Boosting, revving up, but not pulling. not clutch.

[ShockDSM]

Hey there, I am currently working out an oil leak problem from the drain plug that just wont quit, but the car has been running and pulling strong. Today I drove some customers home from work and took them in the GSX. (1990 5spd). Gave it the hammer and the car felt weak as F. The engine revved up and it built boost all the way up to full boost but the car wasn't pulling like it should. Felt as if the clutch was slipping. I then dropped them off and hit it in 2nd and it pulled just fine. got closer to work and hit it a few more times and the car wouldn't pull normally. Built boost just fine and revved like it should but wouldn't pull. I put it in 5th and smashed the gas to see if the clutch would slip but the car just creeped along and acted normal. No slipping. What could this be? I have hacked 1g maf, 3 inch dp and catback, stock 1g BOV and a boost gauge that I don't think is functioning properly because its reading 18-20 psi on stock fuel system and stock boost setup with no fuel cut or jerking, and over 30 in/hg vacuum at idle and decel cruising. Could this be a boost leak? The car feels like its missing a tiny bit maybe under acceleration but the car has been pulling pretty good for stock for the past few weeks I've owned it.

 

[91-GS]

Only things that come to mind are either stripped gears in the gear box or some clutch component binding up from time to time (throw out bearing maybe?) or some issues with the hydraulic part of the clutch (leaks, air in the system, not enough fluid), although if latter was the case then clutch would be difficult to disengage instead of acting like it's slipping.

 

[jared98gst]

I'd be looking at timing related components, and blt.

Stripped gears binding from time to time? No
Op mentioned it felt like clutch slipping, I'm guessing in the sense of car not pulling as it should and not in the sense of rpms shoot up and clutch slips, considering the 5th gear comment.

Knock sensor, blt, would be where id start, just like the other thread with exact same intermittent symptoms

 

[chrysler kid]

Today I drove some customers home from work and took them in the GSX. (1990 5spd). Gave it the hammer and the car felt weak as F. The engine revved up and it built boost all the way up to full boost but the car wasn't pulling like it should. Felt as if the clutch was slipping. I then dropped them off and hit it in 2nd and it pulled just fine. got closer to work and hit it a few more times and the car wouldn't pull normally. It would boost just fine and revved like it should but wouldn't pull. I put it in 5th and smashed the gas to see if the clutch would slip but the car just creeped along and acted normal.

You've confused me.

So sometimes the car feels different on your butt dyno and sometimes it doesnt.

What have you looked for under the hood to help diagnose your problem, for all we know your air filter could have a family of mice stuck in it

 

[oneslowwdsm]

FYI loading your engine in 5th gear is never a good idea, especially when it's obviously not running right. Boost leak test should be your number one priority. Once that's done, come back and update.

 

[jakk220]

Could possibly be that the clutch is slipping due to oil leaking on it from the rear main seal and only slipping occasionally. I would also 2nd the knock sensor. Do a boost leak test and then report back.

 

[ShockDSM]

I've made a boost leak tester, with a gauge built in I got at harbor freight, but I put some air in and the gauge didn't read at all, needle didn't move. Rubber charge pipes felt as though they inflated though but went limp pretty quick. Also, no mice in the intake, I've taken the air filter and Mas out to clean and inspect. Car was pulling good the day before this started acting up. I've also noticed there is a little bit of fresh motor oil drips on the bottom of the trans by the trans oil drain plug. Hoping it's not rear main leaking oil on the clutch causing it to slip like someone said above. I've got a full timing belt kit from stm I'm about go swap in but I'll hold off if I'm gonna have to pull the clutch for rear main job, and do it all at once. I'm gonna head out to the garage and try the boost leak tester again, my question is how long should the intercooler and pipes hold air after I hit it with the air compressor and how much psi should I have in the compressor tank when I hit the boost leak tester with air? I also have a brand new punishment fmic kit to put on along with RC 550's a walboro 255 (just waiting on purchasing an afpr) and a GM maft that's coming in the mail. It honestly feels like the clutch having oil on it that's how I would describe it.. I'm praying that's not the issue.. The night before this happened is when I tried to use the boost leak tester but was unsuccessful, it was late and I was just about to head in for bed, the compressor had about 35 psi in it but I wasn't going to put all of that in there obviously just gonna hit it a few times, could I have put too much pressure in the pipes?

 

[SomeGoFast]

When you do a boost leak test, you should test the system 10psi above what your running to be on the safe side

 

[ShockDSM]

Do you think it would be terrible if I put in more psi than 10 over? Might have been at the 35 - 40 psi range but I can't say for sure they pipes were deflating pretty quickly as if the air was just leaking right out in 5 seconds or so. I'm gonna go try it again right now.

 

[jakk220]

I would locate the oil leak and see where it is coming from. If you can find it and are pretty sure that it is coming from the rear main then I would suspect that is where your issue lies. As far as the boost leak test as stated above you should go 10 psi above where your boost level is. Spray around with soapy water and listen for leaks to find them. If it wont hold any boost then you probably have a huge leak.

 

[SomeGoFast]

Are you spraying things down with soapy water so you can see where your leak is? There shouldn't be any need to over pressurize the system more than 10psi over what you need.

 

[ShockDSM]

Warming up the garage now. Got my soapy water spray bottle ready to go. Reason why I asked about putting in too much air is because when I put air into the blt the other night my compressor had about 40 psi in it. Wonder if that could have caused this issue.

 

[jakk220]

its not about how much air the compressor had but rather how much you put into the system. You can fill the tank to 140psi and then just hold it on the boost leak tester for about 10 seconds and then look at the boost gauge. Or just have someone sit in the car and watch the gauge for you and have them tell you what psi it is at.

 

[ShockDSM]

Well first of all my boost leak tester was leaking like a sieve at the threads where the cap screws into the end so I unscrewed it and coated the threads with air tight glue and put it back together. Now I'm just gonna let it dry a bit and try it on the car.

 

[jakk220]

yeah I used a 2 step epoxy and coated the inside where the tire stem goes in and comes out and just globbed it all over

 

[ShockDSM]

I used loctite go 2 glue for the valve stem and pressure gauge cause my 2 part epoxy was all dried up. It worked GREAT. So, I just coated the threads of the pcv cap with the same shit and screwed it back together. It even gathered up around the seal that the cap and pvp pipe make I'm sure it will make a great seal now. I almost wanna try it now but don't want to air to blow the wet glue out. I'm sure it wouldn't but I'll just let it dry and be on the safe side. Tomorrow I have a fumoto Oil drain valve coming in the mail that I'm going to install with some permatex high temp thread sealant and a little ultra black on each side of the gasket. Hopefully that will solve my oil drain plug leak. If it does turn out to be oil on the clutch via rear main seal, I should probably save up for an act 2600 and put that in while the tranny is out. I know I'm gonna need it

 

[ShockDSM]

Do you guys think if the rear main was leaking onto the clutch I would have fresh motor oil here on the underside of the tranny? View pics attached.

 

[rough]

Sounds like the clutch pads are gone or the flywheel has glazed over from oil.
Could be the clutch not engaging all the way due to a failing slave cylinder or pedal out of adjustment.
1g's are notorious for their clutch pedal failing.

If the clutch is slipping...
Soon to follow will be the clunking sound of your clutch coming apart.


Time to pull that transmission and check everything out!


If it was a boost leak your airflow would drop and you would see that on your boost gauge, btw a fuel system has nothing to do with a boost gauge. That would be a AFPR gauge "air fuel pressure regulator" This allows you to adjust fuel pressure based on boost. A quality boost and AFPR gauge is a must for any DSM'r! If you had a wide band gauge, that would help you in your diagnostics as well, if you are missing you will see it sag below 14.7 to like 9 or 10 indicating fuel wasn't burned.

If it was a timing issue, the overall sound of the motor/exhaust will change, sound cam'd or backfire on decel. So it's doubtful that's the issue.

You should be around 20 VAC/IDLE, 30 seems off.


Think a video would help your cause the best.

 

[ShockDSM]

Hey there rough, I just finally got my wideband installed last night in the gauge pod. Got the serial cable installed in the dash under the drivers side for logging a/f's, and got the bung installed and calibrated the wideband. Hopefully today I can throw some oil back in the car and start it up and see what its doing. I had a leak from the oil drain plug that just wouldn't quit so I put in one of those Fumoto oil valves with ultra black RTV on both sides of the gasket and Permatex high temp thread sealant on the middle of the threads of the oil valve.

It's been drying for the past 32 hours in the garage on the jackstands, I have been kicking the heater on and off to help it dry properly. Anyway if it doesn't leak anymore I'll finally be able to drive the car again and figure out what's going on with the clutch or.. whatever it is. I'm going to do a boost leak test in a few, now that I have fixed my boost leak tester, (was leaking at the threads pretty bad) and if I feel the oil valve seal has dried enough ill put oil in it and drive it and take some videos.

Thanks for your reply! Will update in a couple hours.

Also, my boost gauge is an ebay special and I'm almost positive its not reading correctly. I need to replace it asap. It's moving both ways much too far. pinning out at 30 vac and hitting 18-20 psi boost. Thats on a completely stock fuel system with a 14b with no mbc running on wastegate.

I have 550s, a 255, a punishment fmic, a gm maf and maft 2.01, nrg bov, a usb dsmcables.com logger and even an safc2 (which I'm probably not going to run) but I'm waiting to install all this fun stuff until I work out the issue it's having. It JUST started doing this the day I put it up to fix this oil drain problem a week ago.

 

[ShockDSM]

Lol well I'm not sure if this is why the cars not pulling... but here is michigan road salt for ya. Air was just blowing out a hole in my vacuum hose at the T fitting in between the wastegate and compressor housing fixed that then hear a woooooshing of air and found this.. Guess it's time to install this frontmount. It's only been sitting here for a week in the box .

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[ShockDSM]

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[rough]

That would be enough to cause fuel cut type symptoms.

If this was the culprit you would be throwing a cel, back firing, popping, massive power loss and stumbling.

I hate to say it man, but it really sounds like something in the transmission

It could be a head gasket but you would see signs of it in the oil and exhaust...

Before my clutch let go it acted the same way, all the roar and boost, just didn't go no where, fast.

 

[ShockDSM]

God damn dude u got me all bummin! Oh well I'm gonna throw on the fmic tonight and put a fresh 4.5 quarts of 10w30 Casterol GTX and watch the oil drain valve for leaks. Rtv should be dry now. Also I found when looking under the car that the transfer case was wet from the drain plug to the beginning of the driveshaft with what looked to me to be pretty fresh engine oil. Would that lead you to think the rear main is leaking? And I noticed there is a bolt missing and broken off inside the transfer case is this going to create a problem? Pic attached.

Also unrelated but when installing my wideband I was under the car looking up at the back of the intake manifold and saw 4 nipples in a row. Two of them had lines coming off of them and 2 were just open and unplugged. I believe the two lines were ones that run over by the fpr solenoid. Is that okay that these are open to the air? Probably not.

One more thing. Would you happen to know if my punishment fmic throttle body elbow will fit my 1990 throttlebody? Its a 1g kit says it fits all 90-94 but there is a different gasket for the 90 and 91-94 tb.

 

[jakk220]

If I had to take an educated guess I would say that it is probably the rear main seal if it is for sure motor oil and not gear oil from the transfer case or transmission, or power steering fluid. The only way you will know for sure I to pull the transmission off and look. You could try and rub a finger inside of the bell housing from where the clutch fork comes out and see if there is oil build up in there. It usually flings it everywhere.