I've never really had any trouble with oiling before, but last year after going to Michigan - the oil pressure would read just above the red zone when idling hot (and only once or twice did it ever even flicker the light when the idle "loped").

Then on Sunday at the Wheatstock track day in Kansas, I was on the last few minutes of my final driving session - after rounding turn 1 (a hard left-hander heading uphill), there was a mild "POP" followed by a large amount of smoke coming out of the deck vents. As I pulled off the track the oil pressure suddenly dropped to zero and I shut it down. Of course after so quickly shutting it off it overheated, but not too badly (turned the fan back on and it cooled off in a reasonable period of time).

So after...

...towing it back to the pits...

...it appeared that oil seems to have burst from the base of the distributor (bad o-ring was assumed) - but only momentarily (as it did not continue to leak at all after that). Upon restart the engine seemed to be running OK and showing pressure - but not as much as it previously had. We picked up a new oil pressure sender and a new Fiero AUX gauge set hoping that it was just a false reading - but even with both parts replaced it still was reading low (like around 10psi at idle) and when it got warm driving home on Sunday it would only show 35psi at cruising speed, and virtually 0psi if left to idle at a stop (but while at the hotel working on it, we left it idle while showing only 10 psi - and we could see some flow inside the valve cover through the filler hole... so it was still pumping).

So the questions are: Any specific ideas or suggestions? I'm planning on picking up a manual Oil pressure gauge to check things out with. Also, isn't the computer supposed to shut down the fuel supply and/or ignition if the oil pressure drops below a certain area (I've heard 9psi) - or is that just when starting? Is it possible for the distributor o-ring to cause a loss of oil pressure without leaking or having any other signs of trouble? (I have a new o-ring and plan to replace it shortly, just-in-case). Any info could certainly be helpful when it comes to guessing. I'm really not planning on pulling the motor just to replace the oil pump - if it comes to that I think I'll just have to accelerate the timeline on my SBC swap project.

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Looking for Fiero posters?

From what i have heard bad oil pressure is due to bad or worn bearing clearences.BUT i was told that 10psi at idle is normal.I had oil pressure problems in my 86 2 days later it was knocking.

Sounds like on that hard left hander you may have sloshed all the oil away from the oil pickup in the pan, and the result would be loss of oil pressure. The oil pressure sender is supposed to cut out the fuel pump if the oil pressure gets real low, but the engine may continue to run for a few seconds till the fuel pressure drops to zero. Can't explain the "pop" other than maybe a backfire, or the oil may have sloshed bad enough up into the engine to cause the pop, but I doubt that the oil came from the distributor o-ring, or it would still be leaking. If you don't care about saving the stock engine, just run it as is while you get your SBC project in order.

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Logic is a systematic method of coming to the wrong conclusion with confidence!

An additional question - when hooking up a manual oil pressure gauge, I assume that it connects directly to the fitting where the Sending unit connects... if this is true, then where does the sending unit go, or does it utilize an inline or "T" connection of sorts? (I assume that the computer wouldn't operate correctly without some sort of signal coming from the oil pressure unit).

quote but I doubt that the oil came from the distributor o-ring, or it would still be leaking

Pretty much everyone who looked at it while at the track agreed that the o-ring was the most likely culprit... althout it is exceptionally strange that it's not still leaking. The oil that collected on the engine was only on the top of the tranny and there was a small "pool" right next to the base of the distributor (but none of the other seals were "wet" at all). [shrug]

[This message has been edited by MinnGreenGT (edited 06-29-2004).]

hi, sorry to hear about your loss, i have hooked up a electronic gage, but they are both the same as far as you have to on v6 use brass fittings, either come with kit, or i got mine at home depot, and form t shape, my after market one is at 90 degrees off stock one facing shock tower and it has it own sender, took me 20 minutes to set up, just be careful unhooking stock sender use right wrenches, also i learned the hard way position it so you can get to other things in there..............................

Silver86se - thanks for the install tips. I'll definitely look into doing it that way, or something simliar.

Also - it isn't a total loss (at least not yet). I did drive it home for about 9hours straight yesterday without loosing the engine! But I just won't be driving it much until I'm a little more confident in the oil pressure situation

About that oil pressure/fuel pump thing... The oil pressure switch just provides a backup to the primary fuel pump circuit.
If the ECM stops telling the pump to run, the presence of oil pressure will still do it. If oil pressure goes away, the ECM will still keep the pump running.
Hope the situation isn't too bad. Everyone has pretty much already offered the same suggestions that I would have.

Here's a long shot... If there was a blockage in the lubrication system somewhere, it could possibly have built up pressure behind that O-ring, and forced it's way out past it, without damaging it. That would have been about the time you shut it down. That would have let the oil pressure drop, and possibly let the obstruction fall away. Of course this is all just wild speculation.

If it was oil-starved at high RPM, you may have worn some of the bearings to the point that they aren't holding pressure.

Personally, I would change the oil and filter, and that O-ring, and see what happens.

Best.

[This message has been edited by Raydar (edited 06-29-2004).]

First, which oil pan are you using? If you are going to be doing autoX or road course driving you need to add a baffle in the oil pan or at least a hi-volume oil pump. If the oil sloshed and the pressure dropped enough to cause the bearings to score, than you would have less pressure. You may be able to make the engine last longer by going to a higher weight (If using a 5W oil, switch to a 10W oil) But that will just "band-aid" the problem. Once scored, the bearings will continue to wear down until ine of them spins.

Swap out the oil pump. Every time I've had a "Low Oil Pressure" problem with a Fiero, it was because the pump went bad. Stick a new one in there and see what happens. If you're really worried about the bearings, plastigauge them while you have the pan off....

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My Cardomain page
www.FFDET.com
Please rate me if I've been helpful...

Thanks guys for the suggestions...

Raydar - I like long shots... there's always some hope in them As mentioned, I think I'll start with the obvious things (oil/filter change, increase oil weight, replace o-ring - then do a manual pressure check with a different gauge setup).

Oreif - AFAIK (it's been a number of years since the motor went together) I'm using the stock (2.8) oil pan. And no, I don't plan on doing this often... just when the opportunity arises at shows and such (I've never even autocrossed or dragged the car). It's only ever been raced at Waterford and Heartland Park. As to the exact sequence of events, it all happened so fast that I wasn't able to distinguish whether the pressure dropped first, or I started noticing smoke (although I think it was smoke first, then the pressure fell away as I slowed the car).

Freshj - replacing the pump itself will be my last resort if I don't see some results in the other tests & experiments. But unless it's actually detrimental to the engine (like it really doesn't have any pressure at idle) I may just carefully run it the rest of the season and spend the additional money on a high performance oil pump for the Small Block

Again... thanks everyone for the suggestions - and if anyone has anything further, you're welcome to add to it!

quote Originally posted by Raydar: About that oil pressure/fuel pump thing... The oil pressure switch just provides a backup to the primary fuel pump circuit. If the ECM stops telling the pump to run, the presence of oil pressure will still do it. If oil pressure goes away, the ECM will still keep the pump running.

Raydar is correct on this after looking in the Fiero shop manual. It states that the oil pressure switch provides battery feed to the fuel pump should the pump relay fail. The ECM/relay circuit and the oil presure switch would both have to fail once the engine is running before the fuel pump would stop.

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Logic is a systematic method of coming to the wrong conclusion with confidence!

quote Originally posted by MinnGreenGT: I think I'll just have to accelerate the timeline on my SBC swap project.

I knew it... you put sand in the oil-fill, didn't you? j/k... I wish you luck in obtaining whatever outcome you really want

yeah, I remember you posting when I had my oil pressure drop after the Waterford Hills tracks day, saying yours dropped too. I let it go for awhile, even drove the car down to Virginia, to do some camping & hot dogging on the Blue Ridge Parkway. Then, another forum member was having a problem with his 3.1, hearing a slight knock, so he wanted to check mine, and sure enough, I had the same knock - right around 2000-2500 RPM. I had a worn rod bearing. I went & dropped the pan, cleaned the crank journal with 800 grit, and put in a new bearing. This helped my pressure & knock, but the pressure wasnt as quite where it was, but it was better. Now - up to today. I am putting a new cam in my motor (again....ug), and have the motor on a stand, and decided to tear it all down & check the condition of the bearing I had replaced. looked great. most the other rod bearings looked pretty good, 2 of them had minor scratches. but the mains had some pretty good scratches in them. My pressure drop was all from WORN bearings, not spun/bad bearings. Sooner you drop that oil pan, the more likely you can save your crank.

quote Originally posted by Pyrthian: yeah, I remember you posting when I had my oil pressure drop after the Waterford Hills tracks day, saying yours dropped too. I let it go for awhile, even drove the car down to Virginia, to do some camping & hot dogging on the Blue Ridge Parkway. Then, another forum member was having a problem with his 3.1, hearing a slight knock, so he wanted to check mine, and sure enough, I had the same knock - right around 2000-2500 RPM. I had a worn rod bearing. I went & dropped the pan, cleaned the crank journal with 800 grit, and put in a new bearing. This helped my pressure & knock, but the pressure wasnt as quite where it was, but it was better. Now - up to today. I am putting a new cam in my motor (again....ug), and have the motor on a stand, and decided to tear it all down & check the condition of the bearing I had replaced. looked great. most the other rod bearings looked pretty good, 2 of them had minor scratches. but the mains had some pretty good scratches in them. My pressure drop was all from WORN bearings, not spun/bad bearings. Sooner you drop that oil pan, the more likely you can save your crank.

Great ...not exactly what I wanted to hear - but I guess it at least makes sense (although the oil on the top of my tranny is still somewhat of a mystery). I'll have to see about getting into the motor one of these days then (not really looking forward to it). Thanks for the info!

Wow It sounds like it's running hot too. Why would it overheat like that, The hotter the engine gets the less viscosity the oil will have. Make sure your running at a good temp. Get the thermostat from hypertech 160°, make sure your timing is right and the coolant flows well. Make sure your cooling fan is coming on. If you have a/c you can manually turn your cooling fan on by turning on the a/c. Keep an eye on your temp gauge.

quote Originally posted by nosaj1985gtjason: Wow It sounds like it's running hot too. Why would it overheat like that, The hotter the engine gets the less viscosity the oil will have. Make sure your running at a good temp. Get the thermostat from hypertech 160°, make sure your timing is right and the coolant flows well. Make sure your cooling fan is coming on. If you have a/c you can manually turn your cooling fan on by turning on the a/c. Keep an eye on your temp gauge.

I am running the hypertech 160° Thermostat - but the car didn't overheat for nearly a minute after I shut it down. I hopped out of the car, took off my helmet and popped the decklid & checked it out. By the time the tow truck arrived and we ducked under the front to hook it up - it had started boiling out of the overflow tank. I believe that if I had simply left the key in the "on" position, the fan would've continued to run until it had cooled to a reasonable temp. I otherwise haven't had temp issues for years.

Maybe dumb questions, but

1) Can the guages from an 85+ Fiero 4 cylinder be added to an 84?

2) Can you replace the 85mph speedometer with the 120 in the 4 cylinder cars?

3) Can the aux guage pod from a V6 car be made to work with a 4 cylinder car?

[This message has been edited by RWDPLZ (edited 06-30-2004).]

Sounds like worn rod bearings to me, just like Pyrthian said.

If the crank isn't scored you can probably get away (for a while) with just replacing the bearings. It'll hold you over until your V8 and it'll be cheap dollar-wise, if not time-wise.

Or just put some thicker oil in it and continue to drive it. As far as thicker oil, though, it's not the bottom number you need to raise, it's the top number. The 5W or 10W are the cold (winter) viscosity. The second number is the hot viscosity. If you're running 5W-30 you might change to 10W-40 or 0W-50.

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Doug Chase
Chase Race
Custom roll cage and exhaust fabrication

Rob,

Check for a clogged screen in the oil pickup. Or perhaps a a bad oil pickup / pump if engine is making no other unusal noises.

quote Originally posted by RWDPLZ: Maybe dumb questions, but 1) Can the guages from an 85+ Fiero 4 cylinder be added to an 84? 2) Can you replace the 85mph speedometer with the 120 in the 4 cylinder cars? 3) Can the aux guage pod from a V6 car be made to work with a 4 cylinder car?

Yes, yes, and yes.

It don't take much to wear bearings fast when turning hard. Since my son went to SCCA an driving school he has wasted 2 MR2 engines, each by taking an exit ramp way too fast. Just one ramp and bye bye bearings! An both were freshly built engines with nice turbo setups. Just too many Gs at high rpm. He knid of got use to his monster MR2 and it's never-run-out of pressure dry sump oil system. BTY: I won't let him drive my GT without me. Fiero's are no better and maybe worse at holding pressure in long hard turns than MR2s.

MinnGreen: I too agree you have a bearing problem, but since you plan on continuing to drive the car, there are a couple of things to try.
1. Invest in an oil cooler if possible. It will help to keep the vis up.

During all that turning on the track, it is possible that you stirred up some sludge or debris from the bottom of the pan, and it is now pressed into the screen, tho this is a remote possibilty. I had it happen on Jane's 84, but due to a diferent set of circumstances. Here's how I took care of it, and the engine lasted fine for another year. It's a long shot, but worth a shot.
2. On the chance that you have a partially clogged oil suction screen:
Get at least 5 gals of a solvent you are comfortable with. I used 1/2 diesel-1/2 kerosene mixed.
A. Drain the oil. Make sure the engine is cool. Replace the drain plug.
B. Pour in the solvent, using a little more than the usual oil capacity, as fast as you can. Do NOT start the engine! Let it sit for at least 10 minutes.
C. Get on one of the rear 'fenders' and just shake the bejezus out of the rear quarter of the car, which will slosh the solvent back and forth across the oil screen. Do this for about 5 minutes, or until ya get tired.
D. Drain the solvent thru a terry cloth. This will show you what was in there. If you see anything that you think may have clogged the screen, repeat the whole thing a few times, using clean solvent each time. If you see metal, or bearing material, well, at least you now know you have more serious problems. On the last time you do it, leave the plug out, so the solvent can flow right out, hopefully carrying anything it encounters, out with it.
E. Leave the drain plug out overnight, so every bit of the solvent comes out. Replace the plug. Fill with oil. Start the engine. Let it run a while, then change the oil again, and the filter. Good luck.

I don't know which engine you have, but is there any chance the pickup tube came loose? Is that even possible?
Good luck, and I sure hope it turn out you have a minor problem.

[This message has been edited by maryjane (edited 07-07-2004).]

I'm sure someone you know has a spare 2.8 around. Drop the cradle, swap over the 2.8 and reinstall the cradle. With a few friends and a couple beers, it shold be done in one full saturday.. Check out your bearings/etc, and offer the engine in return for their help and replacement if its still alright, unless the motor was a spare for them, then maybe you can put in new bearings and keep it handy yourself??

Well, tonight I changed the oil (to SAE 40) and installed a manual oil pressure gauge to verify the readings... good news is that the sender is sending the correct info - and the gauge is reading accurately. The bad news is that the engine is no longer producing oil pressure at idle once it warms up (on cold start it begins around 50psi then slowly drops to pretty much nothing). I'm quite certain it's bearings now. I'll have to check it again tomorrow when I'm not so tired, but when I started it up to move around a bit in the garage - I'm pretty sure I heard an audible "knock" from the engine)

Looks like it may be time to move forward a bit more quickly on that SBC Project!

Depending on how my time falls the rest of the summer (and if I can get my Dad to move his project '87GT off the hoist in his shop) I may still do some quick bearing replacements on the 3.1L - I may also try Don's suggestion of "flushing" the system with a good cleaner. In any case, I won't be driving the GreenGT much for awhile (I'd still like to bring it to Fierorama - so that gives me until September to work something out!).

Thanks again to everyone for your suggestions - I really appreciate the support, knowledge, and experience that makes up this forum. Just wish I didn't always have to rely on the accurate bad news - as before, any further suggestions are still welcome!

I would replace the rod bearings after inspecting the crank for damage, likely that will help a lot. Adding thicker oil helps the guage reading because the sender is by the oil filter, but thicker oil doesn't circulate near as well, especially on cold startup. Another option would be a high volume oil pump, which you can install at the same time as the bearings. Both combined plus the oil pan gasket should run under $100, along with some plastigage for clearance checking.

JazzMan

Since we don't have much ground clearence to add deeper pans or much space to make the of pan bottom widder, I've been toying with an idea for a while that might help. Too the rear of the car (some inches from the pan) there's enough space to install an auxilary oil tank (for lack of a better word). It could be connected to the oil pan by three lines. Two large, maybe 2" dia and one 1/4" vent line. The vent line would go to the top of the aux tank (a 4"dia x maybe 12" long tube) and then to upper part of the oil pan. That would allow the aux to fill up and drain. The other two lines would simply be feeds/returns between the aux and the pan. Where this aux tank would be mounted latterialy I think it would work well to keep oil at the pump pickup. The setup my or may not require a G force controled check valve. I've study it some and it will fit. The setup would add between 2 and 3 quarts. Perhaps after we get production of our Hi-Flo manifolds going, I try building one. Anybody have any thoghts on it? Don't know if I explained it clearly enough, if not, let me know and I'll make a drawing.

An Accusump (pressure accumulator) would be much easier and more effective.

GL

Any updates on this situation Rob?

Hey, I had an oil pressure problem also, I replaced all the bearings and pump, the pump looked alright but I replaced it anyway. The bearings were wore out but i saw on one it was low on oil. After all that my pressure remained hot at 10lbs ilde, 10lbs per 1000rmp is what i always hear....must be fine now...all cost me 65$ and 5 hours...

Rob?

hey rob, i was talking to somone about your problem the other day. he had an intereting idea. his son races on an oval track and he ice races. well, one time, when they were racing, they had a similar thing happen to their car as what happened to yours. i dont know if you have pulled the pan yet, but if you havent, i'd pull it and get an idea. the oil pick up sits in the pan and has a larger end on it. it then goes to a tube. what happend to their race car is the end poped off, so all that was sitting in the oil was the tube. the tube can get some oil, but nto enough to read much pressure on the gauge. he said all they did was pop it back on and it worked fine. i also told him that you thought it migh tbe the bearings, but he didn tthink so since you could drive it all the wya back and have no problems. take a look at that! no matter what, you need to pull the pan anyways. hopefully it will be somthing easy like that.

Joel
87 GT 5-speed

I have been trying to figure out this oil pressure problem for some time. When oil pressire drops from 70 to 80 pounds down to 10 pounds that is a big loss even if you do have bad bearings. Most cars that I have owned would have oil pressure like 50 pounds at start up and about 40 pounds after warm . At least no more than 20 pounds loss. I have come up with one more theory. I have not tried it yet because I am not physical fit to do a lot of work. Here is my idea' is it possible for the spring in the oil pump release valve to get week when it gets hot and the by-pass valve opens and then you would have less pressure. the reason I thought of this, because my Mom bought a new 86 ford and it got to where it would blow the oil filter as soon as you let it run for a while. the problem was the oil by-pass valve was stuck shut. Just a thought.
Don

Hey guys... sorry for the slow response - I didn't notice this being bumped back up!

I still haven't taken the time to pull the pan (need to help my dad finish the front suspension on his project car so I can use his lift). But I haven't driven since we got back from Kansas.

justa6 - thanks for the info... that's definitely something I'll check. I am planning on cleaning the car up this week and bringing it over to the MOA meet... it certainly won't get any worse in that distance

As for my other progress - I just received my SBC Exhaust manifolds and Mini Race starter. Still need a waterpump (CSI Remote is the plan) and a oil filter relocation kit

[This message has been edited by MinnGreenGT (edited 08-10-2004).]