the worn cam before, as well as now, we will assume that you should be getting at least 17-17.5" vacuum. This is still slightly low but let's get back to there first.

I'm not sure what your mods are but unless they are significant, 42 psi fuel pressure is probably more than you need. Try turning it down to 39 for now, until you find other causes for low vacuum.
Pete Dunham


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Ryan H Offline
Posting Freak
#4
I reset the cam/crank timing the best I could again. I found the problem with my pointer.. it is seperated from the plastic cover and the spring retaining pin is holding it in place [Image: frown.gif]

My vac is back up to 18", sometimes 17.5.. Car idles and runs great now, but still only 10-11 PSI of boost. I am gonna reset the computer and take it for a good spirited run and see what comes up [Image: smile.gif]

On edit: I let the car idle and cool down while I looked over the board and made this post. Just went out and checked the vac again, it holds steady at 18" now.

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Ryan Harris

88 TC, 5 speed, B&M Ripper Shifter, Walbro 190 LPH, Aeromotive FPR, K&N, 3.73's, 88K miles

[This message has been edited by Ryan H (edited 08-17-2005).]
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
Reply

Ryan H Offline
Posting Freak
#5
Just got back, reset the computer and took her for a nice hard run. No codes to report at all! Did KOEO first, nothing. No CM codes, just kept getting code 11 repeatedly. Turned the car on and ran the test again, usual 74 & 77.

Things that are odd:

I noticed the car had the EGR recall done from the sticker. However the recall is not there.. Looks like someone reverted it back to the old style, perhaps to get rid of the code 34? And on another note I made, my KS is disconnected, however I do not get a code 25. Is this normal?

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Ryan Harris

88 TC, 5 speed, B&M Ripper Shifter, Walbro 190 LPH, Aeromotive FPR, K&N, 3.73's, 88K miles
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Pete D Offline
Administrator
#6
Quote:And on another note I made, my KS is disconnected, however I do not get a code 25. Is this normal?

The code 25 is set when the EEC "looks for" a signal from the KS that says there is detonation (knock) but no signal is sent to the EEC. It does not matter is the KS is unplugged, or it is plugged in but no "knock" is occuring, no signal is sent to the EEC and no code 25 is set.

I can't explain why you are not getting a code 25, you should be getting it???
Pete Dunham


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Ryan H Offline
Posting Freak
#7
Odd.. As a side note, I turned the timing back to 10*. Can the recalling the EGR recall (lol) have any effect on my motor?

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Ryan Harris

88 TC, 5 speed, B&M Ripper Shifter, Walbro 190 LPH, Aeromotive FPR, K&N, 3.73's, 88K miles
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Ryan H Offline
Posting Freak
#8
A little update. My turbo wasn't clocked right from the shop I got it from, so I reclocked it using a good used set of factory intercooler hoses I got from the JY while back. I installed the IC with the housing loose, snugged one of the bolts, took the IC off and snugged the rest of the bolts up.. Now I don't have to fight the IC to get it back on! LOL.

Anyway, did that, and added zip ties to all of the vac lines in the turbo side of the engine bay. Boost is still at 10 PSI with the BCS bypassed [Image: frown.gif] It got 17 before this.. What exactly can affect the boost that isn't an outside vac leak/air source?

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Ryan Harris

88 TC, 5 speed, B&M Ripper Shifter, Walbro 190 LPH, Aeromotive FPR, K&N, 3.73's, 88K miles
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
Reply

Ryan H Offline
Posting Freak
#9
Fixed it guys.

The wastegate has a groove machined in it, I guess for boost control. Either way, it was letting boost out way too fast, so I completley bypassed the wastegate and it goes to 17 now.

I called the shop I bought it from and they said I can send them my old turbo and they'd fix it for me [Image: biggrin.gif]

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Ryan Harris

88 TC, 5 speed, B&M Ripper Shifter, Walbro 190 LPH, Aeromotive FPR, K&N, 3.73's, 88K miles
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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